release guide - msc nastran 2016

Main Index

MSC Nastran 2016

Release Guide

Main IndexMain Index

Worldwide Webwww.mscsoftware.com

DisclaimerMSC Software Corporation reserves the right to make changes in specifications and other information contained in this document without prior notice.

The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and are not intended to be exhaustive or to apply to any particular engineering problem or design. MSC Software Corporation assumes no liability or responsibility to any person or company for direct or indirect damages resulting from the use of any information contained herein.

User Documentation: Copyright 2016 MSC Software Corporation. Printed in U.S.A. All Rights Reserved.

This notice shall be marked on any reproduction of this documentation, in whole or in part. Any reproduction or distribution of this document, in whole or in part, without the prior written consent of MSC Software Corporation is prohibited.

This software may contain certain third-party software that is protected by copyright and licensed from MSC Software suppliers. Additional terms and conditions and/or notices may apply for certain third party software. Such additional third party software terms and conditions and/or notices may be set forth in documentation and/or at http://www.mscsoftware.com/thirdpartysoftware (or successor website designated by MSC from time to time). PCGLSS 8.0, Copyright © 1992-2014, Computational Applications and System Integration Inc. All rights reserved. PCGLSS 8.0 is licensed from Computational Applications and System Integration Inc. METIS is copyrighted by the regents of the University of Minnesota. A copy of the METIS product documentation is included with this installation. Please see “A Fast and High Quality Multilevel Scheme for Partitioning Irregular Graphs”. George Karypis and Vipin Kumar. SIAM Journal on Scientific Computing, Vol. 20, No. 1, pp. 359-392, 1999. MPICH2 is developed by Argonne National Laboratory. Copyright + 2002 University of Chicago.

MSC, Dytran, Marc, MSC Nastran, Patran, the MSC Software corporate logo, e-Xstream, Digimat, and Simulating Reality are trademarks or registered trademarks of the MSC Software Corporation and/or its subsidiaries in the United States and/or other countries.

NASTRAN is a registered trademark of NASA. LS-DYNA is a trademark or registered trademark of Livermore Software Technology Corporation. FLEXlm and FlexNet Publisher are trademarks or registered trademarks of Flexera Software. All other trademarks are the property of their respective owners.

Revision 0. April 26, 2016NA:V2016:Z:Z:Z:DC-REL

Corporate Europe, Middle East, AfricaMSC Software Corporation MSC Software GmbH4675 MacArthur Court, Suite 900 Am Moosfeld 13Newport Beach, CA 92660 81829 Munich, GermanyTelephone: (714) 540-8900 Telephone: (49) 89 431 98 70Toll Free Number: 1 855 672 7638 Email: [email protected]: [email protected]

Japan Asia-PacificMSC Software Japan Ltd. MSC Software (S) Pte. Ltd.Shinjuku First West 8F 100 Beach Road23-7 Nishi Shinjuku #16-05 Shaw Tower1-Chome, Shinjuku-Ku Singapore 189702Tokyo 160-0023, JAPAN Telephone: 65-6272-0082Telephone: (81) (3)-6911-1200 Email: [email protected]: [email protected]

mailto:[email protected]




http://www.mscsoftware.com/thirdpartysoftware

C o n t e n t sMSC Nastran 2016 Release Guide

Main Index

2016Contents

Preface

Preface to the MSC Nastran 2016 Release Guide 7

List of MSC Nastran Books 8

Technical Support 9

Training and Internet Resources 10

MSC Nastran Documentation 11

1 Overview of MSC Nastran 2016

2 Linear Analysis

CWELD/CFAST/CSEAM Element Enhancements 5

MSC Nastran Embedded Fatigue (NEF) Updates 22

3 Acoustics

ERP Enhancements 32

Normal Velocity 34

Vibration Intensity 36

ACLOAD and PEM Interpolation Enhancements 37

Out-of-Core Solver for Large Trim Components of PEM 39

4 Advanced Nonlinear (SOL 400)

Advanced Elements 41

Contact in Small Deformation Simulations 43

MSC Nastran 2016 Release Guide

4

Main

Segment-to-Segment Contact Enhancements 46

Beam Contact 48

Interference Fit 50

Maintaining Geometric Clearance 52

Contact Separation 54

RC Network Heat Transfer Analysis 55

5 3-D Rotordynamics

3-D Rotordynamics in MSC Nastran 57

6 Optimization

Global Optimization 86

Multi Model Optimization 94

Weight as a Function of Material or Property ID 103

7 High Performance Computing

New ACMS with Better SMP Scalability 105

NLEMG with SMP Parallelization 115

Intel MKL Pardiso for SOL 101, 107, 108, 111, and 200 119

Parallel Processing Licensing 126

8 Implicit Analysis (SOL 600)

SOL 600 Upgrade 128

Known Incompatibility with Previous Versions of MSC Nastran 131

9 Explicit Analysis (SOL 700)

New Materials and Equation of States 133

Adaptive Solid Elements to SPH Transform (SOL2SPH) 136

Index

5Contents

Main Index

Enhanced Dynamic Relaxation and Body Forces 138

Reinforcement Inside of Solid Elements 141

Miscellaneous Update 143

10 User Interface

HDF5 Result Database (NH5RDB) 146

F06Reader Utility 184

Solid Elements Coordinate System Enhancement 191

11 Platform Support

Supported Hardware and Operating Systems 196

Main

MSC Nastran Release Guide

Preface

Preface

Preface to the MSC Nastran 2016 Release Guide 7

List of MSC Nastran Books 8

Technical Support 9

Training and Internet Resources 10

MSC Nastran Documentation 11

Index

7Preface

Main

Preface to the MSC Nastran 2016 Release GuideThis Release Guide contains descriptions for the MSC Nastran 2016 version, and supersedes the MSC Nastran 2014.1 Release Guide.

Index

8 MSC Nastran Release Guide

Main

List of MSC Nastran BooksBelow is a list of some of the MSC Nastran documents. You may find any of these documents from MSC Software at http://simcompanion.mscsoftware.com/infocenter/index?page=home.

Installation and Release Guides

• Installation and Operations Guide

• Release Guide

Guides

Reference Books

• Quick Reference Guide

• DMAP Programmer’s Guide

• Reference Manual

User’s Guides

• Getting Started

• Linear Static Analysis

• Dynamic Analysis

• Embedded Fatigue

• MSC Nastran Demonstration Problems

• Thermal Analysis

• Superelements

• Design Sensitivity and Optimization

• Rotordynamics User’s Guide

• Implicit Nonlinear (SOL 600)

• Explicit Nonlinear (SOL 700)

• Aeroelastic Analysis

• User Defined Services

• Nastran Embedded Fatigue User’s Guide

• Non Linear User's Guide (SOL 400)

• Utilities Guide

Index

http://simcompanion.mscsoftware.com/infocenter/index?page=home

http://simcompanion.mscsoftware.com/infocenter/index?page=home

9Preface

Main

Technical SupportFor technical support phone numbers and contact information, please visit: http://www.mscsoftware.com/Contents/Services/Technical-Support/Contact-Technical-Support.aspx

Support Center (http://simcompanion.mscsoftware.com)

The SimCompanion link above gives you access to the wealth of resources for MSC Software products. Here you will find product and support contact information, product documentations, knowledge base articles, product error list, knowledge base articles and SimAcademy Webinars. It is a searchable database which allows you to find articles relevant to your inquiry. Valid MSC customer entitlement and login is required to access the database and documents. It is a single sign-on that gives you access to product documentation for complete list of products from MSC Software, allows you to manage your support cases, and participate in our discussion forums.

Corrected Defects ListFor a list of corrected defects in the MSC Nastran 2016 release, please visit our Simcompanion site and see: https://simcompanion.mscsoftware.com/infocenter/index?page=content&id=KI8008617

Known Defects ListFor a list of known defects in the MSC Nastran 2016 release, please visit our Simcompanion site and see: https://simcompanion.mscsoftware.com/infocenter/index?page=content&id=KI8008006

Index

http://simcompanion.mscsoftware.com)

https://simcompanion.mscsoftware.com/infocenter/index?page=content&id=KI8008617

http://simcompanion.mscsoftware.com/infocenter/index?page=content&id=KI8008006

http://simcompanion.mscsoftware.com/infocenter/index?page=content&id=KI8008006


Main

Training and Internet ResourcesMSC Software (www.mscsoftware.com)

The MSC Software corporate site with information on the latest events, products, and services for the CAD/CAE/CAM marketplace.

http://simcompanion.mscsoftware.com

The SimCompanion link above gives you access to the wealth of resources for MSC Software products. Here you will find product and support contact information, product documentations, knowledge base articles, product error list, knowledge base articles and SimAcademy Webinars. It is a searchable database which allows you to find articles relevant to your inquiry. Valid MSC customer entitlement and login is required to access the database and documents. It is a single sign-on that gives you access to product documentation for complete list of products from MSC Software, allows you to manage your support cases, and participate in our discussion forums.

http://www.mscsoftware.com/msc-training

The MSC-Training link above will point you to schedule and description of MSC Seminars. Following courses are recommended for beginning MSC Nastran users.

NAS101A - Linear Static and Normal Modes Analysis using MSC Nastran

This course serves as an introduction to finite element analysis. It includes discussion of basic features available in MSC Nastran for solving structural engineering problems. In this course, all finite element models will be created and edited using a text editor, not a graphical pre-processor. Proper data structure of the MSC Nastran input file is covered. At the conclusion of seminar, the student will be familiar with fundamental usage of MSC Nastran.

NAS101B - Advanced Linear Analysis using MSC Nastran

This course is a continuation of NAS101A - Linear Static and Normal Modes Analysis using MSC Nastran. In this class, you will learn: Theory of buckling analysis and how to perform a buckling analysis About rigid elements - MPC, RBAR,RBE2, and RBE3 Modeling with interface element CINTC and connectors Lamination theory and composite materials MSC Nastran composite theory Failure theories Linear contact and permanent glued contact Different model checks Modeling tips and tricks

NAS120 - Linear Static Analysis using MSC Nastran and Patran

This seminar introduces basic finite element analysis techniques for linear static, normal modes, and buckling analysis of structures using MSC Nastran and Patran. MSC Nastran data structure, the element library, modeling practices, model validation, and guidelines for efficient solutions are discussed and illustrated with examples and workshops. Patran will be an integral part of the examples and workshops and will be used to generate and verify illustrative MSC Nastran models, manage analysis submission requests, and visualize results. This seminar provides the foundation required for intermediate and advanced MSC Nastran applications.

Index

11Preface

Main

MSC Nastran DocumentationFor quick access to the full set of MSC Nastran Documentation on Windows, one can:

1. Go to your MSCNastran_Installation_DIR\msc2016\Doc\pdf_nastran\

2. Click on nastran_library.pdf and use the Right Mouse Button to Create Shortcut

3. Move the shortcut to your Windows Desktop

MSC Nastran Documentation RequirementsTo view and navigate through the PDF based MSC Nastran Documentation, the following browsers are recommended.

UtilitiesThe MSC utilities including MultiOpt described in this release guide have been moved from the Installation and Operators Guide to their own manual labeled MSC Nastran Utilities Guide.

VendorDesktop

Environment Browser Browser Version

Linux (64-bit) KDE Konqueror 4.3.4 or higher

Linux (64-bit) Gnome Evince 2.28.2 or higher

Microsoft (64-bit) Windows 7 Adobe Reader 10.1.4 or higher

Note: Adobe has dropped support for Reader on Linux. The browsers in the above table have been tested and work with the current version of the MSC Nastran Documentation.

Index

Main

Chapter 1: Overview of MSC Nastran 2016MSC Nastran Release Guide

1 Overview of MSC Nastran 2016

Index

2Overview of MSC Nastran 2016

Main

MSC Software is pleased to introduce you to the exciting new technologies in MSC Nastran 2016 - the premier and trusted CAE solution for aerospace, automotive, defense, and manufacturing industries worldwide. This release includes new features and enhancements in Contact, Fatigue, High Performance Computing, Acoustics, Optimization, and Rotordynamics. This release also changes the default mode in MSC Nastran to i8, or 64-bit integers, instead of the previous default of i4, or 32-bit integers. The i4 version is packaged separately from the i8 version and has its own installer on the SDC site.

Linear Analysis• CWELD/CFAST/CSEAM Element Enhancements, 5

• MSC Nastran Embedded Fatigue (NEF) Updates, 22

Acoustics• ERP Enhancements, 32

• Normal Velocity, 34

• Vibration Intensity, 36

• ACLOAD and PEM Interpolation Enhancements, 37

• Out-of-Core Solver for Large Trim Components of PEM, 39

Advanced Nonlinear (SOL 400)• Advanced Elements, 41

• Beam Contact, 48

• Interference Fit, 50

• Maintaining Geometric Clearance, 52

Rotordynamics• 3-D Rotordynamics in MSC Nastran, 57

Optimization• Global Optimization, 86

• Multi Model Optimization, 94

• Weight as a Function of Material or Property ID, 103

High Performance Computing• New ACMS with Better SMP Scalability, 105

• NLEMG with SMP Parallelization, 115

• Intel MKL Pardiso for SOL 101, 107, 108, 111, and 200, 119

Index


Main

Implicit Analysis (SOL 600)• Workflow for Advanced Analysis, 128

• Material Models, 128

• Large Displacement/Large Strain Analysis , 129

• Contact Analysis, 129

• Computational, 129

• Fracture Mechanics, 130

• Known Incompatibility with Previous Versions of MSC Nastran, 131

Explicit Analysis (SOL 700) • New Materials and Equation of States, 133

• Adaptive Solid Elements to SPH Transform (SOL2SPH), 136

• Enhanced Dynamic Relaxation and Body Forces, 138

• Reinforcement Inside of Solid Elements, 141

• Miscellaneous Update, 143

User Interface• HDF5 Result Database (NH5RDB), 146

• F06Reader Utility, 184

• Solid Elements Coordinate System Enhancement, 191

Platform Support• Supported Hardware and Operating Systems, 196

Index

Main


Chapter 2: Linear Analysis

2 Linear Analysis

CWELD/CFAST/CSEAM Element Enhancements 5

MSC Nastran Embedded Fatigue (NEF) Updates 22

Index

5 MSC Nastran 2016 Release GuideCWELD/CFAST/CSEAM Element Enhancements

Main

CWELD/CFAST/CSEAM Element EnhancementsThe CWELD /CFAST elements have been changed so that there is now a consistent formulation between linear and SOL 400 nonlinear analysis. Additionally, the CSEAM element is now supported in SOL 400 and has a consistent formulation between linear and SOL 400 nonlinear analysis.

Benefits1. The CWELD/CFAST elements provide the same element output formats in both linear and SOL 400 nonlinear

solutions.

2. In the CFAST/CSEAM/CWELD analysis, the auxiliary points generated are in the solution set.

3. The CWELD/CFAST algorithm has been improved to find the Best Possible Projection with zero projection tolerance improvements.

4. The improved CWELD with options "PARTPAT" and "ELPAT", and CFAST elements do not move GA and GB if both are supplied by the user, thus maintaining user mesh integrity.

5. The 3x3 mesh limitation has been removed for the CWELD with options "PARTPAT" and "ELPAT" and the CFAST elements.

6. There are no required changes in the user element input description of the CFAST/CSEAM/CWELD elements.

7. The CFAST/CWELD/CBUSH provides nonlinear force output for SOL 400 "ANALYSIS=NLTRAN".

8. MPC Force output is available for the connector element constraints.

9. Besides global search algorithm control there is now local connector element connectivity control via the new CONCTL bulk data entry.

10. A brief summary of connector projection results is output in the F06 file for each connector type.

11. A new "SWLDPRM, CSVOUT, UNITNUM" entry will produce a comma separated file useful for reports.

12. The CSEAM and CWELD (not by default) can now contribute mass to the structure.

Feature DescriptionDetails of the improved CWELD/CFAST algorithm are described below.

Formulation Changes

In the new consistent formulation for the CWELD/CFAST elements for linear analysis, RBE3 elements are written internally, and the auxiliary points are in the solution set and both are identifiable by the SWLDPRM, PRTSW entry.

1. The auxiliary grids generated start with GRID ID 101000001. There are always four auxiliary grids for patch A and four auxiliary grids for patch B.

2. The RBE3 elements generated start with 100001002. An RBE3 is generated for each auxiliary point for each patch A and B tying each patch grid to that auxiliary point. There is a RBE3 generated for GA tying GA to its patch auxiliary points and a RBE3 generated for GB tying GB to its patch auxiliary points.

3. Both linear and nonlinear output is consistent.

Index

6Linear AnalysisCWELD/CFAST/CSEAM Element Enhancements

Main

The new consistent CWELD/CFAST is selected by default. The old CWELD/CFAST can be actuated by using the "PARAM, OLDWELD, YES" entry.

It has been determined in testing that the above formulation changes produce little or no change in solution results when comparing the old CWELD/CFAST against the new CWELD/CFAST results.

Enhanced Search AlgorithmFor the new connector logic, the search algorithm has been enhanced based on user inputs in an attempt to achieve the best possible connections. The new search tolerance starts with a zero projection tolerance. This may result in changes from the previous connector results using the old CWELD/CFAST elements.

The list below gives a brief summary of the highlights of the improved CWELD/CFAST algorithm.

1. For the CFAST and the CWELD with options "PARTPAT" and "ELPAT", grids GA and GB internally keep the user-specified IDs and the user-specified locations. This change was primarily introduced because many users complained that the location of GA and GB represented their modeling procedures and desired mesh locations.

2. For the CWELD with ELEMID/GRIDID option, grids GA and GB internally keep the user-specified IDs and the user-specified locations, but in the case when GA and GB are associated with shell patches, a duplicate internal grid is generated to avoid singularity of the generated RBE3.

CWELD, 5646, 22, , ELEMID, 3276, 3115 , 2191, 1941CTRIA3, 2191, 8, 3272, 3276, 3271

Grid 3276 as input from standard mesh modeling procedures will automatically be placed in the independent degree of freedom set, or may have been placed by the analyst in a SPC or MPC set at generation time. In either case, the CWELD algorithm must create an internal constraint on this grid using a RBE3 element. This causes a set conflict which is avoided by generating an internal grid.

3. For two stacked connectors having a common patch with a common grid, the program checks duplicated GA/GB and only a single RBE3 is generated for the common patch.

CWELD, 11, 100, 9001, PARTPAT, 3001, 3002CWELD, 12, 100, 9002, PARTPAT, 3002, 3003

4. If the user specifies both grids GA and GB, for the CFAST and the CWELD with options "PARTPAT" and "ELPAT", the SWLDPRM, GSMOVE entry is nonfunctional.

In the CFAST and the CWELD with options "PARTPAT" and "ELPAT", if the user specifies both GA and GB they will not be moved. This may cause the CFAST/CWELD search algorithm to fail for some welds that had passed under the old CWELD/CFAST search algorithm. If this occurs, the user can do one of four things:

a. Determine a better location for GA and GB of the failing welds so that they may project.

b. Remove GA and GB from the CWELD/CFAST entry and replace with a GS entry allowing the CWELD/CFAST algorithm to move and project and generate internal GA and GB locations.

c. Use "SWLDPRM, MOVGAB, 1" to generate internal GA and GB grids at the corrected locations for all CWELD/CFAST. The locations of the original user specified GA and GB are unchanged.

Index


Main

d. Use the new CONCTL Bulk Data entry with "SWLDPRM, MOVGAB, 1" to allow local control of specific welds to correct the locations of grids GA and GB. (See Connector Control section below for detail.)

CONCTL, 83, , MOVGAB, 1 Where: SET3, 83, ELEM, 1345, 2678

5. The maximum tolerance for SWLDPRM, PROJTOL has been relaxed.

a. Regardless of the value of SWLDPRM PROJTOL, the algorithm starts by assuming a zero projection tolerance for the projections of GA/GB for the CWELD option "PARTPAT" or the CFAST option "PROP" and for GAHi/GBHi for the CWELD options "PARTPAT" and "ELPAT" and any CFAST option.

b. The tolerance is increased by 0.02 until a projection is found or the PROJTOL value is reached.

c. This can be turned off while computing the auxiliary grid projection onto EIDA/EIDB by setting PROJTOL= - value where 0.0 ≤ value ≤ 1.0. In this case, the projection calculation starts at tolerance = |PROJTOL|. For the rest of the projection search, the algorithm reverts back to (a) and (b) above.

6. A brief "Connector Summary" of projection results is always output in the f06 file for each connector type: FST-ELEM, WLD-PARTPAT, WLD-ELEMID, etc.

7. For linear connectors, MPCFORCE output is available. In nonlinear SOL 400, the RBE3 elements generated become Lagrange elements if the default RIGID=LAGRANGE is used and are no longer in the MPC set; hence, there will be NO MPCFORCE output for RIGID=LAGRANGE.

8. In the improved CFAST and CWELD, GA and GB are not moved and internal coincident grids are not generated at a new location; thus, two additional restrictions are required.

a. There can be no user-supplied constraints on GA and GB. A fatal message will be issued if there are any.

b. The CWELD length must be > 10-6. The point to patch option defined by ELEMID or GRIDID will, however, still create a new GS internally to obtain a minimum required length; i.e., LDMIN ≤ length/D ≤ LDMAX. For the point-to-patch connection, GS is used as GB. The algorithm will use the new GS as GB but keep the user-supplied GS unchanged. Since the point-to-patch is often used to "tack" two shell corners, the default LDMIN may cause the connector to be unstable. To avoid this, it is recommended that the user set LDMIN=1.E-6 on the appropriate PWELD entry.

C O N N E C T O R S U M M A R Y

ELEM TYPE GOOD/BADNUMBER FOUND

MAX ANGLE B/N SHELL NORMALS GAB/GH (GSPROJ) AT EID

MAX TIMES GSMOVED (GSMOVE) AT EID

MAX TIMES GSMOVED (GSMOVE) AT EID

MAX TIMES DIAMETERREDUCED (NREDIA) AT EID

FST-ELEM G 26B 0

GAB 0.0 (20.00) 6000000 GH 0.0 (0.02) 6000000 0 ( 0) 6000000 1 (4) 6000018

Warning: CWELD will not contribute to MASS by default even if its associated MATi entry has a nonzero density. To react to a nonzero density "SWLDPARM,WMASS,1" is required. If mass is computed, the PARAM,COUPMASS effects the mass calculation.

Index


Main

9. CFAST and the CWELD with options "PARTPAT" and "ELPAT" with the improved formulation has removed the restriction that a connector patch cannot span more than three elements. It will now span over a patch of as many elements that the value of diameter D of the patch encloses and for which projections can be found.

In the following Figure 2-1 (The example for this figure can be found at /tpl/connectr14/cei_103.dat), all element grids contained in the green circle region of say patch A will be used in a RBE3 connection in addition to the RBE3 connections generated for the four auxiliary points. The green circle passes through the four auxiliary points of the patch (The nine digit grid IDs.). The user-specified diameter D on the PWELD and PFAST entries determine the locations of the four auxiliary points. (The green circle diameter is approximately 1.253D.) The element grids shown outside the green circle belong only to the respective auxiliary points.

For higher-order shell elements CQUAD8 or CTRIA6 with no missing midside nodes, the RBE3 relationships use only the midside nodes. If one or more midside node is missing (NEVER RECOMMENDED), then the corner nodes are used.

The diameter D on the PFAST/PWELD entry is used to determine the projection location of these auxiliary points as well as the stiffness properties of the patch to patch connection.

A single RBE3 then connects the four auxiliary points and the shell grids within the green circle to the connector grid GA=4000065.

Reminder: The CWELD ELEMID option still only connects by design two elements. The diameter is only used to compute the beam stiffness.

Figure 2-1

The SWLDPRM, PRTSW entry will list the additional grids located within the green circle under FMESH SHELL A or B GRIDS where FMESH is the f06 file listing title of the additional shell grids connected in the RBE3 relationships for Finer MESH.

Index


Main

Table 2-1 shows the grids associated with auxiliary grid 101000023 of Figure 2-1 for its RBE3 generation. The WTi's are weight factors based on patch shape functions. Grids G1, G2, G3 are selected for RBE3 EID 100001026 because they are the shell grids of the triangular element that contains the projected auxiliary point.

Table 2-2 shows the grids associated with grid GA=4000065 of Figure 2-1 through RBE3=100001022. G5 through Gn are the grids contained within the green circle. Grids G2=4007884, 4007869, 4007815, and 4007830 are NOT included in any of the G5-Gn entries because they are included in their associated auxiliary point RBE3 elements

100001026 because they are the shell grids of the triangular element that contains the projected auxiliary point.

10. The CWELD/CFAST/CBUSH has the additional enhancement that for nonlinear transient SOL 400 with "ANALYSIS=NLTRAN" they will request Element FORCE output for the CWELD/CFAST/CBUSH elements. FORCE=ALL will request force output for all CWELD/CFAST/CBUSH elements. Element FORCE output in SOL 400 nonlinear transient analysis is unique to CWELD/CFAST/CBUSH elements. Other elements will not list force output in SOL 400 nonlinear transient. Beware that if in a SOL 400 nonlinear transient, you have FORCE=ALL and carry this over to say an "ANALYSIS=NLSTAT", you will get Element FORCE of ALL elements capable of force output, such as CWELD, CFAST, CBEAM, CQUAD4, etc.

11. For user convenience, an additional SWLDPRM command useful for reports creates a comma separated file of the SWLDPRM, PRTSW, using the command "SWLDPRM, CSVOUT, UNITNUM" where "UNITNUM" is assigned via the:

ASSIGN USERFILE=myfile.csv, UNIT= UNITNUM , FORM= FORMATTED, DELETE, STATUS=NEW. (See Table 2-3 Report Format.)

Table 2-1 Auxiliary Grid 101000023 and Associated RBE3 100001026

RBE3 EID GAH3 REFC Weight Ci Gi

100001026 101000023 123 WT1 123 G1=4007883

WT2 123 G2=4007884

WT3 123 G3=4007902

Table 2-2 All GHAi + Patch A Green Circle Grids for RGE3 100001022

RBE3 EID GRD_A REFC Weight Ci Gi

100001022 4000065 123456 WT1 123 GAH1=101000021

WT2 123 GAH2=101000022

WT3 123 GAH3=101000023

WT4 132 GAH4=101000024

1.0 123 G5= 4007885

... ... ...

1.0 123 Gn=last

Index


Main

Additional Information

1. In SOL 400, for "ANALYSIS=NLSTAT" or "ANALYSIS=NLTRAN", the generated RBE3 constraints become Lagrange elements and may undergo large rotation. For "ANALYSIS=NLTRAN" with initial conditions (IC=n) in case control that cause large initial stresses in the structure at time t=0, the case control entry RIGID needs to have the value "RIGID=LINEAR" to insure convergence.

2. For user desiring to postprocess the CFAST/CSEAM/CWELD connectors with their own methods, the following is useful:

a. The GEOM2 table contains, after module MODGM2, a record ELCORR that correlates the CFAST/CSEAM/CWELD and its associated RBE3 elements. Also, this module will, for linear analysis and for nonlinear SOL 400 analysis run with RIGID=LINEAR, place the internal generated RBE3 into the GEOM4 table.

b. In SOL 400 with "RIGID=LAGRANGE" (Default), internally generated RBE3 elements go into the GEOM2 (as do all other user specified rigid elements) not the GEOM4 table.

c. The CWELD/CFAST/CBUSH force output for "ANALYSIS=NLTRAN" in SOL 400 is OP2 file output on OEFNLXX data block. If SCR=POST is run, then this force data is also written to the data base file OEFNL3 and op2 file OEFNL.op2 is also written.

3. The DISPLACEMENT (CONNECTOR=) Case Control Command works in the same fashion for both the old connector formulation and the new connector formulation.

4. Reminder: For the CFAST with option "ELEM" and the CWELD with option "ELPAT," the shell elements connected on each patch must have same property identification number of PSHELL entry.

5. Reminder: If parameter OSWPPT is used to specify the offset for internally generated grid IDs, its value should be greater than the maximum identification number of GRID entries to avoid conflict IDs.

Connector Stiffness

Connector contribution to a structural model's overall stiffness is sensitive to the models mesh size and the orientation of the connector relative to the mesh. Thus, the discretization process itself may cause, for example, a model using a fine mesh to be stiffer in torsion than a corresponding model using a coarse mesh. Also for production models that correlate well with test, refining the mesh may cause an inherent overall loss of stiffness due to mesh refinement and hence loss of correlation.

To allow the user some control over stiffness, the improved connectors (CWELD with ELPAT or PARTPAT or CFAST) are provided with two options to provide additional connector stiffness. The two options may be used individually or in combination.

The first stiffening technique is activated by "SWLDPRM, DRATIO, ( )" or "CONCTL, SETID, ,DRATIO, ( )". For this option the diameter, Dratio, is defined as Dratio = DRATIO * Dconnector. This

results in the diameter of the patch taking a value of . The default of DRATIO is a value=1.0 which

implies the diameter of the patch is computed in the standard fashion. For the patch to patch connection for the "beam"

properties of the CWELD, the area is still computed as as defined in the PWELD entry.

1.0 value 10.0≤≤1.0 value 10.0≤≤

D π 2⁄( )Dratio=

Aconnector π D2connector 4⁄( )=

Index


Main

A disadvantage of this method is that as DRATIO is increased using the global command SWLDPRM, DRATIO, value; some connector elements may begin to fail because they may no longer be able to find a patch projection.

To overcome this, the "SWLDPRM, NREDIA," can be increased to a value as high as 8 to allow failing welds to halve their patch diameters up to eight times.

If the "SWLDPRM, NREDIA" is not an approach the user wishes to pursue, then for these failing elements, the bulk data entry CONCTL, SETID, ,DRATIO, value can be used to define a set for failing connectors and set a value of DRATIO for these connectors that allows them to find a projection.

The second stiffening algorithm attempts, based on the diameter of the connector, to determine a measure of the mesh discretization.

This feature is activated by "SWLDPRM, SKIN, 1" or "CONCTL, SETID, ,SKIN, 1". The default is a 0 which implies no stiffening. There is an associated stiffening factor "SWLDPRM, SCLSKIN" with value = 0.10 as default.

Depending on the complexity of the model and the overall mesh size and the number of connectors within the model and the diameter of the connectors relative to the mesh, the default value tends to stiffen a structural model from about 0.4% to about 4%. A value of SCLSKIN=10.0 stiffens coarser mesh models by about 10% to 11% and finer mesh models by about 2% to 6%.

The contribution of the stiffening algorithm to the overall stiffness of the FEM model eventually reaches a limit. For example, a very large value SCLSKIN=100 increases the stiffness of the models overall by only about 0.1% to 2% over the stiffness obtained for SCLSKIN=10.

For a correlated structural model evaluated at a specific mesh size, with an aim to refine the mesh for some portion of this model containing connectors, while leaving other portions containing connectors with an unmodified mesh, it is recommended that the "SKIN, 1" and "SCLSKIN, real value" be entered on the CONCTL bulk data entry referring to

Index


Main

the connectors within the area of the refined mesh. Different refined mesh areas within the structural model can have different values of SCLSKIN associated to the specific connectors in each refined region.

For postprocessing of the SKIN option, for the affected shell elements, an updated EPT table is available after module MODGM2. It contains the PSKNSHL record that correlates the property data of the shells involved and a list of shell elements for each patch modified.

Detailed Projection Algorithm for Best Possible Projection

1. The Enhanced algorithm applies to the following projection calculations:

a. Find projections of GA/GB for the "PARTPAT" format of CWELD and "PROP" format of CFAST.

b. For "ELPAT" format of the CWELD and the "ELEM" format of the CFAST, the user has specified the specific shell elements and therefore no element search for GA/GB projections is required. Though no search is required, GA/GB, however, must project onto the user specified EIDA/EIDB.

c. Find projections of the auxiliary grids GAHi/GBHi for the "PARTPAT" and "ELPAT" options on the CWELD and any CFAST option respectively.

2. The projection algorithm searches for possible projections from shell elements with shell grids that are closest to GS. The closest grid may connect to several shell elements; hence, more than one shell element may get a projection from GS for curved patches. The shell elements with projections from GS are collected and the selection is based on the SHIDA/SHIDB pair with the smallest angle between their normal vectors.

a. The old CWELD/CFAST algorithm used the first shell elements found to get a projection and used SWLDPRM, GMCHK, 1 and 2 to provide some control. These two options have no effect on the new formulation.

b. Backward connections sometimes occur if the patch is near the boundary of a structure, and there is a "vertical" flange associated with the patch elements. In this case, SWLDPRM, GMCHK, 3 may be used to prevent backward projection. (See Figure 2-2.)

Figure 2-2

3. The minimum angle selected above must be ≤ SWLDPRM GSPROJ if GSPROJ ≥ 0.0

4. If the user has not specified BOTH GA and GB and the algorithm cannot find a GSPROJ satisfied projection, then for SWLDPRM GSMOVE entry, the point GS will be moved in an attempt to satisfy the projection requirement.

Index


Main

5. Reminder: If user has specified both GA and GB and CFAST and the CWELD with options "PARTPAT" and "ELPAT" are used, then GSMOVE will be ignored and the connector will fail to connect if the user has taken the default "SWLDPRM, NREDIA, 0" for NREDIA. Failed connectors issue USER FATAL MESSAGE 7635.

6. If the GSMOVE specification limit is reached for the CFAST or the CWELD with options "PARTPAT" and "ELPAT" and SWLDPRM NREDIA ≠ 0, then the diameter of the connector will be reduced by half to compute new locations of auxiliary grids. If necessary this is repeated until the NREDIA specified value is reached.

a. When the NREDIA ≠ 0 is initiated, the GS at its current location is used for GSMOVE ≥ 0.

b. When the NREDIA ≠ 0 is initiated, the GS at its original location is used for the new option GSMOVE < 0.

Connector Control:To provide the user with better connector control, the following new Bulk Data entry has been introduced:

This entry provides local connector search algorithm control to override SWLDPRM values.

Please see CONCTL (p. 1594) in the MSC Nastran Quick Reference Guide for the complete Bulk Data entry.

Report Format:Table 2-3 CSV Report Format

CONCTL Parameter SWLDPRM override for CFAST, CSEAM, and CWELD Connector Elements

Index


Main

CSEAM Element1. The CSEAM element has been changed so that it now supports geometric nonlinear analysis. The CSEAM

element internally uses the CHEXA element. The old CSEAM formulation did not support large displacement.

2. Both the linear and nonlinear CSEAM now generate internal RBE3 elements rather than internal constraints.

3. The improved CSEAM formulation is selected by default. The old CSEAM formulation is obtained by PARAM, OLDWELD, YES.

4. The CSEAM currently continues to have the restriction that it cannot span more than a 3 x3 mesh. Figure 2-3 and Figure 2-4 below review the CSEAM structure.

5. The CSEAM now uses by default 2x2x2 Reduced Shear with Bubble Function. The OLD CSEAM used 2x2x2 Reduced Shear only. The IN field of the PSEAM allows for selection of 2x2x2 Reduced Shear only.

Figure 2-3

Warning: The old CSEAM formulation did not contribute to MASS. The new CSEAM will contribute to MASS if it's associated MATi entry has a nonzero density. PARAM,COUPMASS effects the mass calculation.

Index


Main

Figure 2-4

6. The CSEAM entry does not support material nonlinear behavior.

Examples

Test Model 1

Figure 2-5 shows a Hat profile beam that has a dimension of 600 cm long by 100 cm by 100 cm spot welded to a plate with welds 5mm in diameter. It this case the plate is aligned with the edges of the hat flange. Using a refined mesh one can obtain accurate details on the stress distribution in the vicinity of the weld. Based upon the mesh size, and the location of the weld, it may necessary to distribute the load over a 4x4 mesh. This was not achievable in the previous release because of the 3x3 mesh limitation and a fatal error would have occurred. The von Mises stress for the third weld from the left end are shown in Figure 2-6.

Index


Main

Figure 2-5 2mm mesh model

Figure 2-6 von Mises stress in the vicinity of the weld

Test Model 2

The figures below represent a "box" structure of overall physical dimensions of 100cm x 100cm x 100cm. One model is a coarse mesh model and the other a fine mesh model. The vertical center section has the same mesh in both models. Both Models have the same number of CWELD elements (Cluster of blue dots in fringe plots) each of D=5.0 cm at the same spatial locations.

For the coarse mesh the outer horizontal top and bottom panels are 50 cm x 50 cm. The inner horizontal top and bottom panels are 16 cm x 16 cm. The center vertical partition mesh is 20 cm x 20 cm. The outer vertical side panels have mesh 50 cm x 50 cm. The inner vertical side panels have a mesh of 20 cm x 20 cm. The mesh of the horizontal offset panel on the upper right side is 10 cm x 10 cm.

For the fine mesh (shown in Figure 2-8) the inner horizontal top and bottom panels remain a mesh of 16 cm x 16 cm. The outer horizontal top and bottom panels are meshed using CQUAD8 elements at 4 cm x 4 cm. The center vertical partition mesh is 20 cm x 20 cm. The outer vertical side panels have mesh 3.4 cm x 3.4 cm. The inner vertical side panels remain at 20 cm x 20 cm. The mesh of the horizontal offset panel on the upper right side is 10 cm x 10 cm. The mesh of the horizontal offset panel on the upper right side is ~2.6 cm x ~2.6 cm. As shown in Figure 2-7 all the elements contained within the green outlined circle are included in a typical patch of this panel.

Index


Main

Figure 2-7 Coarse and fine mesh model

Figure 2-7 shows the detail of the fine mesh of the horizontal offset panel.

Figure 2-8 Fine mesh horizontal offset panel

As the model mesh is refined there is a well-known tendency for welded models to exhibit a loss of stiffness due to model discretization. This is shown if the next two figures. The coarse mesh model has a maximum displacement of

Index


Main

5.795 cm where the center vertical partition meets the bottom plate. The fine mesh model has a maximum displacement at that location of 13.75 cm at the same edge location.

Figure 2-9 Coarse mesh model displacement

Figure 2-10 Fine mesh model displacement

For design purposes it is desired that the displacement at that location be brought to within 2% of the coarse mesh model. To achieve this the SWLDPRM entry is modified to use a combination of two stiffening techniques available with the CWELD element. This is achieved by modifying the entry SWLDPRM as shown highlighted in red. The DRATIO factor of 5.95 increases the radius of influence of the CWELDs Dpatch = 5.95 Dweld = 29.75 cm. For patch to patch connection, the user supplied PWELD value of Dweld=5.0 is still used to compute the "beam area and moment of area properties.

"SWLDPRM, PRTSW, 2, NREDIA, 4, DRATIO, 5.95, SKIN, 1 , SCLSKIN, 0.255"

Index


Main

The SKIN parameter initiates a process which measures the discretizing of each CWELD relative to its patch and computes an estimate of the local increase in patch bending resistance which is then applied to the shell element local to the patch. For this model, the associated SWLDPRM parameter SCLSKIN is set to a value of 0.255 and is used to measure the discretization of each patch and compute a "WELD" bending moment of inertia to be applied for the specific patch.

The figure below shows the displacement pattern for this case. It is observed that the displacement of the fine mesh model has a maximum displacement of 5.898 cm where the center vertical partition meets the bottom plate which is within the required 2%.

Figure 2-11 Fine mesh model with DRATIO, 5.95 and SKIN, 1 with SCLSKIN, 0.255

For these models, the von Mises stress, in the area of the vertical partition stayed about the same. In the coarse mesh model this was the area of maximum stress. In both fine mesh models the area of maximum stress occurred near the support point of the upper plate furthest from the viewer.

Index


Main

These problems are found at doc\relnotes\v2016/cei008-weld.dat, doc\relnotes\v2016/cei026-weld.dat and doc\relnotes\v2016/cei026-weld-DRSKN.dat.

Test Model 3

Figure 2-12 shows a simple bracket mechanism. The center sheet (red) is clamped along the right edge. The bracket (green) is welded to the center sheet with six CWELD elements using the "PARTPAT" option shown as black lines. A sinusoidal loading is applied to the bracket at the center of the lower-right edge as shown by the red dot in the figure.

Figure 2-12 Bracket Mechanism

The model is run in SOL 400 as "ANALYSIS=NLTRAN" with "PARAM, LGDISP, 1" for geometric nonlinear. Figure 2-13 shows the displacement and stress at t=0.5 seconds.

Figure 2-13 Displacement and Stress at t=0.5 seconds

Index

http://www.mscsoftware.com/doc/nastran/2016/release/cei026-weld.dat

http://www.mscsoftware.com/doc/nastran/2016/release/cei008-weld.dat

http://www.mscsoftware.com/doc/nastran/2016/release/cei026-weld-DRSKN.dat


Main

Figure 2-14 shows a slice of the Force and Stress output for CWELD 7006.

Figure 2-14 Slice of Force & Stress Output

For further details, see MSC Nastran Demonstration Problems Manual, Chapter 96.

Limitations and Guidelines1. The old CFAST/ CWELD formulation and the new CFAST/CSEAM/CWELD formulation only support

geometric nonlinear in SOL 400. They are not supported in SOL106 or SOL129 as nonlinear elements.

2. The CFAST/CSEAM/CWELD elements do not currently support nonlinear material in SOL 400.

3. The current CFAST/CSEAM/CWELD do not support thermal loading.

From release to release, there are often corrections or improvements or both to the connector search algorithm. These modifications, in general, have small effects on the local stiffness of the structure. However, they can have an effect on the force results reported by the CWELD or CFAST elements if the user has selected the default orientation of these connectors. This is because a slight change in the connector orientation of the connector y- and z-axis causes different reporting of force output. If the relative orientation of these axes is important, the user is reminded that the CWELD and CFAST elements allow the user to specify a specific orientation for these axes. Remarks 12 and 16 of the CWELD and Remark 1 of the PFAST in the MSC Nastran Quick Reference Guide explain user-specified connector orientation.

Index

22Linear AnalysisMSC Nastran Embedded Fatigue (NEF) Updates

Main

MSC Nastran Embedded Fatigue (NEF) UpdatesThree major enhancements to NEF are added to SOLs 101, 103, and 112. These include:

• Nodal Averaged Stresses, 22

• Surface Resolved Stresses, 23

• Fatigue Stress Output, 23

Nodal Averaged StressesFatigue analysis can now be performed using nodal averaged stresses or strains. The nodal averaging is done using the grid point stress methods, identically as if GPSTRESS or GPSTRAIN are requested in the Case Control. This is in addition to the existing functionality of using element center or element nodal stresses/strains.

Benefits

• Fatigue damage calculated from a more realistic quantity

• Less calculation points, thus increased computation speed

• Greater clarity because only a single fatigue damage result per grid

• Postprocessing does not average fatigue life/damage due to multiple values per grid

• Less conservatism in the damage prediction

Default Changes

Please be aware that the default value of the LOC field on the FTGPARM entry has changed to LOC=NODA. In previous releases, the default was LOC=NODE, meaning that element nodal stresses or strains were used for the fatigue analysis. Now, the default uses nodal averaged stresses or strains internally via the grid point stress or strain (GPSTRESS/GPSTRAIN) output request functionality (it is not necessary to include GPSTRESS or GPSTRAIN in the case control).

Because of this change, input files created for previous versions of MSC Nastran have to be modified if the LOC field is not provided or the FTGPARM entry is omitted in order for MSC Nastran to continue to calculate the same results. If not modified, results will differ and possibly be slightly nonconservative in comparison. Since nodal averaged stresses/strains are determined from the average of all element nodal contributions, the highest stresses/strains determined for any given node will generally be smaller than the largest element nodal contribution, resulting in less damage and thus, a longer fatigue life (i.e., nonconservative).

Also, the new RECOVER field on the FTGPARM entry uses CORNER as the default. In previous releases, LOC=NODE was equivalent to LOC=SGAGE. The specification of the type of stress recover has been separated from the LOC field into this new RECOVER field. In this release, if RECOVER is not specified, LOC=NODE uses RECOVER=CORNER. The default stress recover method has been changed to CORNER in this release. Thus, slightly different stresses may be passed to the fatigue solver than in previous releases depending on the element type used. This change was made to align with the default recovery method used for the STRESS (or STRAIN) case control output request.

Index

23 MSC Nastran 2016 Release GuideMSC Nastran Embedded Fatigue (NEF) Updates

Main

Limitations

• Standard S-N and ε-N analysis using nodal averaged stresses (LOC=NODA) and fatigue analysis of spot or seam weld cannot be done using the same FID (FATIGUE case control ID). In order to do fatigue analysis of spot or seam welds and a standard fatigue analysis within the same run, you must set up separate FIDs using a case control SET entry. Example:

SET 10 = 42, 43FATIGUE(SET) = 10

In the above example, FID 10 actually refers to SET 10, which contains two FIDs: 42 and 43. FID 42 could be a standard S-N or ε-N analysis, and FID 43 could be a fatigue analysis of spot or seam welds.

Surface Resolved StressesIf the SRESOLVE field is set to YES on the FTGPARM entry, then for any specified set of solid elements (CHEXA, CPENTA, CTETRA) on the FTGDEF entry, the free faces of those solid elements are skinned.

Skinning is the process of creating thin shell elements in the same location as the free faces using the same GRID IDs as the faces of the solid elements. The fatigue analysis then uses the stresses from these skinned shell elements based on the LOC field (element center, element nodal, or nodal averaged).

This results in the analysis using a 2-D state of stress instead of the desired 3-D state of stress on the surface of the model. Since, in reality, the surface normal stress is generally zero (0) unless there is some sort of hydrostatic pressure or equivalent, and the fact that most fatigue cracks initiate on the surface and not interior to the model.

Benefits

• Ensures a 2-D state of stress at the surface

• Results in less calculation points, ignoring interior entities

• Enables multi-axial assessments and correction on 3-D solid models

• Enables use of critical plane stress combination (COMB=CRITICAL) for 3-D solid models

Limitations

• To postprocess results in Patran using the method requires both the model and the results to be imported into an empty database. This is due to the fact that the shell elements are internally generated by MSC Nastran and do not exist in the original input file. If Patran contains only the elements of the original input file, which is the case when importing an imput file, the internally generated elements do not exist in the Patran database, thus simply attaching the results file will not allow postprocessing on the internally generated elements. A new, empty database must be opened, and the MASTER/DBALL file attached using the “Both” (model and results) option. This ensures the generated elements are available to Patran in its database so result can be plotted.

Fatigue Stress OutputNew output request parameters are available using the LAYER and STROUT fields. Previously, the LAYER option was available on the PFTG entry. This has been moved to the FTGPARM entry to be a more global output request setting.

Index


Main

LAYER specifies which layer of results from shell element are printed to the f06 file. The default is to output the worst case layer. Top or bottom can also be specified. Both layers are always output to the results data blocks for postprocessing purposes.

STROUT is a new parameter for requesting the actual stresses (or strains) used in the fatigue analysis. The stresses used in the fatigue analysis are specified on the FTGPARM entry and can differ from those that may be requested from a STRESS, STRAIN, GPSTRESS, and/or GPSTRAIN case control output request. Also, any specific MSC Nastran input file can request more than one fatigue analysis; each possibly requesting different stress settings. Standard case control output requests do not allow visualization/printing in this manner.

By default, STROUT is turned off (set to 0). Setting to 1 prints the stresses used in the fatigue analysis from each set of subcases used in the fatigue analysis. Only the stresses from the entities defined on the FTGDEF entry are output; those being the same entities for which fatigue damage is calculated. With STROUT=1, the fatigue stresses are also output to an OESFTG data block that is available for postprocessing. With STROUT=2, no f06 print is generated, but the output data block is still generated for postprocessing.

Benefits

• Output and view the actual stress (or strains) used in the fatigue analysis

ExampleTo demonstrate the influence of the new options, the problem A Multiaxial Assessment (p. 291) in the MSC Nastran Embedded Fatigue User’s Guide is used. The model is the SAE Shaft used to produce a multi-axial state of stress at the critical location in one of the notches of the shaft using two load cases - bending and torsion. The original model is made up of mostly solid CHEXA elements.

The graphics below first show the original solid model (no shell elements). Using SRESOLVE=YES, the free faces of the solid elements are skinned by creating thin shell elements. The resulting surface resolved, 2-D stress state from the shell elements, is used in the fatigue analysis to compute damage, life, and multi-axial statistics. The model has been clipped to show the inside of the shaft with the solid elements removed. The example files are located at:

• tpl/nef_ug/sae_shaft_resolved.dat

• tpl/nef_ug/sae_shaft_skinned.dat.

Figure 2-15 SAE Shaft Modeled with Solid CHEXA & CPENTA Elements

Caution: Using this output setting can generate a lot of data. Also, using LOGLVL set to 4, outputs stresses to the dtout file. This file should only be used for debugging purposes and can be very large, containing much more than the stresses. It also can adversely affect performance. Please use both with caution.

Index


Main

Figure 2-16 SAE Shaft Skinned Shell Elements with SRESOLVE=YES (Clipped)

Figure 2-17 SAE Shaft Surface Damage on Notched Area Only (Clipped)

The table below shows results of the model using the different options presented in this section. The analysis has been done on both the skinned shell and solid elements using all three types of stress requests: element center (LOC=ELEM), element nodal (LOC=NODE), and nodal averaged (LOC=NODA). Stresses are in MPa and life units are in repeats of the loading time history (in log units). Only the critical location at surface node 50988 and its associated elements is reported. The skinned element IDs were set using SYSTEM(183)=1 as they were generated internally.

Skinned QUAD Elements:

LOC Elem Node LogLife

BiaxialRatio σx σy σz τxy τyz τzx Subcase

ELEM 870 - 2.86 0.1387.3439 38.1174 0.0000 0.0082 0.0000 0.0000 Bending

0.0000 0.0000 0.0000 0.1037 0.0000 0.0000 Torsion

NODA - 50988 2.84 0.12936.9281 6.7862 0.0000 0.0000 0.0000 0.0000 Bending

0.0000 0.0000 0.0000 -0.1019 0.0000 0.0000 Torsion

NODE

870 50988 2.82 0.1417.4648 38.3918 0.0000 0.0082 0.0000 0.0000 Bending

0.0000 0.0046 0.0000 0.1037 0.0000 0.0000 Torsion

872 50988 2.86 0.14238.2513 7.4225 0.0000 -0.0046 0.0000 0.0000 Bending

0.0075 0.0000 0.0000 -0.1017 0.0000 0.0000 Torsion

975 50988 2.83 0.1417.4649 38.3918 0.0000 -0.0082 0.0000 0.0000 Bending

0.0000 -0.0046 0.0000 0.1037 0.0000 0.0000 Torsion

977 50988 2.85 0.1437.4225 38.2513 0.0000 -0.0045 0.0000 0.0000 Bending

0.0000 -0.0075 0.0000 0.1017 0.0000 0.0000 Torsion

Index


Main

Results are as expected with the following comments for emphasis on all the above explanations:

1. The HEX element produced a 3-D state of stress at the surface. This means that

• It is not possible to determine multi-axial parameters (thus the biaxial ratio is not reported).

• The surface normal stress is not zero as this is physically unrealistic. Thus, the stress state at the surface is suspect using these elements and the resulting fatigue analysis is questionable.

2. The element center results (LOC=ELEM) for the HEX element are the least conservative. This is because the stress is from the center of the element, interior to the surface. The stresses are less, and thus, the fatigue life is longer. Since fatigue cracks occur on the surface (generally), it is of little interest to calculate fatigue life interior to solid elements.

3. The results from all analyses (LOC=ELEM/NODE/NODA) of the skinned shell element will either diverge away or converge to the same fatigue life based on the mesh refinement. The smaller the elements, the less it matters which LOC method is used. The more coarse the mesh, the more the results will differ. The mesh of this model is adequate in that the results are very close together (2.82 vs. 2.84 vs. 2.86); which, when considering fatigue life, are the same results. The same would be true of the solid element results, except that there is still the issue of the stress state not being resolved to a surface stress state.

4. The most conservative answers come from using element nodal stresses. This is because the highest calculated stress is retained and not averaged and/or interpolated. The stress is retained at any particular GRID for every associated element. So if four elements share the same GRID, then four stresses are reported. Thus, four fatigue lives are computed. The highest stress is retained and the shortest fatigue life reported.

5. The nodal average method is less conservative than the element nodal method because the stresses are averaged. If four elements share the same GRID, the stress from each element is averaged to give a single stress value at the GRID. With only a single value of stress computed at the GRID, only a single fatigue life is reported.

HEX Elements:

LOC Elem Node LogLife

BiaxialRatio σx σy σz τxy τyz τzx Subcase

ELEM 85828 - 3.68 N/A30.8301 6.4100 3.4829 -0.5621 -0.2695 -6.2777 Bending

0.0000 0.0033 -0.0033 -0.0913 0.0187 0.0080 Torsion

NODA - 50988 2.91 N/A36.2500 7.4320 3.0020 0.0000 0.0000 -6.0050 Bending

0.0000 0.0000 0.0000 -0.1007 0.0152 0.0000 Torsion

NODE

85828 50988 2.97 N/A37.1466 8.1864 3.8139 -0.6785 -0.3982 -7.6290 Bending

0.0019 0.0046 0.0015 -0.1001 0.0262 0.0009 Torsion

85830 50988 2.80 N/A35.2021 8.1837 5.6906 -0.9470 -0.2336 -10.7115 Bending

0.0026 0.0046 0.0014 -0.0979 0.0269 0.0003 Torsion

86335 50988 2.78 N/A37.1466 8.1864 3.8139 0.6785 0.3982 -7.6290 Bending

-0.0019 -0.0046 -0.0015 -0.1001 0.0262 -0.0009 Torsion

86337 50988 2.79 N/A35.2022 8.1838 5.6906 0.9470 0.2336 -10.7115 Bending

-0.0026 -0.0046 -0.0014 -0.0979 0.0269 -0.0003 Torsion

Index


Main

6. The element center method gives the least conservative answer for the shell element also because the stress is reported at the center of the element and interpolated and averaged to that point from the stresses computed at the integration or gauss points of the element. When there is a large stress gradient across the element, the stress is going to be much lower than the highest computed stress at any integration or gauss point.

So when should each method be used? Engineering judgement! So for this reason, all methods are available. Nodal averaged is set to the default for the following reasons:

1. Computational efficiency – a single stress value at each GRID produces a single fatigue result

2. More realistic stress – it is generally felt that averaging the stresses at a GRID gives a better realistic representation of the actual stress - obviously only one stress actually exists at any given location

3. Legacy – most existing processes adopted by engineers use nodal averaged stresses

User InterfaceThe functionality is accessed via the FTGPARM entry as shown here with only the new/changed fields shown/highlighted.

Defines parameters for a fatigue analysis.

Format

See section, Nodal Averaged Stresses, 22, for discussion of the LOC/RECOVER fields and the “NAVG” line.

See section, Surface Resolved Stresses, 23, for discussion of SRESOLVE.

See section, Fatigue Stress Output, 23, for discussion of LAYER and STROUT.

Example 1:

Shows all default values of the new/modified fields:

FTGPARM Fatigue Parameters

1 2 3 4 5 6 7 8 9 10

FTGPARM ID TYPE FACTOR NTHRD LOGLVL LAYER STROUT

“STRESS” or

“STRAIN”

COMB CORR PLAST LOC INTERP RECOVER SRESOLVE

“NAVG” MTHD OUTPUT NORMAL

FTGPARM 42 0 0

STRESS NODA CORNER NO

NAVG TOPO 0 R

Index


Main

Example 2:

This example calls for the usage of nodal-averaged stress to be used in a standard S-N fatigue analysis. All nonspecified fields take on the defaults.

Example 3:

This example calls for surface resolved strains to be used in a standard e-N fatigue analysis. Notice that nodal averaged strains are used as the default for the LOC field is NODA but the recovery method is set to StrainGAGE.

Example 4:

This example calls for surface resolved stresses to be used in a standard S-N fatigue analysis using ELEMent center based stresses. Element NODE can also be used with surface resolution of results. CENTER does not have to be specified as it is the default for LOC=ELEM.

Example 5:

This example calls for NODAveraged streses and the NAVG line has been included to change the defaults of the grid point stress calculation to use the GEOMetric method, output results in the element coordinate system (-1), and the positive fiber direction in the X direction.

Field Contents

FTGPARM 42

STRESS NODA

FTGPARM 42 EN

STRAIN SGAGE YES

FTGPARM 42 SN

STRESS ELEM CENTER YES

FTGPARM 42 EN

STRESS NODA

NAVG GEOM -1 X

Field Contents

LAYER For shell elements, the output results layer to print to the f06 file. Values can be 0=Worst, 1=Top(Z2), 2=Bottom(Z1). (Integer, Default = 0). This is for printed output only. The analysis produces results for both layers, which are always available through the MASTER/DBALL, Output2, or other files for graphical postprocessors.

STROUT Requests output of the actual stresses (or strains) used in standard SN and eN fatigue analyses. Values can be 0=No Output, 1=Print Output, 2=Plot Output. (Integer, Default = 0).Printed output is placed in the F06 file and also available in an OESFTG data block for postprocessing purposes. Plot only places the data in the OESFTG data block.

STRESS or STRAIN Flag indicating that stress (or strain) is used in the fatigue calculation.

Index


Main

Remarks

1. LOC=NODE reports multiple fatigue damage values at each GRID of every contributing element. LOC=ELEM reports fatigue damage at the element center only. LOC=NODA reports a single fatigue damage at every GRID. For LOC = NODA, the stresses or strains at the GRIDs from each contributing element are transformed to a consistent coordinate system and then averaged together for a single stress or strain result at each GRID point using MSC Nastran’s grid point stress/strain functionality.

2. The stresses or strains recovered are based on the same methods as presented in the STRESS or STRAIN output request; see the STRESS or STRAIN case control entry for details.

3. SRESOLVE is an option to evaluate surface stresses instead of volume stresses. SRESOLVE is applicable for all three values of LOC (ELEM, NODE or NODA). With SRESOLVE=YES, a reduced set of elements/nodes is used for the fatigue calculation corresponding to the elements/nodes on the solid element's free surfaces by skinning them and automatically producing thin shell elements. Thus, interior nodes are omitted and only the skinned elements extracted from the solid faces are considered in the fatigue analysis. This option is necessary

LOC Location to report fatigue lives. Valid values are "NODE", "ELEM" or "NODA", based on usage of Element Nodal, Element Center, or Nodal Averaged stresses (or strains), respectively. (Character; Default = NODA). See Remark 1. and 5.

RECOVER Stress or strain recovery method. Valid values are "SGAGE", "CORNER", "BILIN", "CUBIC" or "CENTER" (Character; Default = CORNER for LOC=NODE or NODA; Default = CENTER for LOC=ELEM and any other setting is ignored.). See Remark 2.

SRESOLVE Flag for requesting surface resolved stresses from 3-D solid elements to be used in the fatigue analysis. (Character, YES or NO (Default = NO). See Remark 3.

NAVG Flag indicating that the parameters that follow are for definition of how nodal average stress or strain results are determined when LOC=NODA for SN or EN analysis. If this line is omitted, all defaults are taken for the nodal averaging. See Remark 4.

MTHD Specifies the method to calculate the average grid point stress or strain. TOPO or GEOM (Default = TOPO)

OUTPUT -1 : Specifies the element coordinate system for output

0 : Specifies the basic coordinate system for output (Default )

CID : Specifies the coordinate system defined on a CORDij bulk data entry for output

NORMAL Specifies the reference direction for positive fiber and shear stress output, but has no effect when OUTPUT=ELEMENT is specified.

R specifies the radius vector from the origin of reference coordinate system to the grid point. (Default = R )

X1, X2, or X3 specifies the direction of the normal.

M specifies the reverse of the directions given by R, X1, X2, or X3 and must be specified as MR, MX1, MX2, or MX3 with no space between the M and the following letter.

Field Contents

Index


Main

when a 2-D state of stress is required at the surface of a 3-D model using CHEXA, CPENTA, and/or CTETRA elements, such as in the case of a multi-axial assessment or when using the critical plane method. The internal element IDs generated by this option can be controlled by using MSC Nastran SYSTEM cell 183 (Default is set to 200000000).

4. These settings correspond to the same settings for grid point stress/strain output. Refer to OUTPUT(POST) Commands - SURFACE Definition. TOPO (the default option) is the less expensive of the two and appropriate in the majority of cases. For a model with high stress gradients or where different element types meet, the more expensive GEOM option could be specified.

5. It is not necessary to specify GPSTRESS or GPSTRAIN in the Case Control to use nodal averaged stresses/strains in the fatigue analysis. This is done automatically when LOC=NODA.

ReferencesPlease see the following for more information and specifically for tutorials on how to setup and run NEF analyses.

• FTGPARM (p. 2104) in the MSC Nastran Quick Reference Guide• A Simple S-N Analysis (p. 81) in the MSC Nastran Embedded Fatigue User’s Guide• A Simple e-N Analysis (p. 131) in the MSC Nastran Embedded Fatigue User’s Guide• A Multiaxial Assessment (p. 291) in the MSC Nastran Embedded Fatigue User’s Guide

Index

Main

Chapter 3: AcousticsMSC Nastran 2016 Release Guide

3 Acoustics

ERP Enhancements 32

Normal Velocity 34

Vibration Intensity 36

ACLOAD and PEM Interpolation Enhancements 37

Out-of-Core Solver for Large Trim Components of PEM 39

Index

32AcousticsERP Enhancements

Main

ERP Enhancements Equivalent Radiated Power (ERP) capability is used to compute radiated acoustic power in the absence of an acoustic model. For MSC Nastran 2016, ERP support is to extend from QUAD4/QUADR/TRIA3/TRIAR to higher order 2-D elements (QUAD8/TRIA6) and 3-D structural element types, namely HEXA, PENTA, and TETRA. In addition, Modal Participation Factor (MPF) for ERP and element ERP will be also included.

Benefits1. Improve flexibility by allowing greater support of element type for practically any structural or FSI model.

2. With MPF of ERP, modal contribution for a ERP can be shown and studied.

3. With element ERP, the contribution of each element of panel can be shown and studied.

User InterfaceAdditional subcommand keywords are added to the ERP case control command. The new subcommand keywords are, MPF, MPFSORT, and ELEMENT, see the ERP (Case) (p. 313) in the MSC Nastran Quick Reference Guide Case Control command for more information.

Test CasesTest case: all 3-D elements

3-D-column plot for ERP and MPF of ERP of 3D_erp deck is shown in following plot. The MPF of ERP is plotted at 40Hz increment while ERP (mode 0) is at 4Hz increment.

Index

33 MSC Nastran 2016 Release GuideERP Enhancements

Main

Element ERP Sample OutputFor following ERP case control command,

ERP(PRINT,ELEMENT,KEY=FRACTION,FILTER=0.0) = ALL

Sample element ERP output sorted based on FRACTION is shown as follows

ALL IN 1 SUBCASE 0 FIRST SUBCASE (1000) SUBCASE 1000 FREQUENCY = 2.000000E+00 E L E M E N T E Q U I V A L E N T R A D I A T E D P O W E R ERPPNL NAME:ERPX0 ERP: 4.3623E-03 AREA: 1.0000E+01 ELEM ID ERP FRACTION ERP(dB) 121 7.262824E-04 1.000000E+00 -3.138894E+01 331 5.803910E-04 7.991258E-01 -3.236279E+01 211 5.705192E-04 7.855336E-01 -3.243730E+01 321 5.054059E-04 6.958806E-01 -3.296360E+01 311 4.616978E-04 6.357001E-01 -3.335642E+01 231 4.493040E-04 6.186353E-01 -3.347460E+01 131 4.369102E-04 6.015707E-01 -3.359608E+01 111 3.796160E-04 5.226838E-01 -3.420655E+01 71111 1.518448E-04 2.090712E-01 -3.818600E+01 71112 8.756132E-05 1.205610E-01 -4.057688E+01 221 1.278043E-05 1.759705E-02 -4.893455E+01

The following test decks are available in the tpl/ae_20160 subdirectory of MSC Nastran installation directory or click on the filename to download the file.

• erphxpta.dat

• erpmpf.dat

• erpq8t6a.dat

• erpq8t6b.dat

• erpoptq8.dat

Guidelines• The CSV file has both ERP and MPF of ERP. Element ERP is not written to CSV file.

• Only the total ERP is the supported response in optimization, SOL 200.

Index

http://www.mscsoftware.com/doc/nastran/2016/release/erphxpta.dat

http://www.mscsoftware.com/doc/nastran/2016/release/erpmpf.dat

http://www.mscsoftware.com/doc/nastran/2016/release/erpq8t6a.dat

http://www.mscsoftware.com/doc/nastran/2016/release/erpq8t6b.dat

http://www.mscsoftware.com/doc/nastran/2016/release/erpoptq8.dat

34AcousticsNormal Velocity

Main

Normal VelocityVELOCITY has been part of the standard MSC Nastran output for dynamic analyses and is provided in the output coordinate system defined on CD field of GRID entries. For acoustic analysis, the velocity normal to the surface is of great interest to engineers. A new case control NVELOCITY has been implemented in MSC Nastran 2016 to output the translational velocity normal to the surface. In addition, the unit normal with respect to the basic coordinate system is also presented.

BenefitsThe normal velocity to the exposed structure provides a direct way for engineers to study acoustic radiation from the structural responses. The output of natural velocity is available in f06, pch, and op2.

User InterfaceA new case control command, NVELOCITY (p. 456) in the MSC Nastran Quick Reference Guide. is available.

Test CasesTest case: car model with mostly 2-D elements

Sample NVELOCITY(ERP) output in f06 is shown as follows,

FREQUENCY = 1.000000E+02 V E L O C I T Y N O R M A L GRID ID U N I T N O R M A L RESPONSE X-DIR Y-DIR Z-DIR REAL IMAG 508078 1.000000E+00 0.000000E+00 0.000000E+00 -7.605058E-03 2.074260E-03 508079 1.000000E+00 0.000000E+00 0.000000E+00 -6.836083E-03 3.575026E-03 508080 1.000000E+00 0.000000E+00 0.000000E+00 -1.321082E-02 -8.084148E-03 508081 1.000000E+00 0.000000E+00 0.000000E+00 -1.360014E-02 -9.710199E-03 508082 1.000000E+00 0.000000E+00 0.000000E+00 -1.392578E-02 -1.124687E-02

Index

35 MSC Nastran 2016 Release GuideNormal Velocity

Main

508083 9.949761E-01 -1.001122E-01 -1.043587E-04 -8.849321E-03 1.153978E-02 508084 9.950486E-01 -9.938970E-02 7.050892E-05 -8.518406E-03 1.257526E-02 508085 9.950164E-01 -9.971110E-02 -3.353163E-04 -1.001583E-02 1.001859E-02 508086 9.950018E-01 -9.985656E-02 -1.280708E-04 -1.139307E-02 7.853719E-03 508087 9.952213E-01 7.442458E-02 6.321043E-02 -1.152199E-02 -1.123693E-02 508088 9.993840E-01 4.897609E-03 3.475112E-02 -8.605826E-03 -1.171262E-02 508089 9.950366E-01 -9.950925E-02 -1.666756E-04 -8.668123E-03 5.844631E-03 508090 9.950239E-01 -9.963606E-02 3.068493E-04 -8.461581E-03 6.424269E-03 508099 1.000000E+00 0.000000E+00 0.000000E+00 6.941264E-03 9.644912E-03 508100 1.000000E+00 0.000000E+00 0.000000E+00 7.193932E-03 1.613807E-02

The response output may also be given as magnitude and phase.

3-D Column plot for all ERPPNLs is shown as follows

PANLA is the summation of all the panels.

The following test decks are available in the tpl/ae_20160 subdirectory of MSC Nastran installation directory or click on the filename to download the file.

• erpnvel.dat

• erpnvel2.dat

• erpnvel3.dat

Index

http://www.mscsoftware.com/doc/nastran/2016/release/erpnvel.dat

http://www.mscsoftware.com/doc/nastran/2016/release/erpnvel2.dat

http://www.mscsoftware.com/doc/nastran/2016/release/erpnvel3.dat

36AcousticsVibration Intensity

Main

Vibration IntensityVibration Intensity (VI) is a measure of power flow per unit area. VI is computed using two existing MSC Nastran output responses, namely element force/element stresses and velocities, and is an element level response in basic coordinate system.

BenefitsThe Vibration Intensity provides a way for engineers to show the magnitude and directions of the power flow paths.

User InterfaceA new case control command, VINTENSITY (p. 573) in the MSC Nastran Quick Reference Guide, activates this capability.

Test Cases

Sample of VI output in f06 is shown as follows,

SUBCASE 1 FREQUENCY = 1.000000E+00 V I B R A T I O N I N T E N S I T Y (HEXA) ELEM ID X-DIR Y-DIR Z-DIR 24 -5.561653E+02 1.781641E+03 -2.333976E+03 25 3.323856E+01 2.027404E+03 -4.087672E+03 26 4.560295E+01 -1.445847E+03 -2.220251E+02 27 6.580253E+02 2.932301E+02 -1.473891E+04 28 -3.086950E+02 3.736709E+01 3.997748E+02 29 -7.216215E+01 1.019957E+02 1.309314E+02 30 5.099537E+03 -1.698603E+04 -8.200218E+04 31 7.031117E+02 6.477779E+03 -7.131067E+03

The following test decks are available in the tpl/ae_20160 subdirectory of MSC Nastran installation directory.

• vintnst1.dat - 1-D element types

• vintnst2.dat - 2-D element types

Index

http://www.mscsoftware.com/doc/nastran/2016/release/vintnst1.dat

http://www.mscsoftware.com/doc/nastran/2016/release/vintnst2.dat

37 MSC Nastran 2016 Release GuideACLOAD and PEM Interpolation Enhancements

Main

ACLOAD and PEM Interpolation EnhancementsACLOAD - ACLOAD is a convenient way to include load vectors produced by Actran as part of the dynamic loading in frequency response analyses. However, it allows only one load case per input file. MSC Nastran 2016 provides enhancement to the ACLOAD capability to accept multiple load vectors per input file.

PEM interpolation – PEM capability performs linear interpolation for Reduced Impedance Matrices (RIM) of each trim component. Since RIM may have been generated with logarithmic distribution of master frequencies, it is advantageous to provide additional interpolation schemes for user to select. Hence, logarithmic interpolation is implemented to compliment the previously available linear interpolation method.

BenefitsACLOAD – Actran can produce load vectors for multiple load cases in a single execution which reduces the Actran run time. With ACLOAD enhancement, MSC Nastran can selectively incorporate any load case in the Actran generated file containing multi-loadcases and apply them as dynamic loads.

PEM interpolation – provides options for RIM interpolation. Logarithmic interpolation is particular useful when master frequencies are unevenly spaced; e.g. octave increments.

User InterfaceACLOAD – ACLOAD bulk data entry field 7 allows the user to specify the load case sequence number of load vectors in an input file.

LSQID field has a default value of 1.

PEM interpolation – a new parameter is provided for user to select the interpolation method.

RIMINTP

RIMINTP can be used to select the interpolation method for Reduced Impedance Matrix(RIM) for PEM. The input options for RIMINTP are LINEAR and LOG10. The default is LINEAR.

Test CasesACLOAD – Following ACLOAD test decks are available in tpl/fsc_2011 subdirectory of MSC Nastran installation directory

• Fsc_07.dat

• Fsc_08.dat

1 2 3 4 5 6 7 8 9 10

ACLOAD SID UNIT1 UNIT2 SCLR SCLI LSQID

Index

http://www.mscsoftware.com/doc/nastran/2016/release/Fsc_07.dat

http://www.mscsoftware.com/doc/nastran/2016/release/Fsc_08.dat

38AcousticsACLOAD and PEM Interpolation Enhancements

Main

The following fatal message will be issued if LSQID has a value which is greater than load cases available,

*** USER FATAL MESSAGE 7952 (SUBDMAP READAC) ILLEGAL SIZE OF MATRICES IN UNIT 42. LOAD SEQUENCE 9 IS GREATER THAN AVAILABLE LOAD CASES 4. USER ACTION: CONFIRM THE FILE FROM ACTRAN.

PEM Interpolation – PEM test decks are available in tpl/pem subdirectory of MSC Nastran installation directory

Index

39 MSC Nastran 2016 Release GuideOut-of-Core Solver for Large Trim Components of PEM

Main

Out-of-Core Solver for Large Trim Components of PEMThe generation of reduced impedance matrix, RIM, for trim components of PEM is subjected to the available memory limitation. In MSC Nastran 2014, PARAM, PEMNPART,n was implemented to split large trim component into smaller pieces such that RIM generation was more likely to succeed. However, PARAM,PEMNPART may interrupt energy flow when splitting the large trim component and causes degradation of accuracy. Therefore, a new out-of-core, OOC, solver has been implemented in Actran to handle large trim components with limited available memory. MSC Nastran 2016.0 PEM capability can take advantage of the OOC solver in Actran to process large trim components. To activate OOC solver, OOC field on ACPEMCP is available as user interface

The value of OOC (field 7 of ACPEMCP), > 1, defines the number of blocks to be used for the Schur complement evaluation. With OOC=n, the RIM is no longer stored entirely in memory but on the disk and by blocks. Only a fraction of the RIM corresponding to the block size (number of reduction DOFs divided by n) is stored in memory.

1 2 3 4 5 6 7 8 9 10

ACPEMCP TID SGLUED SSLIDE SOPEN SIMPER OOC

SCUX SCUY SCUZ SCRX SCRY SCRZ SCFP

Index

Main

Chapter 4: Advanced Nonlinear (SOL 400)MSC Nastran 2016 Release Guide

4 Advanced Nonlinear (SOL 400)

Advanced Elements 41

Contact in Small Deformation Simulations 43

Segment-to-Segment Contact Enhancements 46

Beam Contact 48

Interference Fit 50

Maintaining Geometric Clearance 52

Contact Separation 54

RC Network Heat Transfer Analysis 55

Index

41 MSC Nastran 2016 Release GuideAdvanced Elements

Main

Advanced ElementsIn this release, the enhanced features for SOL 400 using advanced elements include:

Superelement with Advanced Elements• Support in superelement definitions including SESET, SETREE, and its combinations

• Support to directly define advanced elements with PSHLN1, PSLDN1, PBEMN1, PSHEARN, and PRODN1.

• Support to map Conventional Element to Advanced Element with NLMOPTS,SPROPMAP in superelement.

Nonlinear Restart with Advanced Elements• Support to restart the job from previous subcases and steps.

• Support to restart the job form previous results with SPCD.

BenefitsThis release enhances the capabilities of:

1. Superelement analysis with advanced nonlinear elements.

2. Nonlinear restart with advanced nonlinear elements and SPCD.

Superelement and Nonlinear restart used to support MSC Nastran Conventional Elements. But, it will be very important to keep the consistence on model set up and numerical results for both MSC Nastran conventional elements and advanced elements to handle more nonlinear problems. It is also providing the convenience for users to make use of conventional elements and advanced elements in Superelement related analyses and Nonlinear Restart.

ExampleTest cases can be found in tpl/ldr3s400/ldr3se01.dat. It is one of the models to test the capabilities of superelement with advanced elements.

Figure 4-1 Model of ldr3se01

Index

http://www.mscsoftware.com/doc/nastran/2016/release/ldr3se01.dat

42Advanced Nonlinear (SOL 400)Advanced Elements

Main

Residual

The Yellow Part is the residual.

Four QUAD4 elements are using the advanced shell element definition PSHLN1 ID=20.

Superelement 10

The Grey Part is the superelement 10.

Sixteen QUAD4 elements are using the advanced shell element definition PSHLN1 ID=10

Superelement 30

The Red parts are the superelement 30.

Three QUAD4 elements are referring the advanced shell element definition PSHLN1 ID=30

Six QUAD4 elements are referring the advanced shell element definition PSHLN1 ID=31

Known Issues In This Release• In this release, MATUDS for user defined service, MATDIGI for composite, and MATG can't obtain the

corresponding stress results when used in superelement.

• MTRAN with superelement may provide incorrect results.

• Thermal loads should not be applied to the elements condensed out in the superelement.

• Superelements are not supported in linear perturbation with SOL 400.

Index

43 MSC Nastran 2016 Release GuideContact in Small Deformation Simulations

Main

Contact in Small Deformation SimulationsThe accuracy of performing contact simulations in SOL 101 and SOL 400 has been improved when the small displacement procedure is used.

SummaryContact analysis is considered to be a nonlinear phenomenon, in which the constraints are based upon the current deformed state of the contact bodies. In small displacement analysis, when LGDISP is not defined or <= 0, then the equilibrium is based upon the undeformed configuration. In some cases it has been observed that this leads to inaccuracies. This will result in the inability to capture rigid body modes. This may occur for assembly modeling simulations where the contact is effectively rigid or for very small sliding problems.

BenefitsImproved accuracy, reduced oscillation in stresses, and more accurate capture of rigid body modes. This is particularly important in simulation where Inertia Relief is used because of the rigid body modes. These problems occur in both the automotive and aerospace industry.

UsageTo activate the contact constraints based upon the undeformed geometry, use the LINCNT parameter in the BCPARA option; for example:

BCPARA, LINCNT,1

Note that the default is LINCNT is 0; i.e., contact constraints are based upon the deformed configuration.

This parameter should not be used in SOL 400 if LGDISP > 0.

This capability is only available with node-to-segment contact.

Example

Test Model 1

In the first example an L-Connector is in contact with two stacked plates. The simulation is expected to be symmetric about x=0. When using the default method (contact based upon the deformed solution), the solution was not symmetric. As shown in Figure 4-2, the results here are now symmetric.

Index

44Advanced Nonlinear (SOL 400)Contact in Small Deformation Simulations

Main

Figure 4-2 Model with Small Sliding for Linear Contact (von Mises Stress Distribution)

Test Model 2

In the second example, a large automotive model is investigated using SOL 400. Inertia Relief is used to overcome the lack of boundary conditions in the Body-in-White simulation. The key thing is that the Inertia Relief is based upon the undeformed geometry and should be used with the new LINCNT parameter.

Figure 4-3 shows the stress distribution in a key region when using general touching contact analysis, a high stress is obtained. Figure 4-4 includes the stress results with Linear Contact. By comparing with results between SOL 400 Inertial Relief with new linear contact and SOL 400 Inertial Relief without linear contact, the model using the new linear contact does not result in the artificial stress concentration.

Figure 4-3 Artificial High Stress Region with General Contact and Inertia Relief

Index

45 MSC Nastran 2016 Release GuideContact in Small Deformation Simulations

Main

Figure 4-4 Improved Stress Distribution with Linear Contact (LINCNT) and Inertia Relief

Index

46Advanced Nonlinear (SOL 400)Segment-to-Segment Contact Enhancements

Main

Segment-to-Segment Contact EnhancementsThis release enhances the capabilities of the current contact analysis in several aspects: accuracy, performance, and reliability.

Previously, the segment-to-segment procedure required more iterations than the node-to-segment method, which leads to higher computational costs. There are several reasons for this, and some of the issues have been alleviated in this release.

1. The segment-to-segment uses a penalty approach to fulfill the no penetration constraint. The penalty can be defined by user or by the program automatic calculation. With the new default in MSC Nastran 2016, the consequences are as follows:

a. In the case where a deformable body contacts a rigid body, there is no change in the procedure.

b. In the case of deformable-to-deformable contact where the bodies have the same stiffness, a lower value of the penalty is used than in previous releases.

c. In the case of deformable-to-deformable contact and the bodies have different stiffness, the penalty is based upon the lower stiffness.

2. To improve the accuracy and the convergence, MSC Nastran also uses an augmentation method. This augmentation is activated as soon as and remains active as long as the penetration exceeds a certain value and the maximum number of iterations has not been reached. Previously, the value was 1/1000 of the characteristic length. It was found that this value was too small, which led to excessive number of iterations. The default value has been increased in this release.

3. In the case of friction, there is also a value of the Augmented Lagrange penalty value for sticking. In the past, this value was a constant for the whole model or at least for each contact pair. In MSC Nastran 2016, the new procedure results in a value that is dependent on the normal pressure.

Effectively, at low normal stresses this results in the bodies more likely slipping than at high normal stresses.

4. Breaking glue may be applied in segment-to-segment contact. The breaking glue option, which allows the bodies initially glued together to separate if a stress limit is reached, is now available for segment-to-segment contact.

5. In this version for segment-to-segment contact, the contact stiffness is varied gradually with the relative position of the contact surfaces, which may make the contact analysis more smooth and stable. This is particularly true if there are discontinuities in the slope of element faces, often considered to be sharp corners. This is demonstrated in the following example.

6. Initial contact status may be output for all the contact analyses including the permanent glued contact, general glued contact, step glued contact, as well general touching contact.

7. Based on the previous experience and feedbacks, some defaults are changed with consideration of contact, which make the contact analysis more reliable and stable.

a. Default value of MINITER is changed to 2 in presence of contact.

b. Default value of NODSEP is changed to 5 for all the contact analysis including node-to-segment contact and segment-to-segment contact.

Index

47 MSC Nastran 2016 Release GuideSegment-to-Segment Contact Enhancements

Main

UsageThis new procedure is the default in MSC Nastran 2016. To recover the previous procedure, use SYSTEM cell 701.

ExampleA test case can be found in etl/err2016/nas18410d.dat. It is one of the models used to verify the improved contact capabilities with smooth transition of contact stiffness.

Figure 4-5 Model of nas18410d

Without the smooth transition of contact stiffness at sharp corners, one may observe an oscillation of the contact status which leads to unstable contact analysis. A sharp corner is when the interior angle between exterior contact faces is less than 60° as shown in Figure 4-5. With this enhancement, the contact analysis is more stable and reliable.

α

Index

48Advanced Nonlinear (SOL 400)Beam Contact

Main

Beam ContactBeam contact behavior is encountered in many engineering applications including the oil industry in drilling operations, automotive applications including Bowden cables, and biomedical applications such as angioplasty. Beams are commonly used as support structures of shells in many aerospace and civil engineering applications. This includes the use of stringers and spars.

In earlier releases, modeling of beam contact was only supported via the node-to-segment contact algorithm. This had the following disadvantages:

• For contact with non-beams (shells, solids, rigid bodies), beam nodes were directly considered for contact without any provisions made for offsets due to the beam cross section.

• For contact with other beams (beam-to-beam contact), an equivalent contact radius was taken into account thereby considering all beams were considered to be circular cross sections.

• The algorithm was unable to model internal contact of beams with beams (Tube-in-tube contact)

The MSC Nastran 2016 release supports beam contact via the segment-to-segment contact algorithm. All the issues mentioned above are handled through the creation of beam segments which participate in the contact. This is facilitated by the automatic expansion of beam elements to accurately capture their cross-section geomtery when contacting each other or rigid bodies or deformable bodies. The expanded representation of the pipe and beam elements takes the following into account:

• Current position of the beam based on the beam nodal coordinates. • Cross section of the beam • Orientation of the beam • Offsets at the beam nodes

All MSC Nastran beam cross sections (circular tubes, regular solid sections, arbitrary solid sections, thin-walled open sections) are supported when using the PBARL and PBEAML options. By default, all faces on a beam are treated as patches. For example, a square section would have 4, an I-Beam would have 12, and a solid circular section would have, by default, 32 patches. Full control over the beam patches to be created is also provided in order to reduce the computational cost of contact through the use of BCPFLG. Control is also provided for beam ends and beam junctions using the BCSCAP option. The BCSCAP is used to control the number of patches for circular solid beams and pipes. Contact penalty stiffness and contact forces are automatically transferred from the segment positions to the beam nodes via internally generated constraint equations. The option is automatically selected when using geometrically defined beams and activating the segment-to-segment contact option. Large displacements and rotations may be modeled using SOL 400, but there are no changes in the geometry of the cross section.

Index

49 MSC Nastran 2016 Release GuideBeam Contact

Main

See BCPFLG (p. 1350) in the MSC Nastran Quick Reference Guide for more information.

LimitationThe beam contact capability is not available when using arbitrary cross sections using the ARBMODEL option.

Beam-to-Beam segment contact stresses are not available for postprocessing in *.t19 files.

Test CasesFollowing test cases are available in tpl/nl400cn

• cnbeam4.dat

Index

http://www.mscsoftware.com/doc/nastran/2016/release/cnbeam4.dat

50Advanced Nonlinear (SOL 400)Interference Fit

Main

Interference Fit This feature can be used to simulate situations where bodies in contact initially have large gaps or overlaps (interference), and the program should remove these gaps or overlaps. In the previous release, MSC Nastran only supported a small value of interference which was removed in a single increment. The use of a single increment constrained the usage to very interference distances.

BenefitAccurate resolution of large initial geometric interference.

FunctionalityThere are now four new methods available to remove an initial interference between contacting bodies. They are applicable to both node-to-segment contact and segment-to-segment contact. The methods are:

1. Contact Normal

2. Translation

3. Scaling

4. Automatic

The Contact Normal method is useful for situations with small values of interference to be resolved along the normal direction of the touched surface. The user can control the number of increments or the amount of time during which the resolution of interference fit is to be achieved. Methods 2 to 4 are more general and allow larger amounts of overlap between the touching and touched bodies. The general scheme for these methods is to specify an initial artificial movement of one of the overlapping bodies such that the overlap is removed. This is followed by a gradual removal of the artificial movement such that the interference fit is achieved. Except for the Automatic option, the user specifies this artificial movement for one of the overlapping bodies and a ramp down table which defines the variation of the artificial movement. For the Automatic option, MSC Nastran computes an initial penetration of a contact body which is then resolved by specifying a ramp down table. The picture below shows an example with a large overlap, which is resolved with ten increments. The information about the interference fit is defined in the BCONPRG option.

Test CasesFollowing test cases are available in tpl/nl400cn

• cnint1.dat

• cnint2.dat

Index

http://www.mscsoftware.com/doc/nastran/2016/release/cnint1.dat

http://www.mscsoftware.com/doc/nastran/2016/release/cnint2.dat

51 MSC Nastran 2016 Release GuideInterference Fit

Main

See BCONPRG (p. 1294) in the MSC Nastran Quick Reference Guide for more information.

For an example of the interference between a connecting rod and a piston, see MSC Nastran Demonstration Problems Manual, Chapter 98.

Index

52Advanced Nonlinear (SOL 400)Maintaining Geometric Clearance

Main

Maintaining Geometric ClearanceThe Interference Fit option, which gradually removes a large overlap between contact bodies, can be extended to support initial gaps or clearance between contact bodies. With this Initial Gap option, the nodes of a touching body are projected onto the nearest segment of the touched body, resulting in a distance vector at a touching node. This distance vector is then modified to accommodate the user-specified gap or overlap and used to adjust the surface of the corresponding contact body without actually repositioning the nodes (as would be done by stress-free initial contact). During the analysis, the distance vector is continuously updated based on the displacement and the rotation of the associated node. The information about the initial gap and overlap is defined in the BCONPRG option.

BenefitAllows the user to the update thickness of one component without having to readjust coordinate positions.

Accounts for inaccuracies in the CAD modeling or mesh creation.

UsageThe clearance option is invoked by the OGINGP parameter on the BCONPRG option. For contact, one conventionally defines the error tolerance (ERROR on BCONPRG or BCPARA)) which is used to control when bodies are going to be in contact and how much penetration is going to be acceptable. This is usually a very small distance. Here, the clearance is likely to be substantially larger and hence one must give a search distance, known as TOLINGP. This defaults to 100 times the ERROR distance, but this is likely not to be sufficient. One can also indicate when the clearance constraint going to be implemented through the use of MGINGP.

The most natural and common is setting MGINGP to zero in which case the clearance is not changed from the distance between the original coordinate positions of the nodes. This is call the distance D0.

When MGINGP is > 0l, it means the distance between the bodies can shrink (i.e., the bodies can get closer together), but when the distance reaches D0 – MGINGP. The clearance condition is satisfied and this clearance distance (D0 –

MGINGP ) is preserved.

When MGINGP is < 0, it means that it considers the bodies to be overlapping. So it first tries to separate them by a distance = |MGINGP|; then it imposes the clearance condition such that the clearance distance is D0 + |MGINGP|.

Note that this option is available for both node-to-segment and segment-to-segment contact for small deformation simulations. When the rotations are large, the solution is not accurate.

Index

53 MSC Nastran 2016 Release GuideMaintaining Geometric Clearance

Main

ExampleThe following example shows a shell cylinder with another cylinder of a shorter length. There is a clearance between the two cylinders including the shell thickness. This clearance is to be maintained. When the inner cylinder is inflated, then the outer cylinder expands as well with the clearance being maintained.

This capability is available for all geometries, and the initial clearance distance does not need to be uniform. For example, in the following figure, a rigid body is glued to contact body 1 and is moved in the y-direction. The clearance between the two bodies remains uniform.

An additional exampled demonstrating the clearance between a bracket and a shell is found in the MSC Nastran Demonstration Problems Manual, Chapter 97.

Index

54Advanced Nonlinear (SOL 400)Contact Separation

Main

Contact SeparationIn MSC Nastran 2016 the default value of NODSEP of the BCPARA bulk data has been changed from 2 to 5. This controls the checking for separation after a node contacts and separates during the Newton-Rhapson iteration within an increment. The value of 2 was felt to be too low to always obtain accurate solutions. It should be noted that by increasing the value of NODSEP, the number of iterations may increase, resulting in greater computational costs. When the segment-to-segment procedure is used NODSEP is not used.

Index

55 MSC Nastran 2016 Release GuideRC Network Heat Transfer Analysis

Main

RC Network Heat Transfer AnalysisIn the MSC Nastran 2016 release, a few options are no longer supported for heat transfer using the RC Network approach.

If a steady state analysis is performed, using either both the Case Control, ANALYSIS=RCNS and NLSTEP or RCPARM, then the following SOLVER types are no longer supported:

• SSQMR

• SSSPM

If a transient analysis is performed, using either both the Case Control, ANALYSIS=RCNT and NLSTEP or RCPARM, then the following SOLVER types are no longer supported:

• TRSPM

• ATSSPM

• TRQMR

• ATSQMR

Index

Main

Chapter 5: 3-D Rotordynamics MSC Nastran 2016 Release Guide

5 3-D Rotordynamics

3-D Rotordynamics in MSC Nastran 57

Index

57 MSC Nastran 2016 Release Guide3-D Rotordynamics in MSC Nastran

Main

3-D Rotordynamics in MSC NastranFor the past few years, MSC Nastran has supported 1-D rotordynamics using beam/bar elements which is widely used by turbines, jet engine, and airplane manufacturers. The rotordynamics capability allows the user to perform static analysis, obtain real and complex eigenvalues, and determine frequency response and transient response. The 1-D implementation had the limitations that it cannot be used to model complex rotor geometry, and the blades in this analysis are treated as rigid. In MSC Nastran 2013.1, MSC added 2-D rotordynamics capability which allows the usage of axisymmetric harmonic elements. This removed some of these issues; however, it is applicable only where the rotor is axisymmetric.

In order to obtain greater accuracy, use of full 3-D models is required which can be used to perform more detailed analysis of rotors and their support structure. The 3-D capability allows the user to model discrete blades and non-symmetric components of rotors and stators. In the current release, both the fixed and rotating reference frame is supported. (Note that only one reference frame can be selected in a single analysis)

Besides this, several other enhancements have been made in rotordynamic analysis:

a. The user can optionally suppress the effect of the circulation matrix for damping defined in rotors in fixed reference frame.

b. For 3-D rotors in the rotating reference frame, effects of stress stiffening (differential stiffness) can be incorporated in the analysis.

BenefitsResults obtained highlight that the analysis with solid and shell elements capture more flexible modes which cannot be obtained with 1-D or axisymmetric harmonic elements. Many existing MSC Nastran elements have been enhanced for rotordynamics, so standard preprocessing and postprocessing tools like Patran and SimXpert can be used. Analysis in the rotating system is suitable for the study of damages/defect in rotors. Analysis in the fixed system using 3-D solid/shell elements is suitable when the model has an axisymmetric rotating component.

Also, damping for rotors has been revised to make it consistent for all the three kinds of rotors supported in MSC Nastran, namely: ROTORG, ROTORAX, and ROTOR. Hybrid damping is now consistently defined for 1-D, 2-D, and 3-D rotors using the new ROTHYBD bulk data entry. For a 3-D rotor defined using solid and shell elements, the effect of stress stiffening (differential stiffness) can be included in the analysis in the rotating reference frame. This is often required for large flexible disks and blades. For axisymmetric harmonic rotors, the user interface for attaching a concentrated mass has been simplified in this release.

The MSC Nastran 2016 release also includes a detailed rotordynamics manual which describes the current rotordynamics capabilities in MSC Nastran.

Index

583-D Rotordynamics3-D Rotordynamics in MSC Nastran

Main

User Interface

New Bulk Data Entry

Specifies list of grids, elements, or properties that comprise the rotor 3-D model.

Format:

Example:

Remarks:

1. Supported element types for analysis in rotating reference frame:

0-D elements : CONM1, CONM2

1-D elements : CBEAM, CBAR

2-D elements : CQUAD4, CQUAD8, CTRIA3, CTRIA6

3-D elements : CHEXA, CPENTA, CTETRA

ROTOR Rotor Model Definition

1 2 3 4 5 6 7 8 9 10

ROTOR ROTORID FRAME

LTYPE ID1 ID2 ID3 etc.

AXIS GID1 GID2 etc.

ROTOR 10 ROT

ELEM 10 THRU 12

PROP 1 THRU 5

AXIS 101 102

Field Contents

ROTORID Identification number of rotor. (Integer > 0).

FRAME Analysis frame (Char, ROT or FIX, Required, Default: FIX)

LTYPE ELEM or PROP or both, indicating whether the specified list references element IDs or property IDs. (Character; Required; No default)

Note that the order is important. In case both ELEM and PROP are specified, ELEM should be specified first.

Idi IDs of elements or properties comprising the rotor. (Integer > 0; Required; No default)

AXIS Defines grid points which define the axis of rotation.

GIDi IDs of grids comprising the axis of the rotor (Integer > 0; Required; No default)

Index


Main

2. Supported element types for analysis in fixed reference frame:

0-D elements : CONM1, CONM2

1-D elements : CBEAM, CBAR

2-D elements : CQUAD4, CQUAD8 (full 8 nodes are required), CTRIA6(full 6 nodes required), CTRIA3

3-D elements : CHEXA, CPENTA, CTETRA

3. THRU option is supported in ROTOR entry. Note that the order is important for LTYPE. In case both ELEM and PROP are specified, ELEM should be specified first.

4. Analysis can be performed using coupled mass or diagonal mass for all the elements.

5. ROTORAX, ROTORG, and ROTORSE should not be used along with ROTOR in ROT frame. They can only be used with ROTOR in FIX frame. (since ROTORAX, ROTORG, and ROTORSE assume fixed reference frame.)

6. At least 2 grid points need to be defined on AXIS to complete ROTOR definition; these points may not be part of rotor.

7. For unbalance loads, the grid point, at which UNBALNC is defined, should be part of ROTOR AXIS list.

8. In order to include CONM1/2 elements as part of a rotor, its element ID should be listed using ELEM in ROTOR definition.

9. Stator portion of the model should only be defined in residual for external superelement runs in rotating system.

Index


Main

New Bulk Data Entry

Specifies hybrid damping data for rotors.

Format:

Examples:

Remarks:

1. ROTORIDi - HYBDAMPi pair values referencing non-existent rotors are ignored.

2. If there is no HYBDAMP entry defined in the data for a HYBDAMPi specified for a valid ROTORIDi, the program terminates the execution with an appropriate fatal error.

3. Hybrid damping can result in very densely populated damping matrix causing significant performance penalty.

New PARAM Entry

WHIRLOPT

Default = FWD

Control forward whirl or backward whirl analysis for SYNC option in SOL 107 and SOL 108.

Usage:

PARAM, WHIRLOPT, FWD: For forward whirl analysis

PARAM, WHIRLOPT, BWD: For backward analysis

ROTHYBD Hybrid damping for rotors

1 2 3 4 5 6 7 8 9 10

ROTHYBD ROTORID1 HYBDAMP1 ROTORID2 HYBDAMP2

ROTHYBD 1 15

ROTHYBD 10 100 20 200 30 300

Field Contents

ROTORIDi Identification number of rotor. (Integer > 0). See Remarks 1 and 2.

HYBDAMPi Identification number of a HYBDAMP entry defining hybrid modal damping data. (Integer > 0). See Remarks 1 and 2.

Index


Main

Modification to an Existing Entry

Modification to MDLPRM

New entry for table (Addition to 8-47 PARAMi Names and Descriptions)

These features can also be accessed using system cell 695.

Feature DescriptionAs described in the previous section, a new entry "ROTOR" is introduced for defining components of a 3-D rotor and for identifying the axis of rotation. Functionality of the rest of the entries used in rotordynamics (RSPINR, RSPINT, RGYRO) are unchanged.

MSC Nastran elements that are supported in 3-D rotor models for analysis in rotating reference frame are:

1. 0-D elements : CONM1, CONM2

2. 1-D elements : CBEAM, CBAR

3. 2-D elements : CQUAD4, CQUAD8, CTRIA3, CTRIA6 (full 6 nodes are required)

4. 3-D elements : CHEXA, CPENTA, CTETRA

MSC Nastran elements that are supported in 3-D rotor models for analysis in fixed reference frame are:

1. 0-D elements : CONM1, CONM2

2. 1-D elements : CBEAM, CBAR

3. 2-D elements : CQUAD4, CQUAD8 (full 8 nodes are required),CTRIA3, CTRIA6 (full 6 nodes are required)

4. 3-D elements : CHEXA, CPENTA, CTETRA

Solution sequences for which ROTOR entry is supported are listed here:

1. SOL 101, static analysis (RFORCE is supported for fixed reference frame only)

Name Description, Type, and Default Values

RDBOTH Parameter to select Rayleigh damping approach as implemented in V2005, Integer. A cumulative sum can be provided in case multiple features are desired in the analysis.

0 Uses current implementation for Rayleigh Damping as described in RSPINR/RSPINT entry description (Default)

1 Switch to V2005 implementation of Rayleigh damping where damping coefficients specified in the model through "PARAM, ALPHA1" and "PARAM, ALPHA2" are applied to the complete model and Rayleigh damping specified through "ALPHAR1" and "ALPHAR2" in RSPINR/RSPINT is set to 0.0.

2 Ignore circulation effects in rotordynamic analysis.

4 Include effect of stress stiffening using method = 1 (see RFORCE entry)

8 Include effect of stress stiffening using method = 2 (see RFORCE entry)

Index


Main

2. SOL 103, real eigenvalue analysis

3. SOL 107, complex eigenvalue analysis

4. SOL 108, frequency response

5. SOL 109, transient response

6. SOL 129, non-linear transient response

7. SOL 200, without sensitivity or optimization of the rotor

8. SOL 400, only for linear analysis with RIGID = LINEAR; no advanced elements are allowed in the rotor

Other features that are supported for 3-D rotors are listed here:

• Effect of stress (differential) stiffness for asynchronous analysis in rotating reference frame.

• Use of hybrid damping for all the rotors

• Option to suppress the effect of the circulation matrix for damping defined on rotors for analysis in fixed reference frame.

• Unbalanced loads for frequency response and transient analysis.

• Static and dynamic reduction for the full rotor model

• External superelement analysis

• Permanent glued contact usage

• Support for composite material

• Includes effect of damping

ExamplesAll the test cases described here can be obtained from "../tpl/3drot" directory.

Test cases for analysis in rotating reference frame

In order to validate this capability, a rotor model is created using solid and shell elements as shown in Figure 5-1.

Index


Main

Figure 5-1 Model with Shell and Solid Elements (for Analysis in Rotating System)

For the purpose of comparison, the rotor-disk configuration shown in Figure 5-1 is also modeled using bar elements. Here, the disk is treated as rigid and modeled using a CONM2 element. Critical frequencies obtained from this bar model in the fixed system are listed in Table 5-1.

Critical frequencies in rotating system are shown in Table 5-2. Backward whirl analysis in synchronous analysis (for SOL 107 and SOL 108) is triggered by using following PARAM entry:

PARAM WHIRLOPT BWD

Table 5-1 Critical Frequencies for Bar Model in Fixed System

Mode Critical Frequencies (Hz)

First backward whirl 7.08

First forward whirl 10.22

Second forward whirl 10.74

Second backward whirl 25.5

Table 5-2 Critical Frequencies for Bar and Solid Model in Rotating System

Mode Critical Frequencies (Hz)

3-D model WHIRLOPT=FWD

3-D model BWD Bar Elm FWD Bar Elm BWD

First backward whirl 6.5 6.58

First forward whirl 9.19 9.23

Second forward whirl 10.77 10.74

Second backward whirl

21.88 23.43

Index


Main

Results presented in Table 5-1 and Table 5-2 indicate that the analysis in rotating system using models with bar and solid elements captures the critical frequencies obtained from the analysis in fixed system. Mode shapes corresponding to first four forward whirling modes obtained for the solid model are shown in Figure 5-2.

Figure 5-2 Model with Shell and Solid Elements (for Analysis in Rotating System)

The output includes mass summaries for each rotor defined. Mass summaries provided by different rotors are listed below:

a. ROTORG defined using bar elements in fixed system

MASS PROPERTIES OF ROTOR 400 GRID ID AXIAL MASS TRANSVERSE MASS POLAR MOMENT TRANSVERSE MOMENT -------------------------------------------------------------------------------------------------- ALL 2.29585E+03 2.29585E+03 3.75800E+05 2.26615E+05

b. ROTOR defined using bar elements in rotating system

MASS PROPERTIES OF ROTOR 400

-------------------------------------------------------------------------------- AXIAL MASS TRANSVERSE MASS POLAR MOMENT TRANSVERSE MOMENT -------------------------------------------------------------------------------- 2.29585E+03 2.29585E+03 3.75800E+05 2.26615E+05 --------------------------------------------------------------------------------

c. ROTOR defined using solid/shell elements in rotating system

MASS PROPERTIES OF ROTOR 11

-------------------------------------------------------------------------------- AXIAL MASS TRANSVERSE MASS POLAR MOMENT TRANSVERSE MOMENT -------------------------------------------------------------------------------- 2.29021E+03 2.29021E+03 0.00000E+00 4.19333E+05 --------------------------------------------------------------------------------

Index


Main

Input Decks

Rotor model with bar in fixed system (ROTORG): rg107a1.dat

Rotor model with bar in rotating system for forward whirl speed: r3d107e1.dat

Rotor model with bar in rotating system for backward whirl speed: r3d107e2.dat

Campbell diagram for rotor model with solid/shell in rotating system: r3d107f1.dat

Critical frequencies for rotor model with solid/shell in rotating system (forward whirl) : r3d107f2.dat

Critical frequencies for rotor model with solid/shell in rotating system (backward whirl): r3d107f3.dat

Reduction using ASET and QSET Degrees of Freedom

The solid rotor model analyzed earlier and shown in Figure 5-1 is modified here to include springs at the end to represent symmetric bearings. The following changes were made in the Case Control and Bulk Data sections to create a dynamically reduced model.

In case control:

METHOD = 3000

In Bulk Data:

EIGRL 3000 50PARAM AUTOQSET YESASET1 123456 9101 9100

Model without reduction: r3d107g1.dat

Model with reduction: r3d107g2.dat

The reduced model includes two grid points as part of ASET DOFs and AUTOQSET option for normal modes. Critical frequencies obtained for the model with and without reduction are listed in Table 5-3. For this model, dynamic reduction resulted in a 20% reduction in computational time.

Note: The transverse moment is determined about the origin and the starting point for solid model is not at the origin.

Table 5-3 Effect of Dynamic Reduction

Critical Frequencies (Hz)

Mode Number Without Reduction With Reduction

1 35.32 NA

2 31.88 31.88

3 42.92 42.92

4 98.52 98.52

5 101.48 101.48

Index

http://www.mscsoftware.com/doc/nastran/2016/release/rg107a1.dat

http://www.mscsoftware.com/doc/nastran/2016/release/r3d107e1.dat


http://www.mscsoftware.com/doc/nastran/2016/release/r3d107f1.dat



http://www.mscsoftware.com/doc/nastran/2016/release/r3d107g1.dat



Main

Unbalanced Response (SOL 108)

The frequency response was performed on the solid model by applying an unbalanced load at the center of the disk. The variation of the unbalanced load with rotational speed (frequency) is shown Figure 5-3.

Figure 5-3 Unbalanced Loads

Frequency response for the tip displacement for different damping options is shown in Figure 5-4. Backward whirl analysis is triggered by using following PARAM entry:

PARAM WHIRLOPT BWD

6 145.46 145.46

7 147.51 147.51

8 171.58 171.58

Table 5-3 Effect of Dynamic Reduction (continued)

Critical Frequencies (Hz)

Mode Number Without Reduction With Reduction

Index


Main

Figure 5-4 Unbalanced Response

Forward whirl analysis shows a peak at the first forward critical frequency while the backward whirl analysis shows a peak at the second backward critical frequency. The effect of damping depends on the analysis option selected. Damping is specified in the analysis in the rotating frame using RSPINR entry. Gyroavg = -1 is the fast approach.

Undamped forward whirl: r3d108a1.dat

Damped forward whirl, gyroavg = 0 : r3d108a2.dat

Damped forward whirl, gyroavg = -1: r3d108a3.dat

Undamped backward whirl: r3d108a4.dat

Damped backward whirl, gyroavg = 0 : r3d108a5.dat

Damped backward whirl, gyroavg = -1: r3d108a6.dat

Transient Response

Transient response was performed by applying a time-dependent force at the center of the disk. Analysis was performed for three different cases:

• zero rotor speed (r3d109a1.dat)

• nonzero rotor speed (r3d109a2.dat)

• nonzero rotor speed with damping (r3d109a3.dat)

The results obtained for variation of load and displacement for a time-dependent force are shown in Figure 5-5. The results obtained highlight the effect of rotor speed and damping on transient response. Damping is specified in the analysis in rotating frame using RSPINT entry.

Index

http://www.mscsoftware.com/doc/nastran/2016/release/r3d108a1.dat










Main

Figure 5-5 Transient Response

External Superelements

The stator portion of the model should be defined only in the residual for external superelement analysis in rotating system.

Here also the model described in Figure 5-1 is modified and spring supports are used at the end. In order to validate the external superelement capability, the complete rotor is defined in the external superelement for this particular example and spring supports and rotor usage entries are defined in the assembly run. The results obtained are compared with single-shot run, see Table 5-4. The external superelement usage for 3-D rotors is the same as that for other rotors (ROTORAX and ROTORG).

Creation Run: r3d103h1.dat

ROTOR 11 ROT PROP 1 2 3 AXIS 900001 900002

Assembly Run: r3d107h2.dat

Single Shot Run: r3d107h3.dat

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-1

-0.5

0

0.5

1x 10

5

Time (s)

App

lied

Lo

ad

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-0.01

-0.005

0

0.005

0.01

Time (s)

Dis

pla

cem

ent

Rotor at 0 RPMWithout DampingWith Damping

Index

http://www.mscsoftware.com/doc/nastran/2016/release/r3d107h2.dat




Main

Permanent Glue

The 3-D rotordynamics capability implemented also supports permanent glued contact for rotor components. The model used for the analysis is shown in Figure 5-6. The rotor definition does not change due to the presence of permanent glued contact. The frequencies obtained from complex eigenvalue analysis at different rotation speed (Table 5-5) show no change in results.

Connected Rotor: r3d107i1.dat

Disconnected rotor with permanent glue: r3d107i2.dat

Figure 5-6 Rotor Model with Permanent Glue Contact

Table 5-4 Complex Frequencies from SOL 107 Analysis for Rotor in EXTSE

Single Shot (Hz) EXTSE Assembly (Hz)

0 RPM 6000 RPM 0 RPM 6000 RPM

1.02 31.88 1.02 31.88

1.02 31.88 1.02 31.88

3.25 42.92 3.25 42.92

3.25 98.52 3.25 98.52

3.62 101.48 3.62 101.48

42.93 145.46 42.93 145.46

78.36 147.51 78.36 147.51

78.36 171.58 78.36 171.58

Index

http://www.mscsoftware.com/doc/nastran/2016/release/r3d107i1.dat



Main

Test Cases for Analysis in Fixed Reference FrameIn order to validate the analysis in fixed reference frame, the hollow rotor model shown in Figure 5-7 is used for the analysis. This model is meshed using different types of solid and shell elements to validate the implementation.

Figure 5-7 Hollow Rotor Model

Complex Eigenvalue Analysis using Solid Elements

Input Decks:

r3d107k1.dat :With 8-noded CHEXA elements (Campbell Diagram)

r3d107k2.dat :With 20-noded CHEXA elements (Campbell Diagram)

rotg107.dat : Model using beam elements and ROTORG (Synchronous Analysis)

r3d107m1.dat : Model using 8-noded CHEXA elements (Synchronous Analysis)

r3d107m2.dat : Model using 20-noded CHEXA elements (Synchronous Analysis)

r3d107m3.dat : Model using CPENTA elements (Synchronous Analysis)

r3d107m4.dat : Model using 4-noded CTETRA elements (Synchronous Analysis)

r3d107m5.dat : Model using 10-noded CTETRA elements (Synchronous Analysis)

Table 5-5 Complex Freq (Hz) for Connected Rotor and Disconnected Rotor using Permanent Glue

For Connected Rotor Using Permanent Glue

0 RPM 10000 RPM 0 RPM 10000 RPM

268.5 106.8 268.5 106.8

268.5 425.9 268.5 425.9

776.5 615.4 776.5 615.4

776.5 936.3 776.5 936.3

1006.1 992.0 1006.1 992.0

1297.1 1155.9 1297.1 1155.9

1298.0 1434.7 1298.0 1434.7

1457.9 1449.7 1457.9 1449.7

1885.7 1732.6 1885.7 1732.6

1886.1 2039.0 1886.1 2039.0

Index

http://www.mscsoftware.com/doc/nastran/2016/release/r3d107m3.dat

http://www.mscsoftware.com/doc/nastran/2016/release/r3d107k1.dat


http://www.mscsoftware.com/doc/nastran/2016/release/rotg107.dat






Main

Campbell diagram obtained using solid elements is shown in Figure 5-8. Here, the results obtained are compared with those obtained using beam element (shown in SOLID lines)

Figure 5-8 Campbell Diagram for Hollow Solid Rotor

The number of elements used in the different finite element models is listed in Table 5-6. Critical frequencies for the hollow rotor meshed using different kinds of solid elements are shown in Table 5-7. Here it can be seen that the results for different cases are very close. Variation in results is due to different mesh densities and number of grids per element used in the analysis.

Table 5-6 Finite Element Model Details

Model Number of Elements Number of Grids

Beam 10 12

Hex-20 200 1567

Hex-8 1600 3002

Tet-10 8000 15064

Tet-4 600 293

Penta-6 3200 2600

Table 5-7 Critical Frequencies for Hollow Rotor Meshed using Solid Elements (Hz)

Mode Beam Hex-20 Hex-8 Tet-10 Tet-4 Penta

1 75.53 74.86 75.80 75.20 87.42 75.80

2 76.03 75.35 76.30 75.69 87.76 76.22

Index


Main

Frequency Response for Rotor Defined using Solid Elements in Fixed System

Input Decks:

r3d108m1.dat : Rotor with 8-noded CHEXA elements, undamped

r3d108m2.dat : Rotor with 8-noded CHEXA elements, damped without circulation

r3d108m3.dat : Rotor with 20-noded CHEXA elements, undamped

r3d108m4.dat : Rotor with 20-noded CHEXA elements, damped without circulation

Frequency response for unbalance loads obtained for the undamped case using SOL 108 analysis is shown in Figure 5-9. In all the cases, peaks are observed near forward whirl critical speeds, which is around 76 Hz and 460 Hz (see Table 5-7).

3 447.7 441.75 446.14 444.03 520.24 447.39

4 466.71 460.72 465.72 463.13 533.58 463.85

5 785.9 784.69 784.51 774.69 1143.93 784.89

6 1164.13 1140.28 1147.68 1146.87 1276.36 1154.87

7 1263.06 1246.58 1256.69 1254.18 1360.07 1246.32

8 1267.23 1266.47 1266.29 1266.39 1434.49 1266.72

9 2092.12 2026.15 2031.23 2038.91 2456.04 2051.63

10 2356.52 2341.17 2351.88 2343.59 2675.34 2320.07

Table 5-7 Critical Frequencies for Hollow Rotor Meshed using Solid Elements (Hz) (continued)

Mode Beam Hex-20 Hex-8 Tet-10 Tet-4 Penta

Index






Main

Figure 5-9 Frequency Response for Undamped Rotors

Structural damping of 0.05 is introduced for the rotor through the RSPINR entry. Frequency response for the damped cases is shown in Figure 5-10, where consistent results are obtained for the beam and solid rotor. For these analysis, circulation effects are not included in the analysis (nastran system(695)=2).

Figure 5-10 Amplitude for Damped Case for 3-D Rotor

Index


Main

Test Decks:

r1d101m1.dat : Beam rotor, static analysis

r1d129m1.dat : Transient response for beam rotor using SOL 129

r1d400m1.dat : Transient response for beam rotor using SOL 400

r3d109m1.dat : Transient response for solid rotor with 8-noded CHEXA elements using SOL 109






Transient response to ramp-force for different kinds of rotors is shown in Figure 5-11. Results obtained using SOL 109, SOL 129, and SOL 400 are close for all the rotors considered.

Figure 5-11 Transient Response for 3-D Rotors using Different Solution Sequences

Rotor with Shell Elements

Test Decks:

r3d107n1.dat : Rotor with CQUAD4 shell elements, Campbell Diagram

r3d107n2.dat : Rotor with CQUAD4 shell elements, Critical Frequencies

r3d107n3.dat : Rotor with 8-noded CQUAD8 shell elements, Campbell Diagram

r3d107n4.dat : Rotor with 8-noded CQUAD8 shell elements, Critical Frequencies

r3d107n5.dat : Rotor with CTRIA6 shell elements, Campbell Diagram

r3d107n6.dat : Rotor with CTRIA6 shell elements, Critical Frequencies

Index

http://www.mscsoftware.com/doc/nastran/2016/release/r3d107n5.dat
















Main

r3d107n7.dat : Rotor with 8-noded CTRIA3 shell elements, Campbell Diagram

r3d107n8.dat : Rotor with 8-noded CTRIA3 shell elements, Critical Frequencies

Results for critical frequencies for a rotor defined using shell elements are shown in Table 5-8 and compared with those obtained using a rotor model developed using axisymmetric harmonic elements. Results indicate that the shell model captures various local deformation modes which could not be captured using an axisymmetric rotor model. Corresponding Campbell diagram and mode shapes are shown in Figure 5-12 and Figure 5-13.

Table 5-8 Critical Frequencies for Hollow Rotor Meshed using Shell Elements

Axis CQUAD4 CQUAD8 CTRIA3 CTRIA6

1 17.50 17.18 17.24 17.28 17.24

2 17.60 17.30 17.36 17.40 17.36

3 101.40 99.75 100.01 100.24 100.03

4 106.10 104.23 104.53 104.72 104.56

5 108.13 106.74 109.79 106.55

6 108.29 106.91 109.95 106.70

7 113.58 112.23 115.59 112.13

8 114.69 113.40 116.73 113.22

9 143.42 142.21 146.97 142.37

10 146.69 145.66 150.34 145.59

11 171.89 172.14 171.59 171.63

12 207.95 206.61 214.12 207.18

13 216.33 215.44 222.76 215.43

14 257.00 252.89 253.33 253.99 253.37

15 282.00 276.61 277.18 277.61 277.27

Index




Main

Figure 5-12 Campbell Diagram for Rotor with Shell Elements

Index


Main

Figure 5-13 Modeshapes for Shell Rotor Model

Index


Main

3-D Rotor with Both Solid and Shell Elements

Test Decks:

r1d107p1.dat : ROTORG with bar elements, Campbell Diagram

r3d107p1.dat : ROTOR with solid and shell elements, Campbell Diagram

The model shown in Figure 5-1 developed using solid and shell elements was analyzed again in the fixed reference frame. Results for the 3-D rotor are compared with those obtained using 1-D bar elements and a concentrated mass. Campbell diagram for this case is shown in Figure 5-14, while the corresponding mode shapes are shown in Figure 5-15.

Figure 5-14 Campbell diagram for 3-D rotor with disk

Index

http://www.mscsoftware.com/doc/nastran/2016/release/r1d107p1.dat



Main

Figure 5-15 Modeshapes for the Disk-rotor Model

Stress Stiffening for 3-D Rotors

Test Decks:

r3d107q3.dat : Rotor with shell elements in rotating reference frame with stress stiffness

r3d107q4.dat : Rotor with shell elements in rotating reference frame without stress stiffness

Effects of stress stiffening are important for 3-D rotors, especially when the model includes large flexible structure away from the axis of rotating, high rotational speeds and/or large diameter blades. In order to demonstrate its effect, a hollow shell rotor model (similar to that shown in Figure 5-7) is analyzed in rotating reference frame. Results shown in Figure 5-16 highlight the increase in stiffness with increase in rotor speed.

Index

http://www.mscsoftware.com/doc/nastran/2016/release/r3d107q3.dat



Main

Figure 5-16 Effect of Stress Stiffness in Rotating Reference Frame

Rotor Model with All Three Rotor Types

Test Deck: r3d107s1.dat : Test deck with ROTORG, ROTORAX, and ROTOR.

When the analysis is performed in fixed reference frame, all the three types of rotors supported in MSC Nastran can be included in a model. For this particular case, the mass summary produced in .f06 file is shown in Figure 5-17.

$ ----- Including 3D rotor ---------------------------ROTOR 11 FIXPROP 101AXIS 3001 3002$ ------ Axisymmetric Rotor (ROTORAX) Definition -------ROTORAX,10,PROP,1ROTORAX,10,GRID,61,62$ ------ Beam Rotor (RotorG) Defintion -----ROTORG 400 501 THRU 507

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 105

500

1000

1500

2000

Rotor Speed (RPM)

Fre

qu

en

cy (

Hz)

1PMode 1Mode 2Mode 3Mode 4Mode 5Mode 6

Solid Line: without stress stiffeningDotted Lines: with stress stiffening

Index

http://www.mscsoftware.com/doc/nastran/2016/release/r3d107s1.dat


Main

Figure 5-17 Mass Summary for Different Types of Rotors

Guidelines and Known LimitationsThe main guidelines to be followed while working with 3-D rotors are listed under the Remarks section of the ROTOR entry.

Theoretical limitations for the analyses that can be performed in rotating system are:

a. Multiple rotors at different speeds are not allowed, all the rotors must have the same speed.

b. The supports attached to the rotor must be axisymmetric.

Theoretical limitations for analyses that can be performed in fixed reference frame are:

a. The rotating component of the model must be axisymmetric.

These checks are not performed in the current implementation, and it is the responsibility of the user to ensure that these criteria are satisfied to obtain correct results.

Index


Main

Implementation limitations of the analysis are:

1. For SOL 400, only RIGID = LINEAR option is supported. The default option in SOL 400 is RIGID = LAGRAN, and it needs to be modified for SOL 400 runs. No advanced elements should be used in the rotor.

2. For SOL 200, optimization is currently not supported for rotors. Users can only use rotordynamics in SOL 200 for analysis purposes.

3. For complex eigenvalue analysis, use of CLAN is recommended. Other options like HESS and IRAM are not suitable for large problems usually encountered in 3-D rotor models.

4. AUTOSPC is off by default in SOL 400. This may cause models to fail when switching from a linear solution sequence.

5. In the current version, RFORCE is not implemented in SOL 101 for analysis in rotating reference frame.

6. Only permanent glue option is supported for rotordynamic analysis.

Example SummarySummary of all the test decks is provided in Table 5-9 and Table 5-10.

Table 5-9 Test Decks for Analysis in Rotating Reference Frame

Description Name

Rotor model with bar in fixed system (ROTORG) rg107a1.dat

Rotor model with bar in rotating system for forward whirl speed r3d107e1.dat

Rotor model with bar in rotating system for backward whirl speed r3d107e2.dat

Campbell diagram for rotor model with solid/shell in rotating system r3d107f1.dat

Critical frequencies for rotor model with solid/shell in rotating system (forward whirl) r3d107f2.dat

Critical frequencies for rotor model with solid/shell in rotating system (backward whirl) r3d107f3.dat

Model without reduction: r3d107g1.dat

Model with reduction: r3d107g2.dat

Undamped forward whirl r3d108a1.dat

Damped forward whirl, gyroavg = 0 r3d108a2.dat

Damped forward whirl, gyroavg = -1 r3d108a3.dat

Undamped backward whirl r3d108a4.dat

Damped backward whirl, gyroavg = 0 r3d108a5.dat

Damped backward whirl, gyroavg = -1 r3d108a6.dat

Transient Analysis for zero rotor speed r3d109a1.dat

Index

http://www.mscsoftware.com/doc/nastran/2016/release/rg107a1.dat
















Main

Transient Analysis for non-zero rotor speed r3d109a2.dat

Transient Analysis for non-zero rotor speed with damping r3d109a3.dat

Creation Run r3d103h1.dat

Assembly Run r3d107h2.dat

Single Shot Run r3d107h3.dat

Connected Rotor r3d107i1.dat

Disconnected rotor with permanent glue r3d107i2.dat

Model with composite material: r3d103a1.dat

Model using PSHELL: r3d103a2.dat

Rotorax with concentrated mass raxcnm2b.dat

Table 5-10 Summary of Test Decks for Analysis in Fixed Reference Frame

Description Name

With 8-noded CHEXA elements (Campbell Diagram) r3d107k1.dat

With 20-noded CHEXA elements (Campbell Diagram) r3d107k2.dat

Model using beam elements and ROTORG (Synchronous Analysis) rotg107.dat

Model using 8-noded CHEXA elements (Synchronous Analysis) r3d107m1.dat

Model using 20-noded CHEXA elements (Synchronous Analysis) r3d107m2.dat

Model using CPENTA elements (Synchronous Analysis) r3d107m3.dat

Model using 4-noded CTETRA elements (Synchronous Analysis) r3d107m4.dat

Model using 10-noded CTETRA elements (Synchronous Analysis) r3d107m5.dat

Beam Rotor, undamped r1d108m1.dat

Beam Rotor, damped without circulation r1d108m2.dat

Rotor with 8-noded CHEXA elements, undamped r3d108m1.dat

Rotor with 8-noded CHEXA elements, damped without circulation r3d108m2.dat

Rotor with 8-noded CHEXA elements, undamped r3d108m3.dat

Rotor with 8-noded CHEXA elements, damped without circulation r3d108m4.dat

Beam Rotor, static analysis r1d101m1.dat

Table 5-9 Test Decks for Analysis in Rotating Reference Frame (continued)

Description Name

Index










http://www.mscsoftware.com/doc/nastran/2016/release/raxcnm2b.dat



http://www.mscsoftware.com/doc/nastran/2016/release/rotg107.dat














Main

Transient response for Beam Rotor using SOL 129 r1d129m1.dat

Transient response for Beam Rotor using SOL 400 r1d400m1.dat

Transient response for Solid Rotor with 8-noded CHEXA elements using SOL 109 r3d109m1.dat






Rotor with Axisymmmetric Harmonic Elements, Campbell Diagram rax107n1.dat

Rotor with Axisymmmetric Harmonic Elements, Critical Frequencies rax107n2.dat

Rotor with CQUAD4 Shell Elements, Campbell Diagram r3d107n1.dat

Rotor with CQUAD4 Shell Elements, Critical Frequencies r3d107n2.dat

Rotor with 8-noded CQUAD8 Shell Elements, Campbell Diagram r3d107n3.dat

Rotor with 8-noded CQUAD8 Shell Elements, Critical Frequencies r3d107n4.dat

Rotor with CTRIA6 shell elements, Campbell Diagram r3d107n5.dat

Rotor with CTRIA6 shell elements, Critical Frequencies r3d107n6.dat

Rotor with 8-noded CTRIA3 shell elements, Campbell Diagram r3d107n7.dat

Rotor with 8-noded CTRIA3 shell elements, Critical Frequencies r3d107n8.dat

ROTORG with bar Elements, Campbell Diagram r1d107p1.dat

ROTOR with Solid and Shell elements, Campbell Diagram r3d107p1.dat

Rotor with Shell elements in rotating reference frame with stress stiffness r3d107q3.dat

Rotor with Shell elements in rotating reference frame without stress stiffness r3d107q4.dat

Test deck with ROTORG, ROTORAX, and ROTOR. r3d107s1.dat

Table 5-10 Summary of Test Decks for Analysis in Fixed Reference Frame (continued)

Description Name

Index












http://www.mscsoftware.com/doc/nastran/2016/release/rax107n1.dat

http://www.mscsoftware.com/doc/nastran/2016/release/rax107n2.dat









http://www.mscsoftware.com/doc/nastran/2016/release/r3d107s1.dat


Main


Chapter 6: Optimization

6 Optimization

Global Optimization 86

Multi Model Optimization 94

Weight as a Function of Material or Property ID 103

Index

86OptimizationGlobal Optimization

Main

Global OptimizationMSC Nastran has been supporting structural optimization via SOL 200 for many years. The technology built in SOL 200 uses gradient based optimization algorithms. Many industry optimization applications show that multiple local minima are often obtained when starting from differing initial starting points. This behavior is particularly evident in composite and dynamical response optimizations. Users often want to know whether the optimal design is a local or global optimum. If it is a local, how can they improve the local optimal design with limited computer resources? Mathematically speaking, it is impossible to find a global optimum unless all the possibilities in the design space are exhausted. However, numerically, it is desirable to have a practical global optimization procedure to find an approximate global solution with reasonable computing cost. MSC has developed a multi-start method to solve both unconstrained and constrained global optimization problems. It has four major aspects:

• The global design space is first approximated by a small but intelligent set of points that are derived using Design of Experiment (DOE) methods, such as orthogonal arrays, fractional or full factorial design techniques. This important step enables the subsequent local searches to be performed in a well-balanced but reduced design space.

• Heuristic techniques are applied to quickly find the global optimum. The basic rule is to always start a new local search from the point that has the largest distance from the current best local minimum point. A direct benefit of this is to minimize the number of repeated visits to the same region of attraction.

• A gradient-based optimization tool is used as the local search engine. Specifically, the powerful multidisciplinary design optimization capability in MSC Nastran SOL 200 is used

• Asymptotically correct condition or a user specified time budget is used to terminate the global search process.

More discussion of the method can be found in a paper titled "A Practical Global Optimization Procedure", AIAA-2003-1671, 2003.

BenefitsThe benefit to the user for the automated global optimization (GO) feature is that it combines automatic multi-start global methods and gradient based local optimization algorithms. The heuristics built into the global search algorithm allow users to explore better designs with relatively modest computing resources. It is expected that in certain applications of applying GO will provide surprising variability in the design task and this would provide deeper insight into the design process. GO can also be utilized to search for a feasible design when a local optimization SOL200 was unable to find one.

User InputFor GO applications, a standard MSC Nastran SOL 200 data file can be used to explore global optimization.

Invoking MultiOpt

GO and MMO are features in the program MultiOpt. MultiOpt is invoked using the following command line:

MSC20160 MultiOpt mygofile.xml (or mymmofile.xml)

Index

87 MSC Nastran 2016 Release GuideGlobal Optimization

Main

GO XML File Format

The GO input xml file (mygofile.xml) has this format:

<?xml version="1.0" ?><rc OptType="GO" debug="no"><Job name="deck" MEM="m" SMP="n" SCR="s" blocking="bopt"/><goparam variability="gopt" maxfea="mopt" nglsmax="nopt" fsave="fopt" minmax="mmopt"/></rc>

For example,

<?xml version="1.0" ?><rc OptType="GO" debug="no"><Job name="pcomp" mem="2GB" SCR="yes" blocking="3"/><goparam variability="uplo" maxfea="100" nglsmax="5" fsave="1"/></rc>

where

Option Description

OptType OptType="GO" must be used to perform global optimization

Debug "No" or "yes" (default = no). If turn on debug="yes", the program produces additional diagnostic messages.

Job name=“deck” Indicates the subsequent data is a job name. deck is the basename of the input data model (deck.dat or deck.bdf). No default

MEM=“m” Indicates the subsequent data is a memory request for this model. Integer = amount of memory requested (default=1GB)

SMP=“n” Indicates the number of processors used to efficiently obtain a solution to the simulation. The processors used will be on a single machine (default = no use of parallelization on shared memory tasks).

Scr="s" Option for scratch. Character = yes (default) or no. Scr=“yes” is recommended.

Blocking=“bopt” Indicates whether jobs run in parallel or serially. Integer bopt =1(default) runs the job serially while bopt=n enables running n local optimization jobs in parallel.

goparam Indicates the job has user specified GO control parameters (optional)

Variability Specifies how the global design space is sampled.

=Golden (default) the global design space is sampled at the points determined by Golden Section Ratios. This parameter is only applicable when the number of design variables is greater than 2. When NDV <=2, the design space is always sampled at the lower and upper limits of each design variable.

=Uplo the global design space is evaluated at the lower and upper limits of each design variable.

Note: User must define proper limits on the DESVAR

Index


Main

User OutputThere are four types of outputs from GO.

• A single summary output file multiopt.log that records the history of the search process. The local optimization and final global optimization results can be checked in that file.

• fn_go.dat is the global optimization job (fn is the basename of input model) with a sample design that produces the global optimal solution. The sample design (as a design variable include file) fn_xxxx_desvar.go is also saved for the global optimization.

• fsave="1" can be used to keep all local optimization results with a feasible design. fn_xxxx_desvar.go is a design variable include file containing DESVAR entries where xxxx is a four digit number indicating a particular design run. fn_xxxx.f06 is the local optimization result for the run.

• Patran (or third party postprocessor) can be used to view the global optimal design and optimization history from the best local optimization run.

GO ExampleIn order to validate the GO capability, a problem is obtained from the test problem library for Sol 200 (tpl/optim/d200c01.dat). The following figure shows a composite tube clamped at one end and free at the other end. The tube is built from a composite material with 8 plies. The outer layer pairs are initially at 85° orientations to the hoop direction while 4 core layers are at 60° orientations. The design task is to find the ply thickness and ply angles to minimize weight subject to Hill Failure criteria. The ply thickness is the first design variable and the ply angle of the inner and outer layer pairs and core layers are the remaining design variables . Originally, when the problem was solved with Sol 200, a local minimum solution was found. After the global optimization procedure is exercised, a global optimum solution has been found. See the following Result section for the detailed numbers.

Maxfea Indicates the maximum allowable number of finite element analyses. Integer >0 (default=500). This parameter controls the global search process. The procedure computes the total number of finite element analyses that is the sum of the number of finite element analyses performed for each local search. When the total number of FE analyses exceeds mopt, the GO process is terminated with the appropriate message

Nglsmax Indicates the maximum allowable number of consecutive local searches that do not produce an improved design. Integer (default=8). This parameter also controls the global search process. The global search procedure will be terminated when the number of consecutive local searches that do not produce an improved design exceeds the given nopt parameter.

Fsave By default (fsave=”0”), only the initial local optimization and the global optimization results are saved. If user want to save intermediate local optimization results that have feasible designs, fsave can be set to fsave=”1”

Minmax By default (minmax=”0”), GO explores global minimum objective. Otherwise, minmax=”1” searches for a global maximum objective.

Option Description

Index

http://www.mscsoftware.com/doc/nastran/2016/release/d200c01.dat


Main

The MultOpt input XML file can be found in the test problem library (tpl/go_opt/ d200c01.xml) as:

<?xml version="1.0" ?><rc OptType="GO" debug="no"> <Job name="d200c01" blocking="2"/></rc>

The summary file multiopt.log from this example problem is described below to provide a general discussion of the various output section in the file. Since the other types of files are basically regular MSC Nastran output file, they are not discussed here.

Initial Local Search

This section shows the result from the very first local search that is based on the original user input file. First, the header indicates initial local search. Then, it tabulates three design variables with the starting and final values, bounds, and labels. Finally, the objective and maximum constraint values are shown. This final design is marked as a feasible solution because the constraint value is less than the gmax (a parameter defined on DOPTPRM entry and its default is 0.005). The number of FE analyses used in this local search is also given.

**************************************************************************************** Initial Local Search **** ************************************************************************************

The starting design variables are from your input deck

desvar ID Label Starting Value Final Value Lower Bound Upper Bound ---------- --------- --------------- ----------- ------------- ------------ 1 TPLY 1.0000E+00 5.7385E-02 1.0000E-03 1.0000E+01 2 THETA 1.0000E+00 5.6849E-01 -1.0588E+00 1.0588E+00 3 THETA 1.0000E+00 1.6880E-01 -1.5000E+00 1.5000E+00

THIS IS THE FIRST LOCAL SEARCH BASED ON THE USER INPUT FILE

Index

http://www.mscsoftware.com/doc/nastran/2016/release/d200c01.xml


Main

OBJECTIVE = 9.1709E-02, MAXIMUM CONSTRAINT VALUE = 3.9210E-03 (A FEASIBLE SOLUTION). THE LOCAL SEARCH USED 17 FE ANALYSES.

Note that the actual ply angles are plus or minus 85.0 times the second design variable and plus or minus 60 times the second so that the plies can range from minus 90 to plus 90 degrees. Allowing ply angles to vary over such a broad range is known to result in local minima.

Design Point Table

This section lists the design table (sample points) used for local optimization search if debug=yes is used.

******************** Table of Design Points ********************

Design table is created using the DOE method. The last run is added by taking the center values of all design variables

desvar run 1 run 2 run 3 run 4 run 5 ----------- ----------- ----------- ----------- ----------- ----------- DV 1 7.500E+00 2.501E+00 7.500E+00 2.501E+00 7.500E+00 DV 2 5.294E-01 5.294E-01 -5.294E-01 -5.294E-01 5.294E-01 DV 3 7.500E-01 7.500E-01 7.500E-01 7.500E-01 -7.500E-01

desvar run 6 run 7 run 8 run 9 ----------- ----------- ----------- ----------- ----------- DV 1 2.501E+00 7.500E+00 2.501E+00 5.000E+00 DV 2 5.294E-01 -5.294E-01 -5.294E-01 0.000E+00 DV 3 -7.500E-01 -7.500E-01 -7.500E-01 0.000E+00

Subsequent Local Searches that Produce an Infeasible Solution

This section shows the result from the local search #1. It is actually the second local search if the very initial local search is included. The statement following the header indicates that design run #7 from the design table is used in this local search. If a local search produces an infeasible solution, the output section will indicate it accordingly. As shown here. Basically, the global search procedure simply discards such points and proceeds to another local search based on the new design run.

**************************************************************************************** Local Search # 1 **************************************************************************************** The starting design variables are from run # 7 desvar ID Label Starting Value Final Value Lower Bound Upper Bound ---------- --------- --------------- ----------- ------------- ------------ 1 TPLY 7.5003E+00 2.3414E-02 1.0000E-03 1.0000E+01 2 THETA -5.2941E-01 -3.6165E-02 -1.0588E+00 1.0588E+00 3 THETA -7.5000E-01 -6.9144E-02 -1.5000E+00 1.5000E+00

THIS LOCAL SEARCH DOES NOT PRODUCE A UNIQUE LOCAL MINIMUM. OBJECTIVE = 3.7419E-02, MAXIMUM CONSTRAINT VALUE = 8.9975E-03 (AN INFEASIBLE SOLUTION). THE LOCAL SEARCH USED 21 FE ANALYSES.

Subsequent Local Searches that Produce a Feasible Solution

This section shows the result from the local search #5. The statement following the header indicates that design run #9 from the design table is used in this local search. The starting and final values of three design variables from search #5are listed under the columns of starting and final value. See the highlighted sentence A FEASIBLE SOLUTION. It

Index


Main

is possible that a local search may be trapped in the same region of attraction and the final design will be identical to a previous local minimum. When that happens, the wording in the statement will be different.

**************************************************************************************** Local Search # 5 **** ************************************************************************************

The starting design variables are from run # 9

desvar ID Label Starting Value Final Value Lower Bound Upper Bound ---------- --------- --------------- ----------- ------------- ------------ 1 TPLY 5.0005E+00 2.1409E-02 1.0000E-03 1.0000E+01 2 THETA 0.0000E+00 -6.2499E-03 -1.0588E+00 1.0588E+00 3 THETA 0.0000E+00 -6.2499E-03 -1.5000E+00 1.5000E+00

THIS LOCAL SEARCH PRODUCE A CURRENT BEST LOCAL MINIMUM OBJECTIVE = 3.4214E-02, MAXIMUM CONSTRAINT VALUE = 2.0041E-03 (A FEASIBLE SOLUTION). THE LOCAL SEARCH USED 16 FE ANALYSES.

Final Output Section

The final section shows the global solution with the best objective and the maximum constraint value. The user information message explains how the global search procedure is terminated. In this example case, the job is terminated when all the design points in the design table are invoked. It also shows the total number of FE analyses and the number of local searches being used in this job. The history of local minima shown at the end of the section can be used for an xy-plot to gain the design insight.

0*** USER INFORMATION MESSAGE RUN TERMINATED DUE TO ALL THE DESIGN POINTS IN THE SAMPLE SPACE ARE INVOKED. THIS RUN USED 201 FE ANALYSES AND 9 LOCAL SEARCHES. THE GLOBAL SOLUTION IS: LOCAL OPTIMIZATION RUN # 9 OBJECTIVE = 3.4214E-02, MAXIMUM CONSTRAINT VALUE = 2.0041E-03 (A FEASIBLE SOLUTION).

******************** HISTORY OF LOCAL MINIMA ********************

RUN # LOCAL MINIMUM ____________ ____________ 0 9.1709E-02 9* 3.4214E-02

******************************************* END OF GLOBAL OPTIMIZATION SEARCH ******************************************

MultiOpt is successfully complete

######## [END MULTIOPT: 03/04/2015 10:53:16] ########

Index


Main

Guidelines and LimitationsIt is recommended that the associated SOL 200 jobs be run to insure that the models are well posed before launching GO applications. In addition, here are some ground rules/limitations.

1. It is recommended to use all default values for the first try (SOL200 DOPTPRM default values except DESMAX, plus GO parameter default values).

2. SCR=yes is recommended since less disk space is required

3. Parallel runs and/or SMP>=2 require more memory. GO may fail due to insufficient memory.

4. The upper- and lower-bounds on design variables (DESVAR) must be defined properly since they are used to generate sample points. Otherwise, local optimization SOL200 job may fail due to improper sample points.

5. Shape optimization is a challenge for GO since there is a higher chance to have poor mesh due to large shape changes during a GO search. A good quality of shape vectors and proper upper- and lower-bounds on design variables are essential for global shape optimization. In addition, (DVGRID) must be defined in the basic coordinate system.

6. GO does not support TOMVAR, TOPOPT, BEADVAR, and Part Superelement.

7. The folder path cannot contain blank spaces.

8. No design variables are allowed in any include files.

9. Does not support old IFP, supports mode i8 only.

10. To explore more design space, users can use larger NGLSMAX and/or MAXFEA. In addition, users can have both variability=”Golden” and “UPLO” run, or modify design variable limits.

11. Optimization, including Global Optimization is not available with FEA licensing.

12. To support PEM(Poro-Elastic Material), users need to define additional environment variables.

export MSC_ISHELLPATH=install_dir/nastran/msc20160/actran/linux64/Actran_16.1.b.92885/bin

export ACTRAN_PATH= install_dir/nastran/msc20160/actran/linux64

export ACTRAN_PRODUCTLINE= install_dir /nastran/msc20160/actran/linux64/Actran_16.1.b.92885

export ACTRAN_AFFINITY=reset

export ACTRAN_MPI= install_dir /nastran/msc20160/actran/linux64/Actran_16.1.b.9288/mpi/intelmpi

Index


Main

Global Optimization LicensingIn the MSC Nastran 2016 Release, the licensing and token draw is given below:

Serial Parallel

Supported

License Draw Multiplication

Factor(*1)Uses BLOCKING=N

in XML File


Factor

Single Seat License Yes 1 not achievable (Note 5) N/A

Multiple Seat License (same FLexLM server)

Yes 1 Yes (N+1)/2 (Note 2/Note 4)

Master Key Yes 1 Yes (N+1)/2(Note 2/Note 4)

MSC One Yes 1 (Note 3) Yes (N+1)/2(Note 4)

Note 1: For Global Optimization License Draw based upon features requested in single MSC Nastran input file.

Note 2: For MSC Nastran Embedded Fatigue and Aeroelasticity II, the license draw will be N.

Note 3: MSC Nastran Embedded Fatigue and Aeroelasticity II cannot be used with MSC One.

Note 4: If there are insufficient licenses available, the job will terminate; it is recommended to run in Serial mode.

Note 5: If BLOCKING=2 and NEF and Aeroelasticity II are not used, the job will run with two processors.

Index

94OptimizationMulti Model Optimization

Main

Multi Model OptimizationMulti Model Optimization (MMO) has been available since the 2010 release of MSC Nastran and you are referred to the MultiOpt-Global Optimization and Multi Model Optimization (p. 660) in the Design Sensitivity and Optimization User’s Guide for a comprehensive description of this capability. This section provides an overview to reacquaint users with MMO.

The MMO application starts the processing of the separate design models up to the point where the optimization is to occur. Then, it merges the design information, performs the optimization and partitions the results. Then the individual models are resumed in a design loop that is terminated when either convergence is achieved or the maximum design cycles are reached. A flow chart of this process with two design models is given in the figure below.

Index

95 MSC Nastran 2016 Release GuideMulti Model Optimization

Main

BenefitsMMO allows the user to have separate models that differ in their topology or in their analyses but still perform a combined optimization. The enhanced MMO is able to solve larger problems due to the Mode i8 support. There is no limit to the number of models that can be included.

User InputFor MMO applications, each of the models has its own data deck that is complete to the extent that it could be run "stand-alone" in MSC Nastran SOL 200. The following changes need to be made in each of these separate input files for a MultiOpt submittal:

a. A DESMOD case control command needs to be inserted in each model of the form:

DESMOD = model

Where model is a unique, user specified name of up to eight characters that designates the model

b. The DOPTPRM entry in the separate models control parameters that are used by the optimizer and others that are used in the iterative process. It is recommended that an identical DOPTPRM be used in each model. The DOPTPRM in the first model controls what is used by the optimizer; e.g., OPTCOD, while convergence parameters and DESMAX are controlled by the local DOPTPRM entry.

c. If the objectives are to be combined, the first model must have its DESOBJ request point to a DRESP2 that contains the structure of the combined objective function. This is expanded upon below.

d. MMO requires an addition xml file that drives the simulation. The format of this xml file is described below.

Invoking MultiOpt

GO and MMO are features in the program MultiOpt. MultiOpt is invoked using the following command line:

MSC20160 MultiOpt mygofile.xml (or mymmofile.xml)

MMO XML File Format

The user MMO input xml file (mymmofile.xml) has this format

<?xml version="1.0" ?><rc OptTYpe="MMO" debug="yes"> <Job name="deck1" coef="c1" MEM="m1" SMP="n1" SCR="s1" blocking="b1"/> <Job name="deck2" coef="c2" MEM="m2" SMP="n2" SCR="s2" blocking="b2"/> . . . <Job name="deckn" coef="cn" MEM="mn" SMP="nn" SCR="sn" blocking="bn"/> <Merge MEM="mm" SMP="nm" SCR="sm" /></rc>

For example,<?xml version="1.0" ?><rc OptTYpe="MMO" debug="yes"> <Job name="pcomp1" coef="1.0" MEM=2GB" SMP="2" SCR="yes" blocking="1"/> <Job name="pcomp2" coef="1.0" MEM=2GB" SMP="2" SCR="yes" blocking="1"/> . . .

Index


Main

<Job name="pcompn" coef="1.0" MEM="2GB" SMP="2" SCR="yes" blocking="1"/> <Merge MEM="1GB" SMP="2" SCR="yes" /></rc>

where

Remarks

1. MultiOpt supports new IFP and Mode i8 only.

2. MultiOpt input XML file (for example, mygofile.xml and mymmofile.xml) is a standard XML file. Users can use any XML editor and validator tools to create, validate, and correct.

3. OptType = "MMO" is used to perform multiple model optimization. The merge job in the MultiOpt input XML file is optional.

4. MMO is terminated when either convergence is achieved or the maximum design cycles are reached for each separate models.

5. More discussions about the options MEM, SCR and SMP can be found in MSC Nastran Quick Reference Guide.

Option Description

OptType OptType = “MMO” is used to perform multiple model optimization

Debug No” or “yes” (default = no). If turn on debug=”yes”, the program produces more diagnostic messages

Job name=“deck1”( deck2,…,deckn)

Indicates the subsequent data is a job name. deck1 is the basename of the input data model. deck1, deck2, …, and deckn are n basename in a multiple mode optimization problem

coef= “c1” (c2,…cn) Indicates the subsequent data is a coefficient for this model. c1 is the coefficient that provides the objective weighting for the first model (default=1.0). c2, …c2n are coefficients that provide the objective weighting for the rest models (default=0.0)

MEM= “m1” (m2,..mn, mm)

Indicates the subsequent data is a memory request for this model. Memory for the model m1, m2,…, mn, mm = 1GB (default) . mm is the memory for the merge operation

SMP=“n1” (n2, …nn, nm)

Indicates the number of processors used to efficiently obtain a solution to the simulation (default = no use of parallelization on shared memory tasks).

Scr=“s1” (s2, …, sn, sm) Option for scratch. scr=yes (default) or no. Scr=yes is recommended

Blocking=“b1”(b2, b3, .., bn)

Indicates whether that job is to be run in parallel or serially. The default runs the job in parallel. To run MMO sequentially, set blocking=”0” for each MMO jobs.

Merge Indicates a solution for the merge job (optional)

Index


Main

6. MMO combined objective function

COEF = Coefficient that provides the objective weighting for the model (default: =1.0 for the first model and 0.0 for subsequent models). This default means the objective comes from the first model only .When you are optimizing across several models, the overall objective can simply be the objective of the first model or it can be a linear combination of the objectives from all the models. If the objective is only from the first model, you set up the objective in this model in the same way as a standalone SOL 200 optimization task and not apply any coefficients (coef and ci data in the above options) in the xml file. Combining objectives from several models relies on a DRESP2 in the first model that has to be constructed with some specific rules:

• The DRESP2 must have a "DTABLE" with nmod (the number of models) LABLi values. The value specified for the first LABL1 should be 1.0 and the subsequent LABLi values should be zero. In this way, the objective of the first model is simply the first response. (Other LABLi values in the first model are permitted, but can lead to confusion)

• The DRESP2 must have either nmod DRESP1 quantities or nmod DRESP2 quantities. It is not possible to mix DRESP2 and DRESP1 responses in the combined objective.

• The second through nmod responses in the combined objective of the first model are dummy and will replaced with the second through nmod responses that are the objectives in the second and subsequent models.

• The coefficients actually used for the models are the Ci data provided in the xml file.

• The DEQATN that corresponds to the DRESP2 performs a linear addition of the responses:

COBJ = ΣCi OBJi7. MultiOpt users can also use MSC Nastran RC file to set other MSC Nastran keywords except (MEM, SMP,

and SCR) for GO or MMO. See MSC Nastran Quick Reference Guide.

8. Windows users

In order to run the MultiOpt utility, remotebootstrap.exe should be added to Windows Firewall access list. Otherwise, it will be blocked by it. When MultiOpt is run, users should not disturb the command prompt, especially when there are a large number of jobs; i.e., more than five. The status of execution should be monitored from another prompt. Otherwise, the original one may be unresponsive.

9. The folder path cannot contain blank spaces.

User OutputFor MMO, the separate models each provide their separate .f06 files and any other outputs that would be expected from a SOL 200 run. There is also a merge.f06 file produced from the optimization portion of the process and could provide some insight into how the optimization is progressing and highlight any problems.

Comma Separated Values File

The ASSIGN statement (in File Management) can be used to generate optimization history in Comma Separated Values (CSV) file (see MSC Nastran 2016 Design Sensitivity and Optimization User's Guide). This is still valid for GO (local optimization) and MMO (separate models). To produce the merge optimization design history in CSV file, users must define USERFILE name by the DESMOD model name in Case Control (for example, DESMOD = model where “model” must be uppercase)

Index


Main

ASSIGN USERFILE='model.CSV', STATUS=NEW, FORM=FORMATTED, UNIT=52

(It is necessary to include a PARAM, XYUNIT, 52 in the Bulk Data file)

The merge optimization history CSV file is called mymmofile_mmo.csv where mymmofile is the basename of the MultiOpt input XML file.

MMO Test CaseA simple 3 bar truss (page 671, MSC Nastran Design Sensitivity and Optimization User's Guide, 2016) demonstrates many of the developed features. It is suggested that you review this material for guidance on how to prepare the input file to create the combined objective function.

Here, a more complex example is used to show MMO applications (myfuselage.xml in ~tpl/multiopt). This example considers a scenario where there are 14 different models of airframe fuselage with variation in the rib design and position shown as follows. The aim is to search for an optimum design thickness of fuselage skin that will satisfy the von Mises stress constraints for all model variations.

Figure 6-1 Fuselage

The first deck named fuselage01 contains the design model as

• Case Control DESMOD=F_SUB1

• ASSIGN USERFILE='F_SUB1.csv',status=NEW,FORM=FORMATED, UNIT=52

• DESVAR 10 defines fuselage skin thickness as a common design variables for all 14 models

• DESVAR 30, 50, 70, and 80 define 4 rib thickness as individual design variables

• DESOBJ =35 (DRESP1 35) defines the weight as objective for the merged job

• DCONSTR entries defines stress constraints for this model.

• Param, XYUNIT, 52

Design optimization results are output to a F.SUB1.csv file.

All other13 models have similar design variables (one common for fuselage skin thickness and other 4 individual rib thickness), objective and constraints.

The MultiOpt input XML file, myfuselage.xml, for this job is of the form:

<?xml version="1.0" ?>

<rc OptTYpe="MMO" debug="NO">

<Job name="fuselage01" mem="100Mb" scr="yes" />

Index


Main














</rc>

After 12 MMO design cycles, a feasible optimum design is achieved and design history plots are shown in Figures 6-2 to 6-4. The plots indicate the necessity of increasing the weight to overcome the initially violated stress constraints. The weight increases through cycle 5; at this point, the constraints are not violated. The subsequent design cycles results in a reduction in the weight.

Index


Main

Figure 6-2 Design Variable vs Design Cycle

Figure 6-3 Design Objective vs Design Cycle

Index


Main

Figure 6-4 Maximum Constraint vs Design Cycle

Guidelines and Limitations1. Each model must have a unique DESMOD case control entry.

2. Design variables that are to be shared across models must have the same ID.

3. It is an error to have Design Variables in the separate models that share an ID but have different label, XLB,XUB , XVAL or DDVAL information.

4. Designed properties are assumed to be unique even when they are not. This is because it is almost impossible to verify that the design properties are actually identical (e.g., a DVPREL1 that has identical input may actually be referring to a completely different PSHELL entry in terms of its physical meaning.).

5. Support for shape optimization is minimal; each separate model must have the same topology.

6. The feature that allows the user to define an overall objective that is the weighted sum of individual objective imposes the additional requirement of defining an objective in the first model that represents the desired final model, but with dummy coefficients and objectives. This is described in the input section above.

7. MMO does not support TOMVAR, TOPOPT, BEADVAR, Part Superelement, and TREGION=1.

8. Optimization, including Multi-model Optimization is not available with FEA licensing.

9. To support PEM(Poro-Elastic Material), users need to define additional environment variables.

export MSC_ISHELLPATH=install_dir/nastran/msc20160/actran/linux64/Actran_16.1.b.92885/bin

export ACTRAN_PATH= install_dir /nastran/msc20160/actran/linux64

export ACTRAN_PRODUCTLINE= install_dir /nastran/msc20160/actran/linux64/Actran_16.1.b.92885

export ACTRAN_AFFINITY=reset

export ACTRAN_MPI= install_dir /nastran/msc20160/actran/linux64/Actran_16.1.b.9288/mpi/intelmpi

Index


Main

Multi-Model Optimization LicensingIn the MSC Nastran 2016 Release, the licensing and token draw is given below assuming there are M models.

Serial Parallel

Supported


Factor(*1)Uses BLOCKING=N

in XML File


Factor

Single Seat License not achievable N/A not achievable N/A

Multiple Seat License (same FLexLM server)

Yes (MF+1)/2 See Note 2 and 3


Master Key Yes (MF+1)/2 See Note 2 and 3


MSC One Yes (MF+1)/2 See Note 2 and 4


Note 1: For Multi Model License Draw based upon features requested in each MSC Nastran input file, for the case where all jobs require the same features, then it would be (M+1)/2 license draw for one simulation. If Aeroelasticity II or MSC Nastran Embedded Fatigue is present than M Aeroelasticity II or Fatigue licenses are drawn.

Note 2: MF is the accumulated license for all M models for a particular feature. For example, if there are four models, M=4, if only three use ACMS and one uses exterior acoustics then the license draw for ACMS =(3+1)/2 and the license draw for exterior acoustics will be (1+1)/2=1. The number of licenses drawn for base MSC Nastran is (4+1)/2=2.

Note 3: For MSC Nastran Embedded Fatigue and Aeroelasticity II, the license draw will be MF.

Note 4: MSC Nastran Embedded Fatigue and Aeroelasticity II cannot be used with MSC One licensing.

Note 5: If there are insufficient licenses available, the job will terminate.

Index

103 MSC Nastran 2016 Release GuideWeight as a Function of Material or Property ID

Main

Weight as a Function of Material or Property IDThe MSC Nastran 2014.1 release added a DRESP1 response with RTYPE=WMPID that allowed the weight of a specified material ID (or material ID and property ID combination) to be used as a response in a design task. This response was not available for Topology optimization. This restriction is removed in the MSC Nastran 2016 release.

Other restrictions remain:

• The property referenced on the ATTI field cannot also be invoked by a TOMVAR entry.

• The WMPID response is supported for topology optimization or for shape sizing optimization, but not for both topology and shape sizing optimization.

Index

Main

Chapter 7: High Performance Computing MSC Nastran 2016 Release Guide

7 High Performance Computing

New ACMS with Better SMP Scalability

NLEMG with SMP Parallelization

Intel MKL Pardiso for SOL 101, 107, 108, 111, and 200

Parallel Processing Licensing

Index

105 MSC Nastran 2016 Release GuideNew ACMS with Better SMP Scalability

Main

New ACMS with Better SMP ScalabilityFinding the eigenmodes of a structural mechanical system is fundamental to much of MSC Nastran. It is used in SOL 111 to create and solve the modal frequency response problem or in SOL 112 to create and solve the modal transient response problem in addition to many other solution sequences like SOL 103, 110, and 200. Users of MSC Nastran have relied on two approaches in the past for finding the eigenmodes - the Lanczos method and the Automated Component Modal Reduction (ACMS) method (or its variants). The ACMS method is an approximate method that for large problems can be orders of magnitude faster than the Lanczos method. The ACMS method in MSC Nastran has historically obtained parallelism from a combination of distributed memory processing (DMP) and shared memory processing (SMP). In MSC Nastran 2016.0, we are providing a new implementation of the traditional ACMS method in order to have much greater parallel scalability using only SMP. Focusing strictly on the eigenmode problem, we have observed a 40% parallel efficiency at SMP=16 for certain models whereas previously SMP=16 could at best provide a 20% parallel efficiency. As an additional upgrade to the method, we have also enabled ACMS in SOL 400 for use in linear analysis or perturbation analysis.

BenefitsThe new ACMS implementation with its better SMP parallelization can be used to reduce the wall clock time when finding the eigenmodes of a structural mechanical system. This will be especially helpful for users who cannot access the DMP capability in MSC Nastran due to their inability to control the command line input. It will also help all users with an overall reduction in wall clock time. Also, the new ability to use ACMS in SOL 400 will reduce the wall clock time for a new class of problems.

Technical DiscussionIn this discussion, we define the following execution phases for modal based analysis in MSC Nastran:

Phase DescriptionDMAP ACMS

implementationNew ACMS

implementation

Nastran Phase 1 Job start thru MDACMS begin

IFP, EMG, EMA, MCE, etc.

(no change)

ACMS Phase 1 Component modal reduction to automated Q-set

SubDMAP MDACMS ACMS1 module

ACMS Phase 2 Global eigenvalue computation

SubDMAP INVLAN (no change)

ACMS Eigenvector recovery Recovery of A-set eigenvectors

SubDMAP MDQRCVR ACMS1VR module

Index

106New ACMS with Better SMP Scalability

Main

Execution time for modal based analysis is typically dominated by "ACMS Phase 1", "ACMS Eigenvector Recovery", and "ACMS Phase 3" as defined above. The new ACMS implementation is confined to these three phases. The new implementation improves performance both in raw serial performance and parallel scalability. Note that ACMS Phase 3 does not normally apply to SOL 103 and likewise, ACMS Eigenvector Recovery does not normally apply to SOL 111.

This Technical Discussion is focused primarily on the new implementation of ACMS Phase 1, embodied in the ACMS1 module. In this module, automatically generated components (or domains, generated by the PRESOL module) are synthesized producing a global Q-set. This Q-set is sometimes referred to as the set of "sub-structure modes."

The new ACMS Phase 1 implementation in module ACMS1 includes fundamental changes that enables greater SMP scalability and better overall performance. For example, the old ACMS implementation requires a full binary tree limiting the ability to handle parallelism in unbalanced trees. See Figure 7-1.

Figure 7-1 Example of a full binary tree. The old ACMS method requires such a tree in its implementation.

The new ACMS method relies on a variable depth binary tree that allows for a better decomposition of problems with severe imbalance.

ACMS Phase 3 Matrix and vector reduction (K4, Loads, etc.)

SubDMAPs MDHHRED and MDHRED

MDHHREDX and MDHREDX modules

Frequency Response Modal frequency response calculations

FRRD1 modujle (no change)

Other SDR, etc. SDR1, SDR2, etc (no change)

Phase DescriptionDMAP ACMS

implementationNew ACMS

implementation

Index


Main

Figure 7-2 Example of a variable depth binary tree. The new ACMS method uses such a tree in its implementation.

Another major difference between the new implementation and the DMAP version is that the previous method limits the number of domains in the binary tree, thus limiting parallelism and performance. The new version only limits the problem size at the leaves of the binary tree and thus can yield many thousands of domains and dozens of levels. This in turn provides opportunity for better performance via a reduced number of operations, and for better parallel scalability due to yielding more independent computations.

DMP parallelism can still be used with the new ACMS version but it does not affect the time in the ACMS1 module. DMP is used in SOL 103 for solving the global eigenmode problem (ACMS Phase 2), and it is used in SOL 111 for the frequency response problem. Finally, the old ACMS version is still available and will be the default for this release

Inputs

The default approach for finding the eigenmodes of a structural mechanical system in MSC Nastran is determined by the EIGR or EIGRL bulk data entry. The ACMS method requires the addition of a DOMAINSOLVER command in the Executive Control Section as follows:

SOL 111DOMAINSOLVER ACMSCEND

This command instructs MSC Nastran to use ACMS instead of Lanczos for finding the eigenmodes and to provide additional output requests. The new method will be employed with the following change to the DOMAINSOLVER command.

SOL 111DOMAINSOLVER ACMS (VERSION=NEW)CEND

There are several additional options with the new ACMS method that can be found in the MSC Nastran Quick Reference Guide. Of particular note is the specification of TIPSIZE. The default TIPSIZE is 200 but users may want to also consider a TIPSIZE of 300. The larger TIPSIZE has been helpful for solid-element dominated problems.

SOL 111DOMAINSOLVER ACMS (VERSION=NEW, TIPSIZE=300)CEND

Index


Main

The tip size affects the total number of automatically generated domains and the required memory in parallel calculation using a specific number of processors. The larger the tip size, the fewer domains, and the few parallel processors for a system of a certain physical memory. User Information Message 11709 shows the number of automatically generated domains:

*** USER INFORMATION MESSAGE 11709 (PREMD2) NUMBER OF ACMS COMPONENTS = XXXXX

Differences Between the New ACMS Method and the Previous ACMS Method

Results

The new ACMS implementation may typically produce a smaller number of eigenmodes, compared to the old ACMS version. This is due to the larger number of automatically generated domains used in the new ACMS approach. Testing has shown excellent correlation of frequency response curves. Increased accuracy is possible by increasing the value of UPFACT. UPFACT is the factor applied to the user’s maximum frequency for eigenvalues. The default value for UPFACT is 2.0. Use the DOMAINSOLVER Executive System command to change it:

DOMAINSOLVER ACMS (VERSION=NEW, UPFACT=4.0)

Increasing the value of UPFACT may increase analysis time.

Parallel Processing

The new ACMS implementation relies on shared-memory parallelism (SMP) during the modal reduction phase of the solution in the ACMS1 module. The DMAP ACMS version relied primarily on distributed-memory parallelism (DMP) to do this work. This is also true for the reduction of loads, damping, and acoustic data in ACMS Phase 3. DMP is still used for computation of system modes, and during frequency response calculations.

When specifying both DMP and SMP parallelism, the new ACMS method will use all available CPU cores during modal reduction, for SMP processing. For example, if an analysis is run with new ACMS, and "dmp=N smp=M" is specified, modal reduction calculations will be carried out using "NxM" number of cores.

Implementation

The previous ACMS approach is implemented primarily as a series of SUBDMAPs. The new ACMS approach replaces key SUBDMAPs with DMAP modules.

Function ACMS Version=OLD ACMS Version=NEW

Component modal reduction Subdmap MDACMS Module ACMS1

Eigenvector recovery Subdmap MDQRCVR Module ACMS1VR

Vector recovery (B damping) Subdmap MDHRED Module MDHREDX

Matrix recovery (K4 damping) Subdmap MDHHRED Module MDHHREDX

Index


Main

Memory Requirements

Memory requirements are higher for the new ACMS implementation compared to the previous ACMS method. Models in the 25 to 50 million degrees of freedom range will require 128GB memory or more when run with full parallel options. Examples are shown below from real customer models.

Guidelines

Memory

The memorymaximum keyword remains the recommended method to specify memory. Using memorymaximum (which may be abbreviated memorymax) is recommended, since this will also allocate a portion of memory to the MSC Nastran I/O Buffer Bool.

The following guidelines are both general and conservative:

Analysis jobs that fail due to insufficient memory will print System Fatal Message 3008 with an estimate for required memory.

Parallel

The new ACMS method makes significant use of shared memory parallelism (SMP). Distributed memory parallelism (DMP) is still required for optimal performance for certain classes of problems, listed here:

• Normal modes analysis (SOL 103) requiring a large number of eigenmodes. The broad definition of “large” is about 10,000. Analysis of models containing 15,000 to 20,000 eigenmodes (or more) in the frequency range of interest is becoming more common.

• Frequency response analysis (SOL 111) comprised of a large number of forcing frequencies, as well as any of the following properties:

• Frequency dependent elements and properties

• Nonsymmetric dynamic input

• Weakly coupled exterior-interior acoustic analysis (ACOWEAK)

• Nonuniform structural damping

When DMP is used with new ACMS, the Master DMP process is allocated the majority of the memory requested. By default, the Master DMP process uses 70% of the specified memory amount, while the Slave DMP processes divide

Model Size No. of Threads Suggested memorymax=

Up to 10 million 1-8 32GB

9-16 64GB

10 million to 20 million 1-8 64GB

9-16 128GB

20 million – 40 million 1-8 128GB

9-16 200GB

Index


Main

the remaining 30% equally. The percentage of memory allocated to the Master DMP process may be changed with the dmpmem command line keyword. The default value of dmpmem is 70 (70%).

LimitationsThe following analysis types are not yet supported with new ACMS:

• External Superelements

• A-set Reduction

The following model types may give memory issues with the new ACMS:

• Models with large RBE3 elements connecting many viscous dampers

Information MessagesThe following are information messages that may be of interest to the user:

Number of ACMS Components: the global problem has been divided into this number of smaller domains:

*** USER INFORMATION MESSAGE 11709 (PREMD2) NUMBER OF ACMS COMPONENTS = XXXXX

The following messages are printed only if PRINT=YES.

User Information Message 11706 prints preliminary memory information. The first 11706 message lists memory used to store input data:

*** USER INFORMATION MESSAGE 11706 (ACMS1DR) TOTAL MEMORY AVAILABLE: XXXXX MB MEMORY TO STORE STIFFNESS MATRIX: XXXXX MB MEMORY TO STORE MASS MATRIX: XXXXX MB MEMORY TO STORE LOAD MATRIX: XXXXX MB MEMORY TO STORE TABLE DATA: XXXXX MB

The second 11706 message shows how the remaining memory is used. It is divided into two sections: POOL and STACK:

*** USER INFORMATION MESSAGE 11706 (ACMS1DR) ACMS1 WORKING MEMORY: XXXXX MB SIZE OF DYNAMIC MEMORY POOL: XXXXX MB MEMORY RESERVED FOR STACK STORAGE: XXXXX MB

User Information Message 11708 shows the maximum memory used (POOL and STACK) memory for each thread. For parallel, there will be one message for each thread:

*** USER INFORMATION MESSAGE 11707 (ACMS1PR) THREAD 1 MAX DYNAMIC MEM = XX MB (DOMAIN Y) MAX STACK MEM = XX MB (DOMAIN Y)

User Information Message 11708 shows the maximum simultaneous memory used across all threads (memory high water):

*** USER INFORMATION MESSAGE 11708 (ACMS1PR)

Index


Main

MAXIMUM DYNAMIC MEMORY USED = XXXXX MB MAXIMUM STACK MEMORY USED = XXXXX MB

User Information Message 11701 shows the number of substructure modes (also known as the “Q-set”).

*** USER INFORMATION MESSAGE 11701 (SUBDMAP MDACMSX) NUMBER OF SUBSTRUCTURE MODES = XXXXX.

Test CasesTest cases were run on a Linux cluster comprised of nodes described below:

OS: Red Hat Enterprise Linux Server release 7.1 (Maipo)Model: Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz ( Haswell )Nsocket: 2Ncore: 20 ( 2 X 10 )Cache: 25600 KBRam: 256 GbDisk: 2 X 1 Tb disk on software RAID 0

CASE 1: Automotive power train normal modes analysis (SOL 103)

Number of DOF 17.2 million

Number of grid points 2.9 million

Number of 2D elements 32,000

Number of 3D elements 1.5 million

Number of rigid elements 1,900

Number of modes 450

Index


Main

CASE 2: Automotive interior acoustic analysis (SOL 111)






Number of structure modes 5,700

Number of fluid modes 120

Number of load cases 132

Number of forcing freq 450

Index


Main

CASE 3: Large automotive interior acoustic analysis (SOL 111)






Number of structure modes 12,700

Number of fluid modes 1,600

Number of load cases 4

Number of forcing freq 500

Index


Main
Index

115 MSC Nastran 2016 Release GuideNLEMG with SMP Parallelization

Main

NLEMG with SMP ParallelizationMSC Nastran SOL 400 performance depends on the performance of its two main components: the sparse direct solver, which is used for solving the linearized part of the nonlinear problem, and the NLEMG module, which is used to produce the element stiffness matrices and to do stress recovery. For most models, the wall-clock time spent in the solver and the NLEMG module is comparable. Together, they can consume 80-90% of the simulation time. The wall-clock time can be reduced by taking advantage of parallelism on today's multi-core computing systems. In the 2014 release, a new sparse direct solver was added to MSC Nastran for SOL 400 that showed improved SMP scalability over the existing sparse direct solver. Now, in the 2016 release, we have added SMP parallelism to the NLEMG module as well to further improve the overall performance of MSC Nastran for SOL 400.

BenefitsThe SMP parallelization can be used to reduce the overall wall clock time used by the NLEMG module. For up to four threads, we have observed nearly 75% parallel efficiency implying a nearly 3x speed-up in the NLEMG module. For greater than four threads, the parallel efficiency is lower and is dependent on the particular model.

Technical DiscussionThe NLEMG module is one of the most time-consuming modules in SOL 400. In this release, SMP parallelization is implemented as an alternative to the DMP parallelism. DMP parallelization does not exhibit good performance for more than 2 MPI processes and requires an additional module DISUTIL for distributed domain data partitioning, causing extra overhead. SMP, by comparison, shows better scalability up to eight threads and does not require a communication routine. In case both DMP and SMP flags are specified on the command line, the DMP will override SMP in NLEMG. The hybrid combination of DMP and SMP may become available in future releases. There are several cases when SMP parallelization has been disabled or is not used:

• Heat transfer and coupled analysis simulations;

• Element matrix calculations for MSC Nastran element types;

• Models that have contact between Advanced and MSC Nastran element types;

• Models that have QUADR/QUAD4 or TRIAR/TRIA3 elements mixed in the same element groups1;

To avoid the problem of contact between Advanced and MSC Nastran elements, please use Advanced elements only or use MSC Nastran elements only in regions that do contact Advanced elements. If a problem still occurs resulting in a SYSTEM FATAL MESSAGE, then set sys107=65536+n where SMP=n to turn off the SMP feature for NLEMG but leave SMP enabled for other features.

Inputs

To specify the SMP value, we recommend to add "smp=n" to the command line where n is the number of threads to be used in the NLEMG module to reduce wall clock time. This value of SMP will also affect the number of threads used in the solver whether it be CASI, MSCLDL, or Intel's MKL PARDISO solver. One can also specify the SMP value in the Nastran Executive System section with the following line:

1In SOL 400, it is recommended to use CQUAD4 and CTRIA with PSHLN1.

Index

116NLEMG with SMP Parallelization

Main

NASTRAN SMP=n

This approach is particularly valuable for users who are unable to control the program flow with options on the command line as it simply updates the run file. It can also be set in the RC file for a system wide setting.

Test CasesTest cases were run on a Linux machine with two 8-core Intel© Xeon© processors (2600 MHz). The machine has 128GB memory.

CASE 1: Mixed-Element Model Comparison of MSC Nastran 2014.1 to 2016

Figure 7-3 Comparison of Parallel Performance of Mixed-Element Model

The SMP scalability observed above is derived from the new parallel NLEMG process for element matrix generation and stress recovery as well as the Intel MKL Pardiso solver. An overall 2x performance improvement is obtained just with SMP.

Number of DOF 3.9 Million



Number of subcases 1

Number of increments 1

Index

117 MSC Nastran 2016 Release GuideNLEMG with SMP Parallelization

Main

CASE 2: Shell-Element Model Scalability

Figure 7-4 Total Time and NLEMG Time based upon Number of Cores

The SMP scalability observed above is obtained from the new parallel NLEMG process for element matrix generation and stress recovery as well as the Intel MKL Pardiso solver.






Index

118NLEMG with SMP Parallelization

Main

CASE 3: Solid-Element Model Scalability

Figure 7-5 Total Time and NLEMG Time based upon Number of Cores

The SMP scalability observed above is from the new parallel NLEMG process as well as the MSC sparse direct solver, MSCLDL. NLEMG is a smaller fraction of the overall time due to the higher cost of the matrix solution method in a solid element model

Figure 7-6 Parallel Performance of NLEMG for Solid Element Model

Observed in these results are the 50% parallel efficiency at SMP=8 (gray) as well as the maximum speed-up of 4.25x at SMP=16 (red).






Index

119 MSC Nastran 2016 Release GuideIntel MKL Pardiso for SOL 101, 107, 108, 111, and 200

Main

Intel MKL Pardiso for SOL 101, 107, 108, 111, and 200MSC Nastran performance is dependent on the performance of the linear solver used to solve the underlying equations. In realistic SOL 101 problems for instance, the elapsed time for a direct solver can be 50% or more of the overall time. The elapsed time can be reduced by effective use of the parallelism available on today's multi-core computing systems. In the MSC Nastran 2016 release, we have extended the availability of the Intel MKL Pardiso direct solver to SOL 101, 107, 108, 111, and 200 in order to provide better scalability for the direct solve portion, and thereby lower the overall elapsed time of these simulations.

BenefitsThe Intel MKL Pardiso direct solver can achieve up to 80% reduction in the total elapsed time versus the default MSC solver. For large problems, the new sparse direct solver has been shown to scale up to 30 cores using an SMP approach.

Technical DiscussionThe Intel MKL Pardiso direct solver can be used with in a purely SMP mode, a purely DMP mode, or a combined DMP-SMP mode, depending on solution sequence. For SOL 101, it must be used in a purely SMP mode. In the SMP mode, the maximum number of threads used by Intel MKL Pardiso is defined by the value given to SMP on the command line. For SOL 107, 108, and 111, Pardiso may be used in any of these three modes. In combined DMP-SMP mode, the frequencies are split among DMP processes, and each DMP process uses the number of threads given to SMP on the command line. This is the recommended DMP usage, as pure DMP mode is likely to bottleneck in the direct solve phase.

The Intel MKL Pardiso solver can also be used in SOL 200 where linear statics or direct frequency response are a part of the optimization process. For the case that there are multiple right-hand sides due to multiple response requirements, we have observed 5x speed-up over the existing approach. This is a result of the Pardiso parallelization of multiple right-hand sides.

Note for SOL 107, the Intel MKL Pardiso solver is only available with the Lanczos (CLAN), and that for SOL 108 and 111, it is not compatible with the Krylov method.

The default behavior for the new direct solver is to determine at runtime whether the user has provided enough memory for the direct solver to run in-core or out-of-core. The out-of-core solver is not a fully out-of-core solution and requires the original matrix to be stored in memory. The out-of-core approach reduces the memory footprint by storing part of the largest front during the factorization phase on disk, or in the scratch directory. Typically, the out-of-core solver can reduce the memory footprint by anywhere from 3-6x as compared to the in-core solver.

Lastly, the new direct solver has a higher memory footprint than the existing direct solver in MSC Nastran. In some cases, the difference can be a factor of 4-6x in memory needed to avoid spill or to keep the problem in-core.

Inputs

You are required to use the SPARSESOLVER command in the executive section to indicate that the new solver should be used in the simulation. The following are examples of choosing the new sparse direct solver using the keywords PRDLDL or PRDLU, with its own default SMP ordering method, PRDSMPMS, which is an OpenMP parallelized METIS reordering method.

Index

120Intel MKL Pardiso for SOL 101, 107, 108, 111, and 200

Main

SOL 101SPARSESOLVER DCMP (FACTMETH=PRDLDL,ORDMETH=PRDSMPMS)CEND

SOL 107SPARSESOLVER CEAD (FACTMETH=PRDLDL,ORDMETH=PRDSMPMS)CEND

SOL 108SPARSESOLVER FRRD1 (FACTMETH=PRDLU,ORDMETH=PRDSMPMS)CEND

SOL 111SPARSESOLVER FRRD1 (FACTMETH=PRDLU,ORDMETH=PRDSMPMS)CEND

The command line input used to specify the SMP value is the standard input argument detailed below:

~/nast20160 exampleJob.dat smp=m

where m is the number of requested threads.

Outputs

There are no new outputs. However, sys166=2 can be added to the command line or input deck in order to have additional output from the Pardiso solver sent to the LOG file. This includes number of threads used, size of matrix solved, and solution times.

Index


Main

Test CasesMost test cases were run on a Linux machine with two 8-core Intel© Xeon© processors (E5-2679 2.6 GHz). The machine has 128GB (8x16) DDR3 memory running at 1.6 GHz, and a 4 TB hard disk using SATA 6 GB/s at 5,900 RPM.

CASE 1: SOL 101 Engine Block Model

Figure 7-7 Normalized Total Elapsed Time of SOL 101 Engine Block Model

For SOL 101, the overall time is dominated by the matrix solution process thus yielding the excellent scalability.


Number of grid points 2,456,555


Number of 3D elements 1,458,800

Index


Main

CASE 2: SOL 107 Shell Element Model

Figure 7-8 Normalized Total Elapsed Time of SOL 107 Shell Element Model

For SOL 107, the time is dominated by the forward-backward solver, instead of the matrix factorization, thus yielding a reduced scalability. The results, however, do show the overall performance improvement with using Pardiso for SOL 107.




Number of 3D elements 100

Index


Main

CASE 3: SOL 107 Axisymmetric Rotors Model

Figure 7-9 Normalized Total Elapsed Time for SOL 107 Axisymmetric Rotor Model


Number of grid points 958,943


Index


Main

CASE 4: SOL 108 Shell Element Model

Figure 7-10 Normalized Total Elapsed Time for SOL 108 Shell Model




Index


Main

CASE 5: SOL 111 with ACOWEAK

Figure 7-11 Normalized Total Elapsed Time for SOL 111 Acoustics Shell Model


Number of grid points 41,621



Index

126Parallel Processing Licensing

Main

Parallel Processing LicensingMSC Nastran 2016 introduces a new licensing method based upon the actual number of CPU cores being used in the simulation. This feature is labeled NA_Parallel This replaces the SMP and DMP license features that were labeled NA_SMP and NA_DMP. This licensing method is applicable to all capabilities activated using the DOMAINSOLVER option, or the use of SMP= or DMP= including all the new capabilities discussed earlier in this chapter.

These licenses are offered in bundles, contact your account manager for details.

• MSC Nastran Desktop only provides licensing to 4 cores.

• FEA does not allow any parallel processing.

• ACMS is activated using the NA_ACMS feature which is licensed separately.

Index

Main

Chapter 8: Implicit Analysis (SOL 600) MSC Nastran 2016 Release Guide

8 Implicit Analysis (SOL 600)

SOL 600 Upgrade 128

Known Incompatibility with Previous Versions of MSC Nastran 131

Index

128SOL 600 Upgrade

Main

SOL 600 UpgradeIn the MSC Nastran 2016, the version of Marc that is embedded in SOL 600 has been updated to the Marc 2014.2 release. This means that the technology in SOL 400 and SOL 600 are consistent. The interface in SOL 600 for transferring data from MSC Nastran to Marc and for postprocessing has not been changed. Hence, while a large amount of new capabilities are available they are not directly exposed. One will benefit from the improved reliability of the Marc 2014.2 version over the Marc 2010 version which was the basis of previous SOL 600 releases.

An existing input file MSC Nastran bulk data file will continue to work with the new release. The one exception involves the 3-D 8-node composite brick element and is discussed below.

SOL 600 provides solutions to fundamental problems in nonlinear analysis including material nonlinearity, geometric nonlinearity, and contact. SOL 400 and SOL 600 now have virtually the same capabilities for material nonlinear problems for small and moderate strain levels. As SOL 400 has matured, it may be preferable unless advanced materials, user subroutines, large strain, or Multiphysics is required. In that case, it is often useful to use SOL 600 as a mechanism to generate a Marc input file.

Workflow for Advanced AnalysisThe typical work flow would be:

1. Execute MSC Nastran SOL 600.

2. Write out Marc input file, using STOP=2.

3. Read Marc input file jid.marc.dat into Mentat.

4. Run Marc directly from Mentat or from the command line.

5. Postprocess the post file t16 or t19 with Mentat or Patran.

Material ModelsWhile for conventional structural material models, the capabilities of SOL 400 and SOL 600 are similar, advanced material models that have been incorporated into Marc that are not exposed in SOL 400 or in SOL 600 include:

• Marlow – simplified rate-independent nonlinear elastic

• Bergström-Boyce large strain viscoelastic model

• Parallel Rheological Framework – for large strain elasticity with permanent deformation such as thermal-plastics

• Anisotropic Hypoelastic Material – often used for fiber filled rubber or biological materials

• Chaboche cyclic plasticity model

• Barlat Anisotropic Yield models

• Shima powder model

• Sandia Exponential Cap model – for soil, rocks and concreter

• Anand Viscoplastic model – for solder analysis

Index

129 MSC Nastran 2016 Release GuideSOL 600 Upgrade

Main

• Low tension cracking models

• Bonora Metal Continuum Damage Model

• Mixture model

• Strain Invariant Failure Theory

• Frequency Dependent Damping (with and without Payne effect)

• Grain size

Note that SOL 400 directly supports e-Xstream Digimat material library.

Large Displacement/Large Strain Analysis The base technology in SOL 400 and SOL 600 are identical – but for very large strain using SOL 600, one has the possibility to utilize the Marc Local Adaptive and Global Adaptive meshing capability to improve the mesh during the simulation. This is often important because large strains result in high distortion of the elements which may result in either loss of accuracy, poor convergence, or an element turning inside out. The last is a fatal error in SOL 400. One can either manually add the additional options into the SOL 600 input file, or utilize the work flow described above and activate the capabilities within Mentat. The large strain often occurs when using rubber or foam materials or when performing manufacturing simulation.

SOL 600 can also be used in post-buckling simulation which may not be achievable with SOL 400.

Contact AnalysisThe contact technology in both SOL 400 and SOL 600 are nearly equivalent with the MSC Nastran 2016 release. SOL 400 exposes the Segment-to-Segment (STS) contact procedure which is advantageous over the older Node-to-Segment technology. To access this technology in SOL 600, it is necessary to use the work flow discussed above and activate STS within Mentat. The input changes are too complex to achieve using an editor.

ComputationalPreviously an advantage of using SOL 600, was that it was computationally more efficient than SOL 400 and had better utilization of parallelization including Domain Decomposition. The last few years has continued to see advances in both products, and with the current MSC Nastran 2016 release the differences between the two solution sequences has been reduced.

Index

130SOL 600 Upgrade

Main

This is summarized as

Fracture MechanicsBoth SOL 400 and SOL 600 support the evaluation of the energy release rate and stress intensity factor using the VCCT method. Additionally, SOL 600 supports the Lorenzi method based upon the contour integral approach which is often more accurate. There has been substantial work over the last few years on crack propagation. This is now achievable in Marc using the Global Adaptive Meshing procedure for planar, shells, and 3-D solids. The previously defined workflow should be used. It should be noted that the adaptive method result in a change in the number of grids/nodes, and the results can only be written to a t16/t19 post file.

MultiphysicsBoth SOL 400 and SOL 600 allow both uncoupled thermal-stress, though SOL 600 has greater flexibility. SOL 400 has some thermal-mechanical coupled capability that is not available in SOL 600. For general multi-physics, it is possible to utilize the work flow discussed above and then use Marc to perform multi-physics simulations. This includes to perform:

• Structural

• Thermal

• Electrostatic

• Piezoelectric

• Magnetostatic

• Current Flow

• Induction Heating

• Magnetodynamics

• Diffusion

• Almost all combinations of these basic physics

SOL 400 SOL 600

Effective Domain Decomposition No Yes

Element SMP Assembly and Stress Recovery Yes (Note 1) Yes (Note 2)

SMP Solver Yes (Note 1) Yes

Parallel Eigenvalue (ACMS) Yes (Note 1) No

Note 1: See Chapter 7.

Note 2: Run Marc job through command line using the -NTE option.

Index

131 MSC Nastran 2016 Release GuideKnown Incompatibility with Previous Versions of MSC Nastran

Main

Known Incompatibility with Previous Versions of MSC NastranThe 3-D 8-node composite brick element has changed between the Marc 2010 and Marc 2016 release. In particular the orientation of the layers must now be specified. In the previous release, this was not necessary as the layers could only go in one direction. Based upon the translating of the MSC Nastran input file into a Marc input file, when using this capability one will obtain a Marc Exit 13, and no results will be produced.

This capability may have been triggered in SOL 600 by using either:

MRALIAS, 007149

or both PCOMP and PSOLID having the same PID referenced by a CHEXA.

The work around is to edit the Marc input file created jid.marc.dat, and for the composite brick elements, change the GEOMETRY option so the third field of the third line is equal to 1.0. This will produce the same results as before.

Index

Main

Chapter 9: Explicit Analysis (SOL 700) MSC Nastran 2016 Release Guide

9 Explicit Analysis (SOL 700)

New Materials and Equation of States

Adaptive Solid Elements to SPH Transform (SOL2SPH)

Enhanced Dynamic Relaxation and Body Forces

Reinforcement Inside of Solid Elements

Miscellaneous Update

Index

133 MSC Nastran 2016 Release GuideNew Materials and Equation of States

Main

New Materials and Equation of StatesThree new materials and one new equation of states have been added in the MSC Nastran 2016 release.

Unified Creep Model (MATD115)This is 3-parameter time dependent visco-elastic creep material model. The effective strain considers time effect using three parameter. Please check the theoretical background of MATD115 (p. 2531) in the MSC Nastran Quick Reference Guide.

Benefit

• Creep capability in nonlinear explicit analysis

Limitations

• Available for the Lagrangian elements

• Solid, thin shell, thick shell and SPH elements can use the material

Example

In Figure 9-1, the dumbbell specimen made by shell elements with MATD115 is subjected to the static loading at the right tip in the x-direction. The left face is fixed. During the simulation, the loading does not change, but the displacement increases as shown in Figure 9-2. The example is available in tpl/sol700_2016/mat115.dat.

Figure 9-1 Dumbbell Specimen Subjected to Static Loading

Index

http://www.mscsoftware.com/doc/nastran/2016/release/mat115.dat

134New Materials and Equation of States

Main

Figure 9-2 Displacement at the Middle of the Specimen

Thermo Elasto-viscous Plastic Creep Model (MATD188)In this model, creep is described separately from plasticity using Garafalo's steady-state hyperbolic sine creep law or Norton's power law. Viscous effects of plastic strain rate are considered using the Cowper-Symonds model. Young's modulus, Poisson's ratio, thermal expansion coefficient, yield stress, material parameters of Cowper-Symonds model as well as the isotropic and kinematic hardening parameters are all assumed to be temperature dependent. The application of this include: simulation of solder joints in electronic packaging, modeling of tube brazing process, creep age forming, etc. Please see MATD188 (p. 2643) in the MSC Nastran Quick Reference Guide.

Benefit

• Creep capability in nonlinear explicit analysis

Limitations


• Solid, thin and thick shell elements can use the material

RHT model (MATD272)Riedel-Hiermaier-Thoma model has the following capabilities associated with brittle material such as concrete.

• Pressure hardening

• Strain hardening

Index

135 MSC Nastran 2016 Release GuideNew Materials and Equation of States

Main

• Strain rate hardening

• Third invariant dependence for compressive and tensile meridians

• Damage effects (strain softening)

• Crack-Softening.

Please check the detail theoretical background in the Remarks of MATD272 (p. 2666) in the MSC Nastran Quick Reference Guide.

Benefit

• Concrete model subjected to impulsive loading in nonlinear explicit analysis

Limitations


• Solid and SPH elements can use the material

• EOSMG2 is required

Mie-Gruneisen Equation of State Model (EOSMG2)

Mie-Gruneisen Equation of state form with a polynomial Hugoniot curve and a compaction model. Please see EOSMG2 (p. 2003) in the MSC Nastran Quick Reference Guide.

Benefit

• Concrete model subjected to impulsive loading in nonlinear explicit analysis

• compaction relationship can be used in the concrete material model

Limitations


p α–

p α–

Index

136Adaptive Solid Elements to SPH Transform (SOL2SPH)

Main

Adaptive Solid Elements to SPH Transform (SOL2SPH)When material starts to fail, the elements may not have enough stiffness and they might deform severely, and the simulation becomes unstable. To prevent the elements from Hourglassing too much, severely damaged elements are commonly eliminated from the simulation. So it is not easy to simulate the debris and take care of the effect of the debris after the elements fails.

The capability of adaptively transforming from solid elements to SPH particles helps users simulate the debris effect. After failure of solid elements, the solid elements will be eliminated from the simulation and they will be replaced by SPH particles. The SPH particles will inherit all of the state variables of the failed solid elements, e.g. mass, kinematic variables, and constitutive properties.

Benefit

• Without hourglassing, the effect of debris can be modeled.

Limitations

• Available for the Lagrangian solid elements

• Users must define the material properties for both solid and SPH properties

• Up to 8 SPH particles replace the failed solid elements

Example

The cantilever solid beams are subjected the loading at the right tip and fixed at left face as shown in Figure 9-3. Each solid element can be replaced by eight SPH particles after it fails. After the cantilever deforms, several elements fail due to plastic strain failure and are replaced by SPH particles as Figure 9-4. The example is available in tpl/sol700_2016/sol2sph.dat.

Figure 9-3 Cantilever Beam Made by Solid Elements (Two Properties and One Material)

Index

http://www.mscsoftware.com/doc/nastran/2016/release/sol2sph.dat

137 MSC Nastran 2016 Release GuideAdaptive Solid Elements to SPH Transform (SOL2SPH)

Main

Figure 9-4 Cantilever Beam After Deformed (Failed Solid Elements are Replaced by SPH Particles)

Index

138Enhanced Dynamic Relaxation and Body Forces

Main

Enhanced Dynamic Relaxation and Body ForcesThree new options are added for the dynamic relaxation and body forces.

Dynamic Relaxation on Body Forces (BDYRELX)Previously dynamic relaxation is only available for the static enforced motion or loading condition. However the dynamic relaxation capability is also required for the bodies subjected to the static body forces such as gravity, rotational velocity, etc. (GRAV, RFORCE and BDYFORC). The new BDYRELX entry can apply the dynamic relaxation for the static body forces. One defines the relaxation as a function of time via TABLED1.

Benefit

• Static body forces can be used without having to slowly increase them.

• Since the effect of body forces can be applied as an initial condition, other initial conditions such as initial velocity can be applied at the start of the simulation.

Limitations


Dynamic Relaxation Output Request (DYPARAM, LSDYNA, BINARY, D3DRLF)During the dynamic relaxation phase, the simulation does not often give the correct answer. Using jobname.dytr.d3drlf files, users can check what happens during the dynamic relaxation phase.

Benefit

• Users can check the intermediate dynamic relaxation results.

Limitations

• Available for Lagrangian elements only

Various Body Forces on Different Bodies (BDYFORC)Generally, body forces are identical for the whole model. However, sometimes different body forces need to be applied on different bodies. The new BDYFORC entry can assign different rotational body forces on different bodies.

• Translational acceleration

• Rotational velocity or acceleration

• Three different types of angular motion

• Body force from centrifugal acceleration

• Body force from Coriolis-type acceleration,

• Body force from rotational acceleration

Index

139 MSC Nastran 2016 Release GuideEnhanced Dynamic Relaxation and Body Forces

Main

Benefit

• Users can apply different body forces on different bodies

Limitations

• Available for Lagrangian elements only

Example of Enhanced Dynamic Relaxation and Body ForcesIn Figure 9-5, two tires are rotating with different angular velocities which are assigned by BDYFORC. The frictions are applied between the road and tires and the static loadings are applied at the center of the wheel. The gravity is also applied to both tires and different initial translational velocities depending on the rotational velocities that are also added to both tires. Because all loadings are applied at the start of simulation, dynamic relaxation (DYRELAX and BDYRELX) is applied to reduce the initial oscillation.

The results in Figure 9-6 show the stresses are not oscillating too much at various times.

Figure 9-5 Rotation of Two Tires with Different Rotational Speed

Index

140Enhanced Dynamic Relaxation and Body Forces

Main

Figure 9-6 Stress Contour Results at Time = 0.0, 0.5, 1.0 and 2.0

Index

141 MSC Nastran 2016 Release GuideReinforcement Inside of Solid Elements

Main

Reinforcement Inside of Solid ElementsA new capability exists that allows one to embed an element within another element. In SOL 700, this has been designed for the insertion of rebar elements into concrete, but it has other applications as well. The LAGINSOL option in the METHOD field in BCONPRG/BCTABLE is added for the simulation of reinforcements inside of another element. Beam, shell, and solid elements can be used to model the steel reinforcements on the inside of solid elements.

Benefit

• The concrete including reinforcing bars can be simulated.

Limitations

• Available for the Lagrangian elements only.

• The capability is only available between beam, shell and solid elements inside of solid elements.

• Nodes of internal elements must not equivalent to nodes of solid elements.

Example

Two cantilever solid beams are made in Figure 9-7. The green one does not have reinforcements while the red one has reinforcing bar elements at the center of the section. The left sides of both beams are fixed and the same loadings are applied on the right tips of both beams. Figure 9-8 shows the deformation behavior of both beams. The red beam which has the reinforcing bars shows stiffer behavior than the green beam. The example is available in tpl/sol700_2016/laginsol.dat.

Figure 9-7 Undeformed Cantilevers Showing Reinforcement in One of Them

Index

http://www.mscsoftware.com/doc/nastran/2016/release/laginsol.dat

142Reinforcement Inside of Solid Elements

Main

Figure 9-8 Deformed Cantilevers Showing Reinforcement in One of Them

Index

143 MSC Nastran 2016 Release GuideMiscellaneous Update

Main

Miscellaneous Update

D3plot Output File Size Control (DYPARAM,LSDYNA,DATABASE,FORMAT)

Using the DYPARAM,LSDYNA,DATABASE,FORMAT card, the single precision format of d3plot file output can be generated although the double precision version of SOL700 is used. It reduces the d3plot file size by half. It will be helpful when the output file size is too large to be handled.

Contact Including Shell Offset (DYPARAM,LSDYNA,SHELL,CNTCO)

The default setting does not consider the shell offset in the contact. However sometimes the shell offset is important and it must be included in contact. DYPARAM,LSDYNA,SHELL,CNTCO controls including shell offset in the contact and the offset location of shells.

Volume Input Instead of Mass in CSPH

The mass is one of the most important factors in SPH calculation. Since users assign the mass to each SPH element, the mass can be different from the mass calculated from the density of material definition. The new capability can assign volume instead of mass on each SPH element and the mass is automatically calculated from the specified volume and material density.

Preloading on Bolt/Spring (TID/SCALE Option in PBSPOT)

The initial axial forces on bolts or springs have high effect on the simulation. Specially, when the axial failure criteria are assigned, the failure points can be different depending on the initial axial forces on bolts or springs. Previous release has the capability but it is only available in the solid element bolt or beam (ISTRSSS). Now the new capability can assign the preloading to beam type of bolts and springs. Due to the initialization issue, the loading must be used with the ramp type table or dynamic relaxation.

Example

In Figure 9-9 two deformable plates are connected through a bolt beam at the center. The initial axial force is given inside of bolt without any additional loading. Figure 9-10 shows the effective stress contour of plates and the axial forces of bolt. It is shown that the axial force is stable during the simulation. The example is available in tpl/sol700_2016/iniaxf.dat.

Index

http://www.mscsoftware.com/doc/nastran/2016/release/iniaxf.dat

144Miscellaneous Update

Main

Figure 9-9 Model of Initial Force on Bolt

Figure 9-10 Results of Initial Axial Forces on Bolt

Index

Main

Chapter 10: User InterfaceMSC Nastran 2016 Release Guide

10 User Interface

HDF5 Result Database (NH5RDB) 146

F06Reader Utility 184

Solid Elements Coordinate System Enhancement 191

Index

146User InterfaceHDF5 Result Database (NH5RDB)

Main

HDF5 Result Database (NH5RDB)In this release, a new MSC Nastran database in Hierarchical Data Format (HDF5) is supported. HDF5 is a data model for storing storing and managing data. The database organizes MSC Nastran input and output data in a hierarchical structure. MSC Nastran data is stored as dataset in database and can be accessed through standard HDF5 APIs or third party packages in multiple languages. The main features of NH5RDB include:

1. A data type schema in XML for database structure and datasets formats.

2. All major MSC Nastran input and output data blocks are supported.

3. Support for multiple MSC Nastran solution sequences.

4. Optional output by MDLPRM parameter.

5. Python module with utility functions for data manipulation.

6. Version control of data blocks.

For more information on HDF5, see HDF5 Software Documentation.

BenefitsThe NH5RDB supports wide range of data types and is capable of defining complicated data structures. In the database, the datasets are stored in a hierarchical structure, making it easy to add, remove, or update dataset in applications. The database supports high precision, compression, and unlimited amount of data. Its open format and multiple programming languages support make it ideal for FEA applications.

Technical Discussion

1. Data type schema

The data type schema is used to define database structure and its datasets formats. The database has a tree structure with its nodes of datasets. Each dataset uses its path in the tree as its identifier and defines a structure data format. The schema is in XML and has elements like <typedef>, <group> and <dataset>. The following example shows the definitions of input GRID and HEXA element stress output datasets.

This schema file and an html based document are included in doc directory with name DataType.xml and DataType.html respectively.

<?xml version="1.0" encoding="utf-8"?><crdb schema="0"> <typedefs> <typedef name="GRID_SS"> <description>Grid strain and stress structure</description> <field name="GRID" type="integer"/> <field name="X" type="double"/> <field name="Y" type="double"/> <field name="Z" type="double"/> <field name="TXY" type="double"/> <field name="TYZ" type="double"/> <field name="TZX" type="double"/>

Index

http://www.hdfgroup.org/HDF5/doc/index.html

147 MSC Nastran 2016 Release GuideHDF5 Result Database (NH5RDB)

Main

</typedef> </typedefs ><groups> <group name="NASTRAN"> <group name="INPUT"> <group name="NODE"> <dataset name="GRID" version="1"> <field name="ID" type="integer"/> <field name="CP" type="integer"/> <field name="X" type="double" size="3"/> <field name="CD" type="integer"/> <field name="PS" type="integer"/> <field name="SEID" type="integer"/> <field name="DOMAIN_ID" type="integer"/> </dataset> </group> </group> <group name="RESULT"> <group name="ELEMENTAL"> <group name="STRESS"> <dataset name="HEXA"> <field name="EID" type="integer"/> <field name="CID" type="integer"/> <field name="CTYPE" type="character" size="4"/> <field name="NODEF" type="integer"/> <field name="SS" type="GRID_SS" size="9"/> <field name="DOMAIN_ID" type="integer"/> </dataset> </group> </group> </group> </group> </groups></crdb>

Example 1. Data schema

2. MSC Nastran input and output data in NH5RDB

The NH5RDB includes MSC Nastran input and output data. The supported data types are summarized in Table 10-1. Viewing the schema, you will observe all the data blocks supported.

Table 10-1 NH5RDB Data Categories

Category Description

Input:

Case control and parameters Case control option and parameter values

Constraint Constraint entries like SPC and MPC

Contact Contact entry like BSURF

Coordinate system Coordinate system entry like CORD1C

Index


Main

3. MSC Nastran solution support

In MSC Nastran 2016.0, the solution sequences supported are given in Table 10-2 . The intention is to add additional key solution sequences in subsequent releases.

Design optimization Design optimization entry like BEADVAR

Element Element entries like CHEXA and CQUAD4

Load Load entries like FORCE and PLOAD4

Material Materials like MAT1, MAT2 and MAT8

Matrix Direct matrix input like CONM1

Node Node entries like GRID and SPOINT

Partition Define set or list like SET1

Property Property like PSHELL and PSOLID

Table Table values in TABLEM1 and TABLEM2

Output:

Acoustic output Acoustic power, participation factor, etc.

Contact output Contact force and stress output

Elemental output Stress, strain, element force, etc.

Fatigue output Fatigue analysis output

Nodal output Displacement, velocity, acceleration, etc.

Optimization data Objective function, constraint, history values, etc.

Special nonlinear format data NLOUT format data

Table 10-2 NH5RDB Supported Solutions

Solution Number Description

101 Statics

103 Normal modes

105 Buckling

107, 110 Complex eigenvalues

108, 111 Frequency response

109, 112 Transient response

Table 10-1 NH5RDB Data Categories (continued)

Category Description

Index


Main

4. NH5RDB optional output by MDLPRM and system cell

The NH5RDB is an optional output. By default, the database will not be generated by MSC Nastran. A new parameter HDF5 is added in MDLPRM for NH5RDB generation. In BULK data section, setting HDF5 parameter to one in MDLPRM will ask MSC Nastran to create the database.

The usage of HDF5 paremeter of MDLPRM in input file is shown as the following:

BEGIN BULKMDLPRM,HDF5,1

As an alternative way, the system cell 702 can be used for NHRDB generation.

The NH5RDB request can be given in command line as the following:

nastran example.dat sys702=1

5. The NH5RDB DMAP modules

There are two DMAP modules to write MSC Nastran input and output data into database for advanced users. The descriptions of the CRDB_IN and CRDB_OUT modules are as the following:

200 Design Optimization

400 Nonlinear analysis

Table 10-3 The HDF5 parameter in MDLPRM

Parameter Name Description, Type, and Default Values

HDF5 Parameter to create NH5RDB database

1 Create NH5RDB with compression

0 Create NH5RDB without compression

-1 Do not create NH5RDB(default)

Table 10-4 System cell for NH5RDB

System Cell Name (Number) Function and Reference

HDF5 (702) Control NH5RDB database creation

1 Create NH5RDB database

0 Do not create NH5RDB database (Default)

Table 10-2 NH5RDB Supported Solutions (continued)

Solution Number Description

Index


Main

Write IFP data blocks in an HDF5 format database. A maximum of five data blocks can be passed in one call.

Format:

Input Data Blocks:

Parameters:

Remarks:

1. The supported input data blocks are GEOM1, GEOM2, GEOM3, GEOM4, EPT, EDT, MPT, DIT, DYNAMIC, CONTACT, MATPOOL, EDOM, FATIGUE, PVT, CASECC and SPECSEL.

2. The SEID, AFPMID and TRIMID indicate which super element, acoustic field point mesh, or trim component the data blocks are from.

3. NDDLNAMi must be provided for all data blocks.

CRDB_IN Write IFP data blocks into the NH5RDB database

CRDB_IN DB1,DB2,DB3,DB4,DB5//NDDLNAM1/ DDLNAM2/NDDLNAM3/NDDLNAM4/NDDLNAM5/SEID/AFPMID/TRIMID/ $

DBi Input data blocks, see remark 1 for supported data blocks.

NDDLNAMi Char8, default=blank NDDL data block name corresponding to DBi

SEID Integer, default=0 Super element id of the data block

AFPMID Integer, default=0 Acoustic field point mesh id

TRIMID Trim id, default=0 Trim component id

Index


Main

Write OFP data blocks in an HDF5 format database. A maximum of five data blocks can be passed in one call.

Format:

Input Data Blocks:

Parameters:

Remarks:

1. The supported output data blocks are OUG. OVG, OAG, OES, OEF, OPG, OQG, OEFTG, OEFTGM, OUGFP, OMPF, OERP, OARPWR, OVGFP, OAPWR2, OAIG, OCOMP, OCOMPM, OMCFRAC, DBCOPT, NLOUT, OFVCCT and OFCON3D.

2. The SEID, AFPMID, TRIMID and DESCYCLE indicate which super element, acoustic field point mesh, trim component, and design cycle the data blocks are from.

3. NDDLNAMi must be provided for all data blocks.

6. Python utility module

For users convenience, a Python module is provided for NH5RDB database access. The module uses Pytable packages and defines functions for data format conversion and derived data calculation. Using these functions, datasets can be accessed for extraction or conversion into other formats, like text and CSV. Some derived data, such as Von Mises stress, can also be calculated from element stress dataset.

HDF5 Browser

The test model below shows the usage of HDF5 parameter and structure of NH5RDB database, the database is opened using the publicly available HDF5 browser HDFView.

CRDB_OUT Write OFP data blocks into the NH5RDB database

CRDB_OUT DB1,DB2,DB3,DB4,DB5//NDDLNAM1/NDDLNAM2/NDDLNAM3/NDDLNAM4/NDDLNAM5/SEID/AFPMID/TRIMID/DESCYCLE/$

DBi OFP data blocks, see remark 1 for supported data blocks.

NDDLNAMi Char8, default=blank NDDL data block name corresponding to DBi

SEID Integer, default=0 Super element id of the data block

AFPMID Integer, default=0 Acoustic field point mesh id

TRIMID Trim id, default=0 Trim component id

DESCYCLE Integer, default=0 Design cycle number in design optimization

Index


Main

Test model file: test.dat

SOL 101TIME 5CENDDISP = ALLSTRESS = ALLFORCE = ALLSPC = 1SUBCASE 1 LOAD = 1BEGIN BULKMDLPRM,HDF5,1GRID,1,,10.GRID,2,,8.GRID,3,,6.GRID,4,,4.GRID,5,,2.GRID,6CBAR,1,1,1,2,,1.CBAR,2,1,2,3,,1.CBAR,3,1,3,4,,1.CBAR,4,1,4,5,,1.CBAR,5,1,5,6,,1.PBAR,1,1,4.,1.3333,1.3333,2.2496,,,PBAR1+BAR1,1.,1.,1.,-1.,-1.,1.,-1.,-1.MAT1,1,30.E06,,.3SPC,1,6,123456,0.FORCE,1,1,,4000.,,-1.FORCE,1,1,,4000.,-1.ENDDATA

Index


Main

NH5RDB database file: test.h5

Reference

MSC Nastran Quick Reference Guide

DMAP Programmer’s Guide

HDF5 Software Documentation

Index

http://www.hdfgroup.org/HDF5/doc/index.html


Main

NH5RDB Data AccessThe NH5RDB is a Hierarchical Data Format (HDF5) database; it organizes and stores data in groups and datasets. For MSC Nastran data, the groups and datasets are defined in a schema file. The NH5RDB structure and data objects will be created from these data definitions in the schema. This document shows how to access data in NH5RDB by the examples using Python and C languages.

Data Schema

The data schema is an XML file. It has elements to define file structure and storing data format in NH5RDB. Like folders in a file system, the <group> element specifies which group the underlying datasets belong to. The <dataset> element defines its storing data format and the <field> element defines each field properties. Below is a snippet of data schema that defines GRID input entry, nodal displacement and HEXA element stress output. A special note is for DOMAINS dataset and DOMAIN_ID field in input and output data. NH5RDB will store same type data in one dataset, for example, all displacement data will be put in the DISPLACEMENT dataset, no matter from which sub case and time step the displacement is. To distinguish data from different cases, the domain concept is introduced. The DOMAINS dataset consists of fields like ID, SUBCASE, STEP, etc. The ID field gives a unique number of the domain. The combination of all other fields makes one domain entry, which indicates the source of data. Correspondingly, a DOMAIN_ID field is attached to input and output data. This DOMAIN_ID is the ID number in DOMAINS dataset. From the DOMAIN_ID, the data source information can be obtained. Example below shows how to relate data with domains.

<?xml version="1.0" encoding="utf-8"?><crdb schema="0"> <typedefs> <typedef name="GRID_SS"> <description>Grid strain and stress structure</description> <field name="GRID" type="integer"/> <field name="X" type="double"/> <field name="Y" type="double"/> <field name="Z" type="double"/> <field name="TXY" type="double"/> <field name="TYZ" type="double"/> <field name="TZX" type="double"/> </typedef> </typedefs > <groups> <group name="NASTRAN"> <group name="INPUT"> <group name="NODE"> <dataset name="GRID" version="1"> <field name="ID" type="integer"/> <field name="CP" type="integer"/> <field name="X" type="double" size="3"/> <field name="CD" type="integer"/> <field name="PS" type="integer"/> <field name="SEID" type="integer"/> <field name="DOMAIN_ID" type="integer"/> </dataset> </group> </group>

Index


Main

<group name="RESULT"> <dataset name="DOMAINS"> <field name="ID" type="integer"/> <field name="SUBCASE" type="integer"/> <field name="STEP" type="integer"/> <field name="ANALYSIS" type="integer"/> <field name="TIME_FREQ_EIGR" type="double"/> <field name="EIGI" type="double"/> <field name="MODE" type="integer"/> <field name="DESIGN_CYCLE" type="integer"/> <field name="SE" type="integer"/> <field name="AFPM" type="integer"/> <field name="TRMC" type="integer"/> <field name="INSTANCE" type="integer"/> <field name="MODULE" type="integer"/> </dataset> <group name="NODAL"> <dataset name="DISPLACEMENT"> <field name="ID" type="integer"/> <field name="VALUE" type="double" size="6"/> <field name="DOMAIN_ID" type="integer"/> </dataset> </group> <group name="ELEMENTAL"> <group name="STRESS"> <dataset name="HEXA"> <field name="EID" type="integer"/> <field name="CID" type="integer"/> <field name="CTYPE" type="character" size="4"/> <field name="NODEF" type="integer"/> <field name="SS" type="GRID_SS" size="9"/> <field name="DOMAIN_ID" type="integer"/> </dataset> </group> </group> </group> </group> </groups></crdb>

Figure 10-1 Data Schema

Index


Main

NH5RDB

The NH5RDB database stores datasets as defined in the schema. To see NH5RDB structure, a NH5RDB database snapshot is shown in Figure 10-2. The tables show nodal displacement and HEXA element stress datasets.

Figure 10-2 NH5RDB Snapshot

Dataset Domain Index

As explained above about DOMAIN_ID, NH5RDB associates all data with domain ID and put the same type of data in one dataset. Therefore, a dataset may have data with multiple domain IDs. For a large dataset, one common operation is to access partial data from interested domain. To improve data retrieval efficiency, NH5RDB will generate domain ID index for corresponding output datasets. Under the root, an INDEX group will be created for domain index datasets. Corresponding to each output dataset, a domain index dataset with the same group and dataset name will be generated in the INDEX group. For example, the nodal displacement dataset is located at /NASTRAN/RESULT/NODAL/DISPLACEMENT in NH5RDB, its domain index dataset will be created as /INDEX/NASTRAN/RESULT/NODAL/DISPLACEMENT. All the index datasets have the same format with three fields DOMAIN_ID, POSITION and LENGTH. The DOMAIN_ID is the domain ID number, the POSITION is the domain ID start position in corresponding output dataset, and the LENGTH is the number of rows for the domain ID. From the start position and number of rows, the data for the domain ID can be located and accessed.

Index


Main

Records of a domain index dataset are sorted based on domain ID, and records with the same domain in a result dataset are sorted based on entity IDs, which are similar to MSC Nastran SORT1 option, the client code can use this feature to implement binary search algorithm for fast search.

Figure 10-3 shows the displacement and its index datasets. From the index dataset, the displacement data for domain ID 5 can be found from position 176 and has 44 rows. The reason that there are 44 rows (or the offset is 44) is because the model had 44 grid points and the Case Control was DISPLACEMENT=ALL.

Figure 10-3 Domain Index Dataset

Index


Main

Database Access Examples

The HDF5 is platform independent and provides multiple programming language APIs for data operations. The examples here are given in Python and C\C++ and Java to show dataset access operations.

The Python examples uses PyTable package for HDF5 file. The PyTable and NumPy packages are required to be installed with Python. The examples show how easy it is to access datasets in NH5RDB.

Requirements of C and C++ Examples

To build and run C and C++ examples, HDF5 library and a C++ compiler is required. All the examples below are built with Visual C++ 2013 on Windows and Intel C++ 2015 and HDF5 livrary 1.8.14 or 1.8.15-patch1, a later version of the C++ compiles and HDF5 library should also work.

Example 1: Read nodal displacements

This example reads nodal displacement dataset and prints the grid ID and displacements from the second row of the table.

import tablesimport numpy

# Open database filefile = tables.open_file("test.h5")

# Get displacement tabledisp = file.root.NASTRAN.RESULT.NODAL.DISPLACEMENT

# Get row number 2 of the tablerow = disp[2]

# Print grid id and its displacementprint row['ID'], row['VALUE']

# Close filefile.close()

Figure 10-4 Example 1: Read Nodal Displacement in Python

Example 2: Extract nodal displacements at time 3.0 and print in CSV format

This example has two steps, it first gets domain id belongs to time step 3.0, then extracts displacement for this time step and writes to a CSV file. In the example, the where clause is used to extract data for specified criterion. The time step and its corresponding displacements are shown in Figure 10-6 and the converted CSV file is shown in Figure 10-7.

import tables as pt

# -------------------------------------------------------------------------# Extract nodal displacements at time = 3.000 and print as CSV# -------------------------------------------------------------------------

# --- open h5 input filefname = "ldr2s400utp02.h5"

Index


Main

h5 = pt.open_file(fname)

# --- step 1: get "domain id" for t = 3.000 # -- path to table with domain idstblDOMAINS = h5.root.NASTRAN.RESULT.DOMAINS

# -- where clauset = 3.000tol = 0.005swhere = "(TIME_FREQ_EIGR > %6.4f)&(TIME_FREQ_EIGR < %6.4f)"%(t-tol, t+tol)

# -- extract domain idfor row in tblDOMAINS.where(swhere) : did = row["ID"] break

# --- step 2: extract the nodal displacements# -- path to table with nodal displacementstblDISPS = h5.root.NASTRAN.RESULT.NODAL.DISPLACEMENT

# -- open CSV output filefp = open("displacements.csv","w")

# -- where clauseswhere = "DOMAIN_ID == %d"%(did)

# -- loop over tablefor row in tblDISPS.where(swhere): gid = row["ID"] disp = row["VALUE"] fp.write("%d,%14.5e,%14.5e,%14.5e,%14.5e,%14.5e,%14.5e\n"%\ (gid,disp[0],disp[1], disp[2], disp[3], disp[4], disp[5]) )

# -- close filesfp.close()

h5.close()

Figure 10-5 Example 2: Extract Displacement and Convert to CSV Format

Index


Main

Figure 10-6 Time Step and Displacement Data

Figure 10-7 Converted CSV Data

Index


Main

Example 3: Extract time history of nodal translation displacements

This example extracts displacements of node number 63 for all time steps, the data is shown in Figure 10-9.

import tables as ptimport numpy as np

# -------------------------------------------------------------------------# Extract time history of translational displacements for node 63# -------------------------------------------------------------------------

# --- open h5 input filefname = "ldr2s400utp02.h5"h5 = pt.open_file(fname)

# --- step 1: extract times from domains table# -- path to table with domain idstblDOMAINS = h5.root.NASTRAN.RESULT.DOMAINS

# -- create empty numpy arrays for domain ids and timesids = np.array([], int)t = np.array([], float)

# -- contruct where clause# (time steps have domain ids 7 to 88 as found in HDFVIEW)swhere = "(ID >= 7) & ( ID <= 88)"

# -- loop over domains tablefor row in tblDOMAINS.where(swhere): t = np.append(t, row["TIME_FREQ_EIGR"]) ids = np.append(ids,row["ID"])

# -- create numpy arrays for resultsnt = t.sizedisp = np.zeros((nt,3), float)

# --- step 2: extract the nodal displacements# -- path to table with nodal displacementstblDISPS = h5.root.NASTRAN.RESULT.NODAL.DISPLACEMENT

# -- create where clause for node 63node = 63swhere = "(ID == %d) & ( DOMAIN_ID >= 7) & (DOMAIN_ID <= 88)"%( node )

# -- loop over tablei = 0for row in tblDISPS.where(swhere): d = row["VALUE"] disp[i,0] = d[0] disp[i,1] = d[1] disp[i,2] = d[2] i += 1

Index


Main

# -- close fileh5.close()

# --- write extracted time history data to output file# -- open time history output filefname = "disp_node_%d.csv"%(node)fp = open(fname,"w")fp.write(" TIME, XDISP, YDISP, ZDISP\n")for i in np.arange(nt) : fp.write("%6.3f,%14.6e,%14.6e,%14.6e\n"%\ (t[i], disp[i,0], disp[i,1], disp[i,2]))

# -- close output filefp.close()

Figure 10-8 Extract Nodal Displacement at all Time Steps

Figure 10-9 Nodal Displacement at Time Steps

The following examples are programs in C language. The HDF5 table APIs are used in these examples. For description of these APIs, please refer to HDF5 reference manual.

Example 4: Read nodal displacements

This example reads all data in the displacement dataset and prints the translation displacements. The dataset format is as its schema definition; its C type structure definition is shown in the example and can be found in dataset header file generated from schema.

Index


Main

#include "hdf5.h"#include "hdf5_hl.h"#include <cstdlib>

/* * Read all nodal displacements */void printDisplacement(){ // displacement dataset name char* table = "/NASTRAN/RESULT/NODAL/DISPLACEMENT";

// displacement structure typedef struct { long long ID; // grid id double VALUE[6]; // displacement long long DOMAIN_ID;// domain id } Type;

// displacement structure size size_t ts = sizeof(Type);

// field offset size_t offset[] = { HOFFSET(Type, ID), HOFFSET(Type, VALUE), HOFFSET(Type, DOMAIN_ID) };

Type type; // field size size_t size[] = { sizeof(type.ID), sizeof(type.VALUE), sizeof(type.DOMAIN_ID) };

// open file hid_t fid = H5Fopen("test.h5", H5F_ACC_RDONLY, H5P_DEFAULT); if (fid >= 0) { hsize_t nField, nRecord; // get field and record number if (H5TBget_table_info(fid, table, &nField, &nRecord) >= 0) { if (nRecord > 0) { // allocate buffer Type* p = (Type*) malloc(ts * nRecord); if (p) { // read displacement dataset if (H5TBread_table(fid, table, ts, offset, size, p) >= 0) { // print translation displacement for (size_t i = 0; i < nRecord; i++) { printf("GRID %d : %e, %e, %e\n", p[i].ID, p[i].VALUE[0], p[i].VALUE[1], p[i].VALUE[2]); }

Index


Main

} free(p); } } } // close file H5Fclose(fid); }}

Figure 10-10 Read and Print Nodal Displacements

Example 5: Read records (rows) of nodal displacements

The above example reads all data in nodal displacement dataset. This example shows reading only specified records (rows) from a dataset. It will read the first 10 records of displacements.

/* * Read the first 10 records of nodal displacements */void printDisplacement2(){ // displacement dataset name char* table = "/NASTRAN/RESULT/NODAL/DISPLACEMENT";

// displacement structure typedef struct { long long ID; // grid id double VALUE[6]; // displacement long long DOMAIN_ID;// domain id } Type;

// displacement structure size size_t ts = sizeof(Type);

// field offset size_t offset[] = { HOFFSET(Type, ID), HOFFSET(Type, VALUE), HOFFSET(Type, DOMAIN_ID) };

Type type; // field size size_t size[] = { sizeof(type.ID), sizeof(type.VALUE), sizeof(type.DOMAIN_ID) };

// open file hid_t fid = H5Fopen("test.h5", H5F_ACC_RDONLY, H5P_DEFAULT); if (fid >= 0) {

Index


Main

hsize_t nField, nRecord; // get field and record number if (H5TBget_table_info(fid, table, &nField, &nRecord) >= 0) { if (nRecord > 0) { // set record number to 10 if (nRecord > 10) { nRecord = 10; } // allocate buffer Type* p = (Type*) malloc(ts * nRecord); if (p) { // read the first 10 records if (H5TBread_records(fid, table, 0, nRecord, ts, offset, size, p) >= 0) { // print translation displacement for (size_t i = 0; i < nRecord; i++) { printf("GRID %d : %e, %e, %e\n", p[i].ID, p[i].VALUE[0], p[i].VALUE[1], p[i].VALUE[2]); } } free(p); } } } // close file H5Fclose(fid); }}

Figure 10-11 Read Nodal Displacement Records

Example 6: Read dataset fields (columns) of HEXA element stress by name

The above example shows reading records (rows) of dataset. This example will show how to read some fields (columns) in dataset. It will read data fields from HEXA element stress output. The specified fields are given by their field names, which are defined in schema.

/* * Read HEXA element stress data by field name */void printHexaStress(){ /* The HEXA stress dataset structure in database

typedef struct { long long EID; // Element identification number long long CID; // Stress Coordinate System char CTYPE[4]; // Coordinate System Type (BCD) long long NODEF; // Number of Active Points long long GRID[9]; // Number of active grids or corner grid ID double X[9]; // Normal X

Index


Main

double Y[9]; // Normal Y double Z[9]; // Normal Z double TXY[9]; // Shear xy double TYZ[9]; // Shear yz double TZX[9]; // Shear zx long long DOMAIN_ID; // Domain identifier } Type; */

// HEXA stress dataset name char* table = "/NASTRAN/RESULT/ELEMENTAL/STRESS/HEXA";

// fields to read from HEXA stress typedef struct { long long EID; long long X[9]; long long Y[9]; long long Z[9]; long long TXY[9]; long long TYZ[9]; long long TZX[9]; long long DOMAIN_ID; } Type;

size_t ts = sizeof(Type); size_t offset[] = { HOFFSET(Type, EID), HOFFSET(Type, X), HOFFSET(Type, Y), HOFFSET(Type, Z), HOFFSET(Type, TXY), HOFFSET(Type, TYZ), HOFFSET(Type, TZX), HOFFSET(Type, DOMAIN_ID) };

Type type; size_t size[] = { sizeof(type.EID), sizeof(type.X), sizeof(type.Y), sizeof(type.Z), sizeof(type.TXY), sizeof(type.TYZ), sizeof(type.TZX), sizeof(type.DOMAIN_ID) };

// field names of HEXA stress to read char* name = "EID,X,Y,Z,TXY,TYZ,TZX,DOMAIN_ID";

hid_t fid = H5Fopen("test.h5", H5F_ACC_RDONLY, H5P_DEFAULT); if (fid >= 0) { hsize_t nField, nRecord;

Index


Main

if (H5TBget_table_info(fid, table, &nField, &nRecord) >= 0) { if (nRecord > 0) { Type* p = (Type*) malloc(ts * nRecord); if (p) { // read fields by name if (H5TBread_fields_name(fid, table, name, 0, nRecord, ts, offset, size, p) >= 0){ for (size_t i = 0; i < nRecord; i++) { printf("EID %d : DOMAIN %d\n", p[i].EID, p[i].DOMAIN_ID); for (int j = 0; j < 9; j++) { printf("\t%e, %e, %e\n", p[i].X[j], p[i].Y[j], p[i].Z[j]); } } } free(p); } } } H5Fclose(fid); }}

Figure 10-12 Read HEXA Element Stress Data by Field Name

Example 7: Read data fields (columns) of HEXA element stress by index

In addition to names, field index can be used to specify the fields to read. This example uses an index array to specify the fields.

/* * Read HEXA element stress data by field index */void printHexaStress2(){ /* The HEXA stress dataset structure in database

typedef struct { long long EID; // Element identification number long long CID; // Stress Coordinate System char CTYPE[4]; // Coordinate System Type (BCD) long long NODEF; // Number of Active Points long long GRID[9]; // Number of active grids or corner grid ID double X[9]; // Normal X double Y[9]; // Normal Y double Z[9]; // Normal Z double TXY[9]; // Shear xy double TYZ[9]; // Shear yz double TZX[9]; // Shear zx long long DOMAIN_ID; // Domain identifier } Type; */

Index


Main

// HEXA stress dataset name char* table = "/NASTRAN/RESULT/ELEMENTAL/STRESS/HEXA";

// fields to read from HEXA stress typedef struct { long long EID; long long X[9]; long long Y[9]; long long Z[9]; long long TXY[9]; long long TYZ[9]; long long TZX[9]; long long DOMAIN_ID; } Type;

size_t ts = sizeof(Type); size_t offset[] = { HOFFSET(Type, EID), HOFFSET(Type, X), HOFFSET(Type, Y), HOFFSET(Type, Z), HOFFSET(Type, TXY), HOFFSET(Type, TYZ), HOFFSET(Type, TZX), HOFFSET(Type, DOMAIN_ID) };

Type type; size_t size[] = { sizeof(type.EID), sizeof(type.X), sizeof(type.Y), sizeof(type.Z), sizeof(type.TXY), sizeof(type.TYZ), sizeof(type.TZX), sizeof(type.DOMAIN_ID) };

// field index of HEXA stress to read int index[] ={0, 5, 6, 7, 8, 9, 10, 11}; int num = sizeof(index) / sizeof(int);

hid_t fid = H5Fopen("test.h5", H5F_ACC_RDONLY, H5P_DEFAULT); if (fid >= 0) { hsize_t nField, nRecord; if (H5TBget_table_info(fid, table, &nField, &nRecord) >= 0) { if (nRecord > 0) { Type* p = (Type*) malloc(ts * nRecord); if (p) { // read fields by index if (H5TBread_fields_index(fid, table, num, index, 0, nRecord, ts, offset, size, p) >= 0){ for (size_t i = 0; i < nRecord; i++) {

Index


Main

printf("EID %d : DOMAIN %d\n", p[i].EID, p[i].DOMAIN_ID); for (int j = 0; j < 9; j++) { printf("\t%e, %e, %e\n", p[i].X[j], p[i].Y[j], p[i].Z[j]); } } } free(p); } } } H5Fclose(fid); }}

Figure 10-13 Read HEXA Element Stress Data by Field Index

Example 8: Write displacement, HEXA element stress and domain datasets

The example writes the nodal displacement, hexahedral element stress, and domain datasets. These datasets use the same formats as defined in NH5RDB schema and table data is appended row by row. Both Python and C programs are given below.

# Write displacement, hexa stress and domain datasets in Pythonfrom tables import *from numpy import *

# Domain structureclass DOMAINS(IsDescription): ID = Int64Col(pos = 0) SUBCASE = Int64Col(pos = 1) STEP = Int64Col(pos = 2) ANALYSIS = Int64Col(pos = 3) TIME_FREQ_EIGR = Float64Col(pos = 4) EIGI = Float64Col(pos = 5) MODE = Int64Col(pos = 6) DESIGN_CYCLE = Int64Col(pos = 7) RANDOM = Int64Col(pos = 8) SE = Int64Col(pos = 9) AFPM = Int64Col(pos = 10) TRMC = Int64Col(pos = 11) INSTANCE = Int64Col(pos = 12) MODULE = Int64Col(pos = 13)

# Displacement structureclass DISPLACEMENT(IsDescription): ID = Int64Col(pos = 0) VALUE = Float64Col(shape = 6, pos = 1) DOMAIN_ID = Int64Col(pos = 2)

# Hexa element stress structureclass HEXA(IsDescription): EID = Int64Col(pos = 0) CID = Int64Col(pos = 1) CTYPE = StringCol(4, pos = 2) NODEF = Int64Col(pos = 3)

Index


Main

GRID = Int64Col(shape = 9, pos = 4) X = Float64Col(shape = 9, pos = 5) Y = Float64Col(shape = 9, pos = 6) Z = Float64Col(shape = 9, pos = 7) TXY = Float64Col(shape = 9, pos = 8) TYZ = Float64Col(shape = 9, pos = 9) TZX = Float64Col(shape = 9, pos = 10) DOMAIN_ID = Int64Col(pos = 11)

# Open fileh5 = open_file('test.h5', mode = 'w')# Create domain tabledomain = h5.create_table('/NASTRAN/RESULT', 'DOMAINS', DOMAINS, createparents = True)# Set domain valuesrow = domain.rowfor i in xrange(1, 2): row['ID'] = i row['SUBCASE'] = 1 row['STEP'] = 0 row['ANALYSIS'] = 1 row['TIME_FREQ_EIGR'] = 0 row['EIGI'] = 0 row['MODE'] = 0 row['RANDOM'] = 0 row['DESIGN_CYCLE'] = 0 row['SE'] = 0 row['AFPM'] = 0 row['TRMC'] = 0 row['INSTANCE'] = 0 row['MODULE'] = 0 row.append()domain.flush() # Flush table to file

# Create displacement tabledisplacement = h5.create_table('/NASTRAN/RESULT/NODAL', 'DISPLACEMENT', DISPLACEMENT, createparents = True)# Populate displacement, the values are for example only.row = displacement.rowfor i in xrange(1, 10): row['ID'] = i # grid id row['VALUE'] = array(i * arange(6)) # 3 translation + 3 rotation row['DOMAIN_ID'] = 1 # domain id row.append()displacement.flush()

# Create hexa element stress tablehexa = h5.create_table('/NASTRAN/RESULT/ELEMENTAL/STRESS', 'HEXA', HEXA, createparents = True)# Populate hexa stress, the values are for example only.row = hexa.rowfor i in xrange(1, 6): row['EID'] = i row['CID'] = 0 row['CTYPE'] = 'GAUS' # Gauss point

Index


Main

row['NODEF'] = 8 row['GRID'] = array(i * arange(9)) # grid ids including center row['X'] = array(i * arange(9)) # x normal stress of grids row['Y'] = array(i * arange(9)) row['Z'] = array(i * arange(9)) row['TXY'] = array(i * arange(9)) # xy shear stress of grids row['TYZ'] = array(i * arange(9)) row['TZX'] = array(i * arange(9)) row['DOMAIN_ID'] = 1 # domain id row.append()hexa.flush() # Close fileh5.close()

Figure 10-14 Write Nodal Displacement, Hexahedral Element Stress, and Domain Datasets using Python

// Write displacement, hexa stress and domain datasets in Cvoid writeStressHexa(){ char* result = "/NASTRAN/RESULT"; char* nodal = "/NASTRAN/RESULT/NODAL"; char* stress = "/NASTRAN/RESULT/ELEMENTAL/STRESS"; char* dptable = "DISPLACEMENT"; char* hxtable = "HEXA"; char* dmtable = "DOMAINS"; hsize_t chunk = 50;

// displacement structure typedef struct { long long ID; // grid id double VALUE[6]; // displacement long long DOMAIN_ID;// domain id } Displacement;

// displacement structure size size_t dp = sizeof(Displacement);

// displacement field offset size_t dpo[] = { HOFFSET(Displacement, ID), HOFFSET(Displacement, VALUE), HOFFSET(Displacement, DOMAIN_ID) };

// displacement field size Displacement disp; size_t dps[] = { sizeof(disp.ID), sizeof(disp.VALUE), sizeof(disp.DOMAIN_ID) };

// displacement field name const char* dpn[] = {

Index


Main

"ID", "VALUE", "DOMAIN_ID" };

// hexa stress structure typedef struct { long long EID; // Element identification number long long CID; // Stress Coordinate System char CTYPE[4]; // Coordinate System Type (BCD) long long NODEF; // Number of Active Points long long GRID[9]; // Number of active grids or corner grid ID double X[9]; // Normal X double Y[9]; // Normal Y double Z[9]; // Normal Z double TXY[9]; // Shear xy double TYZ[9]; // Shear yz double TZX[9]; // Shear zx long long DOMAIN_ID; // Domain identifier } Hexa;

// hexa stress structure size size_t hx = sizeof(Hexa);

// hexa field offset size_t hxo[] = { HOFFSET(Hexa, EID), HOFFSET(Hexa, CID), HOFFSET(Hexa, CTYPE), HOFFSET(Hexa, NODEF), HOFFSET(Hexa, GRID), HOFFSET(Hexa, X), HOFFSET(Hexa, Y), HOFFSET(Hexa, Z), HOFFSET(Hexa, TXY), HOFFSET(Hexa, TYZ), HOFFSET(Hexa, TZX), HOFFSET(Hexa, DOMAIN_ID) };

// hexa stress field size Hexa hexa; size_t hxs[] = { sizeof(hexa.EID), sizeof(hexa.CID), sizeof(hexa.CTYPE), sizeof(hexa.NODEF), sizeof(hexa.GRID), sizeof(hexa.X), sizeof(hexa.Y), sizeof(hexa.Z), sizeof(hexa.TXY), sizeof(hexa.TYZ), sizeof(hexa.TZX),

Index


Main

sizeof(hexa.DOMAIN_ID) };

// hexa stress field name const char* hxn[] = { "EID", "CID", "CTYPE", "NODEF", "GRID", "X", "Y", "Z", "TXY", "TYZ", "TZX", "DOMAIN_ID" };

// domain structure typedef struct { long long ID; // Domain identifier long long SUBCASE; // Subcase number long long STEP; // Step number long long ANALYSIS; // Analysis type double TIME_FREQ_EIGR; // Time, frequency or real part of eigen value double EIGI; // Imaginary part if eigen value (if applicable) long long MODE; // Mode number long long DESIGN_CYCLE; // Design cycle long long RANDOM; // Random code long long SE; // Superelement number long long AFPM; // acounstic field point mesh id long long TRMC; // trim component id long long INSTANCE; // Instance long long MODULE; // Module } Domain;

// domain structure size size_t dm = sizeof(Domain);

// domain field offset size_t dmo[] = { HOFFSET(Domain, ID), HOFFSET(Domain, SUBCASE), HOFFSET(Domain, STEP), HOFFSET(Domain, ANALYSIS), HOFFSET(Domain, TIME_FREQ_EIGR), HOFFSET(Domain, EIGI), HOFFSET(Domain, MODE), HOFFSET(Domain, DESIGN_CYCLE), HOFFSET(Domain, RANDOM), HOFFSET(Domain, SE), HOFFSET(Domain, AFPM), HOFFSET(Domain, TRMC),

Index


Main

HOFFSET(Domain, INSTANCE), HOFFSET(Domain, MODULE) };

// domain field size Domain domain; size_t dms[] = { sizeof(domain.ID), sizeof(domain.SUBCASE), sizeof(domain.STEP), sizeof(domain.ANALYSIS), sizeof(domain.TIME_FREQ_EIGR), sizeof(domain.EIGI), sizeof(domain.MODE), sizeof(domain.DESIGN_CYCLE), sizeof(domain.RANDOM), sizeof(domain.SE), sizeof(domain.AFPM), sizeof(domain.TRMC), sizeof(domain.INSTANCE), sizeof(domain.MODULE) };

// domain field name const char* dmn[] = { "ID", "SUBCASE", "STEP", "ANALYSIS", "TIME_FREQ_EIGR", "EIGI", "MODE", "DESIGN_CYCLE", "RANDOM", "SE", "AFPM", "TRMC", "INSTANCE", "MODULE" };

// domain field type hid_t dmt[] = { H5T_NATIVE_LLONG, H5T_NATIVE_LLONG, H5T_NATIVE_LLONG, H5T_NATIVE_LLONG, H5T_NATIVE_DOUBLE, H5T_NATIVE_DOUBLE, H5T_NATIVE_LLONG, H5T_NATIVE_LLONG, H5T_NATIVE_LLONG, H5T_NATIVE_LLONG, H5T_NATIVE_LLONG,

Index


Main

H5T_NATIVE_LLONG, H5T_NATIVE_LLONG, H5T_NATIVE_LLONG };

// create file hid_t fid = H5Fcreate("test.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); if (fid >= 0) { hid_t lpid = H5Pcreate(H5P_LINK_CREATE); if (lpid >= 0) { if (H5Pset_create_intermediate_group(lpid, 1) >= 0) { // create domain dataset memset(&domain, 0, dm); hid_t gid = H5Gcreate2(fid, result, lpid, H5P_DEFAULT, H5P_DEFAULT); if (gid >= 0) { if (H5TBmake_table("", gid, dmtable, 14, 0, dm, dmn, dmo, dmt, chunk, NULL, 1, NULL) >= 0) { domain.ID = 1; domain.SUBCASE = 1; domain.ANALYSIS = 1; H5TBappend_records(gid, dmtable, 1, dm, dmo, dms, &domain); } H5Gclose(gid); }

// create displacement dataset gid = H5Gcreate2(fid, nodal, lpid, H5P_DEFAULT, H5P_DEFAULT); if (gid >= 0) { hsize_t dim[1] = {6}; hid_t ar = H5Tarray_create2(H5T_NATIVE_DOUBLE, 1, dim); if (ar >= 0) { // data types hid_t dpt[3] = {H5T_NATIVE_LLONG, ar, H5T_NATIVE_LLONG}; if (H5TBmake_table("", gid, dptable, 3, 0, dp, dpn, dpo, dpt, chunk, NULL, 1, NULL) >= 0) { // populate displacement for (int i = 0; i < 10; i++) { disp.ID = i + 1; disp.DOMAIN_ID = domain.ID; for (int j = 0; j < 6; j++) { disp.VALUE[j] = i * 10 + j; } H5TBappend_records(gid, dptable, 1, dp, dpo, dps, &disp); } } H5Tclose(ar); } H5Gclose(gid); }

// create hexa dataset gid = H5Gcreate2(fid, stress, lpid, H5P_DEFAULT, H5P_DEFAULT); if (gid >= 0) { hsize_t dim[1] = {9};

Index


Main

hid_t ai = H5Tarray_create2(H5T_NATIVE_LLONG, 1, dim); hid_t ad = H5Tarray_create2(H5T_NATIVE_DOUBLE, 1, dim); hid_t ct = H5Tcopy(H5T_C_S1); if (ai >= 0 && ad >= 0 && ct >= 0 && H5Tset_size(ct, 4) >= 0) { // data types hid_t hxt[12] = {H5T_NATIVE_LLONG, H5T_NATIVE_LLONG, ct, H5T_NATIVE_LLONG, ai, ad, ad, ad, ad, ad, ad, H5T_NATIVE_LLONG}; if (H5TBmake_table("", gid, hxtable, 12, 0, hx, hxn, hxo, hxt, chunk, NULL, 1, NULL) >= 0) { for (int i = 0; i < 10; i++) { memset(&hexa, 0, hx); hexa.EID = i + 1; hexa.NODEF = 8; strncpy(hexa.CTYPE, "GAUS", 4); hexa.DOMAIN_ID = domain.ID; for (int j = 1; j < 9; j++) { hexa.GRID[j] = i * 10 + j; hexa.X[j] = i * 10 + j; hexa.Y[j] = i * 20 + j; hexa.Z[j] = i * 30 + j; hexa.TXY[j] = i * 10 + j; hexa.TYZ[j] = i * 20 + j; hexa.TZX[j] = i * 30 + j; } H5TBappend_records(gid, hxtable, 1, hx, hxo, hxs, &hexa); } } } if (ai >= 0) H5Tclose(ai); if (ad >= 0) H5Tclose(ad); if (ct >= 0) H5Tclose(ct); H5Gclose(gid); } } H5Pclose(lpid); } H5Fclose(fid); }}

Figure 10-15 Write Nodal Displacement, Hexahedral Element Stress and Domain Datasets using C

Example 9: Query and print result value by user specified domain and entities

This C++ example shows how to search records by a specified domain ID and entity IDs from a result dataset in the database. This search procedure can be implemented by reading records one by one and checking to see if IDs agree; however, it is very slow when the dataset becomes huge. To improve performance, the program can first search for where the domain is located by using domain index dataset, which is prepared when creating NH5RDB database; then read all the records with the specified domain into memory and find the records with the specified entity IDs. Both search procedures should use binary search because

1. Domain IDs in index dataset are sorted

2. Within the same domain ID, the entity IDs are also sorted.

Index


Main

We have a NH5RDB file shown in Figure 10-16 where the first 10 domains are from nonlinear static analysis. Suppose

we want to query displacement values of grid 25, 31 to 38 in the 4th increment, this increment has domain ID 4. The procedure is shown in Figure 10-18.

Index


Main

Figure 10-16 Processing Flow of the Query

Calling search_domain () function to searches for the record with domain id 4 from domain index dataset /INDEX/NASTRAN/RESULT/DISPLACEMENT, this is done by calling binary search function std::lower_bound().

POSITION 132 and LENGTH 44 are returned from the search_domain() call, read 44 records from dataset /NASTRAN/RESULT/NODAL/DISPLACEMENT started from 132 row(zero based index) into memory, call std::lower_bound() for each input entity to search the record, set them back to caller side

1

2

1 2

Index


Main

For details to build and run the program, read README.txt in nh5_examples/nh5qry.

Here shows source code of below two functions, check nh5qry.cpp for other details under nh5_examples/nh5qry.

Below is the function to search domain:

//// Purpose: search the start position and length (number of rows) of a domain// in a dataset// Input: // hid_t file: hdf5 file id// const std::string& restype0: result type // long long domain_id: domain id to be searched// output:// long long& pos: the start row position of the domain// long long& length: number of rows of the domain// return:// 0: successfull// !0: fail//int search_domain(hid_t file, const std::string& restype0, long long domain_id, // output long long &pos, long long& length ){ hid_t index_dset = 0; std::string fullname; int err = get_dset(file, restype0, true, index_dset, fullname); if (err != 0) return err;

// // read domain index dataset into memory // // get number of rows of domain index dataset hid_t space_id = H5Dget_space(index_dset); hsize_t dims_out[4]; int status_n = H5Sget_simple_extent_dims(space_id, dims_out, NULL); hsize_t total_row = dims_out[0];

// read all rows in one call std::vector<DomainIndex_T> indics; err = read_h5(index_dset, 0, total_row, indics); if (err != 0) return err;

// binary search the interesting domain, domain dataset is sorted based on DOMAIN_ID DomainIndex_T index = { domain_id, 0, 0 }; auto bound = std::lower_bound(indics.begin(), indics.end(), index, DomainIndex_Cmp()); if (bound != indics.end() && bound->DOMAIN_ID == domain_id) { pos = bound->POSITION; length = bound->LENGTH;

Index


Main

return 0; } else { fprintf(stderr, "No domain %d found in the damain index dataset %s\n", domain_id, fullname.data()); return -1; }}

Figure 10-17 Example to Search Domain Index

Below is the function to search records of specified IDs in a domain:

//// Purpose: search and print out records of specified ids in a domain// Input:// hid_t file: hdf5 file id// long long domain_id: domain id to be searched// const std::string& restype0: result type// DISPLACEMENT, DISPLACEMENT_CPLX, QUAD4, QUAD_CN are valid words// const std::string& id_str: a srting to specify ids// "1:6 8 10" means 1 through 6, 8 and 10. // return:// 0: successful// Non 0: fail//template<typename T>int do_search(hid_t file, long long domain_id, const std::string& restype0, const std::string& id_str){ long long pos, length; int err = search_domain(file, restype0, domain_id, pos, length);

if(err == 0 && length > 0) { hid_t dset = 0; std::string fullname; int err = get_dset(file, restype0, false, dset, fullname); if (err != 0) return err;

printf("Row range of domain %ld, %ld %ld\n", domain_id, pos + 1, pos + length); std::vector<T> displacements; print_head(displacements);

// // read all rows into memory and call binary search algorithm. // if the number of rows is huge, it is better to implement a binary // search algorithm to the hdf5 file directory for memory efficiency // // std::vector<typename T> displacements; err = read_h5(dset, pos, length, displacements); if (err != 0) { H5Fclose(file); return err;

Index


Main

}

std::vector<long long> ids = parse_id_string(id_str); for(auto id_it = ids.begin(); id_it != ids.end(); ++id_it) { long long id = *id_it; // records in a dataset is sorted based on MSC Nastran sort1, binary search // the interesting ID T disp0 = { id }; auto bound_rec = std::lower_bound(displacements.begin(), displacements.end(), disp0, CompareID<T>()); if (bound_rec != displacements.end() && match_id(*bound_rec, id)) { auto const & disp = *bound_rec; size_t dist = std::distance(displacements.begin(), bound_rec); print_row(disp); } else fprintf(stderr, "Cannot find record of id %ld from dataset \n", id); } }

return 0;}

Figure 10-18 Example to Search and Print Out Records

Example 10: Read nodal displacement dataset in Java

This example demonstrates how to access a dataset in NH5RDB in Java. The Java HDF Object Package, which wraps HDF Java interfaces in an object model, is used in the program. The package consists of several Java jar files and shared libraries. It can be obtained from HDF group website.

In the example, the nodal displacement dataset is read in first. Then each field data, including ID, VALUE and DOMAIN_ID, is obtained and print out to the system output.

/* * This example uses Java HDF Object Package to access NH5RDB. * */import ncsa.hdf.object.*;import java.util.*;

/** * The NH5RDB class defines methods to access NH5RDB. * */public class NH5RDB { /** * Read nodal displacement dataset and print to system output * * @param file the NH5RDB file name * @throws Exception */ public void printDisplacement(String file) throws Exception { FileFormat ff = null;

Index


Main

try { ff = FileFormat.getFileFormat( FileFormat.FILE_TYPE_HDF5).createInstance(file, FileFormat.READ); ff.open(); CompoundDS ds = (CompoundDS) ff.get("NASTRAN/RESULT/NODAL/DISPLACEMENT"); List data = (List) ds.getData(); long[] ID = (long[]) data.get(0); double[]VALUE = (double[]) data.get(1); long[] DOMAIN_ID = (long[]) data.get(2); int[] order = ds.getMemberOrders(); for (int i = 0; i < ID.length; i++) { System.out.println("ID: " + ID[i] + ", Domain: " + DOMAIN_ID[i]); for (int j = 0; j < order[1]; j++) { System.out.println("\tValue[" + j + "] = " + VALUE[i * order[1] + j]); } } } finally { if (ff != null) { ff.close(); } } }

/** * @param args the command line arguments */ public static void main(String[] args) { try { NH5RDB h5 = new NH5RDB(); h5.printDisplacement("test.h5"); } catch (Exception e) { e.printStackTrace(); } } }

Figure 10-19 Example to Read nodal displacement in Java

Example Files• DataType.html

• DataType.xml

• Example 1

• Example 2

• Example 3

• Example 4

• Example 5

• Example 6

Index

http://www.mscsoftware.com/doc/nastran/2016/release/DataType.html

http://www.mscsoftware.com/doc/nastran/2016/release/DataType.xml

http://www.mscsoftware.com/doc/nastran/2016/release/ex1.zip







Main

• Example 7

• Example 8a

• Example 8b

• Example 9

• Example 10

Index


http://www.mscsoftware.com/doc/nastran/2016/release/ex8a.zip

http://www.mscsoftware.com/doc/nastran/2016/release/ex8b.zip



184User InterfaceF06Reader Utility

Main

F06Reader UtilityThe F06 Reader is a tool to read MSC Nastran output text files (F06, F04, LOG) and produce a friendlier, modern and more useful format of important MSC Nastran information.

More comprehensive documentation including updated versions of the tool can be found on SimCompanion document DOC10731 (https://simcompanion.mscsoftware.com/infocenter/index?page=content&id=DOC10731).

BenefitsThe F06Reader’s primary output is an HTML file with:

• A Synopsis of analysis; what Solutions sequence is used, is there contact, are there Super Elements, etc.

• Pop-up messages (you can add your own) for specific MSC Nastran options/errors

• Links to MSC SimCompanion for FATAL Errors/Warnings

• Link to a local Quick Reference Guide

• Data (in some cases X-Y plots) which can be copied into reports, spreadsheet, etc.

XY Plots of data are only available through the Windows 7 executable. Most linear and nonlinear reports will include Maximum Displacement vs Maximum SPCForce. This is retrieved from the F06 and PARAM PRTMAXIM YES request. If PRTMAXIM is not requested or the data is suppressed from the F06, these plots will not be generated. For

Index

https://simcompanion.mscsoftware.com/infocenter/index?page=content&id=DOC10731


185 MSC Nastran 2016 Release GuideF06Reader Utility

Main

linear analysis with a single subcase, the plot is of a single point, not a line. For multiple subcases or a nonlinear analysis, a curve is generated.

Below is a plot of a SOL 400 analysis from F06 data. The upper plot is load percent vs maximum displacement and list grid with maximum displacement. Below this are the three iteration error plots; displacement, load and work. If the job fails to converge it may give some insight as to the problem.

• What was the maximum percentage load reached

• If displacement is unrealistic and at what grid

• Which convergence error criteria was not satisfied

SOL 106 is limited to load percent vs maximum displacement and does not list errors.

For aeroelastic flutter analysis, the F06Reader will display Damping vs Dynamic Pressure. Nearly duplicate curves will be filtered out and placed on a second plot labelled (Omitted lines). Removing the nearly duplicate curves highlights the fundamental behavior and makes investigation easier. The logic used to identify the nearly duplicate curves is heuristic, and may not be acceptable for all application. All of the data is available and can be copied into a spreadsheet for further investigation.

Index


Main

• Note that with flutter and duplicate removal logic, the number of plots generated can range from 10 to a 100. Processing time will take a few minutes to complete, generally less than five.

F06Reader UsageThe F06Reader is only available on Windows 7. If one is executing on Linux then one either need to have your file system cross-mounted and have write permission or copy your (F06, F04, LOG) files back to your local directory. There are three methods to invoke / use the F06Reader to improve engineering productivity. For occasional use it is easiest to use the graphical user interface that is highlighted in the examples in the next section.

For experienced users the F06Reader can be executed from the command line using command line argument.

If a series of simulations are going to be performed, it is often useful to indicate in the system RC or the local RCF that one wants the F06 reader to be invoked at the end of each MSC Nastran job that is submitted. To achieve this add the following line in the RC or RCF file.

Post=C:\MSC.Software\MSC_Nastran\ver_num\util_ver\x06Reader.exe

Note this is only achievable when executing MSC Nastran on Windows.

See the SimCompanion document DOC10731, interface Help/F06 Reader Documentation included with executable or MSC Nastran Installation article for more information.

The HTML files created will be placed in a directory called \fo6_reports\

The F06Reader works in conjunction with your local default browser. For the MSC Nastran 2016 release it has been tested on the English version of:

• Chrome

• Firefox

• Internet Explorer

Index



Main

RC File Example Usage

Double click on the executable at the following location in the MSC Nastran installation directory to open the GUI: C:\msc_software_2016\msc2016\win64i8\F06reader.exe

LimitationsThe F06 Reader may not work with older versions of MSC Nastran files and does not support all solution sequences / options.

ExampleThe following three images represent major features and benefits for an unsuccessful MSC Nastran job.

In the first image, the upper-left dropdown navigation Table of Contents shows the System/User Messages in red. This indicates a problem. Additionally, it lists how many Warning and FATALs were reported in this run. In the System, Users & Fatal Messages table, it lists all MSC Nastran messages with Warnings in blue and FATALs in red. The text box has a minimum of two lines from the message with additional lines in some cases. See the original F06 file for the full message, it is hyperlinked at the top of the HTML page.

Two other high value features of the message table are shown in Figure 10-20:

• Hovering or clicking on the symbol next to Warnings and FATALs opens the pop-up. This message will contain a link to MSC SimCompanion and initiate a search with the Warning or FATAL + number. If you are not familiar with the MSC Nastran error code, this is the first place to search. If nothing relevant is found contact MSC Support.

• The pop-up also contains text for common messages. This may be helpful as-is. The third image below shows how to link user generated pop-up messages to F06Reader via an XML file. These new messages overwrite text provided in the executable and overwrites built-in messages.

Index


Main

On the first image, next to hyperlinked MSC Nastran files is Data/Time information. The MSC Nastran Data/Time is found from within the text F06, LOG, F04 files. The File Data/Time is the file time stamp. Comparing these times indicates if the files were modified after the analysis, indicating that the data has potentially been manipulated, or is a mix of old and new files.

Index


Main

Figure 10-20 Mouse Hover or Click on the MSC Nastran Warning or FATAL Message

Figure 10-21 Link F06Reader to user-created XML file. This can be used to change pop-up messages the user sees and are permanently stored with the HTML report.

Index


Main

Limitations and GuidelinesThe F06 Reader is designed to collect, summarize and display information in other files. It is not designed to retrieve and perform user defined calculations with the data.

The F06Reader 2016 provided with MSC Nastran 2016 is the first public release of this tool. Reading text file input is sometimes problematic. Errors in functionality (executable failures) are expected. An F06Reader failure will not affect MSC Nastran results or generation of files.

The F06 reader may not work with older versions of MSC Nastran and does not support all solution sequences and options.

If a problem occurs, note the version being used locally and check SimCompanion for updates. If updates do not resolve the problem check SimCompanion article for whom to contact or contact MSC Support.

Index

191 MSC Nastran 2016 Release GuideSolid Elements Coordinate System Enhancement

Main

Solid Elements Coordinate System EnhancementThe MSC Nastran SOLID elements CHEXA, CTETRA, and CPENTA have an additional element coordinate system available on the PSOLID entry field 4 CORDM with a value of (-2) specified.

BenefitsThe standard internal coordinate system for the solid elements is based on eigenvalue techniques to insure non bias in the element formulation and designated as element coordinate system (-1). For irregular shaped elements, this system is difficult to visualize. An alternative element system has been introduced that provides a better visual understanding of its orientation and is designated as element system (-2).

The (-2) element system applies to stress and strain output and for anisotropic material specified on the MAT9 material entry.

Feature DescriptionFor the CHEXA element the (-2) element coordinate system is defined as:

Index

192User InterfaceSolid Elements Coordinate System Enhancement

Main

For the CTETRA element the (-2) element coordinate system is defined as:

For the CPENTAA element the (-2) element coordinate system is defined as:

ExampleThe example (tpl/ecs/ECS-2-RG.dat) shows a cylinder with an inner radius of 5 cm and an outer radius of 9 cm. The cylinder is 5 cm thick. It is simply supported using the three grids shown. It is subject to an internal pressure as shown by the rings of red dots.

The PSOLD entry is:

PSOLID 1 1 -2

Index

http://www.mscsoftware.com/doc/nastran/2016/release/ecs-2-rg.dat

193 MSC Nastran 2016 Release GuideSolid Elements Coordinate System Enhancement

Main

For this model, the CORDM=-2 is equivalent to the cylindrical coordinate shown in the center of the figure and defined as:

CORD2C 200 0. 0. 0. -1. 0. 0. 0. -1. 0.

Thus for the stress shown below, the element X(-2) axis is radial, the element Y(-2) axis is tangential, and the element Z(-2) axis is normal to the plane of rotation.

This example also used a MAT9 entry specifying an anisotropic material property. Thus the CORDM=-2 system was also used in defining the orientation of the material properties.

S T R E S S E S I N H E X A H E D R O N S O L I D E L E M E N T S ( H E X A ) CORNER ------CENTER AND CORNER POINT STRESSES--------- DIR. COSINES MEAN ELEMENT-ID GRID-ID NORMAL SHEAR PRINCIPAL -A- -B- -C- PRESSURE VON MISES 1 -2GRID CS 8 GP CENTER X -7.536923E+02 XY 8.269787E+00 A 1.600733E+03 LX 0.00 1.00-0.00 -2.811371E+02 2.083270E+03 Y 1.600670E+03 YZ -7.328754E+00 B -7.537229E+02 LY 1.00-0.00-0.00 Z -3.566650E+00 ZX 1.056068E+00 C -3.598534E+00 LZ-0.00-0.00-1.00 36 X -7.460766E+02 XY 1.284230E+02 A 1.786352E+03 LX 0.05 1.00-0.01 -3.424948E+02 2.260184E+03 Y 1.779788E+03 YZ -9.864753E+00 B -7.526190E+02 LY 1.00-0.05-0.01 Z -6.227168E+00 ZX 4.223301E+00 C -6.249172E+00 LZ-0.01-0.01-1.00 41 X -7.473914E+02 XY 1.284230E+02 A 1.424715E+03 LX 0.06 1.00-0.01 -2.240228E+02 1.916755E+03 Y 1.417116E+03 YZ -3.168922E+00 B -7.550099E+02 LY 1.00-0.06-0.00 Z 2.343537E+00 ZX 4.223301E+00 C 2.363164E+00 LZ-0.00-0.01-1.00 16 X -7.607948E+02 XY 1.284230E+02 A 1.428291E+03 LX 0.06 0.99 0.15 -2.197578E+02 1.941430E+03 Y 1.420666E+03 YZ -4.468450E+00 B -7.857184E+02 LY 1.00-0.06-0.02 Z -5.981386E-01 ZX -1.173036E+02 C 1.670096E+01 LZ-0.01 0.15-0.99 11 X -7.619092E+02 XY 1.284230E+02 A 1.790808E+03 LX 0.05 0.99 0.15 -3.374952E+02 2.285703E+03 Y 1.784180E+03 YZ -1.147237E+01 B -7.858845E+02 LY 1.00-0.05-0.02 Z -9.784829E+00 ZX -1.173036E+02 C 7.561574E+00 LZ-0.01 0.15-0.99 6 X -7.593786E+02 XY -1.118834E+02 A 1.789667E+03 LX-0.04 0.99-0.15 -3.383576E+02 2.282077E+03 Y 1.784598E+03 YZ -1.162533E+01 B -7.825614E+02 LY 1.00 0.04-0.02 Z -1.014606E+01 ZX 1.194157E+02 C 7.967381E+00 LZ-0.01-0.15-0.99 7 X -7.581757E+02 XY -1.118834E+02 A 1.427161E+03 LX-0.05 0.99-0.15 -2.206424E+02 1.937506E+03 Y 1.421350E+03 YZ -4.718880E+00 B -7.820474E+02 LY 1.00 0.05-0.02 Z -1.247328E+00 ZX 1.194157E+02 C 1.681368E+01 LZ-0.01-0.15-0.99 2 X -7.484072E+02 XY -1.118834E+02 A 1.423296E+03 LX-0.05 1.00 0.00 -2.239823E+02 1.914703E+03 Y 1.417524E+03 YZ -3.318358E+00 B -7.541781E+02 LY 1.00 0.05-0.00 Z 2.829675E+00 ZX -2.111166E+00 C 2.829304E+00 LZ-0.00 0.00-1.00 1 X -7.474048E+02 XY -1.118834E+02 A 1.785136E+03 LX-0.04 1.00 0.00 -3.423435E+02 2.258712E+03 Y 1.780138E+03 YZ -9.992974E+00 B -7.523564E+02 LY 1.00 0.04-0.01 Z -5.702890E+00 ZX -2.111166E+00 C -5.748799E+00 LZ-0.01 0.00-1.00

Index

194User InterfaceSolid Elements Coordinate System Enhancement

Main

Limitations and GuidelinesFor the CTETRA and CPENTA elements in SOL400 when using enhanced materials or PSLDN1, the coordinate (-2) is ignored and the basic system is used.

You can only view these results using F06, OP2, or HDF5 file types.

Index

Main


Chapter 11: Platform Support

11 Platform Support

Supported Hardware and Operating Systems 196

Index

196Platform SupportSupported Hardware and Operating Systems

Main

Supported Hardware and Operating SystemsThe MSC Nastran 2016 release is provided and certified on the following hardware/software platforms:

Software Development Kit (SDK)The MSC Software Development Kit 2016 is required for users who want to customize MSC Nastran 2016 with features like User Subroutines, User Defined Modules, OpenFSI, and Beam Libraries. The SDK can be downloaded separately from the "MSC Software Development Kit" product page.

Capability DiscontinuanceThe MSC Nastran 2014.1 release was the last release that supported the MATM option for composite material behavior. This has been replaced with the MATDIGI option that provides superior technology.

MSC is planning on eliminating support for mode=i4, that is small integer support. Based upon modern computer hardware it is felt that the mode=i8, large integer support provides significant benefits for running large engineering simulations.

Vendor OS HardwareFORTRAN

Version C Version Default MPI

Linux (64-bit) RHEL 6.3SuSE 11 sp2

Intel EM64T Intel 15.0 Intel 15.0 Intel MPI 5.0

Microsoft (64-bit) Windows 7 Intel EM65T Intel 15.0 Microsoft VS 2013 C/C++

Microsoft HPC Pack 2012 R2

Index

release guide - msc nastran 2016

Documents