CLEANING UP AND MESHING THE HOOD MODEL USING ANSA

OBJECTIVE:

To cleanup and meshing the given hood geometry model with element size of 5 mm.

Given geometry:

Fig.given hood geometry model (inner view)

METHODOLOGY:

• The given hood geometry has several topological errors and are eliminated by using topo option,deleting the contradicting surfaces and creating the surface where single cons exists.
• After cleanedup the geometry,geometry check has made to check whether the other errors such as needle face,single cons,cracks exist and resolved.

fig.performing geometry check

• Midplane extraction: Midplane is normally extracted for the geometries consisting of sheet metals of thickness less than 6mm.
• In order to perform the mid plane extraction,create an offset using faces>offset and offset value is given as -0.75/2.
• After creating the midplane,the geometry check has made to check and eliminate the errors.

fig.midplane geometry check.

• Symmetry: Using the faces>Rm.Dbl option to see whether the geometry is symmetry or not.Deleting the symmetry faces on one side and perform meshing the other half,copy it to the other side using default symmetry plane under transform>copy>symmetry option.
• Set the PID and material property for the mid plane.
• For the outer panel,extracted the midplane using mid.surf skin option and set the PID.
• Hemming: Hemming is an important process to join the inner and outer closure panels together.This process is also carrried out on all four closures such as vehicle-front door,rear door,hood,trunk.
• Formula to calculate the hemming thickness =2*outer thickness + inner thickness.
• hemming process is done by deleting the extra surfaces and merged it as a single region.In order to do that ,isolate only the midplane of the outer and inner panels.Project the edges of outer panel to the inner panel as well as the outer panel itself.Delete the crimpin region and join cons of the edges of the inner panel with outer panel,it form cyan colour (triple con) which is fine for this application.

fig. geometry model after done the hemming process

• From the figure, the green colour pid indicates the hemming region,Blue colour indicates the inner panel,Yellow colour pid indicates the outer panel.
• MESHING:

• Mesh generation>Best-To mesh the midplane of the geometry with target element size of 5mm.
• eliminated the surface mesh quality criteria errors.

RESULTS:

Shell quads:80175

Trias:2687

Total:82860.

CONCLUSION:

The given hood geometry model has cleaned up and meshed perfectly.

Link:https://drive.google.com/open?id=193IGe4PbrjXCWdT7mOxXqQEQaqmHgKMx