Project 2- Meshing and connection for Rear Suspension using ANSA

OBJECTIVES :

To mesh the Rear Suspension model in ANSA under given quality criteria. Take midsurface for components thickness less than 5mm. Remaining go for volume mesh. Apply necessary connections.

Quality Criteria :

Quality Criteria for Tria Elements (Tyre and Rim):

S.No	Quality Criteria	Value
1	Target/Average length	7.5
2	Minimum Length	5
3	Maximum Length	10
4	Skewness	45

Quality criteria for Tria Elements (For other components):

S.No	Quality Criteria	Value
1	Target/Average length	4
2	Minimum Length	2
3	Maximum Length	6
4	Skewness	45

Common Quality Criteria for Tetra elements:

S.No	Quality Criteria	Value
1	Tet-collapse	0.2

Quality criteria for Mixed elements (For Midsurface only):

S.No	Quality Criteria	Value
1	Target/Average length	4
2	Minimum Length	2
3	Maximum Length	6
4	Aspect	3
5	Warpage	15
6	Skewness	45
7	Jacobian	0.7
8	Minimum Quad Angle	45
9	Maximum Quad Angle	135
10	Minimum Tria Angle	30
11	Maximum Tria Angle	120

PROCEDURE :

1. Import the Rearsuspension.step model to ANSA.

FIG 1: REAR SUSPENSION CAD MODEL

2. Measure the thickness of the assembly at various edges to mesh components with midsurface.

3. Check the geometry for error using Checks Manager and rectify errors like triple cons, single cons , needle faces, collapsed faces, cracked faces,etc.

FIG 2 : GEOMETRY CLEAN UP

4. Assign each component as a PART under MODEL BROWSER for a Batch meshing Scenario.

FIG 3 : CREATING NEW PART

5. Create Batch Meshing Scenarios for all components with variable thickness and mesh them with tria elements by assigning the mesh parameters and Quality criteria.

FIG 4: BATCH MESHING SCENARIO

6. Mesh the uniform thickness component after taking midsurface under specified quality criteria.

7. Define Volumes for all parts while errors like duplicate errors, penetration errors, Macros Internal bounds may appear. Remesh using TetraRapid or Tetra FEM.

FIG 5 : DEFINED VOLUMES

8. Unstructured Elements are formed in components after volume meshing.

FIG 6 : UNSTRUCTURED ELEMENTS FORMED IN VOLUME MESHED COMPONENTS

9.Give Seam Weld connection to the midsurface obtained component using overlap solid under Connections Manager.

FIG 7 : SEAM WELDING CONNECTION

10. Now RBE2 connections are made to the bolted areas using NASTRAN module > ELEMENTS > RBE2.

FIG 8: RIGID BODY CONNECTIONS

11. Create Suspension spring as a 1D element. Apply thickness under Presentation Parameters. Select as solids under Line Elements CrossSection.

FIG 9: 1D AND 2D ELEMENTS REPRESENTATION

12. The Entire FE model is then transformed symmetrically to obtain a Full suspension model.

FIG10:FE REPRESENTATION OF REAR SUSPENSION ASSEMBLY

Conclusion:

1. The suspensions model was cleaned for geometric error and meshed to satisfy the given quality
2. All the features were captured properly
3. The suspension model was assembled using appropriate connections.