Week- 5 - Solid meshing

SOLID TETRA MESH

OBJECTIVE:

To create a tetra 3D mesh for a given mirror holder with satisfying quality criteria.

INTRODUCTION:

Solid meshing is classified into 2 types Hexahedral and Tetrahedral. Hexa mesh contains solid box-type elements which have the perfect shape. So that it named as structural mesh. Where else tetra mesh was 3 triangular mesh which shapes according to geometry and it named as un-structural mesh. Hexa meshing needs more time comparing to tetra meshing as well as analysis time.

PROCEDURE:

Import geometry and Geometry cleanup:

• Geometry imported on Ansa and created links to surfaces by using option TOPO.
• While trying to split faces it found that 2 surfaces shared cons and create it as a triple con.
• Those cons are released from surfaces and made connection properly using option
• The model then segregated and split into 4 variants:
  • Bottom holder.
  • Universal rotating ball.
  • Mirror holder.
  • Mirror.
• These surfaces split and saved as different lock views.
• Then all surfaces checked for geometry check and find it clears all quality parameters.

Pic 1: Topology clean-up

Pic:2 Geometry check

Pic:3 Lock views

2D tria mesh:

• Before meshing started it has to be created hot points in equal distances. For that purpose, the option Perimeter > Length option is used.
• Then the short length of the model was identified and made a model modification.
• In the mesh parameter, the minimum and maximum sizes of the elements are entered.
• Mesh quality values entered.
• Using SPOT MESH each and every surface meshes with tria elements.
• Curved area meshes with ORTHO TRIAS and flat areas are meshed with
• Mesh re-constructed if required.
• Quality for a mesh, like minimum and maximum length is checked and corrected if failed.

Pic:4 Tria mesh

3D Tetra mesh:

• 2D meshed surfaces are checked for geometry and connectivity for its mesh.
• After that closed surfaces are defined for volume and created a solid property for it.
• This was done by option Volumes > Define.
• Then the model re-meshed with Tetra rapid and Tetra FEM.
• The meshed model then inspected for collapse quality.
• If any elements fail for collapse then those meshes are re-constructed until its satisfies it quality values.
• Some exceptional cases which violate collapse values, those elements length are manually increased in order to make elements within tolerance.

Pic:5 Volume list

Pic:6 Quality check

RESULT:

Given mirror, the model has been meshed with 2D tria elements and created 3D tetrahedral elements within tolerances.

Pic:7 Result