Week 7- Meshing of Backdoor Challenge

Aim

To mesh the given backdoor geometry with the size of 5 Units following the quality criteria using Hypermesh.

Procedure

Imported the CAD geometry using the import geometry option on Hypermesh. As it supports the .igs file hence the challenge .iges file is successfully opened. Chose the optistruct profile to carry out the preprocessing.

After opening the file in the components section it was seen that 190 components hence organized all the 190 components to a single component using Tools>Organize>collector>Selected all the components by collector>selected destination component>move. Then again segregated the the component into outer, inner and below panel based on the thickness which in turn helped working on the model more efficiently.

Before generating the midsurface it can be seen that there are cracks, missing surface, overlapping surface, damaged surface in the original component.

Hence carried the geometry cleanup for the whole component. Though we can generate midsurface and carry out geometry cleanup which will save much time. Used the toggle edge, filler surface, replace points, release points, project point, supress edge in Quick edit panel extensively with spline, ruled surface creation to perform cleanup. Used the visualisation tab to view the free edges.

Measurements were taken for the backdoor component.

Used the Geometry>midsurface>automidsurface>extract option with extraction options as "offset+planes" to generate the midsurface for the inner panel and for the outer and lower panel used the surface edit>offset option to generate the midsurface.

Hence the whole midsurface was generated.

Geometry checkup for the whole component is performed using autocleanup by providing the target element size as 5 in both parameter settings and criteria settings. Also used toggle, split, supress, replace edge options wherever required especially while removing some of the construction lines.

Also captured the filleted bead like structures at the center using split at its highest points and supressed the adjacent construction lines.

Now quality criteria is given in the question is as under:

Target Element size - 5 Units

S.N	Quality Criteria	Value
1	Aspect Ratio	5
2	Skewness	45
3	Warping	15
4	Taper	0.5
5	Min. Length	3 Units
6	Max. Length	7 Units
7	Min angle Quad	45
8	Max angle Quad	135
9	Min angle Tria	30
10	Max angle Tria	110
10	Tria %	15

Now quality criteria is provided for quality checks so that the component is devoid of quality issues so that boundary conditions and loads can be applied further.

Then went to the 2D option and clicked on automesh. Given the element size as "5" units and selected the mesh type as "mixed", selected all the sufaces of the misurface using surfs>displayed and then meshed the component clicking on the mesh command. Used the automesh and rebuild mesh command to achieve better mesh flow, used qualityIndex>cleanuptools> drag tria element, Combine, Split, replace to remove trias at the edges and the boundaries and also used this to combine opposite trias using combine option in the element edit option. After all these, viewed the component "By Quality Criteria" and used the quality index with Fail as a threshold and cleared the failed element quality using the cleanup tools>Element optimize, Place node, Node optimize, Replace nodes etc. At first meshed the lower panel. Also used the node edit>align option to allign the ndes wherever required.

Outer panel:

As the inner panel component is symmetrical so we can mask one half of the total surface and work with another half and finally we can reflect the other half elements. This will save a lot of time. For this at first used the quickedit>split with line to create a cut along the symmetry and then used the tools>mask and deleted one half of the geometry.

Meshed the inner panel half:

After checking the dependency, penetration and geometry procedded further to reflect the other half elements of the inner panel. Before reflecting the elements at first the elements were duplicated. After this the identical parts are refleted to the other side by using Tool>Reflect>Elements-Displayed>Direction>base node>reflect.

To verify the connection between elements and generate the connection found the free edges, previewed equivalence and finally provided equivalence between the nodes respectively by using the Tool>Edges>Elements>Find edges>Elements>Preview Equivalence>Equivalence(Tolerance value between 0.1 to 3).

After this used Tool>Check elements>Duplicates>Save failed>mask-element retrieved>reverse>delete to find out the presence of duplicate elements and delete them respectively.

Viewed all the elements in component mode and under quality index tab:

Created a property and material for the midsurface component and provided the thickness as 0.75mm, 0.6mm and assigned the material and property to the midsurface component so that the component and mesh can be viewed with 2D detailed representation.

Viewed when "2D detailed element representation" option is turned on:

When viewed with quality criteria:

Learning Outcomes

At the end of this challenge I am more familiar with Hypermesh workflow, can perform cleanup, can generate mid surface, can perform defeaturing, can generate mesh with the given quality criteria.

Conclusion

Hence, the given backdoor component with target element length of 5 Units is meshed with the given quality criteria using Hypermesh.