Week 8-3D Tetra Meshing Challenge

Week 8 - 3D Tetra Meshing in Hypermesh.

Objective 1:- Create a Teramesh for Housing Component with the following quality criteria.

Tetra Mesh Generation Method :- 2D to 3D conversion

Quality Criteria:- Min.length - 2 units, Target length - 5 units,Max.length-7 units, Tet-collapse-0.15

Procedure:-

1) Import:-

1. The given model is in.STP format hence we need to import using Import~Geometry~.STP~Import

The below image shows the procedure.

Fig 1. Given Model ( Housing )

2).Deleting Solids:-Once the model is imported we will delete the solids in the model.

3) Geometry cleanup and Defeaturing :- We will check the model for any free surface by viewing the model in Wireframe mode.The given model had no free surface, hence we proceed with defeaturing,here we will remove the lines where minimum thickness error may occur.However few area could not be defeatured as feature capturing was getting affected.

2-D Meshing:-

As per the requirement we have to convert 2d mesh to 3d we need to first set the Quality criteria . Below image shows same.

Fig 2. 2D Meshing Element quality criteria

Fig 3. 3D Meshing Element Quality Criteria.

Once the quality criteria is set we can proceed with meshing.To do we will go to 2D~ automesh~surf.

Once the mesh is created it is important to clear all off elements from the mesh.as it may tet collapse in the final mesh.Once the off elements are cleared, we check for errors like connectivity issue,duplicates and equivalence errors.if found we will fix them.

Converting 2d to 3d Mesh :- As per the requirement we will convert 2d mesh into 3d mesh. In order to do so we will go to 3d~ Tetramesh~Tetramesh~Elements.

Once Tetra mesh is created we will check for quality issues.In the given model Tet collapse is of most importance,hence we will check it by going to Tools~check elements~3D~Tet collapse.as we had resolve the off elements in 2d mesh there was no Tet collapse issue in the 3d mesh.

Fig 4.Image showing No tetcollapse elements in Housing.

Fig 5. 3D elements created on the model.

Objective 2:- For the given model, Create a 3d Teramesh with the following crteria.

Quality criteria:-Target Element size:3units, Tet collapse:0.15

TeraMesh Generation method:- Quick Tetra Mesh/Volume Mesh

Procedure:- For doing Quick Tetra it is important to make sure that the model is closed completely.Hence we look for any free edges in the model.

Fig 6. Given Model

Meshing:- In order to mesh the given model with tetra elements we will use Quick Tetra Meshing.this method is compartively very less time consuming.In order to mesh we will go to View~Browsers~Geom/Mesh~quick Tetra Mesh.

Fig 7. Quick Tetra Mesh

Once we have reached the above page, we can select the component and surface.we can enter mesh size which is our Target element length and proceed.This method first creates 2d mesh and using it Tetra Mesh is created.The 2d mesh can be deleted after Tetra Mesh is created.

Element cleanup:-

Once elements are we will check for Tet collapse, To check we will go to Tool~Element check~3D element check~Tet Collapse.

In order to resolve we will go to Tetra Mesh tool ~ Mesh Parameters~Enter elem.quality target ~Tet collapse (O.15)

Now go to Tetra remesh ~ Elements ~Displayed ~ Confirm. After this we will again check for Tet Collapse,this method resolve all Tet collapse. Below image shows the procedure and result.

Fig 8. Tetra Mesh Parameters

Fig 9. Tetra remesh

Fig 10. Image showing no Tet collapse elements in the model.

Fig 11. 3D elements created on the model

Objective 3:-

For the given assembly model,create a 3D Tetramesh with the following quality criteria.

Quality criteria:-

Target Element size:4 units, Tet collapse:0.15

TetraMesh Generation Method:-

Quick Tetra Mesh/Volume Tetra Mesh

Procedure:-

Import:-

The given model is in .HM format, we imported the model using Import tool~Model. Below image shows the method.

Fig 12. Given Model

Geometry check and Defeaturing:-

Once the model is imported we will view the model in wireframe view to check any issue.The model did not had geometrical issue.

Once done we can isolate the components one by one to check and Defeature wherever required.In the given we defeature the surface where min.length issue could occur.

In the below image we have defeatured the surface fillets using Defeature ~ Surface fillets

In central hub and hub we had to defeature some surface, however not all fillets could be defeatured as it was affecting the feature capturing.

Meshing:-

In the given we have used volume mesh method,in order to use this we have to make the geometry is closed.we will go to 3d~Tetra Mesh~Volume Mesh. We isolated each component and mesh one by one The below image shows the method.

Fig 13.Volume Tetra Mesh

Once meshing is done we will check for Tet collapse in the meshing.

The off elements were removed using using similar method as used in model 2.We set the Tetramesh Parameters and remeshed the elements, Which resolved most of the element issues.