Meshing a CAD model

The quality of the mesh used in your analysis determines the accuracy of your results.

The models you worked with so far have already been meshed, but this is not how a model is imported from a CAD program.

In this task, you will:

• Import a CAD model
• Generate a mesh on the model, with the default auto-sizing option.
• Compare this default mesh with a mesh generated without the default auto-sizing option.

We usually choose to import model as Dual-Domain for the following reasons:

• Most part geometry is shell-like in appearance, which is suitable for Dual Domain analysis.
• When an analysis that can only be performed on a midplane mesh is required, the mesh is usually generated in an external CAD package and imported as a midplane mesh.
• A 3D mesh requires a good Dual Domain mesh of the model as its starting point. This Dual Domain mesh is then converted into a 3D mesh. A solid part that obviously requires a 3D mesh analysis would still be imported as a Dual Domain mesh.

1. Download the model mold12_study.sat.
2. Ensure the Mesh tutorial project you used in the previous task is active. If it is not already open, click ( Start & Learn tab > Launch panel > Open Project) and select Mesh tutorial.
3. Click (Home tab > Import panel > Import).
4. In the Files of type drop-down list, select SAT (v4-v7) (*.sat).
5. Navigate to your download folder.
6. Select mold12_study.sat and click Open.
7. In the Import dialog, ensure Dual Domain is the mesh type selected.
8. Click OK.

   Later in this task, you are going to compare the mesh generated by Use auto sizing option with the mesh generated by Use global parameters non optimal option. Duplicate this model so that you can compare results.

9. Select mold12_study in the Study Tasks pane.
10. Right-click on mold12_study and select Duplicate from the drop-down menu.
11. Right-click on mold12_study (copy) , and select Rename from the drop-down menu. Alternatively, press F2.
12. Enter the new study name mold12_global parameters and click Enter.
13. Let's now generate a Dual Domain mesh for this part. Double-click mold12_study in the Study Tasks pane.
14. In the Study Tasks pane, double-click Create Mesh.

    The Generate Mesh pane of the Tools tab appears.

15. Ensure the General tab is selected.
16. Note the suggested Global edge length of about 1.86 mm.
17. Click CAD tab
18. Ensure Use auto sizing option is selected.
19. Click Mesh Now. The generation of the mesh will take a short time.
20. Double-click mold12_global parameters in the Study Tasks pane.
21. In the Study task pane, double-click Create Mesh.
22. In the General tab, leave the Global edge length at the default.
23. Select the CAD tab.
24. Click Use global parameters.
25. Click Mesh Now.
26. When the mesh has been created, rotate the part to examine the mesh.
27. Click (View tab > Windows panel > Tile), and select Tile Horizontally or Tile Vertically. Then click (View tab > Locking panel > Lock All Views). You can now compare both models more easily.
28. Rotate and zoom in on the part to examine the mesh, especially around the spikes, the holes and on the top face. Notice that the edge length and chord angle in mold12_study have been automatically adjusted on the spikes and around the holes. Notice that the mesh of mold12_global parameters in these areas is not as well refined than mold12_study.

    The mesh density should be optimized as far as possible so we recommend to accept the default Use auto sizing.

29. From the Application menu , click (Close > Project). Save each study if you are prompted to do so.

Click the Next topic link below to move on to the next task of the tutorial.