Week 12:Project 2-Meshing of Rear Wheel Holder challenge

AIM:

• To perform preprocessing on the given rear wheel holder sheet metal component using hypermesh preprocessing software

OBJECTIVE:

• To generate the mid surface manually and do a geometric cleanup on the component
• To generate mesh flow and to get proper mesh flow on the given component with low tria concentration
• To check the element quality according to the given quality criteria
• To assign a thickness for the component

PROCEDURE:

1. Import:-

• Import given cad model into hypermesh

• switch to the topo mode and examine whether the solid exists in the component or not, if solids exist, delete the solid

• we need to check whether any errors in geometry
• clear the free edges in the body then only we can extract mid surface properly

2.Mid surface:-

• Organize into a single component and delete the unnecessary component
• we need to measure the thickness of a given component to check whether all region is uniform thickness is .75mm
• Extract mid surface using auto mid surface option by offset + planes + sweep

• The middle surface is assigned to a new collector

3. Geometry cleanup:-

• Fix geometric deformation in certain areas by deleting the surface and recreating a new surface there
• Fix all connectivity issues by repacing edges with a suitable tolerance

• Do geometric cleanup on mid surface
• check for free edges, if any toggle them and remove it
• Fill the surface with filler surface option
• The split surface line to create split on the surface by node and to line
• Project point to project a point to another line
• In quick edit panel, mostly used tools - toggle edge for toggling
• Add remove point for add and removing points
• Replace point to replace one point to another
• Split surface node to create split on the surface by nodes
• some surfaces are done by ruled option in surfaces
• Delete pinholes

• All geometric cleanup is completed then go to meshing

4. Meshing:-

• Enter the quality criteria as given and save the criteria

Target Element Length = 5 Units

S.N	Quality Criteria	Value
1	Aspect Ratio	5
2	Skewness	45
3	Warping	15
4	Taper	0.5
5	Min. Length	2 Units
6	Max. Length	8 Units
7	Min angle Quad	45
8	Max angle Quad	135
9	Min angle Tria	20
10	Max angle Tria	120
10	Tria %	10

• start manual meshing from the center region and spread to geometry

• while meshing do partitions on geometry and mesh manually to improve quality of mesh flow
• Use rebuild mesh after meshing to get good mesh flow with minimized tria, algorithm behind rebuild mesh give you better mesh flow
• Set critetia for rebulid mesh

• Eliminate opposite tria , trai on edges,trias on fillets, rotational quads
• In converging areas, we get more tries

• Reflect certain symmetric geometry to save time

1. Eliminate element failure:

• Use options quality index to eliminate failures
• Especially drag tria for removing tria
• Swap edge to move tria
• Split collapse edge
• Element optimizes for optimizing elements
• smooth for smoothing
• combine tria to combine adjacent tria
• After every meshing is done smoothing properly for proper mesh flow
• To eliminate warpage we want to translate most deflected node from plane to inwards the plane
• To eliminate the max quad, minimum quad and trais are by going to distance and set the angle per criteria

• By doing repeated operations and eliminations of failed elements finally, we got all elements passes quality criteria

i

Cheak for tria %

5. Checking for free edges and normals:

• Check for the free edges from the tools+edges.

• For normal go to tools+normal, adjust normals.

6. Assign dummy material and property:

• Create a property for the component, and assign it to mesh.

• The thickness of the part is uniform so give a thickness of 0.75mm in the property.