Challenge

Project 2

MESHING AND CONNECTIONS DEPLOYMENT FOR REAR SUSPENSION OF A CAR:

AIM:

To check for the geometrical errors and clean the geometry.
To perform the solid mesh on the areas where the thickness is more than 6mm and to deploy the shell mesh where the thickness is less than 6mm.

QUALITY CRITERIA:

Quality Criteria for Tria Elements (Tyre and Rim):

Quality criteria for Mixed elements (For Midsurface only):

Quality criteria for Tria (For other components):

Common Quality Criteria for Tetra elements:

S.No	Quality criteria	Value
1	Tet collapse	0.2

PROCEDURE:

Geometry cleanup:

Import the cad model into the ANSA database using the open option present in the FILE tab.
The next step is to set the perimeter length to 1mm using the length option present in the mesh module.
Then, topo operation is performed in order to stitch all surfaces together.
The next step is to run the geometry check tab in order to find out all the geometrical errors present in the model.
Initially, all the unchecked faces present in the model is corrected by using the manual method.
Then, all the other errors include triple cons, needle faces etc are all corrected by using both auto fix and manual method.
The geometry check tab is run again to find out any errors still present in the model.

Mid surfacing:

Use the weld spot to measure the thickness of the model.
The mid surface is generated for the parts which are having the thickness less than 6mm.
The mid surface is generated by using the offset option present in the face module under topo mode.
The mid surface which is generated can be put into separate PID's with assigning the thickness value.
With the Quality criteria mentioned above the mesh is generated by using different algorithms.
The mesh quality can be improved by using Commands like reconstruct, smooth, split, swap.

Volume mesh:

Initially, the construction lines are refined properly in order to get a better flow of mesh.
The reconstructing includes defeaturing the fillet areas which is falling below the minimum element length criteria.
Similarly, all the surfaces are checked properly whether all the features are captured properly.
Then the mesh is deployed by using different algorithms present in the mesh module.
The quality of the mesh is improved by using the commands like reconstruct, split, swap etc.
Then, the volume is defined by using the define option present in the V.mesh module.
Then by using the Tetra rapid or Tetra FEM the defined volume has meshed.
Then, the tet collapse error is checked for the Volume mesh. The error is fixed by using the fix quality option module.

CONNECTIONS:

After Meshing, the mesh is released by using the release option present in the elements tab under the mesh module.

RBE2 SINGLE CLUSTER CONNECTION:

This type of connection is deployed on two or more holes which is nearer to each other. This type of connection will lock the surface in all directions. This type is generated by using the RBE2 option under Nastran deck.

Bolt Representation:

In this type initially, we use the RBE2 many node option single cluster is generated for both the holes. Then, by using the two-node option the master node of both the holes is selected and then stem-like representation indicates the bolt.

C-Bar representation:

The spring in the shock absorber is captured as C-bar representation.
The first step is to create the middle curve by using the middle option present in the curves tab under topo module.
Then, select C bar option in elements module in NASTRAN deck.
Select C bar then select curve box and select ok and enter element length and select ok and then C-bar will be generated.
Then, open the C-bar property id which is created and select area and enter the radius value in that box.

Learning outcomes:

Ship work like this
in your own course.