Project-2-Meshing of Door Inner Panel Challenge

AIM :

To extract mid-surface, geometry clean up and create the shell (two dimensional) mesh for the given side door inner panel according to the given quality criteria by using HYPERMESH.

THEORY:

Door inner panel:

• Door panels serve as an interface between the interior of the car and the inner workings of the door, and between vehicle occupants and the door.
• They are expected to meet a variety of design specifications regarding safety, aesthetics, and functionality. In addition, they are expected to continue the material theme of the dashboard and pillars while concealing intricate electrical and mechanical components for operating locks, windows, and other features.
• The door panel has evolved from a simple two-part system of the latch and simple winding mechanism to a more sophisticated enclosure.
• Doors currently have an inner full-width panel consisting of electronic windows, a central locking system, and speakers. These panels typically consist of a foamed core covered with either textiles or plastics.

Objective

• Import and perform a geometry cleanup on the given model using Hypermesh.
• Assign thickness and generate a Proper mid-surface with the proper technique.
• Mesh the generated mid-surface and reconstruct the mesh to satisfy the following quality criteria.
• Model Checks

Quality Criteria

Target Element Length = 4 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	6 Units
7	Min angle Quad	45
8	Max angle Quad	135
9	Min angle Tria	20
10	Max angle Tria	120
10	Tria %	10

Fig 01: Isometric View Of Model.

3. Procedure

Step 1: Importing the File

• First We have to import the file to hyper mesh. Here, the file is in IGES and STP format.

Step 2: Geometric Cleanup and Extracting Midsurface.

• We can see that thickness is not constant throughout the geometry by taking thickness measurements. So given geometry is a plastic model. After the geometry cleanup, try the Manual mid-surface option to extract the mid-surface.
• The extracted mid-surface has issues like missing surfaces, orientation, and mismatching surfaces.
• These issues are addressed by commands like 'Split Surf Line, Toggle Edge, Filler Surfs, Delete Surfs, Extend Surf, Offset, Ruled, Project, etc. After that, the mid-surface is generated and it is ready for meshing.

Fig 02: Mid Surface Extraction

Step 3: Property, Material, Measuring Parameters and Quality Criteria

• This is a plastic model, which means that there are components with different thicknesses.
• So organise those components separately and assign properties based on thickness. Create material, and add Quality Criteria and Measuring Parameters.

Fig 03: Property and Material

Fig 04: Quality Criteria

Step 4: Meshing the Surface

• The meshing is carried out the surface to surface. Also, adjusting the number of nodes for good mesh flow.
• 2D >> Automesh >> Select Surface >> Ok.
• The mesh flow should be improved especially in feature areas. For that, we can use these functions,
• 2D >> Rebuilt >> Select the mesh elements which to be reconstructed.
• 2D >> Edit element >> Create/Combine/Split

Fig 05: Generated Mesh

• After correcting the mesh flow, the element quality should be checked.
• 2D >> Quality Index >> Cleanup Tools
• Using the following tools, Place nodes/Smooth/Modify holes and washers/Split and Collapse Edge/Swap edge/Drag tria element/node optimise/element optimise/split quad element/combine tria element, we can simply modify elements to obey element criteria.

Fig 06: Quality Index

Fig 07: Final Mesh

Step 5: Model Checks

• Check For Free Edges And Equivalence
• Tools >> Edges >> Select Elements >> Adjust The Tolerance Value (~0.10) >> Find edges. >> Delete Edges >> Preview Equivalence >> Equivalence.

Fig 08: Model checks

Check For Connectivity and Duplicates

For Connectivity

• Tools >> Check Elements >> 2D >> Connectivity.

For finding duplicates,

• Tools >> Check Elements >> 2D >> Duplicates.

Fig 09: Connectivity and Duplicates

Fig 10: Final Result