Week 11-3D Tetra Meshing Challenge

MODEL 1 - 2D to 3D Conversion method.

AIM:

To Create a Teramesh for Housing component with the following quality criteria by following TetraMesh Generation Method: 2D to 3D Conversion.

GIVEN DATA:

The given data are the inputs to work. Here the given data are,

• CAD model.
• Quality criteria.

 1.Cad model:

                           Figure 1. CAD MODEL - GIVEN DATA

2. Quality criteria:

Elements sizes: Min- 2 Units, Target- 5 Units, Max- 7 Units 

Tet collapse: 0.15

THEORY:

MESHING :

• Meshing - Automated net generated.
• A mesh is a network that is formed of cells & points. It can have almost any shape in any size & is used to solve partial differential equations. Each cell of the mesh represents an individual solution of the equation which, when combined for the whole network, result in a solution for entire mesh.
• FEM allowed for mixed types of mesh cells & unstructured meshes became feasible.
  • 2D - Structural mesh.
  • 3D - Unstructured as well as structured mesh.

Process of Meshing:

• Definite element size.
• Choose types of element.
• Shell mesh (2D - tria & quad)
  • Various methods.
  • Surface less meshing.
• Solid mesh (3D - tetrahedron, hexahedron, pyramid, wedge)
  • Tetra mesh ( Unstructured mesh).
  • Hexa mesh ( Structured mesh).
• Quality cruteria check.
• Remesh - Quality improvement.

ORTHO TRIA Vs TRIA ELEMENTS:

• Ortho tria capture the features more accurately than tria elements.
• Mostly, otho tria will be used in curved surfaces whereas trias will be used mostly in flat surfaces.
• Surface distortion can happen in the curved faces while we using normal trias, So to avoid those distortion we go with ortho tria elements for curved faces.

PROCEDURE:

• Import the cad geometry - Input the given cad model.

                                Figure 2. CAD MODEL - GIVEN DATA

• Geometry Cleanup - To generate FEM we clean up the geometry. Surface patch up, creating new surfaces, eleminating of triple cons in unwanted area, converting single cons to double cons in necessary area are comes under geometry cleanup phase.
• Quality criteria - Every product which is been produced will go through the set of quality check. If quality check fails other steps like B/C & applying loads will not be feasible, So element quality check will be performed. The given quality criteria values been enterd in  Preferences --> Criteria file settings. These colours are customizable and can be seen while meshing if the elements are beign failed. These failed elements should be corrected and the elements should matches the quality criteria.

                      Figure 3. Criteria file setting tab

Here in tetra modelling, we have to consider only for minimum & max. length in shells criteria and to consider the tetcollapse in solids criteria.

• Meshing - Automated net generated.
  • Step1:
    • Surface meshing has been performed for both component considering the min. & max. quality criteria. GO to --> 2D --> Automesh.
    • To solve 2D element failure go to --> 2D --> Quality index --> Clean up tools.

                   

                                                                               Figure 4. 2D automesh tab

                    

                                                    Figure 5. Surface mesh - 2D (Isometric & Section view)

                

                                                               Figure 6. Surface mesh - 2D (Isometric & Section view)

• • Step2:
    • Tetra meshing has been performed. GO to --> 3D --> Tetramesh.
    • To solve tet collapse GO to --> 3D --> Tetramesh --> Tetraremesh. Change the tetraremesh parameter if needed.

                     

                                                                    Figure 7. Tetra mesh & Tetra Remesh tab - 3D 

                          

                                                                   Figure 8. Surface mesh & Tetra mesh ( Section views)

                             

                                                                      Figure 9. Surface mesh & Tetra mesh ( Section views)

CONCLUSION :

As per the aim, the given component has been checked for the geometrical errors and mesh with the given element Quality criteria. Also tetra elements are used to model the component and there has not been any kinks and dips on the surface of the component. Tetra model has been performed by eliminating all the tet collapse.

                                                                  Figure 10. Tet collaspse check

LEARNING OUTCOMES :

At the end of this challenge, I can able to

• Perform Tetra modelling for any complex automotive components.
• Identify the quality failure and resolve the failure & improve the mesh quality.
• Work on HYPERMESH with a flow.

MODEL 2 - QUICK TETRA MESH METHOD

AIM:

To Create a Teramesh for the given model, by following quick tetramesh method with the following quality criteria. 

GIVEN DATA:

The given data are the inputs to work. Here the given data are,

• CAD model.
• Quality criteria.

1.Cad model:

               Figure 1. CAD Model - Given data

2. Quality criteria:

TetraMesh Generation Method: Quick Tetra Mesh 

Target Element size: 3 Units.

Tet Collapse: 0.15

THEORY

• Quick Tetra mesh is a direct method to mesh without performing surface mesh manually.
• By performing Quick tetra mesh it automatticaly performs surface mesh first then it performs the tetra mesh.
• This method is used when there is no importance given to the quality criteria. 

PROCEDURE:

• Import the cad geometry - Input the given cad model.

 

                          Figure 2. CAD Model

• Geometry Cleanup - To generate FEM we clean up the geometry. Surface patch up, creating new surfaces, eleminating of triple cons in unwanted area, converting single cons to double cons in necessary area are comes under geometry cleanup phase.

• TETRA MESH (Direct method):

  • Quick Tetra mesh is a direct method to mesh without performing surface mesh manually. By performing Quick tetra mesh it automatticaly performs surface mesh first then it performs the tetra mesh. This method is used when there is no importance given to the quality criteria. 

    • Step 1: GO TO ---> View ---> Browser --> Hypermesh ---> Utility.
    • Step 2: Under utility ---> GO to Geometry/mesh ---> Quick tetra mesh as shown below.
    • Step 3: Perform quick tetra by doing some changes as shown in below figure.
    • To solve tet collapse GO to --> 3D --> Tetramesh --> Tetraremesh. Change the tetraremesh parameter if needed.

                                                        Figure 3. Quick tetra Tabs

                                  Figure 4. Surface mesh & Tetra mesh - SECTION VIEWS

CONCLUSION :

As per the aim, the given component has been checked for the geometrical errors and mesh with the given element Quality criteria. Also tetra elements are used to model the component and there has not been any kinks and dips on the surface of the component. Tetra model has been performed by eliminating all the tet collapse.

                                                        Figure 5. Tet collapse check

LEARNING OUTCOMES :

At the end of this challenge, I can able to

• Perform Tetra modelling for any complex automotive components.
• Identify the quality failure and resolve the failure & improve the mesh quality.
• Work on HYPERMESH with a flow.

MODEL 3 - VOLUME TETRA METHOD.

AIM:

To Create a Teramesh for the given assembly model, by 3D Volume Tetramesh method with the following quality criteria.

GIVEN DATA:

The given data are the inputs to work. Here the given data are,

• CAD model.
• Quality criteria.

 1.Cad model:

                                        Figure 1. CAD Model

2. Quality criteria:

TetraMesh Generation Method: Volume Tetra Mesh

Target Element size: 4 Units.

Tet Collapse: 0.15

THEORY

• Volume Tetra mesh is a direct method to mesh without performing surface mesh.
• It performs tetra mesh directly without aa surface mesh.
• As like quick tetra method, This method is also used when there is no importance given to the quality criteria. 

PROCEDURE:

• Import the cad geometry - Input the given cad model.

                        Figure 2. CAD Model

• Geometry Cleanup - To generate FEM we clean up the geometry. Surface patch up, creating new surfaces, eleminating of triple cons in unwanted area, converting single cons to double cons in necessary area are comes under geometry cleanup phase.

• Volume Tetra mesh: 
  • GO TO ---> 3D --> Tetra mesh --> Volume tetra mesh.
  • To solve tet collapse GO to --> 3D --> Tetramesh --> Tetraremesh. Change the tetraremesh parameter if needed.

                                                Figure 3. Volume tetra mesh tab

                                                 Figure 4. Tetra remesh tab

                                                Figure 5. Tetra mesh 

                                               Figure 6. Tetra mesh 

CONCLUSION :

As per the aim, the given component has been checked for the geometrical errors and mesh with the given element Quality criteria. Also tetra elements are used to model the component and there has not been any kinks and dips on the surface of the component. Tetra model has been performed by eliminating all the tet collapse.

                                                                           Figure 7. Tet Collapse check

LEARNING OUTCOMES :

At the end of this challenge, I can able to

• Perform Tetra modelling for any complex automotive components.
• Identify the quality failure and resolve the failure & improve the mesh quality.
• Work on HYPERMESH with a flow.