MSC.visualNastran Desktop FEA

Exercise Workbook

Foot Support

WS3.1-2VND101, Workshop 3.1

WS3.1-3VND101, Workshop 3.1

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 OverviewIntroduction 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.

WS3.1-4VND101, Workshop 3.1

WS3.1-5VND101, Workshop 3.1

Step 1: Open New File / Import Part

1) Open the part WS3.1_Foot.x_b or WS3.1_Foot.sat in C:\Training\vnd101_files/Workshop 3.1 as shown in 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.

1) Click Open.

2) In the ACIS Import Settings window that appears, accept Use Built-in ACIS file units.

3) Click OK.Figure 1 Open file

Figure 2 Unit selection

WS3.1-6VND101, Workshop 3.1

Step 2: Display and Simulation Setting

1) From the World menu select Display Setting or click the Display Setting button.

2) Click the Units tab.

3) Choose unit set SI (degrees) and change Distance to “cm”.Once “cm” is selected the unit set will automatically change to Custom. Refer to Figure 2.

1) Click Close.

Figure 2 Display Settings - Units

WS3.1-7VND101, Workshop 3.1

Step 2: Display and Simulation Setting

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

6) Click on the FEA tab and select Vibration for Analysis type.

7) Specify 5 for Lowest modes in Desired modes.

8) Make sure the Desired outputs Displacement and Stress are selected.Refer to Figure 3.

5) Accept all other defaults and click Close.

Figure 3 Simulation Settings - FEA

WS3.1-8VND101, Workshop 3.1

Step 3: Specify MaterialIn this step you will create a new material and specify its properties.

1) Double-click on the foot support in the simulation window.2) Select the Material tab.3) Click Edit.4) The Material Selector window appears. Select Custom.5) Enter values for the material properties as shown in Figure 5.6) Click OK.7) Click the Appearance tab.8) Type in “foot support” for the Name and leave everything else default. Click Apply and close.

Figure 5 Material Selector

Figure 4 Properties of body - Material

WS3.1-9VND101, Workshop 3.1

Step 4: Apply Restraints

Figure 6 Restraints applied

1) Rotate the foot support to get a better view of the holes.The faces of the holes will be selected for the restraint.

2) To apply restraints select Insert from the menu and choose Restraint or click the Restraint button.

3) Select the face of one of the holes.

4) Repeat step 2 and 3 for the next hole.Restraint symbols appear on the geometry. The model with restraints applied is displayed in Figure 6.

WS3.1-10VND101, Workshop 3.1

Step 5: Meshing the Geometry

1) Double-click on the model in the simulation window. The Properties of body window appears.

2) Select the FEA tab and check Include in FEA.

3) Check Show mesh and enter “2.0” cm for the Default Mesh Size. Accept all other defaults.Refer to Figure 7.

4) Click the Mesh button to mesh the model.

5) Close the Properties window.Simulation window now shows the model with mesh elements.

Figure 7 FEA – Mesh setting

WS3.1-11VND101, Workshop 3.1

Step 5: Meshing the Geometry

Figure 8 Meshed part

WS3.1-12VND101, Workshop 3.1

Step 6: FEA Analysis

1) Click the Solve FEA button in the playback controls.

2) The MSC.Nastran analysis window appears to display analysis is in progress.

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

4) 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. Refer to Figure 10.

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

6) Select the FEA Display tab and check on the respective result to display, as shown in Figure 11.

Figure 10 Contours

Figure 9 MSC.Nastran

Figure 11 Properties of body – FEA Display

WS3.1-13VND101, Workshop 3.1

Step 6: FEA Results

1) Click the Display setting icon and select FEA Results.

2) 5 modes of vibration are shown. The current mode shown in the simulation window is 29.3 Hz. Each mode can be selected and animated in the simulation window. Refer to Figure 12.

Figure 12 Display Settings – FEA Results of different modes of vibration

WS3.1-14VND101, Workshop 3.1

Step 6: FEA Results

Figure 13 Mode 5 result

3) Click the Display setting icon and select FEA Results.

4) 5 modes of vibration are shown. The current mode shown in the simulation window is 29.3 Hz. Each mode can be selected and animated in the simulation window. Refer to Figure 13.

WS3.1-15VND101, Workshop 3.1

Step 7: Results Animation

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

2) Choose one of the five modes and animate.

3) Figure 15 displays a frame from the animation of a 63.9 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.

4) 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. Refer to Figure 14.

Figure 15 Animated result

Figure 14 Hide

WS3.1-16VND101, Workshop 3.1

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.