Week 3

Aim: Perform Mid surface extraction and Meshing of Automotive Hood component with proper geometry cleanup, maintaining element quality and assigning thickness to each part.

Procedure:

• Geometry model cleanup
• Mid surface extraction
• Meshing with Element quality parameters

Geometry model cleanup:

1. Importing CAD model file into ANSA
2. Viewing whole model to just get an overview of model and then using perimeter>length and macros to make whole hot points at 1 mm distance inorder to have smoothness of whole model
3. Performing TOPO for whole model to convert single CON to double CON.
4. Now, view each part of model individually and perform Geometry check in Checks panel to see error and try to overcome those errors. Recheck Geometry checks again until all the errors are overcome.
5. Make sure to use Orient option so that all the faces have same grey or yellow color.

Images of Inner and Outer panel with zero goemetry errors

Images of Hinge and Latch enforcement with zero goemetry errors

Image of imported Hood model with zero geometry error

Mid surface Extraction:

1. Mid surface extraction can be performed in two ways: Auto midsurfacing and Manual midsurfacing. In order to choose which option is to be used user must check the model thickness . If parts of model are having uniform thickness then Auto midsurfacing can be done as it will time saving option. For sheet metal applications, Skin option is prefered in Mid surface tab present in TOPO of ANSA
2. By using Skin option , we dont need to assign any PID and thickness value as it will automatically calculate the thickness of the part and will create new PID for it alongwith thickness value.
3. After extracting mid surface, make sure to perform geometry check in Checks panel to see other type of errors present in model.

Images of Extracted Mid surface Inner and Outer panel

Images of Extracted Mid surface Hinge and Latch enforcement

Image of Extracted Mid surface for whole Hood component

Meshing with Element quality parameters:

As we have extracted Mid surface of 3D component and converted it to 2D component so 2D shell mesh is performed by used Best option in MESH generation panel present in MESH. In order to proper quality for our model , Element quality parameters are set which is alloted to us.

After setting Element quality and mesh, now checking for symmetry is done. Symmetry is a concept which can be use when model is having identical face from imd portion. In order to check symmetry of model , Rimdvl option is present in TOPO which helps in identifying how much model is symmetry. If model is symmetry for more than 90% , then we can delete half of the entities of model and mesh only half portion then use transform symmetry options to reflect entities to other half so that whole part will have mesh elements which helps in saving a lot of meshing time. Tools such as swap , split , reconstruct , join , cut , paste etc are used to overcome failing elements for quality. Since Inner and Outer panel parts are having symmetry so half part is meshed and then reflected to other half.

Image of Half meshed model of Inner panel

Image of meshed model of Inner panel

Image of meshed model of Outer panel

Images of meshed Hinge and Latch enforcement

3D Representation of Shell to Solids:

Below are the images of all parts alongwith complete model shown in solid form:

Learning Outcomes:

• Got knowledge of how to do proper geometry cleanup of imported CAD model and make proper orientation of model
• Got knowledge of performing better Mid surface extraction for provided CAD geometry
• Got knowledge in time saving for meshing of components by half meshing of symmetrical parts
• Got knowledge in peforming and maintaining good element quality

Conclusion:

Successfully performed Mid surface extarction with Meshing of component by maintaining Element parameter quality.