Week- 5 - Solid meshing

SOLID MESHING OF REAR VIEW MIRROR USING ANSA

AIM :

In the Rearview Mirror model check for the geometrical errors and mesh with volume tetra elements as per the given quality criteria and there should not be kinks and dips on the surface of the component.

S.No	Quality Criteria	Value
1	Target/Average length	1
2	Minimum Length	0.5
3	Maximum Length	2
4	Tet Collapse	0.2

FIG: REARVIEW MIRROR IN CAR

PREPROCESSOR USED: ANSA

PROCEDURE:

Solid meshing is a 3D meshing where we can use this meshing if the thickness of the component is above 5mm similarly 2D mesh is for a component which has below the 5mm thickness. here we can fill an entire volume with the mesh that's why it is called the volume mesh. volume mesh requires more computational rather than shell mesh.

There are two types of solid mesh:

1.Structured meshing: We are having only the quad elements in the mesh; there are no elements rather than Hexa elements.

2.Unstructured meshing: We are having a mix of tria elements and ortho tria elements, namely called tetra elements.

There are sequential steps for solid meshing

1. Importing the geometry in ansa
2. Geometry clean up
3. Surface meshing
4. Defining the volume for the meshing
5. Volume meshing
6. Releasing the fe from cad

1. Importing the geometry in ansa :

ANSA. File->Open->File Location

2. Geometry cleanup :

Go to Topo-->Faces-->Topo option and select all CONS and Click ok to stitch all CONS with each other.

Go to Tool-->Checks-->Geometry for Geometry Clean up.

In the above Checks Manager window click Execute to check any error occurred in the Model and fix the Error and Cleanup the Geometry.

after fixing all the error and rerun the geometry check.

After the geometry check we should check the fillets and feature and distance between the cons for min element length criteria if there are any requirement then remove the construction line not geometrical line this is called the defeaturing.

3. Surface meshing :

After Loading the mesh parameter and quality criteria then First always mesh the fillet and feature. For tetra meshing use spot mesh algorithm using ortho tria at fillet region and tria at flat surface then reconstruct the region .

4. Volume meshing :

After surface meshing all the components it is required to fill volume with the element which is called volume meshing.

Before going through the volume mesh we have to enable the Tet collapse in the quality criteria to go to solids there we can give Tet collapse value is 0.2.

For volume meshing first defining the volume is required so that ansa can detect the volume

Go to Volume Mesh-->Volumes--Define-->Manual option and Define the Volume.

For volume meshing Volumes-->list option and check the defined volume and apply tera rapid and tetra fe algorithm for meshing

Check the volume meshing using tet collapse quality criteria.Mesh-->Grids-->MV Free option and select the nodes and move in x,y,z, direction to clear the quality issue.Similarly eliminated all other off elements (Min & Max length) by using MV Free option.

OUTCOMES :

• I understand how to generate the volume mesh or tetrahedral mesh in this challenge.
• I learned where we should use the normal trias and ortho trias.
• Different types of mesh Tetra rapid and Tetra FEM.
• How to fix the Tet collapse issues in the model.

CONCLUSION :

The given Rearview mirror component checked for the geometrical issues and meshed with tetrahedral mesh with given quality criteria with no Tet collapse.