WS14-1VND101, Workshop 14

MSC.visualNastran 4D

Exercise Workbook

Foot Support

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Objectives This exercise is design to introduce

vibration analysis in visualNastran Desktop.

You will determine the natural frequencies of the part

Learn how to display the mode shape contours for the foot support.

Exercise Overview Introduction to visualNastran Desktop 4D

vibration analysis. Import/Open a model from various CAD

applications. Simulation and Display Settings. Create a material. Apply restraints. Mesh the model. Solve model. Evaluate result.

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I - Open New File / Import Part

1) Open the part “Foot Support.x_b” or “Foot Support.sat”. (Figure 1)

If you are working with the following CAD package: SolidWorks, Solidedge, or Mechanical Desktop, you can also open the Bracket in the native CAD environment and Connect the part over.

2) Click “Open”.

3) If opening an ACIS file, in the ACIS Import Settings window that appears, accept “Use Built-in ACIS file units”.

4) Click “OK”.

Figure 1 Open file

Figure 2 Unit selection

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II - Display and Simulation Setting

5) From the World menu pick Display Settings or click the Display Settings tool.

The properties dialog box for that bracket will appear.

6) Click the Units tab.

7) Set the Unit system to be “SI (degrees)” and change “Distance” to “cm”. (Figure 3)

Once “cm” is selected the unit set will automatically change to “Custom”. (Figure 3)

8) Click Close.Figure 3 Display Settings - Units

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II - Display and Simulation Setting

9) From the World menu select Simulation Settings or click on the Simulation Settings button.

Notice that the Display Settings menu is the same as the Simulation Settings menu.

10) Click on the FEA tab and pick “Vibration” for “Analysis Type”.

11) Make sure the “Desired Outputs” are “Displacement” and “Stress”. (Figure 4)

Accept all other defaults.

12) Click the plus sign next to FEA in the tree and pick Modes.

13) Specify 5 for “lowest modes” in the “Requested Modes” area.

14) Close the Simulation Settings dialog box.

Figure 4 Simulation Settings - FEA

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III - Specify MaterialIn this step you will create a new material and specify its properties.

15) Double-click on the foot support in the simulation window.

This opens the Properties dialog box.

16) Go to the Material tab and click “Change”. (Figure 5)

The Material Properties window appears.

17) Enter values for the material properties shown in Figure 6 and click “OK”.

18) Click “OK” in the resulting pop-up menu.

19) Click the Appearance tab.

20) If not already assigned, type in “Foot Support” for the “Name” and leave everything else default. Click “Apply” and “Close”.

Figure 6 Material PropertiesFigure 5 Properties of body - Material

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IV - Apply Restraints

Figure 7 Restraints applied

21) Use the Rotate Around and Box Zoom tools to rotate the foot support to get a better view of the holes.

The faces of the holes will be selected for the restraint.

22) To apply restraints, go to Insert>Restraint or click the Restraint tool on the toolbar.

23) Select the inside face of one of the holes.

Only half of the face will be restrained.

24) Repeate steps 21 through 23 to place a restraint on the other half of the hole.

25) Repeat steps 21 and 24 for the next hole.

Restraint symbols appear on the geometry. The model with restraints applied is displayed in Figure 7.

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V - Meshing the Geometry

26) Double-click on the model in the simulation window.

The Properties of body window appears.

27) Go to the FEA tab and check “Include in FEA”. (Figure 8)

Checking “Include in FEA” will activate the rest of the window.

28) Check “Show mesh” and enter “2.0” cm for the “Default Mesh” Size. Accept all other defaults. (Figure 8)

30) Click the “Mesh” button to mesh the model.

The simulation window now shows the model with mesh elements. (Figure 9)

31) Close the Properties dialog box.

Figure 8 FEA – Mesh setting

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V - Meshing the Geometry

Figure 9 Meshed part

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VI - FEA Analysis

32) Click the “Solve Vibration FEA” button in the playback controls.

The MSC.Nastran analysis window appears to display analysis is in progress. (Figure 10)

33) After results are completed, visualNastran Desktop will display the result in the simulation window.

34) If not already shown, results such as Mesh, Contours, Deformation and Forces can be displayed by right-clicking on the model in the simulation window. (Figure 11)

35) Another way would be to click on FEA display in the Properties List and the Properties of body window appears.

36) Pick the FEA Display tab and check on the respective result to display. (Figure 12)

Figure 11 Contours

Figure 10 MSC.Nastran

Figure 12 Properties of body – FEA Display

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VI - FEA Results

37) Click the Display settings tool and go to the FEA Display tab. (Figure 13)

38) Five modes of vibration are shown. The current mode shown in the simulation window is 31 Hz. Each mode can be selected and animated in the simulation window. (Figure 13)

Figure 13 Display Settings – FEA Results of different modes of vibration

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VI - FEA Results

Figure 14 Mode 5 result

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VII - Results Animation

39) The playback control buttons will allow you to animate the results.

40) Choose one of the five modes and animate.

41) Figure 15 displays a frame from the animation of a 68.5 Hz animation.

Noticed that one of the restraints is turned off. All objects listed in the Object List maybe turned off/on or Hide/Show.

42) To hide/show an object, right-click on that object in the simulation window and choose Hide/Show. Or right-click on the object from the Object List and choose Hide/Show. (Figure 16)

Figure 15 Animated result

Figure 16 Hide

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Review

You learned how to perform vibration analysis in MSC.visualNastran Desktop. You determined the natural frequencies of the part. You learned how to display the mode shape contours.

WS14-16VND101, Workshop 14