Project-2-Meshing of Door Inner Panel Challenge

AIM: The main aim of this challenge is to mesh the given side door model as per below element quality criteria.

OBJECTIVE: The objectives of this challenge are as follows:

1. To perform geometry clean up and generating mid surface for the given plastic component.

2. To mesh the given component with less tria concentration and good mesh flow.

3. Finally all the elements should pass for given element quality criteria.

PROCEDURE:

1. The CAD file in Hypermesh can be opened by selecting import model option.

2. The parent geometry of the plastic model is shown in the below figure.

3. After opening the file, manual cleanup was performed to remove free edges and non- manifold edges.

4. Several commands like split surface, toggle edges& delete surfaces were used from quick edit sub panel (GEOMETRYàQUICK EDIT). Where ever it was necessary and possible to remove the free or non-manifold edges, all those edges were corrected.

5. After removing all the free edges and non-manifold edges by manual cleaning, mid- surface for base surface was extracted using manual offset method by giving offset distance as 1.4 units. (GEOMETRY à SURFACE EDITà OFFSET).

6. All the mid-surfaces of the features that were attached to the base surface were taken by using several options like surface pair (GEOMETRYàMIDSURFACEàFINAL EDIT TOOLSà SURFACE PAIR), by creating a midline (GEOMETRYàMIDLINE) and surface (GEOMETRYàSURFACE). For extending the feature surfaces on to the base surfaces surface edit panel (GEOMETRYàSURFACE EDIT) commands were used.

7. After mid surface extraction, meshing was performed using auto mesh command by importing the quality criteria (2DàAUTOMESH).

8. Elements failing at the critical features were then corrected using commands like split quad element, swap edges, element optimize, node optimize, smooth etc. from quality index sub panel (2DàQUALITY INDEX).

9. Where ever the base surfaces are getting distorted because of the feature surface extension, in those places only mesh of the features was extended on to the mesh of the base surface.

10. The final components after meshing is shown in the below image.

CHECKING: After finishing the following checks must be performed:

1. Checking for free edges in the component to ensure nodal connectivity. If any free edges are present in the middle of the component, those free edges can be removed by equivalence option or pasting the nodes manually (TOOLSà EDGES).

2. Checking normals (TOOLSà NORMALS) of the elements to ensure a consistent normal is maintained for the given component. If normal of the elements were not consistent then they were adjusted using adjust (TOOLSà NORMALSàELEMENTSàADJUST) option.

3. To find whether a proper contact has been established between elements and surfaces, we must do surface comparison (GEOMETRYàCHECKàSURFACEà COMPARISION).

4. Check for penetrations and dependency.

5. After all the checks, finally automatic thickness (MESHàASSIGNàMID MESH THICKNESS) was assigned to the elements. Select surfaces (parent geometry) and elements (all elements) and click on calculate thickness by setting the range interval. Manual thickness was assigned to the some of the features Where ever the thickness of the mesh was not matching with the parent component.

Note: As per the given question, area shown in the below image is not modeled.

CONCLUSIONS:

1. Learnt about geometry clean up and extracting the mid surface manually.

2. Learnt about how to mesh a component for a given quality element criteria.

RESULTS:

Geometry cleanup, mid surface extraction and meshing of the given component was done successfully. Trias % was limited to less than 1%.