msc nastran 2012 release guide

MSC Nastran 2012

Release Guide

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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.

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Revision 0. November 8, 2011NA:2012:Z:Z:Z:DC-REL

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C o n t e n t sMSC Nastran 2012 Release Guide MSC Nastran 2011 Release

Guide

Table of
Table of Contents
Preface to the MSC Nastran 2012 Release Guide viii

List of Books viii

Technical Support ix

Online Resources ix

MSC Nastran Documentation ix

1 Overview of MSC Nastran 2012

Overview 2

2 Linear Analysis

Smart Linear Contact Defaults (SOL 101) 6

3 Advanced Nonlinear (SOL 400)

Nonlinear Convergence Robustness – Smart Default and Adaptive Time Stepping Adjustment 14

Segment-to-Segment Contact Improvements 19

4 Explicit Nonlinear (SOL 700)

Introduction 24

DMP for FSI Applications with Adaptive Euler 25

DMP Improvements for Coupling and Editing 29

DMP Support for importing Eulerian ARC output files for restart 31

Thermal Capability 34

MSC Nastran 2012 Release Guide

iv

New Material Models (Wood and Ice) 40

Euler Body Force 41

Output Support for Genoa Damage Models 45

5 Implicit Nonlinear (SOL 600)

SOL 600 Enhancements 48

6 Numerical Methods and High Performance Computing

ACMS 52

Performance Improvements for Unsymmetric Solutions 56

New Complex Eigenvalue Extraction Method: IRAM 59

GPU Support 62

Intel AVX Support 65

7 Composites

Data Recovery of Dynamic Responses at Ply Level in Composites 68

8 Optimization

Design of Control Surfaces 76

9 Aeroelasticity

Improvements in Spline Blending 82

Alternate Trim Definition 84

Small Difference in Answers Based on Doublet Lattice Aerodynamics 87

10 Acoustics

Weakly Coupled Acoustics 90

Efficient Participation Factor Analysis with ACMS and DMP 92

vContents

Frequency Dependent Analysis with ACTRAN Trimmed Material and/or Acoustic Pressure Load Matrices 95

Panel Participation Factor Analysis for Structure Response 102

Compute Element Sensitivity based on Frequency Response Function and Element Matrix 106

Output Particle Acceleration on Wetted Surface 114

Output ADF Format File for Frequency Response Function 117

11 DMAP Module Updates

New DMAP Modules 122

Modified DMAP Modules 123


vi

MSC Nastran Release Guide Preface

Preface

Preface to the MSC Nastran 2012 Release Guide

List of Books

Technical Support

Online Resources

MSC Nastran Documentation

MSC Nastran 2012 Release GuidePreface to the MSC Nastran 2012 Release Guide

viii

Preface to the MSC Nastran 2012 Release GuideThis Release Guide contains descriptions for the MSC Nastran 2012 version, and supersedes the MD Nastran 2011 & MSC Nastran 2011 Release Guide.

List of BooksBelow is a list of some of the Nastran documents. You may find any of these documents from MSC.Software at www.simcompanion.mscsoftware.com.

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

• MSC Nastran Demonstration Problems

• Thermal Analysis

• Superelements

• Design Sensitivity and Optimization

• Implicit Nonlinear (SOL 600)

• Explicit Nonlinear (SOL 700)

• Aeroelastic Analysis

• User Defined Services

• EFEA User’s Guide

• EFEA Tutorial

• EBEA User’s Guide

ixPreface

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)

Support Online. The Support Center provides technical articles, frequently asked questions and documentation from a single location.

Online ResourcesMSC.Software (www.mscsoftware.com)

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

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

1. Go to your Nastran_Installation_DIR\msc20121\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

http://simcompanion.mscsoftware.com

http://www.mscsoftware.com/Contents/Services/Technical-Support/Contact-Technical-Support.aspx

www.mscsoftware.com

MSC Nastran 2012 Release GuideMSC Nastran Documentation

x

Chapter 1: Overview of MSC Nastran 2012 MSC Nastran & MSC Nastran Release Guide

1 Overview of MSC Nastran 2012

Overview

MSC Nastran 2012 Release GuideOverview

2

OverviewMSC.Software is pleased to introduce you to the exciting new technologies in MSC Nastran 2012, the premier and trusted CAE solution for aerospace, automotive, defense, and manufacturing industries worldwide. This release includes new features and enhancements in Contact, High Performance Computing, Acoustics, Aeroelasticity, and Explicit Nonlinear SOL 700.

Linear Analysis• Smart Linear Contact Defaults (SOL 101) (Ch. 2)

Advanced Nonlinear (SOL 400)• Nonlinear Convergence Robustness – Smart Default and Adaptive Time Stepping Adjustment

(Ch. 3)

• Segment-to-Segment Contact Improvements (Ch. 3).

Explicit Nonlinear (SOL 700)• DMP for FSI Applications with Adaptive Euler (Ch. 4)

• DMP Improvements for Coupling and Editing (Ch. 4)

• DMP Support for importing Eulerian ARC output files for restart (Ch. 4)

• Thermal Capability (Ch. 4)

• New Material Models (Wood and Ice) (Ch. 4)

• Euler Body Force (Ch. 4)

• New LS-Dyna libraries (Ch. 4)

Numerical Methods and High Performance Computing (Performance)

• ACMS (Ch. 6)

• Performance Improvements for Unsymmetric Solutions (Ch. 6)

• New Complex Eigenvalue Extraction Method: IRAM (Ch. 6)

• GPU Support (Ch. 6)

• Intel AVX Support (Ch. 6)

Composites• Data Recovery of Dynamic Responses at Ply Level in Composites (Ch. 7)

3CHAPTER 1Contents

Optimization• Design of Control Surfaces (Ch. 8)

Aeroelastic Enhancements• Improvements in Spline Blending (Ch. 9)

• Alternate Trim Definition (Ch. 9)

Acoustics• Weakly Coupled Acoustics (Ch. 10).

• Efficient Participation Factor Analysis with ACMS and DMP (Ch. 10)

• Frequency Dependent Analysis with ACTRAN Trimmed Material and/or Acoustic Pressure Load Matrices (Ch. 10)

• Panel Participation Factor Analysis for Structure Response (Ch. 10)

Product Unification

Future Platform SupportThe Linux 32 bit platform will be discontinued starting in the year 2012.

Sun SOLARIS may not be available in future releases.

HP Unix - IPF may not be available in future releases.

IBM AIX may not be available in future releases.

MSC Nastran 2012 Release GuideOverview

4

Chapter 2: Linear AnalysisMSC Nastran 2011Release Guide

2 Linear Analysis

Smart Linear Contact Defaults (SOL 101)

MSC Nastran 2012 Release GuideSmart Linear Contact Defaults (SOL 101)

6

Smart Linear Contact Defaults (SOL 101)

IntroductionThis feature provides a user-friendly interface to improve performance and accuracy of linear contact modeling.

BenefitsThe users will benefit from ease of use in SOL 101 contact analysis by specifying keywords of their preference. MSC Nastran sets best solution control parameters based on the keyword specified by the user to either improve the accuracy or reduce computational costs.

Feature DescriptionThe users specify their preference of achieving better performance or accuracy. MSC Nastran selects default values of control parameters accordingly. The users can also change the values of some specific control parameters based on their analysis requirements.

User InputsThe analysis preference is specified from the first line of NLSTEP Bulk Data Entry using “LCPERF” or “LCACCU” keyword. This entry also allows the user to customize values of specific control parameters through the new “LCNT” keyword. For the complete entry see NLSTEP (p. 2666) in the MSC Nastran Quick Reference Guide.

Specifies the convergence criteria, step size control between coupled loops and step/iteration control for each physics loop in MSC Nastran SOL 400. Defines analysis preference and control parameters for linear contact analysis in MSC Nastran SOL 101.

Format: (For SOL 101)

NLSTEP Describes the Control Parameters for Mechanical, Thermal and Coupled Analysis in MSC Nastran SOL 400 and for Linear Contact Analysis in MSC Nastran SOL 101.

1 2 3 4 5 6 7 8 9 10

NLSTEP ID CTRLDEF

“LCNT” NINCC CONVC EPSUC EPSPC EPSWC MAXDIVC MAXBISC

MAXITERC MINITERC

7CHAPTER 2Contents

Example: (Select the default control parameters for accuracy preference)

Example: (Four increments, P convergence criterion with error tolerance 1.e-4. The other parameters are defaults for performance preference)

Remarks:

15. “LCPERF” specifies the performance preference during analysis, while “LCACCU” prefers accuracy for analysis. The NLSTEP is selected by the Case Control Command. For SOL 101, only CTRLDEF and LCNT keywords can be selected. The CTRLDEF keyword must be defined if the smart linear contact default is required. Specification of LCNT keyword is optional. Listed below are default control parameters for linear contact analysis if LCNT keyword or some of its fields are not defined.

NLSTEP 10 LCACCU

NLSTEP 10 LCPERF

LCNT 4 P 1.e-4

Field Contents

CTRLDEF Keyword to specify the analysis preference of (1) nonlinear analysis (Character=”QLINEAR”, “MILDLY” or “SEVERELY”; No default) See Remark 14, or (2) linear contact analysis. (Character=“LCPERF” or “LCACCU”; No default). See Remark 15.

“LCNT” Keyword to indicate that the linear contact analysis should be used. See Remark 15.

NINCC Number of increments. (Integer > 0; Default = 1)

CONVC Flags to select convergence criteria. (Character=”U”, “P”, “W”, “V”, or any combination; Default = “PV” for CTRLDEF = “LCPERF”; Default = “UPV” for CTRLDEF= “LCACCU”).

EPSUC Error tolerance for displacement (U) criterion. (Real > 0.0; Default = 1.0E-3 for CTRLDEF = “LCPERF”; Default = 1.0E-2 for CTRLDEF= “LCACCU”)

EPSPC Error tolerance for load (P) criterion. (Real > 0.0; Default = 1.0E-3 for CTRLDEF = “LCPERF”; Default = 1.0E-2 for CTRLDEF= “LCACCU”)

EPSWC Error tolerance for work (W) criterion. (Real > 0.0; Default = 1.0E-7 for CTRLDEF = “LCPERF”; Default = 1.0E-2 for CTRLDEF= “LCACCU”)

MAXDIVC Limit on probable divergence conditions per iteration before the solution is assumed to diverge. (Integer 0; Default = 3 for CTRLDEF = “LCPERF”; Default = 5 for CTRLDEF= “LCACCU”).

MAXBISC Maximum number of bisections allowed for each load increment. (-10 < Integer < 10; Default = 5)

MAXITERC Limit on number of iterations for each load increment. (Integer > 0, Default = 25)

MINITERC Minimum number of iterations of a load increment. (Integer > 0; Default = 0)


8

Guidelines and LimitationsThe performance of “LCPERF” selection is expected to improve by two to seven times for most models compared to the current default settings of linear contact analysis. However, this enhancement applies to SOL 101 Linear Static Analysis only. For some contact models, specifying “LCPERF” or “LCACCU” preference may result in poor convergence. In these cases, the user may increase the number of increments (NINCC) to achieve optimal results.

Example (rg_lcdf.dat)This model consists of a pin as the contact body ID 1 and a clevis as the contact body ID 2. The pin is the master body and has the SPLINE option on (BCBODY “IDSPL”). The contact table was set up to use single sided contact (ISEARCH=1). Stress free initial contact is enabled.

To specify the Performance preference, define NLSTEP Case Control Command and NLSTEP Bulk Data Entry as follows.

NASTRAN SYSTEM(316)=19$SOL 101CEND

CTRLDEF NINCC CONVC EPSUC EPSPC EPSWC MAXDIVC MAXBISC MAXITERC MINITERC

LCPERF 1 PV 1.e-3 1.e-3 1.e-7 3 5 25 0

LCACCU 1 UPV 1.e-2 1.e-2 1.e-2 5 5 25 0

9CHAPTER 2Contents

$TITLE = THIS IS A DEFAULT SUBCASE. ECHO = NONE BCONTACT = 0SUBCASE 1 TITLE=This is a default subcase. SUBTITLE=Linear_contact NLSTEP = 1 BCONTACT = 1 SPC = 2 LOAD = 2 DISPLACEMENT(PLOT,SORT1,REAL)=ALL SPCFORCES(PLOT,SORT1,REAL)=ALL STRESS(PLOT,SORT1,REAL,VONMISES,BILIN)=ALL BOUTPUT(PLOT,SORT1,REAL)=ALL$BEGIN BULK$PARAM PRTMAXIM YESNLSTEP,1,,LCPERF:

Similarly, the Accuracy preference can be specified by replacing the following NLSTEP Bulk Data Entry

NLSTEP,1,,LCPERF

With

NLSTEP,1,,LCACCU

The von Mises stress results are shown below.


10

Running on a Linux LX8664 machine, the Performance preference shows 7.3 times improvement in CPU time and 8.2 times improvement in convergence comparing with the baseline model that uses original default values of control parameters. The Accuracy preference shows 5.5 times improvement in CPU time and 5.5 times improvement in convergence. The following table lists detail comparisons of these three models.

By selecting LCPERF or LCACCU one effectively modifies the convergence control variables as shown in the following table.

Model Parameters \ Simulation Baseline Model

Accuracy Preference

Performance Preference

Results (comparison to baseline)

-- Good(results match

baseline)

Good(results match

baseline)

CPU time improvement(baseline CPU / current)

1.0 5.5 7.3

# of iterations 41 7 5

Improvement in convergence(baseline iterations / current)

1.0 5.9 8.2

# of bisections / cutbacks 0 0 0

11CHAPTER 2Contents

Max. Displacement (from .sts file) -3.2688E-04 -3.2688E-04 -3.2688E-04

% difference from baseline 0.00% 0.00% 0.00%

# of increments

NINC

blank(default: 10)

blank(default: 1)

blank(default: 1)

Convergence criteriaCONV

blank(default: PV)

blank(default: UPV)

blank(default: PV)

Convergence: Displacement EPSU

blank(default: 1.0E-2)



Convergence: Force EPSP




Convergence: Work EPSW




Max. # of iterationsMAXITER

blank(default: 25)

blank(default: 25)

blank(default: 25)

Limit on divergence condition MAXDIV

blank(default: 3)

blank(default: 5)

blank(default: 3)

Model Parameters \ Simulation Baseline Model

Accuracy Preference

Performance Preference


12

Chapter 3: Advanced Nonlinear (SOL 400) MSC Nastran 2012 Release Guide

3 Advanced Nonlinear (SOL 400)

Nonlinear Convergence Robustness – Smart Default and Adaptive Time Stepping Adjustment

Segment-to-Segment Contact Improvements

MSC Nastran 2012 Release Guide Nonlinear Convergence Robustness – Smart Default and Adaptive Time Stepping Adjustment

14

Nonlinear Convergence Robustness – Smart Default and Adaptive Time Stepping Adjustment

IntroductionIn MSC Nastran 2012, the adaptive time stepping procedure, NLSTEP, is extended. NLSTEP specifies the convergence criteria, step size control between coupled multi-physics loop and step/iteration control for each physics loop in MSC Nastran SOL 400. Also, NLSTEP defines analysis preference and control parameters for linear contact analysis in MSC Nastran SOL 101. The NLSTEP option provide a rich selection of controls for users; however, the entries are complicated for novice users. Therefore a new user-friendly entry is introduced. With this new feature, users have only to select limited entries based on their judgment of the nonlinearity of the model to be analyzed.

Also, a new automatic time step adjustment based on the dominant frequency of the system is introduced, which can be combined with iteration based adaptive time stepping adjustment by the desired number of iterations, NDESIR

BenefitsUsers can now set the adaptive load/time stepping procedure with just a few entries based on their judgment on the degree of nonlinearity of the targeted model/ job.

With the new ADAPT procedure for NLTRAN, users can run nonlinear transient analysis in a more efficient way without compromising the accuracy of the results

Feature DescriptionThe new keyword CTRLDEF in NLSTEP automatically sets up the entries for the time stepping adjustment and convergence tolerance. The keyword CTRLDEF has four values available as "QLINEAR", "MILDLY", "SEVERELY" , or blank, based on the nonlinearity of the targeted model.

“QLINEAR” may be used for linear analysis but with contact nonlinearity; “MILDLY” may be applied to general nonlinear problem including geometry nonlinearity, material nonlinearity, contact nonlinearity, and their combination; “SEVERELY” is suitable to nonlinear problem involving severe large displacement, large strain, multi-contact pairs, and so on. Leaving it blank activates all the default values of available entries.

The current procedure for ADAPT for NLTRAN has been significantly improved to be compatible to the old TSTEPNL option. The output request has been made consistent with design of NLSTEP which is controlled by the INTOUT entry.

The new procedure for ADAPT does not apply any bounds on the time step adjustment. The number of step (MSTEP) to integrate the dominant period response of the system (internally calculated using the information of the system stiffness matrix, mass matrix, and incremental displacement vector) is automatically set.

15CHAPTER 3Contents

Guidelines and LimitationsIn SOL400 nonlinear transient analysis, the use of keywords "QLINEAR", "MILDLY", and "SEVERELY" or leaving blank cannot properly set the number of increments (NINC) when the fixed time step procedure is used or initial time step (DTINITF) when the adaptive load step procedure is used. "FIXED" NINC value or an "ADAPT" DTINITF value hence the user STILL MUST set whichever one of these keyword entries is selected for a transient run.

The new ADAPT for NLTRAN analysis is activated by setting MSTEP=-1. For this case, although the number of time step adjustment (ADJUST>0) can be variably set, it is recommended to set ADJUST=1. In this case, every significant change in the nonlinearity of the system can be detected promptly. The stiffness matrix update should also be set to PFNT. This setting should be used when a highly nonlinear response in structure is expected; e.g., contact, plasticity, and large strain.

For mildly nonlinear response, users may choose the time step adjustment with bounds (RB on the NLSTEP, ADAPT). When it is combined with ADJUST > 1, it may give the most efficient solution in term of CPU times

Test CasesThe following test case, rg_nas75ex, for CTRLDEF is from TPL in directory /tpl/md400ug/nug_17.

It is a double-side contact problem and involves large displacement, large strain and large slide. Figure 3-1 depicts the FE model of the test case. Material used in the problem is characterized by elasto-plasticity. Four-node 2D plane strain elements are used. Adaptive time step adjustment was implemented by ADAPT in NLSTEP. The parameters for adapt time stepping adjustment is automatically determined by keyword SEVERELY in NLSTEP. A total of 63 increments were used in the analysis. Figure 3-2 shows the serial snapshots of deformed configuration. Figure 3-2 (a) to 2(c) depicts the distribution of y-displacement on the deformed configuration at various load levels, i.e., around 30%, 60%, and 100%, respectively.

Figure 3-1 Numerical Model of the Test Case for CTRLDEF


16

(A)

(B)

17CHAPTER 3Contents

Figure 3-2 Y-displacement Distribution on Deformed Configuration

The following test case is n75nlstp1 taken from TPL in directory /tpl/utn75nlstp.

A 2D beam model as described in Bergan's paper is subjected to dynamic load at an end as shown in Figure 3-3. This dynamic load is a sinusoidal function of time as 450*sin(2*pi*9*t). Three time stepping methodologies were used here, i.e., old NLSTEP, new NLSTEP with combination of frequency and iteration based time stepping adjustment, as well frequency based time stepping adjustment. For new NLSTEP decks, the parameters concerning are set up as follows:

MSTEP=-1, ADJUST=1, and NDESIR=5.

(C)


18

Figure 3-3 2D beam subjected to dynamic load at an end

Figure 3-4 includes the curves of the displacement of the end over time obtained by three different time stepping methodologies, respectively. It may be seen that old NLSTEP yields very large time step and couldn't capture the displacement history accurately. The new NLSTEP with frequency and iteration based time step adjustment appropriately controls the time step adjustment and is sensitive to the change of the energy and boundary conditions. It results in very similar results as others.

Figure 3-4 Y-displacement history of the beam end

19CHAPTER 3Contents

Segment-to-Segment Contact Improvements

IntroductionThis feature supports friction analysis in segment-to-segment contact modeling in MSC Nastran. Major enhancements include implementation of a nonsymmetric stiffness matrix for sliding friction and a finite sliding capability for deformable contact bodies.

BenefitsCurrent MSC Nastran users benefit from this functionality by being able to compute friction forces in segment-to-segment contact analysis. The program is also improved to handle segment-to-segment contact analysis with finite sliding. In the 2012 release of MSC Nastran the previous restriction of small sliding in segment-to-segment contact analysis has been removed. The large sliding between deformable bodies and friction is now a pre-release capability.

Feature DescriptionSeveral new flags or parameters are provided to allow the specifications of finite sliding support, maximum allowed sliding distance, nonsymmetric friction matrix selection, neglecting thickness, and error calculation option.

User InputsFive new parameters, SLDLMT, SEGSYM, THKOFF, ERRBAS and DDULMT are added in BCPARA Bulk Data Entry. In addition, a new flag SEGLARGE in the existing METHOD parameter is provided to support segment to segment contact with finite sliding. For the complete entry see BCPARA.

Defines contact parameters used in SOL 101 and MSC Nastran SOL 400. This entry is not available in SOL 700.

Format:

BCPARA Contact Parameters

1 2 3 4 5 6 7 8 9 10BCPARA ID Param1 Value1 Param2 Value2 Param3 Value3

Param4 Value4 Param5 Value5 etc.

MSC Nastran 2012 Release Guide Segment-to-Segment Contact Improvements

20

Example:

Table III.D – 1Contact Parameters

Remarks:

1. – 8. Same as current QRG.

9. Parameters MAXSEP, ICSEP, IBSEP, RVCNST, BEAMB and NLGLUE are not supported in segment to segment contact analysis.

10. The default of SLDLMT parameter is 5 times the default error tolerance. See the description of ERROR parameter for the definition of default error tolerance.

LimitationsSegment-to-segment contact with finite sliding does not support brake squeal analysis, thermal analysis, coupled analysis with multiple physics, and segment-to-segment contact with adaptive meshing. These features will be supported in future releases.

BCPARA ERROR 0.1 BIAS 0.5

Field Contents

: : (Same as current QRG)

NameDescription, Type and Value (Default is 0 for integer, 0.0 for Real Unless Otherwise

Indicated)


METHOD Flag to select Contact methods. (Character)

NODESURF Regular 3D Contact (Default: node to surface contact)

SEGSMALL Segment to segment contact with small sliding.

SEGLARGE Segment to segment contact with finite sliding.


SLDLMT Maximum allowed sliding distance, beyond it the contact segments are redefined, for segment to segment contact analysis with large deformation. (Real > 0.0; Default = 0.0 see Remark 10)

SEGSYM Specify symmetric or non-symmetric friction matrix in segment to segment contact analysis. (Integer 0 = symmetric matrix or 1 = non-symmetric matrix; Default = 0)

THKOFF Ignore thickness from the tolerance used by ISEARCH=2 in node-to-surface contact or from the characteristic length (for PENALT and AUGDIST) in segment-to-segment contact. (Integer 0 = do not ignore thickness or 1 = remove thickness; Default = 0)

ERRBAS Error computation option. (Integer 0 = compute error globally or 1 = calculate error based on each pair of slave-master; Default = 0)

DDULMT Maximum value of DDU in a Newton-Raphson cycle. (Real > 0.0; Default = 0.0, no limitation)

21CHAPTER 3Contents

Example (rg_stsl.dat)This model demonstrates the segment to segment contact with friction using HEXA8 elements and non-symmetrical friction matrix. It consists of the following two load steps.

1. The first step pushes down the upper small block in z direction and fixes the bottom of the big block. The enforced displacements are displayed below.

2. The second step adds the enforced displacements of the upper small block in x and y directions so that the displacements of the upper grids are (1.4, 0.9, -1.e-3).

To model segment-to-segment contact with finite sliding, define BCONTACT Case Control Command and BCTABLE, BCPARA, BCBODY and BSURF Bulk Data entries as follows.

SOL 400CEND$TITLE = THIS IS A DEFAULT SUBCASEECHO = NONESUBCASE 1STEP 1 ANALYSIS=NLSTATIC BCONTACT = 1 SPC = 11 LOAD = 1 NLSTEP=9 DISPLACEMENT(SORT1,REAL)=ALL SPCFORCES(SORT1,REAL)=ALL STRESS(SORT1,REAL,VONMISES,BILIN,PLOT)=ALLSTEP 2 ANALYSIS=NLSTATIC BCONTACT = 1 NLSTEP=9 SPC=2 LOAD = 1 DISPLACEMENT(SORT1,REAL)=ALL SPCFORCES(SORT1,REAL)=ALL STRESS(SORT1,REAL,VONMISES,BILIN,PLOT)=ALLBEGIN BULKPARAM,LGDISP,1

MSC Nastran 2012 Release Guide Segment-to-Segment Contact Improvements

22

BCTABLE 1 1 SLAVE 2 0. 0. 0.5 0. 0 0 0 0 0 0. 0 FBSH .9 HHHB 0. 0. 0. 0. 0. 0. MASTERS 1$PARAM POST 0PARAM PRTMAXIM YESBCPARA,0,FTYPE,6,SLDLMT,0.01,SEGSYM,1,,THKOFF,1,ERRBAS,1,METHOD,SEGLARGE:$ Deform Body Contact LBC set: topBCBODY 1 3D DEFORM 6 0BSURF 6 403$ Deform Body Contact LBC set: bottomBCBODY 2 3D DEFORM 7 0BSURF 7 404 405 406 407 408 409 410:

Note that friction type, symmetry of friction matrix, and finite sliding contact method are specified by FTYPE, SEGSYM and METHOD parameters of BCPARA entry.

The reaction forces of the last increment are shown below.

Chapter 4: Explicit Nonlinear (SOL 700) MSC Nastran 2012 Nastran Release Guide

4 Explicit Nonlinear (SOL 700)

Introduction

DMP for FSI Applications with Adaptive Euler

DMP Improvements for Coupling and Editing

DMP Support for importing Eulerian ARC output files for restart

Thermal Capability

New Material Models (Wood and Ice)

Euler Body Force

Output Support for Genoa Damage Models

MSC Nastran 2012 Release GuideIntroduction

24

IntroductionMSC Nastran 2012 includes several major new capabilities in the Explicit Nonlinear Solution – SOL 700. These capabilities are primarily focused in the areas of High Performance Computing (HPC) for fluid-structure interaction (FSI) applications, multi-physics, enhanced material models and robustness.

New Capabilities in Explicit Nonlinear (SOL 700)The following new capabilities are added in this release:

• Distributed Memory Parallel (DMP) support for FSI applications with Adaptive Euler

• Optimization of Coupling and Editing algorithms to improve performance

• DMP support for importing Euler Archive files for restart analysis.

• Thermal Capability for structures

a. Coupled Thermal Structural Analysis

b. Thermal Contact

c. Thermal Materials

d. Thermal Loading & Boundary Conditions (Temperature, Flux, Conduction, Convection & Radiation

• New material models (Wood and Ice)

• Capability to define Euler Body Force on select parts of the model

• Composites – Output support for Genoa Damage variables at individual layers

• Upgrade LS-Dyna libraries to R 5.1

In addition, several software defects are corrected in this release.

25CHAPTER 4Explicit Nonlinear (SOL 700)

DMP for FSI Applications with Adaptive EulerThe DMP in MSC Nastran 2012 is extended to include the support for adaptive Euler. The adaptive meshing technology in SOL 700 automatically generates the Eulerian meshes as needed during the analysis. When the structure undergoes severe deformation, the adaptive mesh is expanded to follow the movement of coupling surfaces, preventing the creation of extraneous elements at the start of the analysis and, therefore, resulting in significant reduction in simulation runtime. The DMP support for adaptive Euler capability will allow the users to run the CPU intensive FSI applications on multiple cores and further improve the performance runtimes. There are no GUI requirements for this new capability.

One important feature in DMP support for adaptive mesh is the load balancing schema. During the DMP simulation with adaptive mesh, the Eulerian mesh is decomposed into many domains, and each domain is spawned onto different processors. The load balancing is intended to ensure that all cores have about the same amount of work for an efficient computation as the meshes are transported from one core to the next during the analysis. There are many FSI applications that can result in poor performance due to lack of proper load balancing. For optimal speed-ups, the Euler mesh has to be re-partitioned across the cores. For example, during the fluid-filled bottle droptest on two cores, the fluid moves through the Euler mesh leaving one core and entering the second core. As a result, one core is off-loaded as the second core is loaded. Load balancing ensures that both cores have a balanced amount of processing, and it is also a major step towards good scalability on multiple cores.

Adaptive meshing can result in shorter run times for tank sloshing simulations especially when there is significant movement of the tank through the Euler mesh. Running these simulations with adaptive meshing in combination with DMP may result in poor performance in some cases. This happens because of inefficient load unbalancing across the processors. When the tank moves, the adaptive mesher creates Euler elements at the front of the tank and deletes the elements at the back of the tank. Consequently elements are deleted on one processor and are created on another one. This causes load unbalance that might lead to poor performance. To overcome load unbalancing, Euler cubes can be moved from one processor to the other processor when there is sufficient number of cubes present in the simulation. But if the number of Euler cubes is not sufficient, the re-allocation of cubes is not possible and causes load unbalance.

Whether or not load unbalance problems have occurred, it can be checked by the message in the OUT file:

***************************************************************************** * * * MESH (ID=101) HAS BEEN REDISTRIBUTED ACROSS CPUS AT CYCLE 191400 * * * * NUMBER OF FINITE VOLUME ELEMENTS ON EACH TASK: * * * * TASK 0 : 197772 * * TASK 1 : 52013 * * * *****************************************************************************

In the example above, there are only two cubes for the entire tank sloshing that were used and the message shows the load unbalance. By adding more cubes in the direction of tank motion there will be more cubes to move around and will resolve the load unbalance problems. Caution must be exercised in

MSC Nastran 2012 Release GuideDMP for FSI Applications with Adaptive Euler

26

creating excessive number of cubes since it can lead to overhead costs. For this reason the number of cubes should be limited to about 100. The overhead costs for simulations with adaptive meshing on 8 or more cores may results in degraded performance.

Load balancing is not available for fixed Euler meshes.

The following droptest simulation of a fluid-filled plastic bottle demonstrates the DMP performance with adaptive mesh on 1, 2 and 4 cores on Linux 8664(Intel(R) Xeon(R) CPU E5420 @ 2.50GHz, 32GB RAM):

Figure 4-1 Fluid Filled bottle droptest with gravity

Figure 4-2 DMP Performance of Fluid Filled bottle droptest with gravity

The capability allows many CPU intensive FSI applications such as fuel tank sloshing, airbags, and occupant safety that require adaptive meshes to dramatically increase their performance and reduce the simulation time. The following is an airbag example with adaptive mesh run on up to 8 cores on Linux 8664:


Air enters with time dependent mass flow

T=0.000 seconds T=0.012 seconds T=0.02 seconds

MSC Nastran 2012 Release GuideDMP for FSI Applications with Adaptive Euler

28

It should be noted that the model has to be sufficiently large for typical parallel simulation to benefit from this capability. Although the performance for parallel simulations is problem dependent, the communication costs among multiple processors beyond eight cores might have an adverse impact on performance and scalability with adaptive mesh.

T=0.032 seconds T=0.04 seconds


DMP Improvements for Coupling and EditingSeveral performance benchmarks have been conducted on previous releases to first identify the bottleneck areas in the code that are CPU intensive and second to improve the performance. The coupling and output generation (aka "editing" among users) calculations during a DMP FSI application has been identified as one of the major bottlenecks where it consumes a significant amount of CPU time in MSC Nastran SOL 700. This is clearly evident as the numbers of the processors are increased (see figure below for 2010)

The new performance enhancement to coupling and output generation algorithms dramatically improves the performance on FSI applications as shown below.

Each color on the curves demonstrates a different benchmark. As shown in the overall performance charts at the top, most of the benchmarks in 2010 release shown in the charts to the left are around 3-5.5 range (performance numbers are compared to one core) whereas the same benchmarks run with 2012 version start at around 5 at a minimum and go up in performance up to 20 as the number of processors

MSC Nastran 2012 Release GuideDMP Improvements for Coupling and Editing

30

are increased to 32 cores. There is one problem that is outlier (shown in light green at the top of same chart) which did not experience any significant improvement.

The greatest performance improvements were achieved in output generation shown in second chart from the top where all benchmarks achieved dramatic speedups. Integration schemes including subcycling without initialization and output generation as well as clumping and coupling areas in the code were also improved in performance in the 2012 release.


DMP Support for importing Eulerian ARC output files for restartThe DMP support for importing Euler ARC dramatically enhances the performance for applications such as blast.

In blast wave simulations, the Euler mesh has to be sufficiently fine enough to capture the initial expansion and propagation of the blast wave through the medium. Once the blast wave has expanded enough to reach its target, the blast wave characteristics are recorded in the Archive output file and the blast wave results are used as an initial state in the subsequent runs where a much coarser mesh is constructed instead. Running the initial full model with both structure and explosives with fine mesh is CPU intensive and requires a much longer simulation time.

This capability is especially useful in blast simulation where the distance between the structure and the blast location is often large, resulting in excessive CPU time for the blast wave to reach the structure. In addition, the simulation may have to be repeated several times for different structures or for different positions. To reduce the simulation time, the simulation is split up into two parts. In the first simulation, the structure is omitted. In subsequent runs, the result can be imported into a simulation which includes the structure. The blast wave almost immediately hits the structure at the start of the run without using a lot of CPU time. In addition, importing the Euler archive also allows mapping the fine mesh results to a coarser mesh resulting in significant performance improvement and accuracy.

Another technique to reduce the simulation time in the blast applications is to take advantage of the symmetry boundary conditions where only a small portion of the entire model such as half-symmetry or quarter symmetry is constructed for the analysis. The limitation of this technique is that not all models are symmetric. Therefore, using an initial fine mesh to capture the blast wave physics followed by a coarse mesh in subsequent runs is a general approach for all blast wave application. This new capability in MSC Nastran 2012 will allow the users to import the Archive files using the DMP to speed up the simulation.

Blast wave example with single domain

This is a typical example where the fine Eulerian mesh is used to capture the details of the blast wave and the results are stored in ARC file. In subsequent runs, a coarser mesh of Euler is used with a fine structural mesh. The blast wave from initial run is mapped on to the structure in the second run using the DMP capability on four processors to speed up the simulation.

The user has to do the following steps:

• Create a model with a small but fine Euler mesh .

• Run the model and see when the blast wave approaches the boundary of the Euler mesh. Select a time for this.

• Create a coarse and larger 3-D model and use the EULINIT/eid option to point to the archive of the fine but small 3-D model. Also, add the selected time to EULINIT/eid.

• If required, repeat the above steps a few times.

• This example uses four cores in DMP mode.

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A. Initial Run (Euler only) End Pressure

B. Continuation Run (Euler + Lagrange) Initial Remapped Pressure


Pressure after 1 ms (1 CPU) Pressure after 1 ms (2 CPU)

Pressure after 1 ms (4 CPU)

MSC Nastran 2012 Release GuideThermal Capability

34

Thermal CapabilityIn this release, we are pleased to introduce thermal capability in Nastran explicit solver SOL 700. It is another milestone in our multi-physics development roadmap, bringing unprecedented new technologies for explicit dynamics applications. The thermal capabilities in SOL 700 include:

• Coupled Thermal Structural Analysis

• Thermal Contact

• Thermal Materials

• Thermal Loading and Boundary Conditions (Temperature, Flux, Conduction, Convection and Radiation

The thermal capability for SOL 700 includes thermal contact capability to transfer temperature and structural response using thermal conductivity and heat conductance. Several new material models are added to support the thermal capability. These are:

1. MATD004 Elastic Plastic Temperature dependent material

2. MATD021 Linearly elastic material with orthotropic temperature dependent coefficients

3. MATD106 Elastic viscoplastic material with thermal effects

4. MATDT01 Isotropic thermal properties

5. MATDT02 Orthotropic thermal material

6. MATDT03 Temperature dependent isotropic material

7. MATDT04 Temperature dependent orthotropic material

8. MATDT05 Temperature dependent isotropic material with phase change

9. MATDT06 Temperature dependent isotropic material with tables

PSHELLD, PSOLIDD, and PTSHELL property entries are extended to support the thermal capabilities for explicit solver for shells, solids and thick shells respectively. In addition “BCTABLE” is also updated to include the thermal contact capability for SOL 700.

Thermal loading to apply temperature on nodes and elements and boundary conditions including boundary flux, boundary radiation, boundary convection, and boundary temperature are supported by extending a number of existing Nastran bulk data entries and creating a few new entries. These are:

Remarks:

For SOL700, TEMP or TEMPN1 entries are only available when ANALYSIS = HTRAN.

See TEMP, TEMPN1, TEMPD for the complete entries.

TEMP/TEMPN1/TEMPD Grid Point initial Temperature for thermal or thermal-structural coupling

TTEMP/TMPSET Thermal loading for structural analysis only


Remarks:

For SOL700, TTEMP or TMPSET entries are only available when ANALYSIS = NLTRAN (default).

See TTEMP, TMPSET for the complete entries.

See SPC, and SPCD for the complete entries.

See CHBDYE, and CHBDYG for the complete entries.

Remark:

SOL 700 ignores IVIEWF, IVIEWB, RADMIDF and RADMIDB options.

See QBDY1 and QBDY4

Define flux boundary conditions for a thermal or coupled thermal/structural analysis. Used in MSC Nastran SOL 700 only.

See RADBC2 and CONV3

In addition to these entries, initialization of thermal analysis is designed to be consistent with SOL 400 in the case control section. The following table summarizes capabilities and entries used for thermal analysis.

SPC/SPCD These entries support time dependent or constant nodal thermal loadings.

CHBDYE + CHBDYG These entries are extended to support the SOL 700 thermal boundary conditions.

QBDY1 Extended to define heat flux on element faces in SOL 700.

QBDY4 SOL 700 Only. New entry to define Boundary Heat Flux

RADBC2 New entry to define Radiation Boundary to Environment

CONV3 New entry to define Convection Boundary


36

CASE CONTROL SECTION BULK DATA SOL 700 Support

ANALYSIS=NLTRAN

TEMP(LOAD)=m

DLOAD=n

TEMP,m,…

TEMPD,m,…

…

TTEMP,m,p,…

TMPSET,p,…

Yes

ANAYSIS=HLSTAT

TEMP(INIT)=n1

SPC=n2

TEMP,n1

TEMPD,n1

SPC,n2

No

ANALYSIS=HTRAN

IC=n1

SPC=n2

DLOAD=n3

TEMP,n1

TEMPD,n1

SPC,n2

TLOAD1,n3,n4

SPCD,n4

Yes

Coupling thermal and structural analyses (Steady state)

TEMP,n1

TEMPD,n1

SPC,n2

TLOAD1,n3,n4

SPCD,n4

No

Coupling thermal and structural analyses (Transient state)

STEP=1

SUBSTEP=10

ANALYSIS=HTRAN

IC=n1

SPC=n2

DLOAD=n3

SUBSTEP=20

ANALYSIS=NLTRAN

DLOAD=n4

IC=n5

SPC=n6

TEMP,n1

TEMPD,n1

SPC,n2

TLOAD1,n3,n4

SPCD,n4

Yes


LimitationsThe following limitations exist in MSC Nastran 2012 thermal capability:

• Only transient thermal analysis is supported in SOL 700. For steady state thermal analysis, SOL 400 should be used instead.

• Only radiation to environment is supported.

• Adaptive thermal mesh is not supported.

ExampleSheet Metal Forming with initial temperature and thermal contact

The following example demonstrates a coupled thermal-structural sheet metal forming analysis. A one-fourth symmetric model was constructed with hemisphere punch with a 100 degrees initial temperature traveling with a time dependent velocity (shown below) impacting the sheet metal with an initial temperature of 200 degrees.

Please see MSC Demonstration Manual for detailed examples.


38

Contact:

1. Punch-sheet: thermal/structural contact

2. Die-sheet: structural contact

3. Clamp-sheet: structural contact

Temperature condition:

• Punch: 100 (no change)

• Sheet: 200 (initial condition)

Boundary condition:

• Punch: move downward with time dependent velocity.

Green: punch

Yellow: die

Red: sheet

Blue: clamp


Figure 4-3 Die : fully fixed

Additional Boundary Conditions:

• Clamp: Downward pressure (0.01) is added to fix the sheet.

Results:

MSC Nastran 2012 Release GuideNew Material Models (Wood and Ice)

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New Material Models (Wood and Ice)Two new material models are added to SOL 700 explicit solver to benefit the following applications:

• Helicopter blade impact on trees

• Ship impact on piers and wooden debris

• Hail impact

• Ship collision to icebergs

• Construction

Wood Material - MATD143 This is a transversely isotropic material that is available for solid elements only. You have the option of inputting your own material properties or requesting default material properties for Southern yellow pine (PINE) or Douglas fir (FIR). This model was developed by Murray [2002] under a contract from the FHWA.

Ice Material - MATD155: Plasticity Compression Tensions EOSThis is an isotropic elastic-plastic material where unique yield stress versus plastic strain curves can be defined for compression and tension. Also, failure can occur based on a plastic strain or a minimum time step size. Rate effects on the yield stress are modeled either by using the Cowper-Symonds strain rate model or by using two load curves that scale the yield stress values in compression and tension, respectively. Material rate effects, which are independent of the plasticity model, are based on a 6-term Prony series Maxwell mode that generates an additional stress tensor. The viscous stress tensor is superimposed on the stress tensor generated by the plasticity. Pressure is defined by an equation of state, which is required to utilize this model. This model is for solid elements only.


Euler Body ForceA new capability is added to SOL 700 to allow the users to define a time dependent acceleration field over a geometric subregion which contains a fluid. It also provides the user extended capability over the existing EULFOR option in two respects:

• Allows the direction of acceleration field to change in time.

• Allows the definition of the acceleration field to be specified on different regions and on a specific material in the Euler domain.

There are many applications can that benefit from this new capability to reduce their simulation runtime. One application is sloshing that can be quite CPU intensive. In sloshing simulations, a partially filled tank is usually moved through an Euler mesh box to predict the sloshing behavior of the fluid inside the tank. The tank structure acts as a coupling surface between the fluid inside and the surrounding media. This method can results in significant CPU time due to excessive coupling surface computations as the tank is moving forward within the Euler mesh box which has to be fine enough to capture the sloshing details inside the tank. With this new capability, there is no need to define a mesh box. A coordinate system is defined for the tank which is kept stationary, and, instead, a time dependent acceleration field via “EULFOR1” is applied to the fluid inside the tank to simulate the movement of the tank. Since the new method will prevent expensive coupling surface computations, the performance of sloshing simulations can be dramatically improved.

The following example demonstrates a typical fuel tank sloshing filled with air and water that is moving in x-direction. The time dependent acceleration as shown below is only applied to the air and water inside the tank to define the tank motion. No Euler mesh box is constructed.

Figure 4-4 Body Acceleration on AIR and Water in x-direction Only:

Air

Water

Fuel Tank

MSC Nastran 2012 Release GuideEuler Body Force

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Results (FMAT)

T=0.00 Seconds T=0.05 Seconds

T=0.1 Seconds T=0.15Seconds


Another application to greatly benefit from this capability is fluids that act like magnetic particles in continuous media. The flow of these fluids can be manipulated by magnetic fields. These fluids are called colloidal ferrofluids and their behavior is the subject of ferrohydrodynamics. One important application of ferrofluids in SOL 700 is to define the behavior of toner and magnetic material inside copiers. The “EULFORCE1” can be used to define the disposition of toner particles in their toner process as shown in the figure below. The toner particles behave as if a magnet was dipped into a ferrofluid and the material was attached to it.

In application of ferrofluids magnetic, force is not derived from Lorenz forces, but occurs because of magnetic polarization forces. These polarization forces originate from material magnetization. The magnetic polarization give rise to magnetic dipole sources that yields a magnetic field that diminishes linearly with distance. So in general, the magnetic force can vary with distance. When the variation of the magnetic field within the fluid region of interest is moderate, then a small number of EULFOR1 entries suffice. Each EULFOR1 entry models, a fluid region at a certain distance to the sources of the magnetic force. By defining sufficient number of EULERFOR1entries, the variation of magnetic force can be accounted for. If needed, a FORTRAN program can be written by the user to automatically create these entries. The regions can be defined by a box, sphere, or a cylinder. Force can be either put on a specific material or on all the materials inside the Euler region.

Figure 4-5 Simulation of Toner Inside a Copier Machine

T=0.2 Seconds

MSC Nastran 2012 Release GuideEuler Body Force

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Another example, as demonstrated below, shows how the fluid flow was predefined for water (material 5) while water in the tank (material 4) was held steady.

Air:Material 3

Water:Material 5

Injection Speed250 m/sec Water:

Material 4y

z

Material 4 Material 5


Output Support for Genoa Damage ModelsIn MSC Nastran 2010, the Genoa Progressive Failure Analysis (PFA) was implemented and could be accessed by using the MATM entry. However, the damage index for failure modes for individual layers was not supported. In this release, SOL 700 supports the damage index that includes 24 different damage modes (Honeycombs failure modes not included). The damage index is an important design consideration to predict the failure modes of the composite layers under severe conditions.

• S11T = Bit 14 -- S11T longitudinal tension

• S11C = Bit 13 -- S11C longitudinal compression

• S22T = Bit 12 -- S22T transverse tension

• S22C = Bit 11 -- S22C transverse compression

• S33T = Bit 10 -- S33T normal tension

• S33C = Bit 09 -- S33C normal compression

• S12S = Bit 08 -- S12S in-plane shear

• S23S = Bit 06 -- S23S out-plane shear

• S13S = Bit 04 -- S13S out-plane shear

• MDE = Bit 02 -- MDE MDE

• RROT = Bit 01 -- RROT Relative rotation

• TSAI = Bit 26 -- TSAI Tsai-Wu

• HILL = Bit 27 -- HILL Tsai-Hill

• HOFF = Bit 28 -- HOFF Hoffman

• R11C = Bit 17 -- R11C Fiber crushing

• D11C = Bit 18 -- D11C Delamination

• F11C = Bit 19 -- F11C Fiber micro-buckling

• EPST = Bit 20 -- EPST tensile strain

• EPSC = Bit 21 -- EPSC compression strain

• EPSS = Bit 22 -- EPSS shear strain

• HONY = Bit 15 -- Honeycomb fail theory

• WRNK = Bit 23 -- Wrinkling failure theory for honeycomb

• CRMP = Bit 24 -- Crimping failure theory for honeycomb

• DIMP = Bit 25 -- Dimpling failure theory for honeycomb

The damage index is output in the time history binout file. The “L2A” tool available in MSC Nastran 2012 installation directory “C:\MSC.Software\MSC_Nastran\20121\20121\win32\” can be utilized to extract the failure indexes into ASCII format. Please refer to MSC Nastran Demonstration manual for more details.

MSC Nastran 2012 Release GuideOutput Support for Genoa Damage Models

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New LS-Dyna librariesIn Nastran 2012 release, the LS-Dyna libraries are upgraded to R5.1 for SOL 700.

Chapter 5: Implicit Nonlinear (SOL 600) MSC Nastran 2012 Release Guide

5 Implicit Nonlinear (SOL 600)

SOL 600 Enhancements

MSC Nastran 2012 Release GuideSOL 600 Enhancements

48

SOL 600 Enhancements

IntroductionThe MSC Nastran 2012 release of Implicit Nonlinear (SOL 600) now utilizes the Marc 2010.2 release. This release contains defect corrections to the previous version. Both a list of closed defects and a list of known defects may be found at:

http://simcompanion.mscsoftware.com/infocenter/index?page=content&channel=KNOWN_ISSUE&cat=11OR46

The MSC Nastran 2012 release may also be used with the Marc 2011 release. In this case one needs to obtain the Marc release from the download center independently of the Nastran download. Additionally, one needs to use the PATH command on the SOL 600 Executive Control Statement to point to the location of the Marc 2011 release.

The highlights of the Marc 2011 release that can be exposed through Nastran are as follows:

Pardiso SolverThe Pardiso direct parallel solver is now available for out-of-core solutions. This solver is only available for Shared Memory Parallel (SMP) shows similar performance for both in-core and out-of-core behavior. The results shown below are for a Linux environment.

One can also see that the performance improvements with increased number of cores also give similar performances. The Pardiso Solver is invoked using MARCSOLV=11 Param.

Size of example X 1,000,000

http://simcompanion.mscsoftware.com/infocenter/index?page=content&channel=KNOWN_ISSUE&cat=11OR46

49CHAPTER 5Contents

MUMPS SolverThe MUMPS direct parallel solver is now available i8 (large integer) mode. This allows virtually unlimited size models to be executed in either a Shared Memory Parallel (SMP) or a Distributed Memory Parallel (DMP) environment. The MUMPS solver is invoked using MARCSOLV=12 Param.

MSC Nastran 2012 Release GuideSOL 600 Enhancements

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Chapter 6: Numerical Methods and High Performance Computing MSC Nastran & MSC Nastran 2011 Release Guide

6 Numerical Methods and High Performance Computing

Shared Memory Parallel

ACMS

Performance Improvements for Unsymmetric Solutions

New Complex Eigenvalue Extraction Method: IRAM

GPU Support

Intel AVX Support

MSC Nastran 2012 Release GuideShared Memory Parallel

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Shared Memory Parallel With the advent of multi-core architectures from multiple vendors, the use of Share Memory Parallel technology is becoming more prevalent. While the technology has been available in MSC Nastran for a long time, it is now commonly available on both desktops and laptops providing greater access to more users. Combined with the availability of inexpensive memory; allows larger problems to be solved in a fraction of the time.

To utilize the full capabilities of your computer requires one to define additional input parameters.

To invoke Shared Memory Parallel use the SMP or PARALLEL command line options or use System Cell 107 to specify the number of processors. Because you may be using different hardware, with different number of cores, one can always define a large number (like 16) and it will be reduced to the available number.

If you are the only user on your computer and performing a SOL 101 or SOL 400 simulation to better utilize your memory then use MEM=MAX on the command line. If one is also utilizing DMP it is advantageous to set the memory to 0.8 *memory in the machine / (number of DMP processes).

53CHAPTER 6Contents

ACMS

IntroductionThe MSC Nastran Automated Component Modal Synthesis (ACMS) capability is vital to large scale modal frequency response analysis applications such as automotive Noise and Vibration analysis. The MSC 2012 release of Nastran features parallel scalability improvements to ACMS that result in significantly reduced analysis times on systems with multiple processors.

BenefitsEnhancements to MSC Nastran parallel processing allows for Distributed Memory Parallel (DMP) and Shared Memory Parallel (SMP) to efficiently utilize multi-CPU and multi-core processor systems. In this way, jobs using ACMS may utilize all available processing power on a multi processor system or on a cluster of multi processor systems to reduce run times.

Technical DiscussionIn addition to solution enhancements for reduced disk I/O, a multi-level DMP strategy has been implemented using MPI group technology. Briefly, a Master DMP process may utilize available DMP Slave processes only where needed for intensive computational tasks. This strategy avoids costly duplication of effort and the accompanying load on scratch databases and file systems.

Each DMP process makes use of multiple cores by running in SMP mode. In addition, rudimentary support for multi-level SMP is implemented in MSC Nastran 2012. This allows for optimal use of multi-core systems in the shared memory paradigm.

These developments combine for improved performance via parallel scalability, while at the same time providing a framework for future development in parallel processing.

InputThere are no input changes associated with this enhancement.

OutputThere are no output changes associated with this enhancement.

MSC Nastran 2012 Release GuideACMS

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Guidelines and LimitationsUsers must specify appropriate combinations of DMP and SMP processes to fit available hardware. For example, on a two quad-core machine (two sockets), the following parallel combinations will make effective use of the entire system:

• dmp=2 smp=4

• dmp=4 smp=2

Similarly, on a two hex-core machine:

• dmp=2 smp=6

• dmp=4 smp=3

• dmp=6 smp=2

Parallel utilization will be especially effective for large problems, especially problems requiring a large number of eigenvalues and forcing frequencies (mid to high range frequency response analysis).

The enhanced parallel scalability is limited to SOL 103 and SOL 111.

55CHAPTER 6Contents

Test CasesThe example is based on a typical model from one of our users and is not available.

Hardware used in the examples below is a single system consisting of two hex-core 1600MHz Intel Nehalem CPUs (two sockets), 96GB main memory, Linux RedHat 6.

Case 1: Large automotive example

SOL: 111

Number of grid points: 1.2 million

G-size DOF: 7.3 million

Number of structure modes: 3600

Number of forcing frequencies: 320

MSC Nastran 2012 Release GuideACMS

56

Case 2: Large automotive example

SOL: 111




Number of forcing frequencies: 450

57CHAPTER 6Contents

Performance Improvements for Unsymmetric Solutions

IntroductionThe high rank update kernels have been enabled in the default unsymmetric sparse direct solver (MSCLU) for both real and complex data types. Previously, a rank-one update was done.

Unsymmetric matrices are generated and solved in an increasing number of analysis scenarios, making high performing unsymmetric solutions a requirement for MSC Nastran.

BenefitsPerformance improvements range up to four times faster than the previous release for the following unsymmetric applications:

• Exterior acoustics

• Complex eigenvalue analysis using Lanczos.

• SOL 400 with friction

Performance benefits are especially evident for large problems.

Technical DiscussionThe sparse multi-frontal algorithm employed by the MSCLU solver is comprised of discrete steps, including an “update” step where contributions from newly computed frontal matrices are used to update pending fronts. Higher performance may be achieve by computing these contributions several columns at a time. This is known as a “high rank update” step. To ensure numeric robustness as well as performance, the diagonal terms are monitored during the factorization process. If any of the diagonal term falls below a 'tiny' threshold, the MSCLU factorization process would be restarted with a tighter pivot tolerance to improve numeric accuracy.

MSC Nastran 2012 Release GuidePerformance Improvements for Unsymmetric Solutions

58

InputThe bulk data entry MDLPRM (p. 2539) in the MSC Nastran Quick Reference Guide with new keyword PIVTHRSH is used to control the pivot tolerance for the MSCLU solver high rank option.

System cell 220 and 221 default values are now set to 64 for the default MSCLU solver (both real and the complex sparse solvers, respectively). These high rank update kernels may be disabled by setting the values of sys220 and sys221 to 1.

OutputIf MSCLU is restarted for numeric stability, User Information Message 7839 is printed in the F06 file for every incidence:

*** USER INFORMATION MESSAGE 7839 (UDCOMP) DUE TO POTENTIAL NUMERIC STABILITY PROBLEMS, THE UNSYMMETRIC DECOMPOSITION IS RERUN WITH A TIGHTER PIVOTING THRESHOLD (ie. MDLPRM,PIVTHRSH,-1). THIS WOULD RESULT IN BETTER ACCURACY BUT A SLOWER RUN TIME.If the tighter pivoting threshold parameter does not remove the tiny diagonal terms completely,User Warning Message 7839 is issued in the F06 file:*** USER WARNING MESSAGE 7839 (UDSFxD) THE UNSYMMETRIC DECOMPOSITION ENCOUNTERED xxx TINY DIAGONAL TERMS. USER ACTION: VERIFY THE NUMERIC SOLUTION ACCURACY OF MSCLU. THE SMALLEST FACTOR DIAGONAL TERM IS yyy, COMPARED TO THE TINY THRESHOLD OF zzz.

The presence of tiny diagonal terms in the factorized matrix doesn't imply the numeric results are invalid, but due diligence should be applied to verify the correctness.

Guidelines and LimitationsBenefits are most pronounced for the X86-64 CPU architecture.

59CHAPTER 6Contents

Test CasesBenefits are most pronounced for the X86-64 CPU architecture. With the high rank update, performance of MSCLU is on par with that of UMFLU for most jobs. On the other hand, MSCLU is out-of-core, and thus has a much smaller memory footprint.

Cases 1 and 2: Exterior acoustics (automotive applications)

SOL: 111

G-size DOF: 1-4 million

http://software.intel.com/en-us/avx/?wapkw=(avx)

MSC Nastran 2012 Release GuideNew Complex Eigenvalue Extraction Method: IRAM

60

New Complex Eigenvalue Extraction Method: IRAM

IntroductionThe Implicitly Restarted Arnoldi Method (IRAM) is a popular Krylov subspace method for computing eigenvalues. This method is now available in MSC Nastran 2012 as a complement to the existing complex eigenvalue solvers including Complex Lanczos (CLAN), Hessenberg (HESS), and Inverse Power (INV).

The IRAM method is based on the ARPACK public domain code. For more information are available at the following URL: http://www.caam.rice.edu/software/ARPACK.

BenefitsThe IRAM method offers high performance and stability for a variety of applications requiring complex eigenvalues and eigenvectors, such as automotive brake squeal, exterior acoustics, and rotor dynamic analysis.

Technical DiscussionTechnically detailed information regarding IRAM is available at the following URL: http://www.caam.rice.edu/software/ARPACK/UG/node45.html.

InputThe user selects the method by specifying IRAM in field 3 of the EIGC bulk data entry, and the number of modes desired in field 8. Note that the IRAM method ignores the contents of fields 5, 6, and 7. Note that the number of modes desired can be at most the order of the generalized eigenproblem minus one. Another limitation of IRAM is that the mass matrix must be symmetric or Hermitian.

OutputComplex eigenvalues and eigenvectors are produced in the standard formats consistent with other complex eigenvalue methods in MSC Nastran.

1 2 3 4 5 6 7 8 9 10

EIGC SID Method NORM G C E ND0

http://www.caam.rice.edu/software/ARPACK

http://www.caam.rice.edu/software/ARPACK/UG/node45.html

61CHAPTER 6Contents

Guidelines and LimitationsThe out-of-core IRAM has small memory footprint and similar performance characteristics as those of CLAN for small models in rotordynamics. However, for large models in brake squeal analysis, IRAM uses more memory and can be significantly slower than CLAN. IRAM is generally speaking more numerically robust than CLAN.

The mass matrix must be symmetric or Hermitian for use in the IRAM method.

Left eigenvectors are not computed by the IRAM method. Thus, IRAM may not be appropriate for applications in structural optimization (SOL 200) .

Known IssuesFor brake squeal analysis, the following DMAP alter should be used to turn off the 'deflation' code to avoid excessively long processing time and System Fatal Messages 3034 and 3008.

Test CasesHardware used in the examples below is 2500MHz Intel Harpertown CPUs, 32GB main memory, Linux 2.6.9-42.ELsmp.

compile ceigrs list noref $alter 14,14IF ( LANCZOS>1000 ) THEN $alter 66,66CEAD CKDD,CBDD,CMDD,EED,CASES,VDXW,VDXW/ CPHDX,CLAMA,OCEIGS,LPHDX,/S,N,NCEIGV $

Case 1: Rotor dynamics

SOL: 107

G-size DOF: 500,000

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63CHAPTER 6Contents

GPU Support

IntroductionMSC Nastran 2012 is now capable of utilizing GPU devices for additional floating point computing power. GPGPU stands for General-Purpose Computation on Graphics Processing Units. Graphics Processing Units (GPUs) are high performance processors that can be used to accelerate a wide range of applications. For more information on GPGPU, see http://gpgpu.org.

MSC Nastran users who want to significantly reduce real symmetric sparse factorization run times for large models can utilize NVIDIA CUDA-capable GPU cards. GPU support for AMD and/or other computational modules will follow in future MSC Nastran releases.

The system requirements for using the GPU computing feature in MSC Nastran are:

• NVIDIA CUDA-capable GPGPU card(s) with at least 1.5GB on-board memory

• NVIDIA CUDA Toolkit 4.0 or later

• NVIDIA CUDA Computing SDK

• NVIDIA Developer Drivers for Linux 270.41.19 or later

• NVIDIA Developer Drivers for Windows 270.81 or later

BenefitsThe target analysis capabilities for this release are:

• Linear and nonlinear static analysis (SOL 101 and 400)

• Normal modes analysis (SOL 103)

• Linear modal dynamic analysis (SOL 110, 111, and 112) (non-ACMS)

• SOL 200 optimization involving any of the above analysis cases

Technical DiscussionAn interface has been developed for the default MSC Nastran sparse direct factorization (MSCLDL) for NVIDIA GPU devices. There is no new functionality introduced. Utilization of GPU devices is for reduced run times only.

Improved performance only results for relatively large models. In particular, only matrices whose front sizes are larger than a certain threshold benefit.

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InputThere are two new runtime parameters that control GPU execution:

Examples1. Select GPU ID number 1 for computation of your MSC Nastran analysis:

nastran myinput gpuid=12. Select GPU IDs 0 and 1 for your Distributed Memory Processing SOL 400 analysis:

nastran myinput gpuid=0:1 dmp=23. Specify a different threshold for GPGPU processing:

nastran myinput gpuid=0 gputhresh=10000

OutputIf a GPU ID is specified on the command line when there is no GPU device, User Fatal Message 7840 will be printed in the F06 file:

*** USER FATAL MESSAGE 7840 (DFMRRD) NASTRAN CANNOT FIND ANY CUDA-CAPABLE DEVICE ON THE SYSTEM. CONTACT THE APPROPRIATE HARDWARE SUPPORT/SYSTEM ADMIN.

The above error message also can be due to a mis-configured software environment. Please see Known Issues, 64.

gpuid gpuid=id,id or gpuid=id:id Default: none

id: the ID of a licensed GPU device to be used in the analysis. Multiple IDs may be assigned to MSC Nastran distributed memory processor (DMP) runs. Separate a list of IDs with a comma or a colon. Each DMP process will be assigned a GPU ID in round robin fashion.

gputhresh gputhresh=value Default 16000

value: an integer representing the minimum threshold for GPU computing in the MSCLDL multi-frontal sparse factorization. If the product of the rank size and the front size of each front is smaller than value, the rank update of the front is processed on the CPU. Otherwise, the GPU device would be used for the rank update of the front. This keyword may also be set with the "sys647" command line keyword.

65CHAPTER 6Contents

Guidelines and LimitationsThe GPU capability is limited to the MSCLDL real sparse factorization.

Speedup is limited to medium to large sized models where the ESTIMATED MAXIMUM FRONT SIZE is greater than 10000.

The System Cell 647 defaults to 16000, we recommend that this be increased to 48000

The System Cell 205 defaults to 64, we recommend increasing to 192

Known IssuesOn Linux, the LD_LIBRARY_PATH_PRE environment variable should be set to point to the directory that contains libcudart.so. This is not necessary on Windows if the CUDA Toolkit is installed.

If a GPU card cannot be detected by MSC Nastran, change to the TCC (Tesla Compute Cluster) mode with the NVIDIA SMI utility. Refer to the pertinent NVIDIA documents for details.

Test Cases

Case 1: linear static analysis

SOL: 101

Number of DOF: 943,000

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Intel AVX Support

IntroductionIntel introduced Advanced Vector Extensions (Intel® AVX http://software.intel.com/en-us/avx/?wapkw=(avx)) on their Xeon® E5® processor in 2011 (also known as Sandy Bridge). MSC Software collaborated with Intel to take advantage of AVX in MSC Nastran 2012 on Linux operating systems. This enhancement automatically happens for users on Sandy Bridge hardware.

BenefitsUse of AVX hardware results in performance improvements for numerically intensive applications such as those found in MSC Nastran.

Technical DiscussionTechnically detailed information regarding AVX is available at the following URL: http://software.intel.com/en-us/avx/?wapkw=(avx).

InputNo new input is required.

OutputNo new output is produced.

Test CasesBelow are some comparisons made on a Sandy Bridge with and without AVX libraries. Jobs are production models from industry ranging from several hundred thousand to several million degrees of freedom.

Figures are elapsed time in seconds. The AVX enhancement resulted in an average of 15% reduction of time.

Job W/O AVX W/ AVX

case1 2,991 2,460

case1 dmp=2 smp=2 1,745 1,589

case2 20,126 17,396

case2 dmp=2 smp=2 14,586 15,050

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Additional Information and ReferencesVisit http://software.intel.com/en-us/avx/?wapkw=(avx) in the second half of 2011 for announcements related the Intel ® Xeon ® E5 product family (aka Sandy Bridge).

case3 16,464 13,080

case3 dmp=2 smp=2 10,019 7,625

case4 7,212 5,342

case4 dmp=2 smp=2 3,006 2,708

case5 8,919 7,279

case5 dmp=2 smp=2 6,947 6,593

case6 17,294 12,640

case6 dmp=2 smp=2 8,422 8,411

case7 21,706 17,908

case7 dmp=2 smp=2 17,531 14,683

case8 2,395 2,009

case8 dmp=2 smp=2 1,406 1,212

Job W/O AVX W/ AVX

http://software.intel.com/en-us/avx/?wapkw=(avx)

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Chapter 7: CompositesMSC Nastran 2012 Release Guide

7 Composites

Data Recovery of Dynamic Responses at Ply Level in Composites


Data Recovery of Dynamic Responses at Ply Level in Composites68

Data Recovery of Dynamic Responses at Ply Level in Composites

IntroductionLamina stresses, lamina strains, failure indices and strength ratios have been enabled for frequency response, transient response and random vibration simulations (SOL 108, SOL 109, SOL 111, and SOL 112). Ply data recovery is supported for PCOMP and PCOMPG properties for CQUAD4, CTRIA3, CQUAD8, CTRIA6, CQUADR, and CTRIAR element types in both SORT1 and SORT2 output formats. GPRSORT is enabled to get composite outputs sorted on global ply ID. XYPLOT is supported for composite output in dynamics problems. SOL 200 and SOL 400 have also been updated to enable the lamina output to be available in them for linear dynamic analysis.

BenefitsThis capability particularly benefits users in the aerospace industry, who need output at the ply level for dynamic solution sequences. This is important for composite structures since failure occurs at the ply level.

TheoryLamina properties specified by the user are converted to equivalent homogeneous or smeared properties. Displacements are evaluated with these smeared properties, and strains are evaluated for each ply from the strains and curvatures at the reference surface. This follows from the Classical Lamination Theory (CLT) according to which (a) there is a linear variation of strain through the laminate thickness (b) laminae are perfectly bonded together, that is, no delamination or relative slip take place.

For frequency response problems, the stresses, strains, etc. are complex numbers. Lamina strains for each ply are calculated from adding the direct strains at the reference surface and contributions from the rotational strains. The phase angles need to be considered, and the addition carried out using the Cosine Law applicable to complex quantities executing harmonic motion with the same frequency but with a phase difference.

Failure Indices and Strength Ratios involve interaction terms and are not harmonic in nature. But the outputs are still useful and, hence, are evaluated. These calculations are done for failure indices and strength ratios at intervals of 1 degree over the complete range of 360 degrees, and the maximum values (which are of interest) are output.

Calculation of complex lamina strainsThe ply strains are related to element reference surface strains by the equation:

p mz m

–=

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Where superscript p refers to ply and superscript m refers to reference surface. are the direct strains

at the reference surface and are the curvatures at the reference surface.

For frequency response analysis, the strains are complex quantities. For a particular lamina at a distance

of say z1, we evaluate the second term, viz. . Then

where ø1 and ø2 are the phase angles associated with the two terms. If we denote , then by the cosine law applicable to the addition of complex vectors, we have:

for a lamina.

where is the lamina strain, is the magnitude and is the phase angle.

Guidelines and Limitations• Previously, the output in dynamic solution sequences was for equivalent homogeneous

plate/shell. With this release, ply level output is available as default. To revert to the output for equivalent homogeneous plate/shell, "PARAM, NOCOMPS,-1" needs to be specified in the bulk data to suppress the ply output.

• For frequency response problems, the component of stresses and strains are harmonic in nature and will be output for each ply. The invariants viz. von Mises stress, Principal stresses etc. involve interaction terms , are not harmonic, and are not output. The real/imaginary or

magnitude/phase of the direct stresses only, viz., 1-, 2 and 12 are output.

• Since output in the global ply order (GPRSORT in Case Control Command section) involves expensive three key (number of elements X number of plies X number of time or frequency steps) sorts, it is recommended to either avoid it or request output only for plies of interest.

• Most of the time, only the extreme plies at the top and bottom are of interest from a stress point of view. For example, if there are 100 plies per element then output need not be requested for the intermediate plies (SOUT = NO on the PCOMP or PCOMPG entry).

• To summarize, use SORT1 with GPRSORT when lamina output sorted on global ply ID is desired. For cases where XY output is desired, request SORT2 without GPRSORT. For the general case, request SORT1.

m

m

z1 m ei wt 2+

·p

mi wt 1+ z1 m ei wt 2+

–=

2 1–=

p sqrt m m z1 m z1 m 2 m z1 m cos++ =

TAN 1– z1 m sin m z1 m cos+ =

· p pei wt + =

· p p



ExamplesPresence of PCOMP/PCOMPG referencing MAT8 in the bulk data section of a dynamic analysis input file is necessary to invoke the dynamic ply responses. Case control command STRESS is required for composite stress output, STRAIN for composite output and FORCE with STRESS or STRAIN for failure indices output. PARAM, SRCOMPS, YES is required for strength ratio output.

Example 1 (TPL/pcompdyn/pcdyn109s1.dat):

Listing 1 shows a complete input file for composite ply output under direct transient analysis for a SORT1 request. Sorting by global ply ID has been requested through the GPRSORT case control command.

Note that SB and FT (5th and 6th fields of 1st line of PCOMP and PCOMPG entries) and SOUTi (the 6th field of all continuation lines of PCOMP and PCOMPG entries) have been supplied. Further note that the MAT8 entries referenced by the PCOMP/PCOMPG entries have values in Xt, Xc, Yt, Yc and S fields. This satisfies the requirement for calculating the Failure Indices that have been requested. Figure 7-1 describes the problem.

Figure 7-1 Transient Analysis Problem Model Description

This is a transient analysis problem with four time steps. Elements 1 and 4 reference PCOMP property, elements 3 and 7 reference PCOMPG property, and elements 2, 5 and 6 reference PSHELL property. The composite elements have three plies each. The composite properties reference MAT8 entries. Grids 11 and 12 are fixed and a dynamic load is applied on grid 1.

Listing 1SOL 109CENDECHO = NONESUBCASE 1 TSTEP=1 SPC = 1 DLOAD = 5

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STRESS(SORT1) = ALL STRAIN(SORT1) = ALL FORCE(SORT1) = ALL GPRSORT = ALLBEGIN BULKPARAM,SRCOMPS,YESPARAM,NOCOMPS,1$11111112222222233333333444444445555555566666666777777778888888899999999MAT1 1 210000. 0.33 7.89E-6MAT2 3 200000. 5000. 120000. 7.89E-6MAT8 4 3.+7 7.5+5 .25 3.75+5 .1 1.5+5 1.+5 6.+3 1.7+4 1.+4PSHELL 1 4 0.1 4 3PSHELL 2 3 0.1 3 3PSHELL 3 1 0.1 1 3PCOMP 4 2500. HILL ++ 4 0.033 25. YES 4 0.033 10. YES++ 4 0.034 15. YESPCOMPG 5 2500. HILL ++ 1 4 0.033 25. YES ++ 2 4 0.033 10. YES ++ 3 4 0.034 15. YES$GRID 1 10. 0.0 0.0GRID 2 10. 2. 0.0GRID 3 8. 2. 0.0GRID 4 8. 0.0 0.0GRID 5 6. 2. 0.0GRID 6 6. 0.0 0.0GRID 7 4. 2. 0.0GRID 8 4. 0.0 0.0GRID 9 2. 2. 0.0GRID 10 2. 0.0 0.0GRID 11 0.0 2. 0.0GRID 12 0.0 0.0 0.0$CQUAD4 3 5 6 5 7 8CQUAD4 4 4 8 7 9 10CQUAD4 5 1 10 9 11 12CTRIA3 1 4 2 3 4CTRIA3 2 2 4 3 5CTRIA3 6 3 4 5 6CTRIA3 7 5 2 4 1$SPC1 1 123456 11 12$$ TIME VARYING POINT LOAD (250 HZ)$TLOAD2, 3, 1, , 0, 0., 8.E-3, 250., -90.FORCE 1 1 1. 30. 30. 30.$ APPLY POINT LOAD OUT OF PHASE WITH PREVIOUS LOAD$TLOAD2, 4, 2, , 0, 0., 8.E-3, 250., 90.FORCE 2 2 1. 30. 30. 30.DLOAD, 5, 1., 1., 3, 50., 4$1111111222222223333333344444444TSTEP 1 10 4.E-4$ENDDATA

Figure 7-2 shows the SORT1 output of stresses for each ply of CQUAD4 elements 3 and 4 after time step 3. Such output is repeated for each time step. Figure 7-3 shows the ply strains for elements 3 and 7 after time step 1. The ply output is invoked by the GPRSORT case control command. Such output is repeated for each time step.



0 SUBCASE 1 TIME = 1.200000E-03 S T R E S S E S I N L A Y E R E D C O M P O S I T E E L E M E N T S ( Q U A D 4 ) ELEMENT PLY STRESSES IN FIBER AND MATRIX DIRECTIONS INTER-LAMINAR STRESSES PRINCIPAL STRESSES (ZERO SHEAR) MAX ID ID NORMAL-1 NORMAL-2 SHEAR-12 SHEAR XZ-MAT SHEAR YZ-MAT ANGLE MAJOR MINOR SHEAR 3 1 -7.47387E+02 -1.97216E+02 -1.89849E+02 -8.49211E-01 3.21777E+00 -72.69 -1.38064E+02 -8.06539E+02 3.34237E+02 2 1.65022E+03 -3.12547E+02 -1.25726E+02 -9.46707E-01 2.78468E+00 -3.65 1.65824E+03 -3.20567E+02 9.89404E+02 3 -3.01357E+02 -3.46879E+02 -1.62850E+02 -1.49966E-08 -9.34749E-08 -41.02 -1.59685E+02 -4.88551E+02 1.64433E+02 4 1 -1.97568E+02 -6.46008E+01 -2.86313E+01 -4.92421E-01 -1.76285E+00 -78.35 -5.86978E+01 -2.03471E+02 7.23867E+01 2 4.81409E+01 -5.46220E+01 -6.00977E+00 -5.48954E-01 -1.52558E+00 -3.34 4.84912E+01 -5.49723E+01 5.17318E+01 3 -1.44636E+02 -3.61486E+01 -4.70722E+00 -8.69587E-09 5.12099E-08 -87.52 -3.59447E+01 -1.44840E+02 5.44474E+011 JULY 18, 2011 MSC NASTRAN 7/13/11 PAGE 36

Figure 7-2 Composite Stresses under Transient Response for SORT1 Request

0 SUBCASE 1 TIME = 4.000000E-04 S T R A I N S I N L A Y E R E D C O M P O S I T E E L E M E N T S GLOBAL ELEMENT STRAINS IN FIBER AND MATRIX DIRECTIONS INTER-LAMINAR STRAINS PRINCIPAL STRAINS (ZERO SHEAR) MAX PLY ID ID NORMAL-1 NORMAL-2 SHEAR-12 SHEAR XZ-MAT SHEAR YZ-MAT ANGLE MAJOR MINOR SHEAR 1 3 -6.26332E-07 -5.32096E-06 -1.63661E-05 -4.08818E-07 1.19429E-06 -37.00 5.53941E-06 -1.14867E-05 1.70261E-05 7 -1.49227E-04 3.53135E-04 3.76723E-04 1.19002E-06 -1.45567E-06 71.57 4.15916E-04 -2.12007E-04 6.27923E-04 2 3 2.55343E-06 -1.70520E-05 -1.45551E-05 -4.55754E-07 1.03354E-06 -18.30 4.95956E-06 -1.94581E-05 2.44177E-05 7 -2.03503E-04 2.38517E-04 -1.01548E-05 1.32664E-06 -1.25975E-06 -89.34 2.38575E-04 -2.03561E-04 4.42136E-04 3 3 2.37196E-07 -2.34165E-05 -2.17634E-05 -7.21949E-15 -3.46935E-14 -21.31 4.48163E-06 -2.76610E-05 3.21426E-05 7 -2.03590E-04 6.71500E-05 -5.04244E-05 2.10150E-14 4.22867E-14 -84.72 6.94778E-05 -2.05918E-04 2.75396E-041 JULY 18, 2011 MSC NASTRAN 7/13/11 PAGE 88

Figure 7-3 Composite Strains Sorted by Global Ply ID under Transient Response for SORT1 Request

Example 2 (TPL/pcompdyn/pcdyn112s2.dat):

This is a frequency response problem with two forcing frequencies. Output is requested in SORT2, magnitude/phase format. Figure 7-4 shows failure indices output at each forcing frequency ply-wise for element 1. The same is repeated for each element. Figure 7-5 shows a similar output for strength ratios. Figure 7-6 shows frequency wise stress outputs for elements 3 and 7 for global ply ID 1. Such output is repeated for each global ply ID.

0 SUBCASE 1 ELEMENT-ID = 1 F A I L U R E I N D I C E S F O R L A Y E R E D C O M P O S I T E E L E M E N T S ( T R I A 3 ) PLY FAILURE FP=FAILURE INDEX FOR PLY FB=FAILURE INDEX FOR BONDING FAILURE INDEX FOR ELEMENT FLAG ID THEORY FREQ (DIRECT STRESSES/STRAINS) (INTER-LAMINAR STRESSES) MAX OF FP,FB FOR ALL PLIES 1 HILL 2.0000E+01 -1.2089 0.0010 4.0000E+01 5.0557 0.0008 6.0000E+01 12.8134 0.0013 12.8134 *** 2 HILL 2.0000E+01 -1.2581 0.0008 4.0000E+01 6.7356 0.0007 6.0000E+01 4.7867 0.0011 6.7356 *** 3 HILL 2.0000E+01 -0.7774 0.0000 4.0000E+01 4.7648 0.0000 6.0000E+01 11.6000 0.0000 11.6000 ***1 JUNE 21, 2011 MD NASTRAN 6/21/11 PAGE 18

Figure 7-4 Failure Indices under frequency response for SORT2 request

0 SUBCASE 1 ELEMENT-ID = 3 S T R E N G T H R A T I O S F O R L A Y E R E D C O M P O S I T E E L E M E N T S ( Q U A D 4 ) PLY FAILURE SRP-STRENGTH RATIO FOR PLY SRB-STRENGTH RATIO FOR BONDING STRENGTH RATIO FOR ELEMENT FLAG ID THEORY FREQ (DIRECT STRESSES/STRAINS) (INTER-LAMINAR STRESSES) MIN OF SRP,SRB FOR ALL PLIES 1 HILL 2.0000E+01 0.4437 2.656036E+02 4.0000E+01 0.1231 6.688708E+02 6.0000E+01 0.0666 4.395694E+02 6.656511E-02 2 HILL 2.0000E+01 0.2258 3.069120E+02 4.0000E+01 0.1018 7.728979E+02 6.0000E+01 0.0690 5.079341E+02 6.896398E-02 3 HILL 2.0000E+01 0.1693 6.570986E+09 4.0000E+01 0.1040 1.654774E+10 6.0000E+01 0.0695

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1.087487E+10 6.951041E-021 JUNE 21, 2011 MSC NASTRAN 6/21/11 PAGE 20

Figure 7-5 Strength Ratios under frequency response for SORT2 request

0 SUBCASE 1 GLOBAL PLY-ID = 1 S T R E S S E S I N L A Y E R E D C O M P O S I T E E L E M E N T S (MAGNITUDE/PHASE) ELEMENT STRESSES IN FIBER AND MATRIX DIRECTIONS INTER-LAMINAR STRESSES ID FREQ NORMAL-1 NORMAL-2 SHEAR-12 SHEAR XZ-MAT SHEAR YZ-MAT 3 2.000000E+01 9.621852E+02 1.436674E+02 2.144121E+02 2.602054E+00 9.412521E+00 3.080000E+01 3.080000E+01 3.080000E+01 2.108000E+02 3.080000E+01 4.000000E+01 1.579233E+03 6.260818E+02 4.229928E+02 1.555931E+00 3.737642E+00 6.059999E+01 6.060000E+01 6.060000E+01 2.406000E+02 2.406000E+02 6.000000E+01 3.850923E+03 1.922733E+03 9.285967E+02 3.250037E+00 5.687384E+00 9.040000E+01 9.040000E+01 9.040000E+01 2.704000E+02 2.704000E+02 7 2.000000E+01 9.437235E+02 5.859678E+02 1.648299E+01 2.779232E+00 4.611066E+00 2.108000E+02 3.080000E+01 2.108000E+02 3.080000E+01 2.108000E+02 4.000000E+01 2.025294E+03 1.336358E+03 1.425279E+01 3.047377E-01 1.168879E+00 2.406000E+02 6.060000E+01 2.406000E+02 2.406000E+02 2.406000E+02 6.000000E+01 2.738384E+03 1.969635E+03 1.421040E+02 8.492455E-02 2.489832E+00 2.704000E+02 9.040000E+01 9.040000E+01 9.040000E+01 2.704000E+021 JUNE 21, 2011 MSC NASTRAN 6/21/11 PAGE 24

Figure 7-6 Composite Stresses sorted by Global Ply ID under frequency response for SORT2 request

ConclusionData recovery of dynamic responses is now available at ply level for composites. However, the user must be cautious about controlling the output and ensure that only desired quantities are output. For large models with many composite elements, time steps/frequencies and with a large number of plies per element, we may notice an increase in the I/O times and CPU times (as compared to the equivalent noncomposite elements) – depending on the number of plies per element. This is because, now the stresses are evaluated for each ply as compared to stresses for the equivalent homogenous element. If we have a situation, say, with 100 plies per element, then the amount of stress output has increased by two orders of magnitude for each element.

Chapter 8: Optimization MSC Nastran 2012 Release Guide

8 Optimization

Design of Control Surfaces

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Design of Control Surfaces

IntroductionA control surface setting can now be treated as a designed quantity within a SOL 200 design task. A new DVPSURF bulk data entry specifies the relationship between a single design variable and a fixed control surface setting in a particular subcase. The optimizer then seeks the value of the design variable that provides an optimal design in the traditional sense of achieving the best design that satisfies all the imposed constraints.

BenefitsThe use of control surfaces to redistribute the loading on an aircraft so as to lessen a critical loading is an accepted practice that has been deployed on a number of air vehicles. The specification of the appropriate control surface setting can be a “trial and error” process that seeks a compromise between structural weight and control surface complexity. By including the ability to design the control surface position as part of an overall structural optimization task, this process can be automated and added insight can be gained from the design process.

User InterfaceThe interface for this new feature is a new bulk data entry that bears some resemblance to the existing DVPREL1/DVMREL1/DVCREL1 entries, but that has tailored to the control surface requirements.

The new entry is named DVPSURF and has the following specification:

Defines the relationship between a control surface setting in a particular subcase and a design variable.

Format:

Example:

DVPSURF Design Variable to Control Surface Setting Relation

1 2 3 4 5 6 7 8 9 10

DVPSURF ID AELABEL TRIMID DVID COEF

DVPSURF 10 OBDFLAP 1 100 0.01746

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Remarks:

1. The relationship between the control surface setting and the design variable is given by SURF = COEF * XDVID

2. The surface called out by AELABEL must also appear on the trim entry specified by TRIMID. The value specified on the trim entry will be overwritten by the value obtained from the relationship of Remark 1.

3. Limits on the control deflection are not provided on this entry but can be specified on the underlying DESVAR

4. The DVID called out on this entry cannot be associated with any other designed property.

5. Note that since the DVPSURF calls out a TRIM ID, it is associated only with a single subcase.

Another part of the user interface is that there must be a means of including the control surface deflection in the objective of the design process. There is no pre-specified way of doing this so that it is left to the user’s ingenuity to devise a strategy that is suited to the task at hand. In general, there must be a way of adding a penalty to the traditional design objective, such as weight, so that the achieved design is realistic in accounting for the increased “cost” of deflecting a control surface as part of the maneuver. The examples given in the test cases below show a straightforward way of introducing this penalty but users should be alert to seeking a specification that is in line with their design task.

Field Contents

ID Unique identification number (Integer>0)

AELABEL LABEL of the AESURF entry that is being designed (Character ,no default)

TRIMID Associated trim set identification number (Integer>0)

DVID DESVAR entry identification number (Integer>0)

COEF Coefficient of linear relation (Real)


78

Test Cases There are two test cases, each variations on the familiar forward swept wing example. The two cases are contained inside the tpl/dvpsurf subdirectory that comes with the delivery.

The first test case is named dvppnch.dat and was developed to validate that the final punch file produced by the run contains the TRIM bulk data input that reflects the design control surface setting. It is a simple single subcase example where he DVPSURF related data includes the following bulk data snippet:

DESVAR 10 PBAR101 1.0 0.001 100.0DESVAR 20 PBAR102 1.0 0.001 100.0DESVAR 30 PBAR103 0.1 0.001 100.0DESVAR 40 flap 1.0 0.001 100.0$vpsurf id aelabel trimid desvar coefdvpsurf 10 flapron 1 40 0.1

This indicates that the designed control surface is name flapron and is associated with TRIMID 1 and has a value of 0.1 * DESVAR 40. Flapron is a pitch controller on the wing that deflects symmetrically. The corresponding TRIM entry is:

TRIM 1 0.9 1200.0 PITCH 0.0 URDD3 -6.0 +TR1A$ LABEL3 UX3 ETC+TR1A URDD5 0.0 flapron 1.0 RUDDER 0.0 URDD2 0.0 +TR1B+TR1B URDD4 0.0 URDD6 0.0

It is seen that the designed value of 0.1 will override the user specified trim value of 1.0.

A design objective is created that combines the weight of the structure with the flap deflection as indicated by the following bulk data input:

DRESP2 10 object 10 desvar 40

dtable wf dresp1 123deqatn 10 obj(xf,wf,weight) = weight - 14050. + wf * xf**2dtable w1 667. w2 1333. w3 50. wf 100.

It is seen that the objective is equal to the total weight of the structure minus 14050 pounds of non-structural (undesigned) weight plus a penalty that is 100 times the squared value of the design variable that controls the flap setting. The only constraints specified in the problem are limits on the stresses in the bar elements representing the wing and the vertical tail and on the aeroelastic twist at the wing tip. The concept is that deflecting the surface could reduce the load on the outboard wing, thereby reducing the stress at the wing root and perhaps helping with the aeroelastic twist.

Adding a new type of designed property necessitated adding additional formatted prints in several areas in the .f06 printout, one of which is shown here:

--COMPARISON BETWEEN CONTROL SURFACE SETTING VALUES FROM ANALYSIS AND DESIGN MODELS--

----------------------------------------------------------------------------- CONTROL TRIM TRIM ENTRY DESIGN SURFACE ID VALUE VALUE FLAG ----------------------------------------------------------------------------- FLAPRON 1 1.000000E+00 1.000000E-01 WARNING

Following a redesign, the updated information is printed as:

79CHAPTER 8Contents

----- DESIGNED CONTROL SURFACES AND FREQVR VALUES -----

------------------------------------------------------------ PROPERTY TRIM OR TYPE OF VALUE NAME SUBCASE ID PROPERTY ------------------------------------------------------------ FLAPRON 1 DVPSURF 1.0000E-01

As mentioned, only a single design cycle was run for this case with design history results given in the .f06 file.

The redesign is just getting started, but it is gratifying to see that the objective has been cut in half while the maximum constraint is only slightly violated. The description of this example finishes with a portion of the output in the .pch file:

PBAR* 103 3 7.50000030E-02 8.68055038E-03* * 1.00000001E-01 2.31481511E-02 0.00000000E+00 * * 5.00000000E-01 3.00000000E+00 5.00000000E-01 -3.00000000E+00* * -5.00000000E-01 3.00000000E+00 -5.00000000E-01 -3.00000000E+00* * 0.00000000E+00 0.00000000E+00 0.00000000E+00 * * TRIM* 1 8.99999976E-01 1.20000000E+03 PITCH * * 0.00000000E+00 URDD3 -6.00000000E+00 1.00000000E+00* * URDD5 0.00000000E+00 FLAPRON 6.19037338E-02* * RUDDER 0.00000000E+00 URDD2 0.00000000E+00* * URDD4 0.00000000E+00 URDD6 0.00000000E+00* *

The punch output is in double field format and therefore difficult to read, but the important thing to notice is that the PBAR entry has been updated with the new designed properties as has the TRIM entry which now has the FLAPRON set at its .0617 radian designed value.

The second test case can be found at tpl/dvpsurf/dvpfat22.dat and is a more comprehensive demonstration of the capability to use control surfaces as design variables. This example has two subcases, each with two designed control surface settings. The two cases correspond to a subsonic and supersonic cruise condition while the control surfaces are the flaperon of the previous example plus a tab that is along the trailing edge of the flap.

The designed properties in this case look like:

DESVAR 40 flap1 1.0 0.001 100.0DESVAR 50 tab1 1.0 0.001 100.0DESVAR 60 flap2 1.0 0.001 100.0DESVAR 70 tab2 1.0 0.001 100.0$vpsurf id aelabel trimid desvar coefdvpsurf 10 flapron 1 40 0.1 dvpsurf 20 tab 1 50 -0.1 dvpsurf 30 flapron 2 60 0.1 dvpsurf 40 tab 2 70 -0.1


80

It is seen that DVPSURF’s 10 and 20 invoke the first trim entry (first subcase) and DVPSURF’s 30 and 40 the second. The objective in this case is:

dresp1 123 weight weightDRESP2 10 object 10 desvar 40 50 60 70 dtable wf wt dresp1 123deqatn 10 obj(xf1,xt1, xf2, xt2, wf, wt, weight) = weight - 14050. + wf * xf1**2 + wt * xt1**2 + + wf * xf2**2 + wt * xt2**2 dtable wf 100. wt 100.

This is similar to the previous example but now there are four penalty terms for the four designed control surfaces.

A study of the design cycle history in the .f06 file for this example shows that SOL 200 was able to reduce the objective from 2405.0 to 969.0 in 8 design cycles. Examination of the .f06 file indicates that the weight component of this final objective value is 808.0 while the control surfaces contribute the remainder. If this same problem is run without the designed control surfaces and the trim entries modified to set these surfaces to zero, the final optimal structural weight is 1174, indicating a 368 lb. (31.3%) weight savings. Of course this is a contrived problem meant to illustrate the benefit of the feature, but it is considered impressive nonetheless.

Guidelines and Limitations The value of the capability is, of course, highest when the critical design constraints can be relieved by the control surface deflection. If a stiffness constraint, such as control surface effectiveness, dominates the design, it will be difficult to achieve weight reduction.

The examples have shown how to create a synthesized objective that makes a tradeoff between structural weight and flap deflection. The user’s ingenuity can be used to pose alternative design tasks. One might be to simply take an existing structural design and determine flap settings for a number of load cases that minimize the control power while constraining the maximum stresses.

A designed control surface must be specified on the TRIM bulk data entry called out on the DVPSURF entry. The designed value overrides the value specified on the TRIM entry.

As with other designed properties, it is recommended that the starting value of the designed value not be zero as it is difficult to obtain accurate sensitivities at this value. Also, it is helpful to know what sign the optimal value will have since changing the sign of the design property requires passing through the problematic zero value.

Chapter 9: Aeroelasticity MSC Nastran & MSc Nastran 2011 Release Guide

9 Aeroelasticity

Improvements in Spline Blending

Alternate Trim Definition

Small Difference in Answers Based on Doublet Lattice Aerodynamics

MSC Nastran 2012 Release GuideImprovements in Spline Blending

82

Improvements in Spline Blending

IntroductionPreviously the concept of spline blending was introduced to improve the accuracy of the solution. With the increasing use of CFD aerodynamics and the dense meshes and smooth displacements CFD requires, a need has arisen to overlap the splines and use blending techniques to average the displacements of the adjacent splines. In complicated situations, it is possible to blend the blend results and MSC Nastran supports a blending hierarchy of any number of blends. This feature was difficult to use since it required you to select the structural and aerodynamic grids that were in the overlap region. The MSC Nastran 2012 release simplifies this by only requiring you to select the splines that participate in the blends and define the depths for the overlap region. MSC Nastran now automatically determines the aerodynamic and structural grids that are within your defined depth and adds them to the relevant splines.

BenefitsYou no longer need to define the aerodynamic and structural grids that are within the overlap region. In the context of CFD meshes with many thousands or aerodynamic grids, this can be a significant benefit when the individual splines are congruent with an aerodynamic component. Attempting to extend this spline into another component currently involves significant manual selection of grid points.

Input

The MDLPRM bulk data entry has the following additional optional parameter:

OutputsThere are no new .f06 outputs as a result of this enhancement. There is ongoing SimXpert development that will display the additional aero and structural grids that the automated blending procedure has identified.

Guidelines and LimitationsYou are still required to complete the SPBLND1/SPBLND2 entries, providing all the same input as before that defines the blending depths and point or line that defines the bounding region.

The feature is intended for the AEGRID/AEQUAD4/AETRIA3 representation of inputting an aerodynamic mesh based on a CFD analysis, but it can support the CAEROi input of aerodynamic models as well. The SPLINE3 is not supported with automated blending. When one or both of the

Name Description, Type and Default Values

SPBLNDX Factor to be applied to D1 and D2 blend depths on the SPBLND1 and SPBLND2 bulk data entries for determining the structural grids in the blended region. (Real, 1.0, default = 1.0 )

83CHAPTER 9Aeroelasticity

blended splines is a SPLINRB, the blending is only applied to the aerodynamic grids and not the structural grids.

The automated blending process can only add aero/structural grids. It never deletes a grid from a given spline. If you have already selected the grids in the overlap region, it is not necessary that they be removed since the automated blending retains them.

Examples

Three small decks in the tpl that exercise automated blending are:

1. Fway.dat - demonstrates the blending of four separate splines. The model is a square plate divided into four equal regions, each with its own splining. Two blends first blend the two top and the two bottom splines, while a third blend blends the top blend with the bottom blend.

$$ Spline Blend: Top_603$SPBLND1 603 210 220 CUB 2011 1.17 1.17

1. 0. 0. 0$$ Spline Blend: Bottom_604$SPBLND1 604 230 240 CUB 2431 1.17 1.17

1. 0. 0. 0SPBLND1 703 603 604 CUB 2211 1.17 1.17

0. -1. 0. 0

2. Blend.dat - a variation of etl deck plate01 which is a simple plate model with 121 structural grids and 441 aero grids. While plate01 has a single spline, the blend model was two splines that split the plate down the middle with an equal number of aero and structural grids in the right and left splines and a set of common structural/aero grids on the line dividing the two splines. A single SPBLND1 provides for an overlap depth on 1.0 for the aero grids and the SPLNDX values increases this to 2.1 for the structural grids.

3. Wing14a.dat - A variation of test library wing14 with the overlap in aerodynamic grids on the separate splines removed so that they will be created with the automated blending algorithm. The SPLINRB is used for the two splines.

GUI Support

This capability is supported in SimXpert which invokes MSC Nastran to allow you to visualize the blend as shown below.

MSC Nastran 2012 Release GuideAlternate Trim Definition

84

Alternate Trim Definition

IntroductionThe existing TRIM bulk data entry requires that you define which aerodynamic controllers are constrained. Any unspecified controllers are either free, linked with an AELINK entry, or scheduled with a CSSCHD entry. Some models have a large number of controllers, most of which are constrained to zero on the TRIM entry. An alternate method of trim definition was created such that undefined controllers are fixed to a value of zero.

BenefitsFor trim cases that have a large number of aerodynamic controllers that are fixed to a value of zero, this new trim definition is simpler. This new format also allows you to specify every controller, making it easier to play with various settings without having to constantly adjust the entry format.

InputA new Nastran bulk data entry called TRIM2 (p. 3367) in the MSC Nastran Quick Reference Guide was created.

Defines the state of the aerodynamic extra points for a trim analysis. All undefined extra points will be set to zero.

Format:

Example:

TRIM2 Trim Variable Definition

1 2 3 4 5 6 7 8 9 10

TRIM2 ID MACH Q AEQR

LABEL1 VALUE1 LABEL2 VALUE2 -etc.-

TRIM2 1 0.9 100.

URDD3 1.0 ANGLEA FREE ELEV 0.2

Field Contents

ID Trim set identification number (Integer>0). See Remarks 1. and 2.

MACH Mach number. (Real > 0.0 and 1.0). See Remark 5.

Q Dynamic pressure. (Real > 0.0)


Remarks:

1. The TRIM2 entry must be selected with the Case Control command TRIM=ID.

2. The ID must be unique among all TRIM and TRIM2 entries.

3. A value of FREE indicates that the controller value will be solved for by the trim process. A value of LINKED indicates that the controller value will be set by an AELINK entry. A value of SCHED indicates that the controller value will be set by a CSSCHD entry. The LINKED and SCHED inputs are optional and provided as a convenience to the user. Nastran will determine the linked and scheduled controller states from the AELINK and CSSCHD entries, respectively.

4. All aerodynamic extra points that have not been defined on a TRIM2, AELINK, or CSSHED entry will be fixed to a value of zero.

5. If MACH is less than 1.0, then the Doublet-Lattice theory is used. If MACH is greater than 1.0, then the ZONA51 theory is used.

6. AEQR=0.0 can be used to perform a rigid trim analysis (ignoring the effects of structural deformation on the loading). AEQR=1.0 provides standard aeroelastic trim analysis. Intermediate values are permissible, but have no physical interpretation (they may be useful for model checkout).

OutputThere are no new output data. All output data that can be created with the TRIM entry can be created with the TRIM2 entry.

Test Case

The trim2a.dat test case is available in the TPL in directory tpl/aero_20112. This test case will define the trim conditions using the TRIM2 bulk data entry.

The first subcase uses trim ID 1. Here, the ANGLEA, ELEV, SIDES, YAW, and ROLL controllers are all FREE, while only the URDD3 controller has a nonzero fixed value. The unspecified controllers, AILERON, PITCH, RUDDER, URDD2, URDD4, URDD5, and URDD6, are all assumed to be fixed at 0.0.

TRIM2 1 0.9 1200.0 ANGLEA FREE URDD3 -1.0 ELEV FREE SIDES FREE

AEQR Flag to request a rigid trim analysis (Real > 0.0 and 1.0; Default = 1.0). A value of 0.0 provides a rigid trim analysis. See Remark 6.

LABELi The label identifying aerodynamic trim variables defined on an AESTAT, AESURF, or AEPARM entry (Character)

VALUEi The value assigned to LABELi. Either a real number that indicates the variable's fixed value, or one of the following words: FREE, LINKED, or SCHED. See Remarks 3. and 4.

Field Contents

MSC Nastran 2012 Release GuideAlternate Trim Definition

86

YAW FREE ROLL FREE

The second subcase uses trim ID 2. Here, all controllers are defined, which could not be done with the original TRIM entry.

TRIM2 2 0.5 700.0 ANGLEA FREE PITCH 0.0 URDD3 -1.0 URDD5 0.0 ELEV FREE SIDES FREE YAW FREE ROLL FREE URDD2 0.0 URDD4 0.0 URDD6 0.0 AILERON 0.0 RUDDER 0.0


Small Difference in Answers Based on Doublet Lattice AerodynamicsIt was found that an adjustment was required in one of the doublet lattice subroutines to handle a special case of highly swept wings at a Mach number of 0.8. Without the fix, both steady and unsteady pressure distributions were erratic for this special case, while the pressures are well behaved with the fix. It has been observed that this change results in negligible differences in results for a number of quality assurance test cases. In all cases the differences were not physically meaningful.

MSC Nastran 2012 Release GuideSmall Difference in Answers Based on Doublet Lattice Aerodynamics

88

Chapter 10: AcousticsMSC Nastran 2010 Release Guide

10 Acoustics

Weakly Coupled Acoustics

Efficient Participation Factor Analysis with ACMS and DMP

Frequency Dependent Analysis with ACTRAN Trimmed Material and/or Acoustic Pressure Load Matrices

Panel Participation Factor Analysis for Structure Response

Compute Element Sensitivity based on Frequency Response Function and Element Matrix

Output Particle Acceleration on Wetted Surface

Output ADF Format File for Frequency Response Function

MSC Nastran 2012 Release GuideWeakly Coupled Acoustics

90

Weakly Coupled Acoustics

IntroductionWith MD Nastran 2010, fluid/structure interaction, FSI, analysis is supported for both interior and exterior acoustic. Semi-infinite elements, e.g. CACINF3/CACINF4, are utilized to model the outward space from the edge of traditional finite acoustic elements. For modal frequency analysis, the convergence for FSI model with both interior and exterior acoustic modeling is slow due to the fact that the semi-infinite elements are not included for fluid modes extraction. The two step approach has been demonstrated to improve the computational performance of acoustic simulations. The two steps are

Step 1: FSI with interior acoustic only in modal formulation and, then,

Step 2: Exterior acoustic only job with loading derived from the results of Job 1 in direct formulation.

The two jobs approach is commonly known as weakly coupled acoustic analysis. It is now possible to combine the two run approach into a single run and to improve the convergence performance.

BenefitsUnlike the two step approach, the required user input to activate weakly coupled acoustic is kept to a minimum. And, for some FSI deck with both interior and exterior acoustic model, the run time is expected to be reduced significantly. However, this performance improvement is not universal for all FSI jobs.

TheoryTypical symmetrical FSI equations, see Reference Manual, in its matrix form is as follows,

(10-1)

where , , , , and are the coupling, ‘mass’, ‘damping’, ‘stiffness’, pressure and source

matrices for interior acoustic

, , , , and are the coupling, ‘mass’, ‘damping’, and ‘stiffness’, pressure and source

matrices for exterior acoustic

, , , and are the ‘mass’, ‘damping’, ‘stiffness’, displacement and load matrices for

structure

e

i

s

e

i

s

fe

fi

s

fe

fi

eis

fete

fiti

s

G

G

P

q

q

u

K

K

K

B

B

AAB

i

MA

MA

M

)

00

00

00

00

00

0

0

00

( 2

Ai Mfi Bfi Kfi qi Gi

Ae Mfe Bfe Kfe qe Gi

Ms Bs Ks us Ps

91CHAPTER 10Acoustics

With the assumption that the interaction between the structure and exterior acoustic is negligible, Equation (10-1) can be solved in stages. The first stage involves the first two rows of Equation (10-1), as shown in Equation (10-2).

(10-2)

With available, exterior acoustic model, the third row of Equation (10-1), becomes

(10-3)

Note that

Equation (10-2) can be solved with either direct or modal formulation.

Equation (10-3) is solved with direct formulation due to the inclusion of semi-infinite elements.

Input The only user input to activate weakly couple acoustic algorithm is ‘PARAM,ACOWEAK,YES’. Note that weakly coupled acoustic algorithm is applicable to FSI decks with following conditions exterior acoustic model and semi-infinite elements, e.g. CACINF3/CACINF4. SOL 111 or 200 with ANALYSIS=MFREQ

Output

There is no new output for FSI decks using weakly couples acoustic algorithm. All current acoustic related output requests are supported; including AFPLRESULTS.

Guidelines and Limitations 1. Interior acoustic model and exterior acoustic model should not contact each other directly. If an

interior acoustic model comes in contact with exterior acoustic model, it is considered as part of exterior acoustic model.

2. Weakly coupled acoustic algorithm can handle the cases with no interior acoustic model.

3. In current implementation, ‘PARAM,ACOWEAK,YES’ is applicable only for SOL 111 and SOL 200 with ANALYSIS=MFREQ.

Test Cases Following test cases are available in TPL lib.

Acoweak1, acoweak2 and acoweak3

i

s

i

s

fi

s

fi

is

fiti

s

G

P

q

u

K

K

B

ABi

MA

M)

0

0

0

0( 2

sU

2– Mfe i Bfe Kfe qe + + Ge Ae

t2us–

=

MSC Nastran 2012 Release GuideEfficient Participation Factor Analysis with ACMS and DMP

92

Efficient Participation Factor Analysis with ACMS and DMP

IntroductionWith MD Nastran 2011.1, mode, panel, or grid participation factor can be requested with PFMODE, PFPANEL, or PFGRID Case Control entries for fluid-structure coupling problem. However, required CPU cost and disk space for these analyses were high when compared to general frequency response analysis with MDACMS and DMP utilized. Hence, the algorithm of participation factor analysis is updated to realize the full advantage of MDACMS and DMP. As a result, calculation time and necessary disk space are reduced significantly when compared to the previous versions. In addition, the definition of panel group for panel participation factor analysis is also updated to allow reading the panel group data in the file exported by AKUSMOD.

BenefitsThe participation factor analyses by PFMODE, PFPANEL, and PFGRID are used to calculate the mode/panel/grid participation factors for the fluid-structure problem. When the large scale FE model with over one million degree of freedoms is analyzed, MDACMS and DMP are very efficient in getting faster results. This algorithm update is better suited for the user who requests the participation factor analysis. For the AKUSMOD user, the panel group definition in AKUSMOD is automatically used for fluid-structure coupling problem when the file is assigned to UNIT 70.

TheoryThe disadvantages for high CPU cost and disk space usage of the algorithm of MD Nastran 2011.1 and before is as follows.

Mode shapes of all grids on wetted surface are recovered before the participation factor analysis for modal decomposition of the panel coupling matrices in MDACMS.

The participation factors were calculated on the master node only even if DMP is applied.

The full functions of MDACMS are applied for modal decomposition of panel coupling matrices. Furthermore, the participation analyses are parallelized by dividing frequencies among DMP nodes available such that the calculation is much faster compared to the previous versions.

Input

The original Case Control, PFMODE, PFPANEL, and PFGRID entries are affected by this implementation. No new bulk data, case control, or parameter entries. When the AKUSMOD file is assigned to UNIT 70, the panel group definition is automatically applied if it exists.


Output No new form of output is produced by this effort.

Guidelines and LimitationsThe new algorithm of participation factor analysis will be applied to the run with ACMS and/or DMP run in SOL111.

The case control command FLSPOUT is not supported.

The other outputs of panel group information are not supported for the panel group definition by AKUSMOD.

Test CasesThe following test cases are available in TPL in directory tpl/fsc_2011.

For non-MDACMS example, fsc_03 and fsc_04 are in same directory.

A large, real world model is used to demonstrate these performance improvements. Hardware used in the example below is 3470 MHz Intel Xeon CPUs, 48 GB main memory, Linux 2.6.18-194EL5.

fsc_01 MDACMS + DMP with Nastran coupling definition

fsc_02 MDACMS + DMP with AKUSMOD coupling definition




Number of fluid modes: 600

Number of load cases: 210

MSC Nastran 2012 Release GuideEfficient Participation Factor Analysis with ACMS and DMP

94

The elapsed time of panel participation analysis (green bar) for dmp=2 is almost same as serial run with MD Nastran 2010.1, but dmp=2 and 4 are much better in this version. And the maximum disk usages including all slaves are reduced compared to the previous version.


Frequency Dependent Analysis with ACTRAN Trimmed Material and/or Acoustic Pressure Load Matrices

IntroductionACTRAN has a function to calculate the property of trimmed material in porous medium and the pressure load due to external acoustic excitation based on free field acoustic analysis. This new function can incorporate the matrices exported by ACTRAN as the trimmed material property and acoustic pressure load property into MSC Nastran frequency response analysis. Both properties are imported as the frequency dependent matrices in fluid-structure coupling problem. The matrices of trimmed material are merged into Nastran system matrices, and its effect can be observed in the results of frequency responses such as DISPLACEMENT, VELOCITY, and ACCELERATION and participation factors via PFMODE, PFPANEL, and PFGRID.

BenefitsThe new capability is to utilize the trimmed material properties and/or define the excitation forces due to acoustic pressure loads calculated by ACTRAN. The effect of trimmed material properties are shown in the results of frequency response analysis such as DISPLACEMENT, VELOCITY, and ACCELERATION and the frequency participation factor analysis by PFMODE, PFPANEL, and PFGRID for fluid-structure coupling problem.

TheoryThis function is computing the frequency response with ACTRAN trimmed material properties. The matrices ACTRAN exports have the property of frequency dependent trimmed materials. The equation of the ACTRAN matrices is as follows.

where is structural domain, is fluid domain, and is angular velocity (frequency). All terms of

are computed by ACTRAN at the user defined frequencies. On the other hand, Nastran symmetries

system can be written as,

iff

isfiss

ij Zsym

ZZZ

.

s f

iZ

2 Ms 0

0 Mf–– i

Bs Asf

sym Bf–

Ks 0

0 Kf–+ +

us

qf Ps

Gf–

=

MSC Nastran 2012 Release GuideFrequency Dependent Analysis with ACTRAN Trimmed Material and/or Acoustic Pressure Load Matrices

96

The coupling term may be conflicted with ; then we need to eliminate the terms of on

the duplicated surface; it’s called as here. As a result, the next equation is applied to frequency

response analysis with frequency dependency.

The panel groups defined by PANEL or AKUSMOD are used for panel contribution analysis. And,

coupling matrices for each panel is re-constructed based on matrix. Linear

interpolation technique are applied if ACTRAN matrices don’t exist for the specific forcing frequency. For the acoustic pressure load from ACTRAN, the next equation is applied.

where is the frequency dependent acoustic pressure load vector from ACTRAN.

Input The new case control entries and bulk data entries are introduced to support ACTRAN trimmed material and acoustic pressure load matrices. These new case control and bulk data entries can be applied in SOL111 and SOL108 only.

The new Case Control entry is:

ACTRIM ACTRAN Trimmed Material Matrices for SOL 108/111

Select ACTRAN trimmed material matrices.

Format:

ACTRIM = name1, name2, … namen

Example:

sfA )( isfZ sfA

sfA

2 Ms 0

0 Mf–– i

Bsi----Zss – Asf

+ i----Zsf +

sym Bf–i----Zff –

Ks 0

0 Kf–+ +

us

qf Ps

Gf–

=

)( isfsf Zi

A

2 Ms 0

0 Mf–– i

Bs Asf

sym Bf–

Ks 0

0 Kf–+ +

us

qf Ps Pa +

Gf–

=

aP


Remarks:1. This entry must be above subcase level or in the first subcase.

2. If the ACTRIM Case Control command selects ACTRIM bulk data entries, Nastran will add the selected ACTRAN matrices to fluid-structure coupling problem in all subcases.

3. ACTRIM is supported in frequency response analysis for fluid-structure coupling problem and the frequency dependent algorithm will be adopted automatically.

4. PARAM, ACSYM, YES should be set for ACTRIM (default).

5. The effect of ACTRIM will be considered in standard frequency response analysis and participation factor analysis by PFMODE, PFPANEL and PFGRID.

The new Bulk Data entries are:

Format:

Example(s):

ACTRIM = FLOOR_F, FLOOR_R, DASH SET 10 = FR_LH, RR_LHACTRIM = 10

Describer Meaning

namei Name of the ACTRAN trimmed material matrices that is input on the ACTRIM bulk data entry, or name list.

ACTRIM ACTRAN Trimmed Material Matrices for SOL 108/111

Defines ACTRAN trimmed material matrices.

1 2 3 4 5 6 7 8 9 10

ACTRIM NAME UNIT1 UNIT2 SCLR SCLI

ACTRIM FLOOR 31 32 2.0 0.5

Field Context

NAME Name of the ACTRAN trimmed material matrices. See Remark 1. (One to eight alphanumeric characters, the first of which is alphabetic)

UNIT1 Fortran unit number of mapped data from ACTRAN. See Remark 2. (Integer > 0)


98

Remarks:1. ACTRAN trimmed material matrices defined by this entry will be used for frequency response

analysis if it is selected via the Case Control ACTRIM = NAME.

2. The following type of ASSIGN should be specified in the FMS section with the vacant unit number (see ASSIGN statements). The unit number cannot be selected twice.

3. ASSIGN INPUTT2=’ACTRAN_trimmed.f70’ UNIT=31

4. ASSIGN INPUTT4=’ACTRAN_trimmed.op4’ UNIT=32

5. Refer the ACTRAN manual for the details of exportation of the trimmed material matrix data for Nastran.

Format:

Example(s):

UNIT2 Fortran unit number of property matrices from ACTRAN. See Remark 2. (Integer > 0)

SCLR The real part of complex scale factor to be multiplied to ACTRAN matrices. (Real; Default = 1.0)

SCLI The imaginary part of complex scale factor to be multiplied to ACTRAN matrices. (Real; Default = 0.0)

ACLOAD ACTRAN Acoustic Pressure Load Matrices for SOL 108/111

Defines ACTRAN acoustic pressure load matrices.

1 2 3 4 5 6 7 8 9 10

ACLOAD SID UNIT1 UNIT2 SCLR SCLI

ACLOAD 101 41 42 1.5

Field Contests

SID Set identification number. See Remark 1. (Integer > 0)

UNIT1 Fortran unit number of mapped data from ACTRAN. See Remark 2. (Integer > 0)

UNIT2 Fortran unit number of property matrices from ACTRAN. See Remark 2. (Integer > 0)

SCLR The real part of complex scale factor to be multiplied to ACTRAN matrices. (Real; Default = 1.0)

SCLI The imaginary part of complex scale factor to be multiplied to ACTRAN matrices. (Real; Default = 0.0)


Remarks:

1. Dynamic excitation sets must be selected with the Case Control command DLOAD = SID for frequency response analysis.

2. The following type of ASSIGN should be specified in the FMS section with the vacant unit number (see ASSIGN statements). The unit number cannot be selected doubly.

3. ASSIGN INPUTT2=’ACTRAN_pressure.f70’ UNIT=41

4. ASSIGN INPUTT4=’ACTRAN_pressure.op4’ UNIT=42

5. SID must be unique for all RLOAD1, RLOAD2, ACSRCE and ACLOAD entries.

6. Refer the ACTRAN manual for the details of exportation of the acoustic pressure load matrix data for Nastran.

7. The residual vectors for ACLOAD will not be computed.

Example InputThe following input is typical for ACTRIM calculation.

File ManagementASSIGN INPUTT2=’ACTRAN_trimmed.f70’ UNIT=31ASSIGN INPUTT4=’ACTRAN_trimmed.op4’ UNIT=32Case ControlACTRIM = TRIM1Bulk DataACTRIM, TRIM1, 31, 32, 1.5, 0.0

The following input is typical for ACLOAD.

File ManagementASSIGN INPUTT2=’ACTRAN_pressure.f70’ UNIT=41ASSIGN INPUTT4=’ACTRAN_pressure.op4’ UNIT=42Case ControlDLOAD = 103Bulk DataACLOAD, 103, 41, 42, 2.0, 0.0

Output No new output is defined.

Guidelines and LimitationsACTRIM support the fluid-structure coupling analysis only and ‘PARAM, ACSYM’ should be ‘YES’.

The panel group for contribution analysis should be defined in MSC Nastran and ACTRIM matrices are divided to each group internally base on the user defined group by PANEL bulk data or AKUSMOD.

ACLOAD can be applied to the general frequency response analysis.


100

Test CasesThe following test cases are available in TPL in directory tpl/fsc_2011. There are four TPL files with the name fsc_05, fsc_06, fsc_07, and fsc_08:

The comparisons of frequency response functions with and without ACTRIM using the examples above are shown in the next figure. Note that the frequency range to be computed was expanded from the original data as follows.

EIGRL, 100, 0.0, 200.0EIGRL, 200, 0.0, 400.0FREQ1, 501, 10.0, 0.5, 180

Some peaks are shifted to the lower frequency and magnitudes are also lower in case with ACTRIM. It should be the damping and mass effects by the trimmed material.

The acoustic response of grid 4001 due to the structure excitation of 13549Z:

The frequency response function by ACLOAD excitation is shown as below. The structure is excited by the acoustic pressure load by the free field sound and the acoustic cavity is also excited by the structure vibration.

fsc_05 ACTRIM entry with MDACMS

fsc_06 ACTRIM entry without MDACMS

fsc_07 ACLOAD entry with MDACMS

fsc_08 ACLOAD entry without MDACMS

1.00E‐06

1.00E‐05

1.00E‐04

1.00E‐03

1.00E+01 1.00E+02

Sound Pressure [kPa]

Frequency [Hz]

4001 w/o ACTRIM

4001 with ACTRIM


The acoustic response of 4001 due to ACLOAD excitation:

1.00E‐05

1.00E‐04

1.00E‐03

1.00E‐02

1.00E+01 1.00E+02

Sound Pressure [kPa]

Frequency [Hz]

4001 due to ACLOAD

MSC Nastran 2012 Release GuidePanel Participation Factor Analysis for Structure Response

102

Panel Participation Factor Analysis for Structure Response

IntroductionUsing the PFPANEL Case Control entry, the panel participation factors can be computed for the acoustic domain responses in previous versions. In this release, the panel participation factor analysis is extended to the structural domain response with new parameters on the PFPANEL entry. This reciprocal panel participation factors allow analyzing the effect of the fluid domain via each panel to the structure response.

BenefitsThis function is used to analyze the effect of the fluid to the structure response via each panel for fluid-structure coupling problem. MD Nastran 2011.1 supports the panel participation factor analysis to the acoustic domain responses only. But, the reciprocal factors are important when we need to know the effect of each panel to the structure domain responses.

TheoryThe purpose of this function is computing the panel participation factors to the structure response; it’s called the reciprocal panel participation factor here. The equation of panel participation factor analysis to the acoustic response that is supported with MD Nastran 2011.1 is as follows.

where is structural domain, is fluid domain and is angular velocity (frequency), and is the

coupling matrix of k-th panel. The reciprocal panel participation factor analysis is computed by the reversing structure terms and fluid terms then,

Note that the size of matrix to be inversed is much larger than the equation to the acoustic response, the CPU cost of this computation may be higher.

Input PFPANEL case control command is updated to compute the panel contribution factor to the structure response.

Pf k– 2 2Mf– i Bf Kf++

1–A

Tsf k– us–=

s f ksfA

Ps k– 2Ms– i Bs Ks++

1–Asf k– qf–=


The updated Case Control entry is (highlighted in red):

Requests the form and type of acoustic panel participation factor output.

Format:

PFPANEL [ ( [ FLUID / STRUCTURE ] , [ PRINT, PUNCH / PLOT ] , [ REAL or IMAG / PHASE ] , [ PANEL = { ALL / setp } ] , [ SORT = sorttype ] , [ KEY = sortitem ] , [ ITEMS = { ALL / (itemlist) } ] , [ SOLUTION = { ALL / setf / NONE } ] , [ FILTER = fratio ] , [ NULL = ipower ] ) ] = { setdof / NONE }

Example:

SET 10 = 10., 12.SET 20 = 1222, 1223PFPANEL (SOLUTION=10, FILTER=0.01, SORT=ABSD) = 20SET 30 = 5001/T2, 6502/T3PFPANEL (STRUCTURE, SOLUTION=10) = 30

Remarks:

(Same as the current documents)

11. The FLUID option selects panel PF calculation for acoustic grid points (one degree of freedom per point) and setdof should be identification numbers.

12. The STRUCTURE option selects panel PF calculation for structure grid points and setdof should be identification numbers and component codes.

Output The output result is almost same as the one due to the existence panel participation factor analysis to the acoustic response, but the title is different as follows (highlighted n red).

PFPANEL Acoustic Panel Participation Factor Output Request

Describer Meaning

FLUID Request output of MPFs for the response of acoustic grid points (one degree of freedom per point). See Remark 11. (Default)

STRUCTURE Request output of MPFs for the response of structure degrees of freedom. See Remark 12.

(Same as the current documents)

MSC Nastran 2012 Release GuidePanel Participation Factor Analysis for Structure Response

104

Guidelines and LimitationsThe usage is same as the one of existent PFPANEL.

The structure degree of freedom to be analyzed should be defined as the combination of grid identification number and component code.

S T R U C T U R E P A N E L P A R T I C I P A T I O N F A C T O R S

GRID POINT = 11310/T3, TOTAL RESPONSE (R/I) = 5.61014E-05 / -4.70489E-06, (M/P) = 5.62983E-05 / 355.21

LOAD FREQUENCY = 3.00000E+01, (SUBCASE 1, DLOAD = 1001)

MAXIMUM PANEL RESP = 5.55428E-05 FOR PANEL = -LOAD- , SORTKEY = PANEL , SORT = ALPHANUMERIC , FILTER = 1.00000E-03

PANEL NAME PANEL RESPONSE PANEL RESPONSE PROJECTION REL. PANEL SCALED RESPONSE

REAL IMAGINARY MAGNITUDE PHASE MAGNITUDE PHASE FRACTION MAGNITUDE

-LOAD- 5.53439E-05 -4.69633E-06 5.55428E-05 355.15 5.55428E-05 -0.06 9.86580E-01 9.99999E-01

PNL_01 5.14766E-07 -4.11540E-09 5.14782E-07 359.54 5.13309E-07 4.34 9.11766E-03 9.24167E-03

PNL_03 -4.08833E-07 3.63991E-08 4.10450E-07 174.91 -4.10445E-07 -180.29 -7.29053E-03 -7.38970E-03

PNL_04 -1.07045E-06 6.90462E-08 1.07267E-06 176.31 -1.07247E-06 -178.90 -1.90498E-02 -1.93089E-02

PNL_05 -4.49836E-07 3.82501E-08 4.51460E-07 175.14 -4.51459E-07 -180.07 -8.01905E-03 -8.12813E-03

S T R U C T U R E P A N E L P A R T I C I P A T I O N F A C T O R S

GRID POINT = 13549/T2, TOTAL RESPONSE (R/I) = 2.64770E-04 / -2.16922E-05, (M/P) = 2.65657E-04 / 355.32

LOAD FREQUENCY = 3.00000E+01, (SUBCASE 1, DLOAD = 1001)

MAXIMUM PANEL RESP = 2.70748E-04 FOR PANEL = -LOAD- , SORTKEY = PANEL , SORT = ALPHANUMERIC , FILTER = 1.00000E-03

PANEL NAME PANEL RESPONSE PANEL RESPONSE PROJECTION REL. PANEL SCALED RESPONSE

REAL IMAGINARY MAGNITUDE PHASE MAGNITUDE PHASE FRACTION MAGNITUDE

-LOAD- 2.69845E-04 -2.20927E-05 2.70748E-04 355.32 2.70748E-04 0.00 1.01916E+00 1.00000E+00

PNL_02 -2.98985E-07 4.65835E-08 3.02593E-07 171.14 -3.01791E-07 -184.17 -1.13602E-03 -1.11466E-03

PNL_03 -9.13222E-07 1.27858E-07 9.22129E-07 172.03 -9.20612E-07 -183.29 -3.46542E-03 -3.40025E-03

PNL_04 -1.35488E-06 1.61869E-07 1.36452E-06 173.19 -1.36358E-06 -182.13 -5.13284E-03 -5.03632E-03

PNL_05 -1.21015E-06 1.54704E-07 1.22000E-06 172.71 -1.21875E-06 -182.60 -4.58766E-03 -4.50140E-03


Test CasesThe following test cases are available in TPL in directory tpl/fsc_2011. There are four TPL files with the name fsc_03 and fsc_04.

For MDACMS + DMP example, fsc_01 and fsc_02 are in same directory.

fsc_03 Nastran coupling definition

fsc_04 AKUSMOD coupling definition

MSC Nastran 2012 Release GuideCompute Element Sensitivity based on Frequency Response Function and Element Matrix

106

Compute Element Sensitivity based on Frequency Response Function and Element Matrix

IntroductionThis is new function to compute and output element sensitivity based on the response DOFs and element set selected by the user. In addition, sensitivity for wetted grids is also computed.

BenefitsThis output of element sensitivity provided here can be viewed as element contribution to a response DOF due to a user-defined excitation. In the element sensitivity by SOL200, so many entries are needed to define the design variables for computing the sensitivities of many elements. This function, however, needs only one Case Control entry then it’s easier and simpler method for frequency response analysis. In addition, the sensitivities of the grids on the wetted surface can be computed in the fluid-structure problem with same manner. The wetted surface sensitivity allows you to know the potion on the wetted surface to be focused in the fluid-structure coupling problem.

TheoryThe symmetric system to define the equation in frequency domains is:

where is structural domain, is fluid domain, and is angular velocity (frequency). Then,

We assume the design variable , the element sensitivity in the case of excitation A, and the response B

is computed by the next equation.

where is the displacement vector due to the excitation to A and is the displacement vector due to

the excitation to B. And the squared sensitivity is written as,

Ms– i Bs Ks++

sym

Asf

2Mf i Bf Kf––

us

qf Ps

Gf–

=

s f

D

iu

Ai

TB

i u

D

u

V

1

A B

**

*2A

i

TBA

i

TB

i u

D

u

D

u

V


where * means the complex conjugate. And should be selected to extract mass, stiffness, or dynamic

terms by the options; MASS, STIF, or DYNAMIC for the element sensitivity and SQMASS, SQSTIF, and SQDYNAMIC for the squared sensitivity. For the wetted surface sensitivity, the coupling matrix

( ) is selected to compute the grid sensitivity on the wetted surface.

Input

Two new case control entries can be utilized to request element sensitivity and wetted grids sensitivity.

The new Case Control entries are:

Format:ELSENS ( [ PRINT , PUNCH / PLOT] , [ REAL or IMAG / PHASE ] , [ THRESH = p ] , RESPONSE = r ,[ SOLUTION = { ALL / setf }] , [ MASS , STIFF , DYNAMIC , SQMASS , SQSTIFF , SQDYNA] ) = { ALL / n / NONE }

ExampleSET 81 = 100.0, 120.0SET 91 = 11240/T3, 4001/T1 SET 96 = 15920 THRU 15950$ELSENS(RESPONSE=91, SOLUTION=81,MASS,STIFF,DYNAMIC) = 96

ELSENS Element Sensitivity Output for SOL 108/111

Select SOLUTION frequencies and RESPONSE DOFs for the generation element sensitivity.

Describer Meaning

PRINT Writes sensitivities to the print file (Default).

PUNCH Writes sensitivities to the punch file.

PLOT Do not write sensitivities to either the print file or punch file.

THRESH The magnitude of element sensitivity less than p will be suppressed in all output files: print, punch, plot, .op2, and .xdb. (Default = 0.0).

RESPONSE Adjoint load response will be computed for unit load applied at grid point components in SET r.

SOLUTION Frequency responses at these forcing frequencies, defined in setf, will be used for element sensitivity computation. (Default=all forcing frequencies)

MASS Sensitivity with element mass matrices will be computed and output.

STIFF Sensitivity with element stiffness matrices will be computed and output.

iu

sfA


108

Remarks:

1. Set r for RESPONSE has no default.

2. The equations various options of ELSENS

ELSENS(MASS) = [Asetf]t[Melem][Ar]

ELSENS(STIFF) = [Usetf]t[Kelem][Ur]

ELSEND(DYNAMIC) = [Asetf]t[Melem][Ar] + [Usetf]

t[Kelem][Ur]

ELSENS(SQMASS) = [Asetf]t[Melem][Ar] + [Asetf]*

t[Melem]* [Ar]*

ELSENS(SQSTIF) = [Usetf]t[Kelem][Ur] + [Usetf]*

t[Kelem]* [Ur]*

ELSEND(DYNAMIC) = [Asetf]t[Melem][Ar] + [Usetf]

t[Kelem][Ur] +

[Asetf]*t[Melem]* [Ar]

* + [Usetf]*t[Kelem]* [Ur]

*

where [Usetf] is the displacement of SOLUTION

[Asetf] is the acceleration of SOLUTION

[Ur] is the displacement of RESPONSE

[Ar] is the acceleration of RESPONSE

[Kelem] is element stiffness matrix

[Melem] is element mass matrix

superscript * means complex conjugate of the term.

DYNAMIC Sensitivity with element stiffness and mass matrices will be computed and output.

SQMASS Squared sensitivity with element mass matrices will be computed and output.

SQSTIF Squared sensitivity with element stiffness matrices will be computed and output.

SQDYNA Squared sensitivity with element stiffness and mass matrices will be computed and output.

ALL Sensitivities for all elements will be calculated.

n Set identification number. Sensitivity for all elements specified on the SET n command will be calculated. The SET n command must be specified in the same subcase as the ELSSENS command, or above all subcases ( Integer > 0 ). The IDs in set n must be EID (element ID).

NONE Elemental sensitivity will not be output.


Format:WETSENS ( [ PRINT , PUNCH / PLOT] , [ REAL or IMAG / PHASE ] , [ THRESH = p ] , RESPONSE = r ,[ SOLUTION = { ALL / setf }] , [WETTED , SQWETT]) = { ALL / n / NONE }

Example:SET 81 = 100.0, 120.0SET 91 = 11240/T3, 4001/T1 SET 95 = 9000000 THRU 9000050 $WETSENS(RESPONSE=91,solution=81,WETTED) = 95

Remarks:

1. Set r for RESPONSE on WETSENS is default to set r on ELSENS. If no ELSENS in the deck, set r for WETSENS must be provided.

2. The equations for various options of WETSENS

WETSENS Sensitivity Wetted Grids for SOL 108/111

Select SOLUTION frequencies and RESPONSE DOFs for the generation of sensitivity for wetted grids.

Describer Meaning

PRINT Writes sensitivities to the print file (Default).

PUNCH Writes sensitivities to the punch file.

PLOT Do not write sensitivities to either the print file or punch file.

THRESH The magnitude of element sensitivity less than p will be suppressed in all output files: print, punch, plot, .op2, and .xdb. (Default = 0.0).

RESPONSE Adjoint load response will be computed for unit load applied at grid point components in SET r.

SOLUTION Frequency responses at these forcing frequencies, defined in setf, will be used for element sensitivity computation. (Default=all forcing frequencies)

WETTED Sensitivity for wetted grids will be computed and output.

SQWETT Squared sensitivity for wetted grids will be computed and output.

ALL Sensitivities for all elements will be calculated.

n Set identification number. Sensitivity for all elements specified on the SET n command will be calculated. The SET n command must be specified in the same subcase as the ELSSENS command, or above all subcases ( Integer > 0 ). The IDs in set n must be GID (grid ID).

NONE Elemental sensitivity will not be output.


110

WETSENS(WETTED) = [Usetf]t[AGG][Ur]

WETSENS(SQWETT) = [Usetf]t[AGG][Ur] + [Usetf]*

t[AGG]* [Ur]*

where [Usetf] is the displacement of SOLUTION

[Ur] is the displacement of RESPONSE

[AGG] is Fluid/Structure Coupling matrix superscript * means complex conjugate of the term.

OutputIn f06, a sample element sensitivity output for STIF is shown as follows. The sensitivities are printed by each element type: BEAM, ELAS1, HEXA, QUAD4, and TETPR.

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (STIF ) ELEMENT TYPE:BEAM RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 6257 3.80848E-07/ -5.38564E-08 6258 -9.94747E-09/ 1.17812E-09 6259 6.96983E-07/ -1.16427E-07 6260 3.02423E-08/ 5.01726E-08

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (STIF ) ELEMENT TYPE:ELAS1 RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 6268 -7.50616E-07/ 3.82246E-08 6269 -7.07820E-07/ 1.35735E-07 6272 -9.45331E-08/ 2.84290E-08 6273 -2.44536E-08/ 3.69334E-09

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (STIF ) ELEMENT TYPE:HEXA RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 5598 3.92281E-07/ -2.83214E-08 5599 2.97181E-07/ -2.11778E-08 5600 6.38211E-07/ -3.87888E-08 5601 1.42306E-07/ 3.08925E-09

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (STIF ) ELEMENT TYPE:QUAD4 RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 1 3.96588E-06/ -6.31571E-07 2 1.81926E-05/ -2.63416E-06 3 1.37873E-06/ -1.54531E-07 4 8.17374E-06/ -8.52649E-07

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (STIF ) ELEMENT TYPE:TETPR RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 100011 2.88784E-10/ -3.43959E-11 100012 3.21860E-07/ -1.23688E-07 100013 2.08642E-07/ -7.88078E-08 100014 -3.62079E-08/ -1.45429E-09

MASS is shown as well. Note that ELAS1 doesn’t have any masses then nothing is printed out.

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (MASS ) ELEMENT TYPE:BEAM RESPONSE DOF: 4001/T1


ELEMENT ID REAL/IMAGINARY 6257 3.01773E-06/ -2.02431E-07 6258 3.00727E-06/ -1.92906E-07 6259 2.16594E-06/ -1.49622E-07 6260 3.09445E-06/ -2.13349E-07

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (MASS ) ELEMENT TYPE:HEXA RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 5598 1.87149E-07/ -4.73409E-09 5599 1.32380E-07/ -4.05157E-09 5600 1.43667E-07/ -4.78662E-09 5601 7.59971E-08/ -2.33647E-09

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (MASS ) ELEMENT TYPE:QUAD4 RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 1 4.73039E-06/ -1.00447E-06 2 -1.14021E-06/ -6.85568E-08 3 4.27465E-05/ -9.49842E-06 4 2.73492E-05/ -6.00055E-06

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (MASS ) ELEMENT TYPE:TETPR RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 100011 -9.92090E-08/ 1.28716E-09 100012 -9.85914E-07/ 6.89206E-08 100013 -1.15959E-06/ 9.04303E-08 100014 -1.36541E-06/ -5.02471E-09


112

For DYNAMIC is:

The result of DYNAMIC is same as summation of STIF and MASS.

For wetted grid sensitivity, a sample output is shown as follows,

FREQUENCY = 3.000000E+01 W E T T E D S E N S I T I V I T Y - (WETTED ) RESPONSE DOF: 4001/T1 GRID ID/DOF REAL/IMAGINARY 10001/T1 1.08566E-05/ -8.97381E-07 10001/T2 5.12367E-06/ 6.81049E-08 10001/T3 1.68916E-06/ -1.41791E-07 10001/R1 2.01494E-13/ 2.04843E-14 10001/R2 8.22658E-11/ -4.15333E-12 10001/R3 -1.25147E-11/ 7.90934E-14 10002/T1 6.95717E-06/ -7.20847E-07 10002/T2 6.06442E-06/ 7.95307E-08 10002/T3 1.23575E-06/ -1.31611E-07 10002/R1 -1.08251E-11/ 5.61736E-13 10002/R2 4.55328E-11/ -2.39474E-12

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (DYNAMIC ) ELEMENT TYPE:BEAM RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 6257 3.39858E-06/ -2.56287E-07 6258 2.99732E-06/ -1.91728E-07 6259 2.86292E-06/ -2.66049E-07 6260 3.12469E-06/ -1.63177E-07

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (DYNAMIC ) ELEMENT TYPE:ELAS1 RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 6268 -7.50616E-07/ 3.82246E-08 6269 -7.07820E-07/ 1.35735E-07 6272 -9.45331E-08/ 2.84290E-08 6273 -2.44536E-08/ 3.69334E-09

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (DYNAMIC ) ELEMENT TYPE:HEXA RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 5598 5.79430E-07/ -3.30555E-08 5599 4.29561E-07/ -2.52294E-08 5600 7.81878E-07/ -4.35754E-08 5601 2.18303E-07/ 7.52780E-10

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (DYNAMIC ) ELEMENT TYPE:QUAD4 RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 1 8.69626E-06/ -1.63604E-06 2 1.70524E-05/ -2.70271E-06 3 4.41252E-05/ -9.65295E-06 4 3.55230E-05/ -6.85320E-06

FREQUENCY = 3.000000E+01 E L E M E N T S E N S I T I V I T Y - (DYNAMIC ) ELEMENT TYPE:TETPR RESPONSE DOF: 4001/T1 ELEMENT ID REAL/IMAGINARY 100011 -9.89202E-08/ 1.25276E-09 100012 -6.64053E-07/ -5.47675E-08 100013 -9.50951E-07/ 1.16225E-08 100014 -1.40162E-06/ -6.47900E-09


10002/R3 -2.97953E-11/ 3.63778E-13 10003/T1 3.71908E-06/ -4.26903E-07 10003/T2 6.00221E-06/ 6.15527E-08 10003/T3 1.20445E-06/ -1.33754E-07 10003/R1 1.52407E-11/ -7.90372E-13 10003/R2 6.80032E-11/ -7.55288E-12 10003/R3 2.47433E-11/ -1.94219E-13 10004/T1 1.20250E-05/ -1.08944E-06 10004/T2 5.28112E-06/ 5.50717E-08 10004/T3 4.77353E-06/ -4.13907E-07 10004/R1 2.96689E-11/ -1.55867E-12 10004/R2 1.44823E-10/ -1.21755E-11 10004/R3 3.82980E-11/ -2.88349E-13 9000001/T1 -2.45535E-06/ 5.96815E-07 9000007/T1 -1.47303E-07/ 1.46009E-09 9000013/T1 -8.69173E-07/ 1.28722E-07 9000019/T1 -5.80879E-07/ 8.53362E-08

Guidelines and LimitationsThe output can be voluminous if all varieties of element sensitivity are requested for all elements in the model.

The value of sensitivity may be very small. THRESH option can be utilized to screen out small value and to reduce the amount of output. Note that it is magnitude of sensitivity which is checked against THRESH.

Test CasesThe following test cases are available in TPL in directory tpl/fsc_2011. There are two TPL files with the name fsc_13 and fsc_14.

fsc_13 with MDACMS

fsc_14 without MDACMS

MSC Nastran 2012 Release GuideOutput Particle Acceleration on Wetted Surface

114

Output Particle Acceleration on Wetted Surface

IntroductionThis is new function that computes the particle acceleration on the wetted surface in the fluid-structure coupling problem. The particle acceleration is the force vector from the fluid domain to structure domain via wetted surface or vice versa. This function is supported only for frequency response analysis.

BenefitsThis output is previously known as the excitation load vector via wetted surface in the fluid-structure coupling problem. This is useful for investigating the effect of each domain on another from the point of view of the wetted area. For example, the grids on wetted surface that have high particle acceleration values should indicate the surface around the grid has higher energy flow between both domains.

TheoryThe purpose of this function is computing the excitation force contour to structure and acoustic domain via wetted surface. The equation of structure and fluid coupling problem in frequency domain is as follows.

Then the input force to each domain via wetted surface is derived from this equation by extracting the

terms with coupling matrix to right hand, that is,

The output data blocks of particle acceleration has the unit of load and the format is same as OPG1.

Input A new case control command, PACCELERATION, can be utilized to request particle acceleration output.

The new Case Control entry is:

2 Ms 0

AT

sf– Mf

– iBs 0

0 Bf

Ks Asf

0 Kf

+ +

us

qf Ps

Gf

=

sfA

Paccel

Asf qf–

2A

Tsf us–

=


Request the form and frequency steps of particle acceleration output.

Format:

PACCELERATION [ ( [ PRINT, PUNCH / PLOT ] , [ REAL or IMAG / PHASE ] , [ SOLUTION = { ALL / setf } ] ) ] = { ALL / setg / NONE }

Example:

PACCELERATION = ALLSET 20 = 104 THRU 204, 1005 THRU 1901SET 50 = 105.0, 250.0, 310.0PACCE (PUNCH, SOLUTION=50) = 20

Remarks:

1. This entry will be available only for fluid-structure coupling problem. The particle acceleration is input force vector to each domain via wetted surface in frequency response analysis.

2. Both fluid and structure grid points can be selected. The particle accelerations of the grid points not on wetted surface will be zero.

3. The selected frequency must be part of the excitation frequencies. If not, the nearest excitation frequency will be selected.

4. Only SORT1 form is supported.

Output In f06, a sample particle acceleration output is shown as follows,

PACCELERATION Particle Acceleration Output Request for SOL 108/111

Describer Meaning

PRINT The printer is the output medium.

PUNCH The punch file is the output medium.

PLOT The particle acceleration output is generated but does not print.

REAL or IMAG Requests rectangular format (real and imaginary). Use of either REAL or IMAG yields the same output.

PHASE Requests polar format (magnitude and phase). Phase output is in degrees.

SOLUTION Selects a set of excitation frequencies for which the particle accelerations will be processed. The default is all excitation frequencies. See Remark 3.

setf Set identification of excitation frequencies.

setg Set identification of grid points on wetted surface. See Remark 2.

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Guidelines and LimitationsOnly frequency response analysis is supported.

This output is computed for the fluid-structure coupling problem only.

Test CasesThe following test cases are available in TPL in directory tpl/fsc_2011. There are two TPL files with the name fsc_09 and fsc_10.f

FREQUENCY = 3.000000E+01 C O M P L E X L O A D V E C T O R (REAL/IMAGINARY)

POINT ID. TYPE T1 T2 T3 R1 R2 R30 10001 G 1.380156E-01 1.696067E-02 -2.841734E-02 -9.359745E-06 -2.874146E-04 1.413643E-04 -2.238114E-03 -2.787633E-04 4.587104E-04 1.304513E-07 4.743302E-06 -2.391997E-060 10002 G 1.116973E-01 2.018262E-02 -3.408696E-02 5.951917E-05 -1.718442E-04 2.218772E-04 -1.830821E-03 -3.307615E-04 5.560872E-04 -9.947405E-07 2.863250E-06 -3.717144E-060 10003 G 8.875655E-02 1.953523E-02 -4.021163E-02 -1.014066E-04 -5.265233E-04 -2.751808E-04 -1.421139E-03 -3.126839E-04 6.439614E-04 1.590505E-06 8.519473E-06 4.346479E-060 10004 G 2.225516E-01 1.715258E-02 -9.498698E-02 -2.087045E-04 -9.299600E-04 -5.032117E-04 -3.557096E-03 -2.746745E-04 1.516871E-03 3.361446E-06 1.498954E-05 8.117353E-060 9000001 S 3.108184E+04 -2.039097E+03 0 9000007 S 3.721781E+03 -2.574180E+020 9000013 S 3.135164E+04 -2.787337E+03 0 9000019 S 6.386666E+03 -9.391546E+02

fsc_09 with MDACMS



Output ADF Format File for Frequency Response Function

IntroductionThis is new function is for output frequency response functions and participation factor functions to ADF format file. The function supports general responses such as DISPLACEMENT, VELOCITY, and ACCELERATION and participation factors via PFMODE, PFPANEL, and PFGRID.

BenefitsADF format file is the binary file of I-DEAS Test Associated Data Files (ADF). ADF supports Function (AFU), Time History (ATI), Modal Parameter (APA), and Mode Shape (ASH) data files. In this function, only the frequency response function (AFU) is supported; the result by DISPLACEMENT, VELOCITY, and ACCELERATION entries ,and PFMODE, PFPANEL and PFGRID entries.

Input The new parameter is introduced to export ADF format file.

The new parameter entry is:

This parameter is used to export the results of frequency analysis responses and participation factors by PFMODE, PFPANEL, and PFGRID in ADF format file. This exportation is requested by setting this parameter to YES. The unit information of the exported functions should be defined by DTI, UNITS statement for this function (see ADAMSMNF statement). If not defined, SI unit will be assumed with the warning message. The ADF file is defined as input data name with the extension “afu” automatically. Alternatively the name can be defined with ASSIGN ADFFILE= statement in FMS section. For the participation factor output, FILTER=0. option should be applied in PFMODE and PFPANEL.

Output The new file has the extension; ‘.afu’ is exported with the F06 message.

The major information in ADF format file to be exported is as follows.

POSTADF Default = NO

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Guidelines and Limitations1. General frequency response results and participation factor results by PFMODE, PFPANEL, and

PFGRID are supported.

2. ADF format file includes the unit information of data, and then DTI, UNITS statement is needed to define it. SI unit is assumed if it is not defined.

1st Comment TITLE of the subcase indicated in MSC Nastran input deck

2nd Comment SUBTITLE of the subcase indicated in MSC Nastran input deck

3rd Comment LABEL of the subcase indicated in MSC Nastran input deck

4th Comment

General Function “OVERALL”

Structure Mode Participation Factor MODE S_mode#”

Fluid Mode participation Factor MODE F_mode#”

Structure Mode Panel Participation Factor

MODE S_mode# PANEL panel#”

Panel Participation Factor PANEL panel#”

Grid participation Factor GRID grid#dof

Note that mode# is mode number, panel# is panel number, grid# is grid ID and dof is X, Y, Z, RX, RY or RZ.

Reference Coordinate

Grid Number Subcase ID

Degree of Freedom 0

Response Coordinate

Grid Number Grid ID of the result data

Degree of Freedom Degree of freedom of the result data

The example of the F06 message for output of ADF format file is as follows.

*** USER INFORMATION MESSAGE 7910 (OUTADFE) DATA BLOCK OAFMPF1 (ACOUSTIC FLUID MODE PARTICIPATION FACTOR) WRITTEN TO ADF FILE. *** USER INFORMATION MESSAGE 7910 (OUTADFE) DATA BLOCK OASMPF1 (ACOUSTIC STRUCTURE MODE PARTICIPATION FACTOR) WRITTEN TO ADF FILE. *** USER INFORMATION MESSAGE 7910 (OUTADFE) DATA BLOCK OAPPF1 (ACOUSTIC PANEL PARTICIPATION FACTOR) WRITTEN TO ADF FILE. *** USER INFORMATION MESSAGE 7910 (OUTADFE) DATA BLOCK OAGPF1 (ACOUSTIC GRID PARTICIPATION FACTOR) WRITTEN TO ADF FILE. *** USER INFORMATION MESSAGE 7910 (OUTADFE) DATA BLOCK OSPPF1 (STRUCTURE PANEL PARTICIPATION FACTOR) WRITTEN TO ADF FILE.


3. ADF needs the data on all computed frequency steps so ‘FILTER=0.’ option is needed for the participation factor due to PFMODE or PFPANEL.

4. The name of ADF file is assumed to be the same as input data. It can be changed by ‘ASSIGN ADFFILE=’ statement on FMS section.

Test CasesThe following test cases are available in TPL in directory tpl/fsc_2011. There are two TPL files with the name fsc_11 and fsc_12.

fsc_11 with MDACMS


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Chapter 11: DMAP Module UpdatesMSC Nastran 2012 Release Guide

11 DMAP Module Updates

New DMAP Modules

Modified DMAP Modules

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New DMAP ModulesThe following DMAP modules were added in the MSC Nastran 2012 release:

• MODUG (p. 1154) in the MSC Nastran DMAP Programmer’s Guide

• OUTADF (p. 1226) in the MSC Nastran DMAP Programmer’s Guide

• PFOFP (p. 1279) in the MSC Nastran DMAP Programmer’s Guide

• TA1M (p. 1456) in the MSC Nastran DMAP Programmer’s Guide

123CHAPTER 11DMAP Module Updates

Modified DMAP ModulesThe following DMAP nodules were updated for the MSC Nastran 2012 release.

DOM12Please see DOM12 (p. 754) in the MSC Nastran DMAP Programmer’s Guide for more information.

New Input Data Blocks

New Output Data Blocks

EDT Element deformation table

DESTBX* A family of DESTAB for each PART SE.

XOS* A family design variable values for each PART SE

PROPOS* A family of property values, for each PART SE

RPART A table used to partition the results of the optimization for each PART SE.

SEDVLIST Merged design variables in each PART SE

XOESL Scaled design variables for ESL with topology

TOBTAB Table of topology variable attributes

TPRELE Table of manufacturing constraints.

NEWTOP Table for topology variable attributes

NEWTPR Updated table of manufacturing constraints

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DOPR1Please see DOPR1 (p. 767) in the MSC Nastran DMAP Programmer’s Guide for more information.



New Parameters

Tomtab Table of Bulk Data entries related to topometry optimization.

Pcompt Table containing LAM option input and expanded information from the PCOMP Bulk Data entry.

GEOM3 Table of Bulk Data entry images related to static loads.

GEOM4 Table of Bulk Data entry images related to constraints, degree-of-freedom membership and rigid element connectivity.

TOPVOL Table containing topological designable element volume based on property ID.

DXDSXI Matrix relating linked and independent sizing and shape design variables.

TOPGID Table containing designable grids for topography optimization.

TOTVOL Table containing topological designable element volume based on TOPVAR entry ID

Nonlnr Input-logical-default=FALSE. Nonlinear structural optimization job flag. Set to true indicates that the design job is an nonlinear structural optimization job.

Optexit Input-integer-default=0 . Design optimization termination option. See the OPTEXIT (p. 904) in the MSC Nastran Quick Reference Guide.


DPDPlease see DPD (p. 784) in the MSC Nastran DMAP Programmer’s Guide for more information.



New Parameters

ROTORT Table of rotordynamic user input for transient analysis.

FRFCONST Table containing CONNPTS set data from the FRF Case Control command in an FRF generation job.

FRFXITPP P-size column matrix generated in an FRF generation job containing coded values for rows indicating whether the DOF corresponding to that row has unit load specified on it via an FRFXIT entry, an FRFXIT1 entry or due to its being a connection DOF (or a combination of these).

FRFLABEL Table containing LABEL information from FRFXIT Bulk Data entries.

ACPOOL Table of ACTRIM Bulk Data entry images.

FRFGEN Input-integer-default=0. FRF generation flag.

0 = Do not generate FRF information

1 = Generate FRF information

NOACLD Output-logical-default=false. Set true if ACLOAD Bulk Data entries are processed.


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DSALPlease see DSAL (p. 817) in the MSC Nastran DMAP Programmer’s Guide for more information.


New Parameters

FRLGPlease see FRLG (p. 897) in the MSC Nastran DMAP Programmer’s Guide for more information.


OARPWRDS Acoustic Power to interior or near field.

OAIGDSN Acoustic Intensity to wetted structural grid.

OUGEXAC Exterior Acoustic pressure/intensity of AFPM.

OVGEXAC Exterior Acoustic velocity of AFPM.

OAPEXAC Exterior Acoustic Power of AFPM.

R1RATIOR Ratio on responses used in ESL.

ESLOPTX Input-integer, default=0, 0=no ESL, >0 = ES2

DESCYCLE Input- integer, default = 0. Current design cycle

DMRESD Input-integer-default=-1 Design model flag. If set to -1, then the design model is limited to the residual structure.

ROTORT Table of rotordynamic user input for transient analysis.

UNBVEC Rotor to global transformation matrix for rotordynamics.

EQDYN Equivalence table between external and internal grid/scalar/extra point identification numbers. (EQEXIN appended with extra point data.)

FRFXITPP P-size column matrix generated in an FRF generation job containing coded values for rows indicating whether the DOF corresponding to that row has unit load specified on it via an FRFXIT entry, an FRFXIT1 entry or due to its being a connection DOF (or a combination of these)

FRFLABEL Table containing LABEL information from FRFXIT Bulk Data entries.

FACLV Family of frequency list vector by ACLOAD statement.

PACLV Family of acoustic pressure load matrix by ACLOAD statement.


GP1Please see GP1 (p. 923) in the MSC Nastran DMAP Programmer’s Guide for more information.

New Output Datablock

GPFDRPlease see GPFDR (p. 935) in the MSC Nastran DMAP Programmer’s Guide for more information.


New Output Datablock

New Parameters

MATMODOption 52 was added to MATMOD please see Option P1 = 52 (p. 1082) in the MSC Nastran DMAP Programmer’s Guide for more information.

VGEXF Exterior acoustic partitioning vector with ones at the rows corresponding to exterior acoustic degrees-of-freedom.

UADJ Displacement vectors from adjoint load.

AGGZT Fluid-structural Coupling matrix.

OELSS1 Table of element sensitivity of stiffness property.

OELSW1 Table of grid sensitivity on wetted surface.

OELSM1 Table of element sensitivity of mass property.

OELSD1 Table of element sensitivity of dynamic property.

OELQS1 Table of squared element sensitivity of stiffness property.

OELQW1 Table of squared grid sensitivity on wetted surface.

OELQM1 Table of squared element sensitivity of mass property.

OELQD1 Table of squared element sensitivity of dynamic property.

OPACC1 Table of particle acceleration on wetted surface.

G Input-real-default=0.0. Uniform structural damping coefficient.

GFL Input-real-default=0.0. Uniform fluid damping coefficient.


128

MKSPLINEPlease see MKSPLINE (p. 1127) in the MSC Nastran DMAP Programmer’s Guide for more information.


New Parameter

PFCALCPlease see PFCALC (p. 1275) in the MSC Nastran DMAP Programmer’s Guide for more information.


ACOMP Aerodynamic components defined on AECOMP entries.

SCOMP Structural components defined on AECOMP entries.

BGPDT Structural Grid Points.

ABGPDT Aerodynamic Grid Points.

AEROEXT Input, Integer, default=1.

1 = no external aerodynamics

-1 = external aerodynamics

UBRS Contribution of the base motion to the displacements at the response degrees of freedom

UBRF Contribution of the base motion to the pressure at the response degrees of freedom

UBWS Contribution of the base motion to the displacements of the wetted surface on structure

APXW* Family of panel fluid-structure coupling matrices (family of panel axw matrices for fluid response)

MSXX Structure mass matrix in the h-set or d-set.

BSXX Structure damping matrix in the h-set or d-set.

KSXX Structure stiffness matrix in the h-set or d-set.

PXS Matrix of structural loads in the h-set or d-set.

UBWF Contribution of the base motion to the displacements of the wetted surface on fluid.

APYW* Family of panel fluid-structure coupling matrix with columns corresponding to degree-of-freedom of the wetted surface only for structure response.

QFRQV* Family of frequency vectors of ACTRIM.

QSXX* Family of ACTRIM matrices on structure domain.



New Parameter

RANDOMPlease see RANDOM (p. 1298) in the MSC Nastran DMAP Programmer’s Guide for more information.



QFXX* Family of ACTRIM matrices on fluid domain.

QAXX* Family of ACTRIM matrices on fluid-structure coupling domain.

QABEH* Family of ACTRIM panel fluid-structure coupling matrices.

QABEF* Family of ACTRIM contribution of the base motion to the displacements of the wetted surface on fluid.

QABES* Family of ACTRIM contribution of the base motion to the displacements of the wetted surface on structure.

QAXW* Family of ACTRIM fluid-structure coupling matrix with columns corresponding to degree-of-freedom of the wetted surface only.

SPPF Matrix of structure panel participation factors.

SPPFD SPPF dictionary table.

OSPPF1 Table of structure panel participation in SORT1 format.

NOACTRM Input-integer-default=0. Number of ACTRIMs selected.

CSIG Table of lamina stresses in SORT2 format.

CEPS Table of lamina strains in SORT2 format.

CFAI Table of lamina failure indices in SORT2 format.

CSRS Table of lamina strength ratios in SORT2 format.

OCSPSD2 Table of lamina stresses in SORT2 format for the PSD function.

OCSATO2 Table of lamina stresses in SORT2 format for the autocorrelation function.

OCSRMS1 Table of lamina stresses in SORT1 format for the RMS function.

OCSNO2 Table of lamina stresses in SORT2 format for the NO function.


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SDRCOMPPlease see SDRCOMP (p. 1359) in the MSC Nastran DMAP Programmer’s Guide for more information.

New Parameters

SOLVITPlease see SOLVIT (p. 1428) in the MSC Nastran DMAP Programmer’s Guide for more information.

New Parameter

OCSCRM2 Table of lamina stresses in SORT2 format for the cross correlation function.

OCAPSD2 Table of lamina strains in SORT2 format for the PSD function.

OCAATO2 Table of lamina strains in SORT2 format for the autocorrelation function.

OCARMS1 Table of lamina strains in SORT1 format for the RMS function.

OCANO2 Table of lamina strains in SORT2 format for the NO function.

OCACRM2 Table of lamina strains in SORT2 format for the cross correlation function.

OCFPSD2 Table of failure indices in SORT2 format for the PSD function.

OCFATO2 Table of failure indices in SORT2 format for the autocorrelation function.

OCFRMS1 Table of failure indices in SORT1 format for the RMS function.

OCFNO2 Table of failure indices in SORT2 format for the NO function.

OCFCRM2 Table of failure indices in SORT2 format for the cross correlation function.

OCRPSD2 Table of strength ratios format for the PSD function.

OCRATO2 Table of strength ratios in SORT2 format for the autocorrelation function.

OCRRMS1 Table of strength ratios in SORT1 format for the RMS function.

OCRNO2 Table of strength ratios in SORT2 format for the NO function.

OCRCRM2 Table of strength ratios in SORT2 format for the cross correlation function.

APPFLAG Input-character-default='STATICS'. Approach flag to indicate the type of analysis, viz.STATICS, FREQRESP, TRANRESP etc.

SORTFLAG Input-integer-default=0. Flag to indicate whether SORT1 ( <= 0 ) or SORT2 ( >0 )

SET Input - character, default = "H" = dof set for the input matrices. Used in identifying dof when a problem occurs.


TA1Please see TA1 (p. 1453) in the MSC Nastran DMAP Programmer’s Guide for more information.

New Input Data Block

New Output Data Block

New Parameters

XYTRANPlease see XYTRAN (p. 1542) in the MSC Nastran DMAP Programmer’s Guide for more information.


N2M Nastran-2-Marc element-type conversion table

ESTNSM NON-STRUCTURAL MASS ELEMENT SUMMARY TABLE

XESTM Input, logical, default=FALSE. Set to True to create ESTM instead of EST.

MultiPhy Input, Integer, default=0. Flag for Multi-Physics

LGDISPU Input, Integer, default=0. Large Displacement flag input by user

Texist Input, Integer, default=0. Temperature Load flag determined by checking CASECC

OESC2 Table of lamina stresses in SORT2 format.

OSTC2 Table of lamina strains in SORT2 format.

OEFC2 Table of failure indices in SORT2 format.

OSRC2 Table of strength ratios in SORT2 format.


132