acostic cavity

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HyperWorks Tutorials

NVH-1000: Acoustic Cavity

Step 1: Set the User Profile to RADIOSS Bulk Data

Step 2: Open the taurus.hm model

Step 3: Hide the seat cushion components

1. Click File > Open > Model.

2. Browse to /tutorials/es/nvh/acoustic.hm.

3. Click Open to open the model into session.

1. Expand the Components folder in the Model Browser.

2. Select Rear_Seat_Cushion, IN-driver seat back cushion, IN-crv seat head rest, IN-driver seat lowercushion, IN-pass seat lower cushion, and IN-pas seat head rest from the list of components.

3. Right click and select Hide.

Page 1 of 14NVH-1000: Acoustic Cavity

17-05-2012file:///C:/Program%20Files/Altair/11.0/help/hwtut/nvh_1000.htm


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Step 4: Preview the mesh

The imported model has been restricted to just those parts that will be used to create the cavity. The seat cavitieshave already been built in this model.

Preview of mesh

The mesh appears in the graphics area and the Acoustic Cavity tab opens in the tab area.

Step 5: Review the mesh

1. Click Mesh > Create > Acoustic Cavity Mesh to open the Acoustic Cavity Mesh Generation panel.

2. Click the comps selector for structure to open the component selection panel.

3. Click comps >> displayedto select all components.

4. Click selectto complete the selection.

5. Click the comps selector forseats.

6. Click the Last Page ( ) button to go to the last page of components.

7. Select the IN pass seat back cushion, IN pas seat head rest and Rear_Seat_Cushion on this page.

8. Click the Previous Page button and select IN driver seat back cushion, IN drv seat head rest, IN driver seat lower cushion, and IN pass seat lower cushion.

9. Click selectto complete the selection of the seats.

10. Make sure the seat coupling toggle is set to node to node remesh.11. Enter40 forelement size=.

12. Enter100 forgap patch size =.

13. Enter200 forhole patch size =.

14. Click the create hole elements option to activate it.

15. Clickpreviewto see a preview of the mesh.




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AC_Structural.1 isolated

1. Right click onAC_Structural.1 in the AcousticCavity tab and click Isolate.

2. Right click on the other components in the list and click Show.

3. Right click onAC_Structural.1 and click Hide.

4. Click the mesh icon next to each of the seat cavities to see the mesh.




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Seats added to the visible components

Step 6: Delete two of the patched holes

5. Select each of the seat cavitys and right click and click Hide.

1. In the Model Browser, right click on the ^patched_holes component and click Show.

2. Zoom into the area shown in the figure.

3. If necessary, right click onAC_Structural.4 and click Hide.




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4. Click the Findicon Findpanel.

5. Click the find attached subpanel.

6. Change the attached to: setting to node.

7. Select the node in the center of the patch as shown in the image below.

8. Click findto find the elements attached to the node.

9. Click save foundto use the found elements later.

10. Click return to exit the panel.

11. Click the Delete icon to open the Delete panel.

12. Set the selector to elems if not already set.

13. Click elems >> retrieve to select the elements saved earlier.

14. Click delete entityto delete the elements.

15. Rotate the model to the view shown below.




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Step 7: Preview the mesh

With the patched holes deleted, the acoustic cavity mesh will be previewed again.

16. Repeat 5-15 to delete the elements on the opposite side.


1. Click Rejecton the AcousticCavity tab.

2. Click the Isometric Viewicon to reset the view of the model.

3. Click Mesh > Create > Acoustic Cavity Mesh to open the panel.

4. Click the comps selector for structure to open the component selection panel.

5. Click comps >> displayedto select all components.


7. Click the comps selector forseats.

8. Click the Last Page ( ) button to go to the last page of components.

9. Select the IN pass seat back cushion, IN pas seat head rest and Rear_Seat_Cushion on this page.

10. Click the Previous Page button and select IN driver seat back cushion, IN drv seat head rest, IN driver seat lower cushion, and IN pass seat lower cushion.

11. Click selectto complete the selection of the seats.

12. Enter40 forelement size=.

13. Enter100 forgap patch size =.

14. Enter0 forhole patch size =.

15. Clickpreviewto preview the mesh.




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Note that the rear door volumes are now a part of the overall volumes.

Step 8: Create the mesh

1. Select AC_Structural.2 through AC_Structural.10, right click and select Hide.

2. Uncheck the boxes in the Mesh column forAC_Structural 2 through AC_Structural.10.

3. Set the Mesh type option to Hexa-tetrahedra.

4. Set the Response points: to Read from file.

5. Click the button to browse for the file.

6. Select ACOUSTIC_RESPONSE_PTS.csv and click Open.

7. Click Mesh to create the mesh.




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Completed mesh

Step 9: Rename the components created by the Acoustic Cavity Mesh

Step 10: Create material cards for the cavities

8. Click Close to close the Acoustic Cavity tab.


1. Open the Components folder in the Model Browser.

2. Right click on AC_Structural.1 and click Rename.

3. Name the component BODY_CAVITY and press Enter.

4. Right click on AC_Seat.1 and click Rename.

5. Name the component DRV_SEAT and press Enter.


7. Name the component REAR_SEAT and press Enter.


9. Name the component PASS_SEAT and press Enter.

1. Right click in the Model Browserand click Create > Material.

2. Set the Type field to FLUID.

3. Enter BODY_CAVITY into the Name field.

4. Select MAT10 forCard image.

5. Activate the Card edit upon material creation checkbox.

6. Deactivate the Close dialog upon creation checkbox as there are additional materials to create.




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Step 11: Create properties for the model

7. Click Create to create the material and edit the material card.

8. Click [BULK]and [C]in the card edit panel and leave the default values.


10. With the Create material dialog open, enterSEAT_CAVITY in the Name field.

11. Click Create to create the material.

12. Click [C]and enter8.8e+4 for the value.

13. Click [BULK]and accept the default value.

14. Click return to complete the card edit.

15. Click Cancelto close the Create material dialog.

1. Right click in the Model Browserand click Create > Property.

2. Set the Type field to all.

3. Enter BODY_CAVITY into the Name field.

4. Select PSOLID forCard image.

5. Click the Material tab to assign a material to the property.

6. Click the Assign material checkbox to activate it.

7. Click BODY_CAVITY for the Name field.

8. Activate the Card edit upon material creation checkbox.

9. Deactivate the Close dialog upon creation checkbox as there are additional materials to create.




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Step 12: Assign the properties to the components

10. Click Create to create the property.

11. Click FCTNto activate the option.

12. Click the FCTNfield and select PFLUID.

13. Click return to exit the property card image.

14. Click the Property tab in the Create property dialog.

15. EnterSEAT_CAVITY into the Name field.

16. Click the Material tab to assign a material to the property.

17. Click theAssign materialcheckbox to activate it.

18. Click SEAT_CAVITYfor the Name field.

19. Click Create to create the material and edit the material card.

20. Click FCTNto activate the option.

21. Click the FCTNfield and select PFLUID.

22. Click return to complete the card edit.

23. Click Cancelto close the Create property dialog.

1. Expand the Property folder in the Model Browser.

2. Right click on the SEAT_CAVITY property and clickAssign.

3. Click elems >> by collectorand select the REAR_SEAT, DRV_SEAT, and PASS_SEAT components.




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Step 13: Renumber the nodes, elements, properties, and materials

Step 14: Export the model


5. Clickproceedto complete the assignment.

6. Right click on the BODY_CAVITY component and clickAssign.

7. Click elems >> by collectorand select BODY_CAVITY.


9. Clickproceedto complete the assignment.

1. Click Geometry > Renumber > Nodes to open the Renumberpanel.

2. Click nodes >> displayedto select the displayed nodes.

3. Enter 9000000 in the start with field.

4. Click renumberto renumber the nodes.

5. Change the selector to elems.

6. Click elems >> displayedto select the displayed elements.7. Click renumberto renumber the elements.

8. Change the selector to props.

9. Clickprops and select BODY_CAVITY and SEAT_CAVITY.

10. Click renumberto renumber the properties.

11. Change the selector to mats.

12. Click mats and select BODY_CAVITY and SEAT_CAVITY.

13. Click renumberto renumber the materials.


1. Click File > Export > Solver Deck.

2. For File Type select RADIOSS.

3. For Template select Bulk data standard format.

4. Browse to a location in the File field and enteracoustic.fem as a name for the model.

5. Expand the Export options.

6. For Export select Displayedfrom the menu.

7. Activate Write HM comments.




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Step 15: Edit the .fem file

The .fem file is edited to remove the begin bulk and enddata cards that will allow it to be added to an include

card at a later date.

8. Click Exportto export the model.

1. Open the file acoustic.fem using a text editor.

2. Use CTRL+F to find the begin bulk entry.




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3. Delete begin bulk from the file.

4. Find the enddata entry.




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The .fem file is now ready to be added to an include. This completes the tutorial.

5. Delete the enddata entry from the file.

6. Save the acoustic.fem file.


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