Ws19 GlobalLocal Disp

WS19-1PAT302, Workshop 19, December 2004Copyright2004 MSC.Software Corporation

WORKSHOP 19

GLOBAL/LOCAL MODELING USINGFEM FIELDS


Problem Description This exercise is used to demonstrate how to map displacement results from

the analysis of a global(overall) model onto the perimeter of a local(detail/component of overall) model. The local model is used for an analysis toobtain results for the detail/component.

The global model and its results are read into an MSC.Patran database. Theresults are used in the creation of a vector FEM field.

The FEM field is used to map the global model displacement results onto thelocal model perimeter. Also, a pressure load is applied to the local model. Ananalysis of the local model is performed.

The displacement results for both global and local models are compared.


Suggested Exercise Steps1. Open a new database.2. Create a group for the global model.3. Use analysis form to read model and results for global model.4. Turn off all labels and reset the view to an isometric view.5. Create a group for the local model.6. Use analysis form to read local model.7. Post only the group for the global model for displaying its results.8. Display the deflections and stresses of the global model.9. Set the displacements to true scale 1.0.10. Create a vector plot of displacements for the global model.11. With the vector plot displayed, create a continuous, spatial, Vector

FEM field using the global displacements.12. Post only the detailed local panel model.13. Create a group to be used for creating LBCs for the local model.14. Create a load case for the local model LBCs.


Suggested Exercise Steps (continued)15. Create a Loads/BCs for the local model.16. Post and make current the group for the local model.17. Create a uniform pressure for the local model.18. Create a MSC.Nastran input file for analysis of local model.19. Run MSC.Nastran.20. Access results.21. Post process results.22. Create a viewport so have one for each model.23. Post both global and local model.24. View the results for each model simultaneously.25. Quit MSC.Patran.


Step 1. Create a New Database

Open database.a. File : New.b. Enter quarter_plate for File

Name.c. Click OK.d. Under New Model

Preferences, select Basedon Model Tolerance.

e. Select MSC.NASTRAN forAnalysis Code.

f. Select Structural forAnalysis Type.

g. Click on OK.

a

g

f

e

d

cb


Step 2. Create a Group for Global Model

Create a group and make it currentfor the global model as follows.

a. Group : Createb. Enter global_loads_model

for New Group Name.c. Select the Make Current and

Unpost All Other Groupscheck boxes.

d. Click on Apply.e. Click on Cancel.

ed

c

b

a


Step 3. Use Analysis to Read Model/Results for Global

Use Analysis to read in both themodel and results of the GlobalLoads Model.

a. Analysis : Access Results /Read Output2 / Both.

b. Click Select ResultsFile

c. Select multi_cell_box.op2for Select File.

d. Click on OK.e. Click on Apply.

e

d

c

b

a


Set the display options to get abetter representation of themodel.

a. Click on Hide all entitylabels.

b. Click on Iso1 view.c. Click on Fit view.

Step 4. Turn off All Labels


Create another group, making itcurrent, called panel_model.

a. Group : Createb. Enter panel_model for New

Group Name.c. Select the Make Current and

Unpost All Other Groupstoggles.

d. Click on Apply.e. Click on Cancel.

Step 5. Create a Group for Local Model

ed

c

b

a

Note that the viewport iscleared


Step 6. Use Analysis to Read Model for Local

Under, Analysis, read in aMSC.NASTRAN input deckthat represents the detailedpanel stress model.

a. Analysis: Read InputFile / Model Data.

b. Click on EntitySelection

c. Click on DefineOffsets

d. Enter 1000 for InputOffset Value for theNodes row and pressthe Enter key.

e. Enter 1000 for InputOffset Value for theElements row andpress the Enter key.

f. Click on OK.g. Click on OK.

ed

cb

ad


Select the input file to read intothe input deck.

a. Click on Select InputFile..

b. Select panel.bdf forSelect File.

c. Click on OK.d. Click on Apply.e. Click OK for the Nastran

input file summary.

c

b

a

Step 6. Use Analysis to Read Model for Local


Step 7. Post Only Global Model Group for Results Display

Now post only theglobal_loads_model group.

a. Group: Postb. Select global_loads_model

for Select Groups to Post.c. Click on Apply.d. Click on Cancel.e. Go to Viewing: Anglesf. Enter 25 60 0 under Angles.g. Click on Apply.h. Click on Cancel.i. Click on the Fit view icon.

hg

f

b

a


Look at the deflection and stresses ofthe global loads model using the basicResults form.

a. Results: Create / Quick Plot.b. Click on the Selects Results

icon.c. Select Default, Static Subcase

for Select Result Case(s).d. Select Stress Tensor for Select

Fringe Result.e. Select Displacements,

Translational for SelectDeformation Result.

f. Click on Apply.

Step 8. Global Model Deflections and Stresses

f

e

d

a

b

c


Now select the displacements toshow true values (scale factor=1.0,direct multiplication).

a. Select Deform Attributes iconb. Select the True Scale toggle.c. Enter 1.0 for Scale Factor.d. Click on Apply.e. After observing the modified

results, reset the graphics.

Step 9. Set the Displacements to True Scale 1.0

c

b

a


Step 10. Create a Vector Plot of Displacements

Now, create a vector plot of displacements.a. Results: Create / Marker / Vector.b. Select Default, Static Subcase for

Select Result Case(s).c. Select Displacements, Translational

for Select Vector Result.d. Click the Display Attributes icon

e. Deselect Show Vector Label.f. Click on Apply.

e

d

c

a

b


The model should now appear as follows:

Step 10. Create a Vector Plot of Displacements (Cont.)


Step 11. Create a Vector FEM Field From Global Displacements

With the vector plot displayed, create acontinuous, spatial, vector FEM field calledDisplacements_Global_Model.

a. Fields: Create / Spatial / FEM.b. Enter Displacements_ Global_Model

under Field Name.c. Select Continuous for FEM Field

Definition.d. Select Vector for Field Type.e. Select All Groups for Mesh/Results

Group Filter.f. Select global_loads_model for Select

Group.g. Click on Optionsh. Select Linear Extrapolation for

Extrapolation Option.i. Click on OK.j. Click on Apply.k. Reset the Graphics.

j

i

h

g

f

e

d

c

b

a


Now post only the group panel_model;it is the detailed model of the panel.

a. Group: Postb. Select panel_model for Select

Groups to Post.c. Click on Apply.d. Click on Cancel.

Step 12. Post Only the Local Model Group for LBCs Creation

b

a


Create a group namedPanel_Model_Edge_Nodes.

a. Group: Create.b. Enter Panel_Model_ Edge_Nodes

for New Group Name.c. Select Make Current and Unpost

All Other Groups.d. Enter Node 10000 T # for Entity

Selection.e. Click on Apply.f. Click on Cancel.

Step 13. Create a Group for Creating Local Model Displ LBC

a

b

c

d


Using the slide bar, make thenodes more visible.

a. Display: Finite Elementsb. Use the slide bar under

Node Size to select 5.c. Click on Apply.d. Click on Cancel.

b

a

Step 13. Create a Group for Creating Local Model Displ LBC (Cont.)


Create a static load case calledPanel_Model_Loads.

a. Load Cases: Createb. Enter Panel_Model_Loads

for Load Case Name.c. Select Make Current.d. Select Static for Type.e. Click on Apply.

Step 14. Create a Static Load Case for Local Model

d

cb

a


Create an enforced nodal displacementboundary condition named Panel EnforcedDisplacements.

a. Loads/BCs: Create / Displacement /Nodal.

b. Enter Panel Enforced Displacementsfor New Set Name.

c. Click on Input Datad. Select Displacements_Global_Model in

Spatial Fields databox for Translations.

e. Click OK.f. Click on Select Application Regiong. Select the FEM Filter.h. Screen pick all the nodes in the

viewport for Select Nodes.i. Click on Add.j. Click on OK.k. Click on Apply.

Step 15. Create a Loads/BCs for Local Model

j

i

h

g

f e

d

c

b

a

d


Set the node size back to 1.a. Display: Finite Elementsb. Select 1 for Node Size by

using the slidebar.c. Click on Apply.d. Click on Cancel.e. Turn off the vector values

using Display: Load/BC/Elem. Props

f. Deselect Show LBC/EI.Prop. Values.

g. Click on Apply.h. Click on Cancel

a e

Step 15. Create a Loads/BCs for Local Model

b

f


Step 16. Post and Make Current the Local Model

Post and make current the PanelModel.

a. Group: Postb. Select panel_model for

Select Groups to Post.c. Click on Apply.d. Click on Cancel.

b

a


Create a uniform pressure called PanelPressure applied to all 2D quads onthe top surface.

a. Loads/BCs: Create / Pressure /Element Uniform.

b. Enter Panel Pressure for NewSet Name.

c. Select 2D for Target ElementType.

d. Click on Input Datae. Enter 2.25 for Top Surf

Pressure.f. Click on OK.g. Click on Select Application

Regionh. Select the FEM Filter.i. Screen pick all the elements in

the viewport for Select 2DElements or Edges.

j. Click on Add.k. Click on OK.l. Click on Apply.

Step 17. Create a Uniform Pressure for Local Model

l

k

i

j

h

g

c

d

b

a

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Illustrated below is the model. After observingthis view, reset the graphics.

Step 17. Create a Uniform Pressure for Local Model


Use Analysis Deck pick to create anMSC.Nastran input file. Call the jobname new_panel.

a. Analysis: Analyze / SelectedGroup / Analysis Deck.

b. Enter new_panel for JobName.

c. Click on Select Group, thenselect Select Current Group.

d. Click on TranslationParameters

e. Select OP2 for Data Output.f. Select Text for OUTPUT2

Format.g. Click on OK.h. Click on Solution Typei. Select Linear Static for

Solution Type.j. Click on Solution

Parametersk. Enter 1.0 for Plate Rz

Stiffness Factor.l. Click on OK.m. Click on OK.

Step 18. Create MSC.Nastran Input File for Local Model

j

i

f

e

dc

b

a

h


Continue to create the input deck.a. Click on Subcasesb. Set Action to Create.c. Enter Panel_Model for

Subcase Name.d. Select Panel_Model_Loads

for Available Load Cases.e. Click on Apply.f. Click on Cancel.g. Click on Subcase Selecth. Select Panel_Model for

Subcases For SolutionSequence: 101.

i. Click on OK.j. Click on Apply.

i

h

g fe

d

c

a

b

Step 18. Create MSC.Nastran Input File for Local Model (Cont.)


If MSC.Nastran is on the network, thejob can submitted using the filenew_panel.bdf for analysis, thenimport the results file,new_panel.op2, into the databaseand look at the model stresses anddeformations.

a. Run MSC.Nastran.b. Find and Open

new_panel.bdf.c. Click on Open.d. Click on Run.e. Check for fatal errors by

opening up the filenew_panel.f06 (it is a text file)and searching for the wordfatal. If no fatal errors exist,then the analysis completedsuccessfully.

Step 19. Run the Analysis

b c

d


Continue to view results in PATRAN.a. Analysis: Access Results / Read

Output2 / Result Entities.b. Click on Select Results Filec. Select new_panel.op2.d. Click on OK.e. Click on Apply.

Step 20. Access Results

c

b

a


View the results in a fringe plot.a. Results: Create / Fringe.b. Select Panel_Model_Loads, Static Subcase for Select

Result Case(s).c. Select Displacements, Translational for Select Fringe

Result.d. Click on Apply.

Step 21. Post Process Results

d

c

b

a


The model should appear as follows:

Step 21. Post Process Results (Cont.)


Compare the two models.a. Viewport: Createb. Enter global_load for New

Viewport Name.c. Click on Apply.d. Viewport: Tile

Step 22. Create a Viewport so Have one for Each Model

c

b

a

d


Change the group being posted in the viewport global_load.a. Make the viewport global_load active by clicking inside the

window.b. Groups: Postc. Select global_loads_model.d. Click on Apply.e. Click on Cancel.

Step 23. Post Model to Each Viewport

c

b

a


Panel_Model_Loads, Static Subcase

View the results for the model in the group global_loads_model.a. Results: Create / Fringe.b. Select Default, Static Subcase for Select Result Case(s).c. Select Displacements, Translational for Select Fringe

Result.d. Select Y component for Quantity.e. Click on Apply.

Step 24. View Results for Each Model Simultaneously

d

c

a

b


In order to simplify comparing the twomodels result a single range will be used.

a. Click inside the viewport thatcontains the panel model(default_viewport) to make it active.

b. Results: Create / Fringec. Select Panel_Model_Loads, Static

Subcased. Select Displacements, Translationale. Select the Display Attributes icon.f. Click on Rangeg. Select Fri_default_Fringe2.h. Select Post Range to Viewport.i. Click on OK.j. Click on Apply

h

g

f

b


c

d

e


Compare the viewports. Notice that the colors on the edges ofthe panel model are identical to those of the global model.



Quite MSC.PATRAN.a. File : Close.

This ends this exercise.

Step 25. Quit MSC.Patran

a

Documents

Ws19 GlobalLocal Disp