Tetra meshing of axle assembly

Aim- To perform Tetra Mesh

Methods to generate Tetra Meshing:

There are three methods to generate Tetra Meshing as stated below:

1. Conversion of 2D tria to Tetrahedral Elements, by using Tetra Mesh panel.
2. Using the Quick Tetra Mesh, from the Utility panel.
3. Using the Volume Tetra Mesh panel.

Conversion of 2D tria to Tetrahedral Elements, by using Tetra Mesh panel.

1. Import the Model into HyperMesh
2. Delete the solid from the model, by selecting the

Delete→ Solid→ Delete entity.

3. Clean the geometry.

3. Now perform the 2D meshing on the model, by selecting the Mesh type as “Trias”.
4. Now the model is ready to perform the Tetra Meshing.

Select the 3D→ tetramesh option.

6. In the tetra mesh panel, select the elements under the “Fixed trias/quads to tetra mesh” option 7. After selecting the elements, click on the “Mesh” button
7. Once the Tetra Meshing was completed, mask a few elements to check the mesh generation.

2. Using the Quick Tetra Mesh, from the Utility panel.

1.Import the Model into HyperMesh and clean the geometry.

2. Delete the solid from the model, by selecting the

Delete→ Solid→ Delete entity.

3. Click on the View→ Browsers→ HyperMesh→ Utility, as shown below:

3. Now select the Geom/Mesh from the “Utility Menu”, then click on the Quick TetraMesh

5. In the Quick Tetra tab, select the Components and Surface.
6. Specify the Mesh size (as per the Quality mentioned).
7. Then change the Mesh type to “Trias only”.
8. Click on the Mesh button to generate the Tetra Mesh.
9. Once the Quick Tetra Mesh was completed, mask a few elements to check the mesh generation.

TetCollapse

Tet collapse is one of the quality parameters, which will be checked while generating Tetrahedral elements. It can be calculated by measuring the distance of a node from the opposite face, then each of the four values will be divided by the Square root of the opposite face’s area. The minimum of four resulting values is then normalized by dividing it by 1.24.

Generally tet collapse can be calculated by the formula = Min of (h/√A) ÷ 1.24

Where, “h” represents the Height, between the Node (N1) and the opposite face of the Triangle. “A” represents the Area of Opposite Face (area of the Triangle).

Clearing tetcollapse error

1.After completing the Tetra Mesh, check for the failed element.

2. Select Tools→ check elems→ 3D→ tet collapse.
3. In the status bar, it will show how many failed elements are present in the model.
4. Click on the “save failed” option to save the tet collapse failed elements.
5. Isolate the failed elements, by clicking on “Mask” option
6. Then right click on “elements”, to select the “retrieve” option.
7. This will automatically select the failed elements as your masking entities.
8. Click on the “mask” to hide the failed elements, then select the “reverse” option to show only the failed elements in the HyperMesh GUI.
9. Now to clear the Tet collapse, select the Tools→ translate command.
10. Manually inspect the failed element and do the following procedure: Pick a node in any one failed element, which has minimum height. Select N1, N2, N3 which represents the opposite plane of the prior selected node. Choose the magnitude value approximately by trial and error method. Click on the “translate” button to move the node.

11. After correcting the failed element, parallelly check the Tet collapse value in the “check elems” option.

3. Volume tetra

Steps to be followed to generate Tetra Mesh:

1. Import the Model into HyperMesh and clean the geometry.
2. Keep the solid of the model, select 3D→ tetramesh.
3. Click on the Volume tetra option, select the solid of the model.Tick the checkboxes of “Use curvature” and “Use proximity” Specify the Minimum element size (as per the quality criteria). Then tick the checkbox of “Cleanup elements”. Click on the “Mesh” button to generate the Volume Tetra Mesh.