Meshing an Automobile Hood Component

Objective:

To mesh the given hood part model respecting all the aforementioned quality criteria.

Procedure:

Step 1. Import the given STEP file geometry, delete the solids and then extract the midsurfaces for each component individually. The midsurface is extracted using "offset+plane+sweep" method.

Step 2. The topology repair or cleanup is performed using "autocleanup" option and again manually to suppress/unsuppress edges in the midsurface to maintain continuity as shown below and to add washer splits near holes.

Step 3. The given element meshing criteria is fed into the quality criteria parameters.

Step 4. The symmetry in the geometry (Inner and Outer Body Extracts) were studied in prior to meshing and the symmetrical halves were meshed and reflected according to the geometry.

In case of meshing the two instances of a single hinge component, the midsurfaces were extracted separately and meshing is performed on a single midsurface and was reflected and moved to the other midsurface.

Step 5. The parts are again meshed individually. The element densities are again modified to fit the curvature in the geometry. The free edges are then deleted.

Step 6. The failed elements are found under the quality index section. The failed elements are extracted alone by masking the rest of the elements. And the adjacent elements of the failed ones were unmasked and meshed again to achieve zero failure. The failed elements were also corrected using the "cleanup tools" options like Place Node, Node and Element Optimize, Combine and Drag Tria Elements and others. Opposite tria elements and rotating quads are undesirable for the stress-strain analyses, so they were gotten rid by implying the above techniques.

Step 7. The meshed elements failure and the gap or other discrepancies were also repaired using split, replace options. Also project to line and surface option and align nodes option were used to achieve a smooth uniform pattern of mesh flow.

Step 8. The remeshed elements were smoothened to achieve an uniformaity in the meshing pattern. The process is repeated until the mesh is successful with no discrepancy and the required meshing criteria are met.

Step 9. The elements are tested for equivalence, dependency, penetration and normal vectors checks and zero failure is ensured. The shrink element option is used to check the over lapping of remeshed elements and were cleared.

Step 10. The material and properties were created and assigned to the respective part components. Material assigned is steel and the properties assigned were element card image as shell and thickness as 1.5.

Result:

The elements were meshed to meet the specified meshing requirement criteria and no element failure is ensured, also respecting and adhering to the best practices.

The elements in the hemming region of the Outer Body Extract were expected to failed, as we try to capture the geometry and defeaturing the surface to eliminate the curvature will not follow the geometry of the component as this is an essential feature and not an aesthetic profiling or feature with no real purpose.

The # of trias for the entire meshing was 1.3%, well less and within the designated limit of 10%

The failed elements in the hemming region of the outer body surface, is unmasked and the consolidated element failure list.

The failed elements in the hemming region of the outer body surface is extracted out and displayed separately and the consolidated element failure list clearly suggests the failure in the above image is because of this only.

After masking the hemming region meshed elements, the element failure is zero.