2D Meshing in Hypermesh

Objective: To perform 2D meshing on the given models.

Procedure:

Model 1:

1. Import the given model into hypermesh.

Fig 1: Given Geometry.

2. By setting the component by topo in the visualization setting, the free edges are visible in red color.

Fig 2: Free edges in red color.

3. The free edge along the fillet and the free edge on the circular surface of the component can be manually done by unsplit/filler options in the quick edit in the geometry menu. By selecting a single free edge, automatically fills the surface, creating a uniform surface.

4. Few edges can be toggled with eliminated the free edges in the geometry.

Fig 3: Quick edit options where toggle edge, filler, and unsplit options are located.

Fig 4: Resolved all the free edges.

5. Trail and error method was done while extracting the mid surface from the component with various extraction options and finally performed "skin offset" extraction method, which yields best mid surface for this component.

Fig 5: Options for extracting mid-surface.

Fig 6: Extracted mid surface.

6. The given element quality criteria are set in the preferences.

Fig 7: Given quality criteria.

7. In the model, few fillet areas must be defeatured; if not, elements won't satisfy the criteria set. To defeature the fillet surfaces, navigate to the defeature option in the geometry menu and enter a value of 0.1 and 3.5 in the minimum and maximum value boxes.

Fig 8: Options for removing fillet surfaces.

Fig 9: Detected fillet surfaces.

Fig 10: Fillet surfaces are removed.

8. Holes with less than 5mm diameter are removed from the surfaces using the unsplit surface option in the quick edit.

9. After the mid-surface is cleared of all the geometrical issues, meshing can be performed. The target element size is five units.

Fig 11: Options for creating mesh on the surface.

10. For achieving proper mesh flow, necessary splits are done on the mid surface in a rectangular manner. With the help of quick edit options, unwanted surface lines are toggled, and new ones are created with node to node or with node to line commands. Auto mesh is generated in each of the rectangular boxes, with five units as element size and mixed element type. Since the rectangular sections are made, all quad elements will be generated if any tria is formed in a particular area. They can be removed either by remeshing or with cleanup tools in the quality index. Other than these options dragging trias out of the mesh, combining two opposite trias, splitting, combining, and creating elements, generate maximum quads and least tria elements.

11. Smoothing and element optimization is done to ensure proper flow and orientation of the mesh. Finally, element check is done.

*** While doing splits in the surface, the features should not be altered drastically, and few feature edges cannot be suppressed because it disturbs the mesh, and element failure happens at those regions. Some of the feature edges should be preserved, and additional lines must be created accordingly.

When tria elements are formed, surrounding elements are selected along with the tia element and meshed again. It may be possible to remove the tria and create a quad element. Again this is a trial and error method to remove tria elements from the mesh. We aim to reduce trias as much as possible because tria elements are stiffer than quad elements; the presence of trias may result in inaccurate results.

Fig 12: Elements check with the quality index.

Fig 13: Generated mesh on the component.

12. A new property is created to give thickness for the mid-surface with PSHELL as card image, and appropriate thickness for the component is entered.

The same procedure is followed for the other two models.

Conclusion: 2D mesh is generated on the given components with a five units element length.

Fig 14: 2D detailed element representation of the component.

Fig 15: 2D detailed element representation of the clip.

Fig 16: 2D detailed element representation of the mounting bracket.