2D meshing and modelling of car hood geometry

OBJECTIVE: To model the given Hood geometry using 2D Mesh and achieving the following criteria.

QUALITY CRITERIA:

PROCEDURE:

1. Import the Hood CAD Model in Hypermesh.

    The Model consists of 6 Components: Inner Body, Outer Body, Hood Body 1, Hood Body 2, Wireframe, Hood Wireframe.

    The Inner body and outer body is symmetric about y-axis and the model as whole is symmetric.

2. Delete the solids first and perform topology cleanup for each component and generate the mid surface of each component seperately.

    Perform topology cleanup on every components mid-surface as well as it my miss some surfaces and toggle unnecessary edges.

    The mid-surface should be an exact replica of the geometry.

3. Since the outer body and inner body are symmetric about y-axis, we can perform meshing operation to only half of the symmetrical component.

    Latter half can be meshed by creating a reflection of the elements of the meshed half using reflect command.

4. Set quality criteria for meshing as shown.

    While meshing try to avoid rotational quads, fixed trias, tria elements touching edges, two trias touching each other, opposite trias in a component.

    Also try to minimize the number of of violations in quality.

5. Mesh of midsurface of Hood_Body_1 and Hood_Body_2component is shown.

8. Mesh of Outer body half is shown.

7. Split surface o Outer_Body into rectangular boxes for appropriate mesh flow and suppress the other edges. This operation can be done using toggle edge command.

    While meshing the outer body the hemming part of body will fail for minimum element size criteria.

    Change the option to keep mesh from advanced mesh while meshing.    

9. The other half mesh of outer body can be created by performing reflect command.

    Tools > Reflect > Select the Hinge 1 lements > duplicate the elements > select y-axis > select base node > Reflect.

10. Mesh for Inner body half is shown.

    The other half can be reflected by using reflect command. For the keyhole portion which does not comes into symmetry, remeshing has to be done on the connecting surfaces.

11. The overall mesh of the model components is shown.

12. After meshing check for normals of each component.

    Tools > Normals > Display > Vesctor Display > set magnitude to 10 > Display. The entire normals should be in one direction only.

13. Check for Dependency.

    Tools > dependency > Elements > select elements > All Displayed > Dependency.

14. Check for penetration.

    Tools > Penetration > Elements > All > Check. check tab tree for results.

15. Keep checking for Free Edges and Duplicates in the components. Also keep checking for criteria qualifcation of every part before proceeding in the adjascent surfaces.

RESULT: 

1. The hood model was meshed to qualify the required quality criteria.

2. The features of the components are captured properly in the mesh.

3. Mesh flow is well organized.

OUTCOMES:

1. Learning Geometry cleanup and Element Cleanup tools.

2. Learning to mesh complex geometry (capture surface features) and learn new tools in Hyperworks Software.

3. Setting and clearing the quality criteria of the model.

4. Learning to check for duplicates, Free edges, Normals, Dependency, and penetration.