Week 5 Challenge : Surface wrap on Automotive Assembly

Aim

• To merge the Engine, Transmission and Gear Box into a one model.
• Generating Surface wrap with target length of 3mm around merged model to have a common volume. 
• Target length for Wrap = 3mm

Introduction

The surface wrap is used to create a watertight surface mesh which replicates the exact geometry of model. the surface wrap is used to perform the external flow analysis which do not require any internal components. The accuracy of surface wrap depends on the element size of mesh, smaller the element size better is the feature capturing of small and intricate parts. For generating smaller sized mesh, the time reqired is also high. So a proper balance between selection of mesh element size and computational time becomes critical. 

Procedure

1. First the model is loaded on to ANSA
2. Unwanted surface are deleted without damaging the outer shape of the geometries.

3. Single cons are resolved mainly here as it would affect negetively on the surface wrapping.

4. After cleaning up the geometry from the unwanted surfaces it is then solved.

5. Then whole three geometries are merged together to form the required system.

6. Surface wrapping tool with constant length of 3mm is chosen from the meshing interface.

• Mesh deck is opened to wrap the surface using ''Constant Length'' in wrap tool. 
• Mesh Deck-Elements-Wrap-Constant Length - New

• EGT_FULL_WRAP- Castellation-enter mesh length-3mm

• Mesh shell type, trias  - Nodes out of Surface - Assign properties from structure

• Select '0' - Give a name - And select all PID's bt (cntrl+A) - by presing green arrow PID's will move to Octree Scenario

• Then select Run and surface wrap will take place.

 7. It is then named and the required parts are selected(all) and the run button is pressed to start the surface wrapping.

Conclusion

• The combined Powertrain model is surface wrapped successfully with element size of 3mm. 
• Surface wrap is effective for outside flow simulations where the volume between the body and wind tunnel is required for flow over the body simulations.
• Surface is easier to perform since it does not depend on the quality of the wrap on each material as we are not interested in physics in the body.