WS10-1 WORKSHOP 10 Tetmeshing Anchor Geometry and Verifying Mesh Quality PAT301, Workshop 10, October 2003

WS10-2 PAT301, Workshop 10,October 2003

WS10-3 PAT301, Workshop 10,October 2003 n Problem Description u Create a tetrahedral mesh using the mesher TetMesh. See the effect of two TetMesh parameters on the mesher by re-meshing and changing the value of the parameters. For both meshes, determine the quality of the tet elements.

WS10-4 PAT301, Workshop 10,October 2003 n Suggested Exercise Steps 1. Open existing database Anchor.db 2. Tet mesh geometric solid Solid 1 using Elements / Create / Mesh / Solid / TetMesh. Elements are to be Tet10 (parabolic), and the element size (Global Edge Length) View free faces using Elements / Verify / Element / Boundaries / Free Faces. 4. Determine the quality of the tet elements using Elements / Verify / Tet / All. 5. Obtain a fringe (color) plot for the aspect ratio for the tet elements using Elements / Verify / Tet / Aspect. 6. Re-mesh using different values for TetMesh Parameters… Create more elements at curved geometry by reducing Maximum h/L to 0.05 and Minimum Edge Length by reducing the multiplier from 0.2 to 0.1. Re-mesh using TetMesh. 7. Repeat Step 4 for the new mesh. 8. Quit MSC.Patran.

WS10-5 PAT301, Workshop 10,October 2003 Step 1: Open Database Open existing database Anchor.db a.File/Open. b.Select Anchor.db. c.Click OK. a b c

WS10-6 PAT301, Workshop 10,October 2003 Step 2: Tet Mesh Geometric Solid Mesh the solid. a.Elements: Create / Mesh/ Solid. b.Select Tet for Elem Shape. c.Select TetMesh for Mesher. d.Select Tet10 for Topology. e.Use default values for TetMesh Parameters… f.Select Solid 1 for Input List. g.Enter 20.0 for Value of the Global Edge Length. h.Click Apply. i.Click Smooth Shaded icon. a b c d e g f h i

WS10-7 PAT301, Workshop 10,October 2003 Step 3: Verify Boundaries Look at the free faces of the tet elements. a.Elements: Verify / Element / Boundaries. b.Select Free Faces for Display Type. c.Click Apply. a b c

WS10-8 PAT301, Workshop 10,October 2003 Step 4: Determine Element Quality Using All Tests Determine the quality of each tet element. a.Element: Verify / Tet / All. b.Click Apply. c.See spread sheet on next page, Continued… a b

WS10-9 PAT301, Workshop 10,October 2003 Step 4: Determine Element Quality Using All Tests (Cont.) Results of quality checks. a.Test performed b.Number of elements that failed test Results of quality checks. c.Poorest quality check result d.Element that had poorest quality check result a b c d

WS10-10 PAT301, Workshop 10,October 2003 Step 5: Element Aspect Ratio Using Fringe Plot Create a color fringe plot for the tet element aspect ratio.. a.Element: Verify / Tet / Aspect. b.Adjust Aspect Ratio to a value near 5. c.Click Apply. d.Obtain fringe plot. e.Click View Corner icon and drag to show close-up view. a b c e e

WS10-11 PAT301, Workshop 10,October 2003 Step 6: Re-Tet Mesh Geometric Solid Re-mesh the solid to try to create an improved mesh. a.Elements: Create / Mesh / Solid. b.Select Tet for Elem Shape. c.Select TetMesh for Mesher. d.Select Tet10 for Topology. e.Click TetMesh Parameters… f.Enter 0.05 for Maximum h/L. g.Enter 0.1 for Global Edge Length multiplier. h.Click OK. i.Select Solid 1 for Input List. j.Enter 20.0 for Value. k.Click Apply. l.Click Yes for delete the existing mesh on Solid 1. a b c d e g f h i j k

WS10-12 PAT301, Workshop 10,October 2003 Step 7: Element Quality Using All Tests for New Mesh Original Mesh Re-Mesh The tables above illustrate the differences between the first mesh and the re-mesh. Observe the large improvements made in each of the characteristics of the model after the remesh.

WS10-13 PAT301, Workshop 10,October 2003 Step 8: Quit MSC.Patran Quit MSC.Patran a.Select File on the Menu Bar and select Quit from the drop down menu a

WS10-14 PAT301, Workshop 10,October 2003