Challenge

Week 8-3D Tetra Meshing Challenge

RRana Pratap Reddy Pidaparthi16 May 2021

WEEK - 8

3D-TETRA MESH GENERATION AND SOLVING TET-COLLAPSE USING VARIOUS APPROACHES IN HYPERMESH

Model-1

Objective:

To create a Tetra-mesh for Housing component with the following quality criteria.
To deploy 2D surface mesh and convert it into 3D mesh.
The minimum length and the maximum length are to be checked only for 2D elements when performing a 2D to 3D Mesh.
To rectify all the Tet collapses in 3D mesh.

Tetra-mesh Generation Method: 2D to 3D Conversion

Quality Parameters:

S. No	Quality Criteria	Value
1	Minimum	2
2	Target element length	5
3	Maximum	7
4	Tet collapse	0.15

PROCEDURE:

1. Import Geometry:

Go to File >> Import >> Model/Geometry

Imported housing Component

2. Defeaturing Fillets:

Go to Geometry >> Defeature >> Surface fillets. Assign minimum and maximum values.
Select all the surfaces where the fillets need to be removed.

Fillets removed on geometry

3. Generate 2D Surface mesh on Geometry:

To deploy the mesh, go to 2D >> auto mesh >> select all the surfaces.
We need to use 2D tis elements while generating surface mesh
After meshing we need clear all the quality issues on surface mesh before converting it into 3D mesh.

2D Surface Mesh 2D Surface Mesh

All the off elements are cleared successfully.
Now we should convert these 2D elements into 3D elements.

4. Converting 2D mesh to 3D mesh:

Solid mesh will be deployed only if the component is either solid or all the surfaces are closed.
To deploy mesh, go to 3D >> tetra mesh >>select the component >> mesh.
Also, check the tetra mesh parameters for better quality of mesh.

3D mesh generated

5. Solving Tet Collapses (Manually):

Checking 3D elements for Tet Collapse

Isolate all failed elements and using mask option

Isolating Failed elements

There are 118 off elements. We can either remesh them or solve them manually by increasing their size
Use tools >> Translate option. Do this individually for each element.

Solving failed elements manually using Translate option

Result for MODEL 1:

The surface mesh is generated and it is converted into volume mesh successfully.
In both cases, all quality parameters are cleared successfully.

Model-2

Objective:

For the given model, Create a 3D Tetra mesh with the following quality criteria.
Tetra mesh Generation Method: Quick Tetra Mesh/ Volume Tetra Mesh.

Quality Parameters:

S. No	Quality Criteria	Value
1	Target Element size	3
2	Tet Collapse	0.15

Procedure:

1. Import Geometry:

Go to File >> Import >> Model/Geometry

Imported geometry

2. Quick Tetra mesh:

In this method, it automatically generated 2D mesh and converts that into 3D mesh.
This method is not preferred as the mesh quality will be bad.

Dialog box of quick Tetra mesh

Features not captured perfectly

3. Volume Tetra mesh :

You can see the holes are not captured properly, so we need to try another method for better mesh generation.
Go to 3D >> tetra mesh >>select the component >> mesh.
Also, check the tetra mesh parameters for better quality of mesh (Assign minimum tetra value, maximum tetra value, Tet collapse value).

Features are captured perfectly

4. Solving Tet Collapses (Using Remesh):

We can see there are 215 elements failed for Tet collapse.
Now isolate all the failed elements using mask option.
Use unmask adjacent option to view neighboring elements.
Now remesh the displayed elements i.e, failed and neighboring elements.

215 elements isolated

After remeshing the failed elements are reduced to 49.
Do this process again until all the off elements are cleared.

Elements after remeshing are reduced to 49

Result for MODEL 2:

Volume mesh is generated successfully without any quality issues.

Model-2

Objective:

To Create a 3D Tetramesh with the following quality criteria,For the given assembly model,

Tetra Mesh Generation Method: Quick Tetra Mesh/ Volume Tetra Mesh

Quality Parameters:

S. No	Quality Criteria	Value
1	Target Element size	4
2	Tet Collapse	0.15

Procedure:

1. Import Geometry:

Go to File >> Import >> Model/Geometry

Imported geometry

2. Volume tetra mesh:

Go to 3D >> tetra mesh >> Volume mesh
Tick curvature and proximity options for better feature capturing of mesh.
Select the required solids or surfaces of each component individually

Volume Tetra dialog box

3. Solving Tet Collapses (Using Fix 3D elements option):

1803 elements failed for Tet Collapse

3D mesh is generated and there are 1803 elements failing for Tet collapse
Now go to tetra mesh >> fix 3D elements
Select all the elements and give Tetra collapse value and number of iterations and click Fix

Fix 3D option for Failed elements

After fixing only 29 elements failed

The majority of the elements are solved automatically
The remaining elements can be remeshed or solved manually until all the tet collapses are solved

Result for MODEL 3:

Note:

As I have used student version software, I can only save up to 100000 nodes. Now we have 1497119 nodes. Therefore, we can’t save these 4 parts in one file.
I have created 4 different files with 4 different parts for challenge submission.