ex 11 solid assembly with linear contact

2-1

Exercise 11 - Assembly Modeling with

Linear Contact

© UGS Corp. 2006. All rights reserved.Femap with NX Nastran 2-2

Exercise 11 - Assembly Modeling

with Linear Contact

Objectives

Learn steps for creating and analyzing an assembly

model in Femap including the use of Linear Contact

solutions with Nastran

Use Model Info and Entity Editor windows.

Learn use of Femap Connections capabilities.

Use the Data Table to report and organize results


Import a Solid Edge assembly

Start Femap from main menu select the File, Import,

Geometry command

Select the file ControlArmAssembly.asm and Yes


with Linear Contact


Using the F8 hotkey (View, Rotate, Model), select the

Dimetric view

Turn on highlighting of selected objects in the Model

Info window


with Linear Contact


Expand the Geometry tree and select ControlArm.par:1

The Control Arm is highlighted as shown in the figure

below.


with Linear Contact


Save the model in your training folder

Review the material properties imported

from Solid Edge

Expand the Model tree and both the Materials

and Properties trees

Select the Material, ControlArm.par:1

Notice that the attributes of the selected are

displayed in the Entity Editor window.


with Linear Contact


View the material attributes in

Entity Editor window.

Double-click the Entity Editor window’s

Title Bar to “undock” the window from

its location. This window then can be

moved and resized

Make any changes you want to the

material. Remember,if you make

changes, you must press the Update

Model icon to apply any changes

made in the Entity Editor window.

To “redock” the Entity Editor window,

double-click on its Title Bar.


with Linear Contact



with Linear Contact

Create connections between of

the assembly parts

Select the Connect, Automatic command.

In the dialog box press Select All and

OK to select all solids in the model

Select Contact as Connection Property

then OK to complete generating of the

connections



with Linear Contact

Change the highlighting style to

transparent

In the Model Info window, select the

Show When Selected pull down icon

menu and select the Transparent

Highlight option

In addition, toggle off the Show Labels

option.

Expand the Connections tree

then Properties, Regions and

Connectors



with Linear Contact

Select and highlight Regions and Connectors

Select one or more Connections objects. The connection surfaces

will appear highlighted as show.



with Linear Contact

Change the name of one of

the Connection Regions

Select and edit the first Connection

Region (1..Untitled)

Double-click on the Title object in

the Entity Editor window.

Enter the new Title as “Key at Arm”

then press Update Model icon to

update the Femap Model with the

new title

Note how the Model Info window

has been updated with the new

Connection Region title.



with Linear Contact

Review the first Connector

Select 1..Region-1.2 and use the right-mouse

button to bring up the context sensitive menu.

Select Edit in the menu (this is equal to use of

Modify, Edit, Connector)

Note that a Contact Connector definition

consists of three objects:

Master Contact Region

Slave Contact Region

Contact Property

Click Cancel to close the dialog box



with Linear Contact

Update NEiNastran

Connection Property

as below

In Title enter the contact

name e.g. Linear Contact

Use 4..Symmetric weld as

Penetration Type

Leave other default

parameters and click OK

to close the dialog box


Constrain the base of the key

Using the mouse middle mouse key, rotate

your model so that the base of the key is

visible as shown.

Select the Create Constraint on Surface

icon from the Constraints toolbar.

In the Create or Activate Load Set dialog

box, enter the Title as Fixed Key Base.


with Linear Contact


Constrain the base of the key

Select the bottom flat surface and the two cylindrical surfaces on the

bottom of the key. In the Entity Selection – Enter Surface(s) to Select

dialog box, press the Highlight Selection icon to confirm your selection

before pressing OK


with Glued and Linear Contact



with Linear Contact

Complete constraining the base of the key

In the Create Constraints on Geometry dialog box, set the constraint

to Fixed and press OK to create the constraints.


Create a pre-load on the top of

the key cap

Rotate your model so that the top of

the Key Cap and the end of the

Control Arm are clearly visible

Select the Create Load on Surface

icon from the Loads toolbar and

create a Load Set as 100 lb Arm

Load - +Y


with Linear Contact


Create a pre-load on the top of the key cap

Select the flat surface at the base of the hex nut . In Selection dialog

box click the Highlight Selection icon to confirm your selection before

pressing OK

In the Create Load on Surface dialog box, set the load Type as Force,

the Direction to Normal to Surface, and the Magnitude = -10. Press OK

to create the load, but do NOT exit the Create Loads on Surface

command.


with Linear Contact



with Linear Contact

Create 100 lb load on the end of the control arm

Select the inside surface of the hole on the end of the control arm and

click the Highlight Selection icon to confirm your selection before

pressing OK to confirm your selection

In the Create Load on Surface dialog box, set the load as Force, the

Direction to Components, uncheck FX and FZ, and set Fy = 100. Press

OK to create the load.



with Linear Contact

Mesh the assembly

In the Model Info window, right-click the

Geometry object, and select Tet Mesh

In the Automesh Solids dialog box,

press Update Mesh Sizing to review the

automatically set mesh sizes



with Linear Contact

Mesh the assembly

The Automatic Mesh Sizing dialog

box appears showing the

automatically computed mesh size

for this assembly. Press OK and

OK to mesh the assembly.



with Linear Contact

Organize the model by creating groups of the three

separate parts of the assembly

Select the menu command Group, Operations, Generate Solids

Select All solids and press OK

In the Group Operations Generate Solids dialog box, check the Create

Multiple Groups, Include Mesh, Loads and Constraints, and the Create

New Groups options on

Press OK to generate the groups



with Linear Contact

Organize the model by creating groups of the three

separate parts of the assembly

In the Model Info window Groups tree right-click the first group object,

1..Solid/Volume 1. to bring up and select Activate.

With the first group still selected, again right-click the object and select

View Active.

Deselect View Active for the first group to display the entire model.



with Linear Contact

Turn off display of all

entities except for

curves, elements and

boundary conditions

Using the Ctrl+Q hotkey, (or

Visibility icon), press the All

Off button

Check the boxes for Curves,

Elements and press the

Constraint button

Press Done to update the

display and close the dialog

box



with Linear Contact

Change names of the groups

In the Entity Editor window double-click

Title and change the name of the group to

“Control Arm”. Select the Update Model

icon to update the new name.

Repeat it for next group, 2..Solid/Volume 2

and rename it to “Key Cap” then Update

Model

And the same for last group,

3..Solid/Volume 3, and rename it to “Keyed

Pin” then Update Model



with Linear Contact

Prepare model for analysis by

creating an Analysis Set

Using Model, Analysis or right-click on

Analyses in the Model Info then selecting

Manage, open the Analysis Set Manager

dialog box

Create a New Analysis Set.

In the Analysis Set dialog box, enter the

Title as NEiNastran Linear Contact,

check 31..NEi Nastran and 1..Static.

Press OK to complete Analysis Set



with Linear Contact

Review the Analysis Set

Expand Analysis Set: 1..

NEiNastran Linear Contact,

Master Requests and Conditions

and Boundary Conditions trees

Note that both the active

Constraint and Load Sets were

automatically added to the

Analysis Set

Start NEiNastran analysis

Click the Analyze button in the

Analysis Set Manager

Save the input file as e.g. Linear

Contact . NAS and press Write



with Linear Contact

Start NEiNastran analysis

Press Analysis-Run (F5) in NEiNastran Editor. Close Editor after solution

and results will be automatically read into the active Femap model



with Linear Contact

Select the results to display

In the Femap graphical window right-click on Post Data

In Select PostProcessing Data, press OK to accept the

default Output Vectors (1..Total Translation and

6031..Solid Von Mises Stress).



with Linear Contact

Display the stress and deformed shape by Post toolbar.

From the Post toolbar, click the Select a Contour View and Select a

Deformed View



with Linear Contact

Modify the name of the Output Set

In the Model Info window, expand the

Results tree and select 1..NEiNASTRAN

In the Entity Editor window, double-click the

Title row, and change the Title to Linear

Weld Contact.

Press the Update Model icon to update the

model. Note how the name is also updated

in the Graphics window.



with Linear Contact

Review the results with a dynamic cutting plane

Toggle off the display of the deformed shape

Select the View, Advanced Post, Dynamic Cutting Plane command

Using the slider control in the Dynamic Section Cut Control dialog box,

move the plane through the model to see stress contours at different

cut planes.



with Linear Contact

View the stress results as Isosurfaces

Select the View, Advanced Post, Dynamic IsoSurface command

Using the slider control in the Dynamic IsoSurface Control dialog box,

change the stress value and see where it occurs in your model.



with Linear Contact

Display the stresses on the three different parts

individually by using Group display.

In the Model Info window, select and Group, Activate. Then, use the

View Active option to display only that group you selected.

After viewing each of the three groups, disable Group, Activate option



with Linear Contact

Modify connection

property

Right-click Connection

Property and select Edit

In the Define Connection

Property dialog box, change

Penetration Type to 2..

Symmetric contact then OK

Finally, rerun analysis



with Linear Contact

Display and compare stresses for both computation

using groups

ex 11 solid assembly with linear contact

Documents

assembly modeling

linear contact ugs

nx nastran

connections ugs

assembly parts

linear contactobjectives

connectors ugs

model info window