Challenge

Week 8-3D Tetra Meshing Challenge

PPallav Sharma27 Feb 2022

3D Tetra Meshing Challenge

Aim :-

To perform 3D/Volume mesh on given components as per quality criteria.

Introduction :-

Tetramesh is a 3-D type of mesh. When we talk about the 3-D mesh, Tetramesh is more preferable as compared to the Hexa mesh in the industry. Because we can create the tetramesh easily in the complex geometry as compare to the hexa mesh. We can do the 3-D mesh by two methods. First is we can do the tetramesh from 3-D panel directly. Second is we create the 2-D mesh on the surface of the component and then we convert it into the 3-D mesh.

So to create the tetramesh we do the tria mesh on the surface of the component and than we convert it into tetra mesh by the many methods.

When the thickness of the component is more than 6 mm then we can't do the 2-D mesh on the component and give the thickness to that component so in that case we do the 3-D meshing. The simulation done on the 3-D mesh are more accurate than the result of the 2-D mesh.

There are 3 method to generate tetra mesh

Conversion of 2D tria to tetrahedral Element, by using Tetra mesh panel.
Using Quick Tetra mesh, from utility panel.
Using Volume tetra mesh panel.

Case 1 : TetraMesh Generation method: 2D/Surface mesh to 3D/Volume mesh

Quality criteria:

Surface Mesh
Target Element length	5 units
Minimun Element length	2 units
Maximum Element length	7 units

Volume Mesh
Tet collapse	0.15

Procedure :-

Step 1 GEOMETRY IMPORT :-

Open HyperWork software, go to file->Import geometry-> select the geometry.

step 2 GEOMETRY CLEANUP :-

As per the requirement the model has to mesh. Prior to mesh geometry cleanup has to be done in order to remove the regions where the elements might fail for a minimum length.

Such areas have to be toggled and changes should be done as per the requirement. Some of the changes are shown below.

Step 3 SURFACE MESHING :

We are going to give the criteria file setting.

in tetra meshing two types of the element used 1. ortho tria 2. tria

ortho tria used on curvi surface to capture surface with proper mesh flow tri used on flat surface

Check for minimum and maximum element size error from and clear the same
Below the image shows there no min and max element size error.

Step 4 volume meshing :

Now we are going to create the tetra meshing with the 2-D elements. So for that, we are going to go the 3-D--> tetramesh. Here we are going to select the 2-d elements and then we are going to click on the mesh. Perform 3D tetramesh using the 2D tria elements, 3D>Tetramesh>select all the elements

Now we want the tet collapse to be less than 0.15. So we are going to check that from the check elements. In that, we are going to the 3-d and we are going to give the value of tet collapse to be 0.15 and we are going to check that how many of the elements are failing for the tet collapse.

No elements are failing for the tet Collapse.

Case2: TetraMesh Generation Method: Quick tetraMesh

Quality Parameter
Target Element Length	3 units
Tet collapse	0.15

Step1: Import Geometry

Open HyperWork software, go to file->Import geometry-> select the geometry.

The first step after Importing geometry is to delete solid by going, delete->select solid -> display-> click on delete.only surface will be available.

step2: Geometry clean up

Remove unwanted construction lines, remove free edges and deform surface to make sure close volume is there. Measure thickness of all the components at different location to decide whether we need to perform shell mesh or Volume mesh. since in this components all the components are more than 6 units, volume mesh is performed.

Step3: To perform 3D tetrahedral Mesh

Go to View->browser->Hypermesh->utility than select Geo/Mesh from utility menu than click on quick tetramesh, assign components elements/mesh size and mesh type as tria only as shown below.

After tetramesh by Quicktetramesh method lot-of off elements will be there. Now its time to remesh the off tetramesh as shown below.

assign tetramesh parameter, than change free boundary faces to remesable. click on remesh

Final tetramesh model

Case 3: TetraMesh generation method: Quick tetra mesh/Volume tetramesh

Quality Parameter
Target Element Length	4 units
Tet collapse	0.15

Turbocharger

Turbocharger is a turbine driven compressor. It is uses the waste energy from exhaust gas to increase the charge mass of air and power of the engine. It located at exhaust side of engine.