Week 8-3D Tetra Meshing Challenge

Week 8-3D Tetra Meshing Challenge

Aim:

To create tetra mesh for the given models with in the given quality criteria.

Procedure:

1. Importing Geometry and cleanup:

• To import the geometry, go to file >> Import >> select the file >> Import.
• After importing the geometry, the geometry is checked for any missing surfaces or triple cons. If there are no errors present in the geometry then the geometry is ready for the mid-surface extraction.

2. Generating Tetra mesh using different methods:

• Tetra mesh can be generated in 3 different methods.

1. Converting 2D or surface mesh to Tetra mesh.
2. Directly using solids.
3. Using surfaces.

• In 1 method, 2D mesh is generated and then the 2D mesh is converted to 3D. To convert the mesh, go to 3D >> tetra mesh >> select 2D elements >> mesh.
• In 2 method, If the solid is present in the geometry then 3D mesh can be generated without the help of 2D mesh or surfaces. To generate 3D mesh directly, go to 3D >> tetra mesh >> volume tetra >> select solid >> give element size >> mesh.
• In 3 method, the tetra mesh can be generated using surfaces but the surfaces should not have any free edges. To generate the 3D mesh, go to 3D >> tetra mesh >> volume tetra >> from the drop-down menu change solids to surfs >> give element size and mesh. In this method if there is a failure in mesh generation then use the following method.
• Go to tool bar >> view >> browsers >> hypermesh >> utility >> goem/mesh >> quick tetra mesh >> enter all the parameters >> select the surfaces >> mesh.

3. Checking and rectifying the elements which failed the quality criteria:

• For tetra mesh only the Tet collapse failure will be considered. To check the Tet collapse failed elements go to tools >> check elements >> click on tet collapse. At the bottom left corner, the number of failed elements will pop up.
• To rectify the failed elements, they are two methods.

1. Manually changing the distance between the nodes.
2. Remeshing the mesh.

• To rectify the elements manually, the failed elements are isolated and then rectified. To do that the failed elements are masked using the mask command and retrieved. Now the distance between the nodes is selected and the nodes with smallest node length is selected and the distance between the nodes is changed using the distance option.
• Remeshing the mesh is the best option compared to fix the quality manually. To remesh the mesh, go to 3D tetra mesh >> tetra remesh >> select elements >> remesh. Before remeshing all the parameters including tet collapse should be given in order to reduce the tet collapse failure.
• The final images of the model are shown below.

Conclusion:

The given models, Tetra mesh is generated using different methods with in the given quality parameters