Week 3-Meshing of Hood Challenge

1. Objective:

• The objective of this challenge is to meshing a car hood in Altair HyperMesh is a crucial step in preparing the model for Finite Element Analysis (FEA).

2. Import Geometry

· Load the model in HyperMesh Using Import > Geometry

· Using .iges, .stp , etc files

3. Geometry Check

· Green edges: shared edges (OK)

· Red edges: free edges (need fixing)

4. Cleanup techniques

· Fill holes: Fill missing surfaces using the filler surf tool

· Toggle edges: Converts free edges to shared by updating topology

· Auto Cleanup: Automatically removes small surfaces, edges, holes, damaged surface, replace the lines

5. Final Geometry check for mid surface

· No free edges

· No duplicate surface or overlapping surface

· Continuous geometry

· All free edges removed (only green edges present).

· Surfaces are properly stitched and continuous.

· Mid-surface accurately represents the original geometry.

· Suitable for 2D shell meshing.

6. Mid Surface Extraction

· Ensure geometry is clean

· Uniform thickness should be followed

· There should not damaged faces

As shown below

7. Auto Mid Surface

· Geometry > Midsurface > Extract

· Input : Sheet metal model

· Tool automatically extract mid surface from solid surface

· Give offset direction

8. Meshing Parameters defining

· Choose element type and target mesh size. A car hood typically uses 2D shell elements

· Element type: 2D Shell Elements (quad-dominated mesh)

· Target element size: 5–10 mm depending on analysis requirements

· Quality criteria :

ü Aspect Ratio – 5

ü Skewness – 45

ü Taper – 0.5

ü Min length – 2

ü Max length - 8

ü Min quad angle – 45

ü Max quad angle – 135

ü Min tria angle – 20

ü Max tria angle – 120

as shown below

9. Surface Meshing

· Go to: 2D > Automesh

· Select surfaces of the hood (outer and inner panels)

· Set : Mesh type: Mixed

· Mesh size: 5mm (example)

· Elements to surfce

· Click Mesh and inspect the result

10. Mesh Quality Check and Cleanup

· Go to Tool > check elems > checks

· Check for Free edges, T Junction

· Element quality : Aspect ratio, skewness, min, max length etc

· Fixing the quality node optimization , split, combine, smooth, replace, etc

· Finally the mesh is done with better mesh flow.

· As shown below;

11. Conclusion

· Meshing the hood in HyperMesh involves geometry, mid-surface extraction, controlled 2D meshing

· Assignment of accurate material and thickness properties.

· Good mesh quality and proper organization are critical to ensure reliable and accurate FEA results.