Project - 2 - Meshing on the suspension Assembly

PROJECT 2

AIM:

To create an FEA mesh for a given model with suitable mesh with perfect quality and make connections between each model assemblies.

OBJECTIVE:

In this project, a rear suspension assembly should have meshed with proper mesh style. This model consists of both Sheet models as well as solid bodies. So mesh should be created as shell and solid respectively. The elements created while meshing should be within quality criteria. At last model, connections are made between them.

PROCEDURE:

IMPORT GEOMETRY:

CAD Model has been imported to ANSA and topology cleanup did on the model.

Pic 1: Model import.

SPLIT MODEL:

Model classified into multiple parts according to its adjacent surfaces. The model after classified, they are then given different properties. So that model can be easily identified.

Pic 2: Properties

MESHING:

While meshing operation, it divided into 2 types,

• 2D or Shell mesh.
• 3D or Solid mesh.

SHELL MESH:

In shell mesh, elements are created as tria or Hexa elements. This will represent 2 dimension phenomenon of a surface.

PROCEDURE:

Initially model checked for geometry issues using geometry check. If no geometry issues are found then the model proceeded for meshing.

Pic 3: Geometry cleanup

MIDSURFACE:

The middle surface for a given model is created by offsetting faces tangentially inside for the center value of the model.

After offset, the model joined each other. And connections are made.

PREPARING GEOMETRY:

Perimeters for the model are created with equal distance as per elements criteria.

ELEMENT CREATION:

For 2D mesh, mixed (Tria, Hexa) mesh are selected for meshing. Each surface is selected and elements are created using option SPOT MESH. The mesh then re-defined until mesh flow get proper and quality criteria are satisfied.

Pic 4: Shell mesh

3D MESH:

The solid mesh consists of tetra-hederal and Hexa-hederal elements which represent 3 dimensional for of the model. These elements are created as boxes with 8 nodded elements Hexa-hederal or 5 nodded pyramid elements. In this model, every solid mesh are created as pyramid elements.

MODEL PREPARATION:

Model checked for geometry issues and proceeded for mesh after finding no errors.

2D TRIA MESH:

A solid model assigned with properties meshes with 2-dimensional tria elements. These meshes are created for given quality criteria. These elements are created using spot mesh and re-conditioned until all elements are satisfied quality criteria.

Pic 5: Tria mesh

3D TETRA MESH:

Using the model created as 2D tria mesh, it converts as a volume first. This was done by defining the closed tria model as a volume.

Pic 6: List

Then tetra hederal mesh is generated on that volume either by Tetra rapid or Tetra FEA.

After creating the model, the model evaluated for quality issues for tet collapse. If no failure elements found it moved for next step.

Pic 7: Tetra mesh.

CONNECTION:

Mechanical bodies on the model connected to each other to form a complete assembly. Various connections are available on ANSA, but here only bolt connections and other rigid connections are only made on the model.

RIM BOLT:

Rim bolt is an important assembly on the model. It made a rigid connection between Rim, break and hub. For this connection, RBE3 and RBE2 elements are created. RBE3 elements for rigid connection for front and back end of the model and RBE2 for creates joints between RBE3 elements.

Blue line --> RBE3

Yellow line --> RBE2

Pic 8: Connections

SEAM WELD:

A seam weld is a permanent joint made between surfaces. In ANSA, seam weld created between models by the following method,

1. Creating curves along with the geometry of the welding area.
2. Converting curve into seam line.
3. Using connection manager, seam weld parameters are inputted.
4. Properties of surfaces to be welded are assigned.
5. Weld formation selected. (Here Overlap shell – Parallel surface)
6. Then seam line creates weld elements according to an inputted parameters.

Pic 9: Seam Weld

SAMPLE IMAGES:

RESULT:

The final model has been created with FEA elements with proper mesh quality. And connections between model also created.