Mid surface extraction and Meshing of a car hood model using ANSA

Objective:

To extract the midsurface and generate 2D mesh for the given hood component of a car according to the given element quality criteria using ANSA.

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

Introduction:

The component provided was Car hood in ‘STEP’ format. The hood has four separate parts such as outer hood, inner hood, hinge reinforcements and latch reinforcement. The thickness of each component of hood is uniform. Hence, the mid surface is extracted and 2D mesh is generated by satisfying the given quality criteria.

Geometry cleanup:

• The given component is checked for geometrical errors using checks manager.
• The errors displayed is cleared using auto fix and tools from hot points, cons, faces & surfaces

Midsurface Extraction:

• The midsurface is extracted separately for each component of the hood.
• The midsurface for outer hood, latch and hinges are extracted using tool midsurface skin option, since it had uniform thickness and less feature.
• The midsurface for inner hood is generated using tool offset option, since it had more fillet features.
• The midsurface of each component of hood is as shown in the following figures.

Outer hood midsurface:

Inner hood midsurface:

Latch midsurface:

Hinge midsurface:

Assigning shell property and thickness

• The midsurface of each component of hood are assigned with new PID’s.
• The thickness assigned for outer and inner hood is 0.75 mm and for latch, hinges is 1.2 mm.

Meshing:

• The quality criteria & mesh parameters values are entered.
• The perimeter length value assigned is 5 mm.
• Using best mesh option each macro area is selected and meshed.
• The quality criteria are achieved by using tools like cut, join, Num +/-, reconstruct, smooth and split options.
• The tria percentage is reduced by deleting unwanted construction lines without losing the feature.
• The smooth mesh flow is achieved by creating small macro areas and restructuring the mesh.
• The meshed model of hood is as shown in figure.

Outer hood meshed:

Inner hood meshed:

Latch meshed:

Hinge meshed:

HOOD MODEL MESHED:

Learning Outcomes:

• Learnt the usage of various tools of ANSA software.
• Able to fix the geometrical errors for given model.
• Able to extract midsurface and assign the thickness.
• Able to mesh the given model by satisfying the quality criteria.

Conclusion:

The given hood model of a car is imported to the ANSA software and the geometrical errors are fixed. The midsurface for each component of hood is extracted and thickness is assigned. The midsurface is meshed successfully by satisfying the quality criteria.