Week - 5 - 2D meshing for Plastic components

Meshing Of Plastic Components - ANSA Week 5 Challenge

1. Aim

• To Generate a mesh on a given Plastic Bottle Cap model after a proper geometry cleanup and mid-surface generation using 'ANSA' Preprocessing Software.
• Ensure the generated mesh obeys the mentioned quality criteria and the corresponding thickness of each surface assigned to the mesh.
• After meshing, Complete the PID and thickness assignment of the model.

2. Objective

• Import and clean up geometry on the given Plastic Bottle Cap model using ANSA GUI.
• Generate a Proper mid-surface with the proper technique.
• Mesh the generated mid-surface and reconstruct the mesh to satisfy the following quality criteria.
• Complete the PID and thickness assignment of the model.

Quality Criteria

Sl No.	Quality Criteria	Value
1	Target/Average length	1
2	Minimum Length	0.5
3	Maximum Length	3
4	Aspect	3
5	Warpage	15
6	Skewness	45
7	Jacobian	0.7
8	Minimum Quad Angle	45
9	Maximum Quad Angle	135
10	Minimum Tria Angle	30
11	Maximum Tria Angle	120
12	Tria Percentage	15

Fig 1: Isometric View of Model

3. Procedure

Step 1: Geometric Checkup of Plastic Bottle Cap Model.

First, the model is imported and loaded on ANSA v22.1.0. The model contains only one PID. After that, the TOPO operation is carried out to convert all single CONS into double CONS. After the TOPO, the geometry cleanup proceeded.

In this model, there are a few errors that can be fixed automatically by ANSA. Apart from that, the geometry is clean.

Fig 2: Successful Geometric Checkup.

Step 2: Proper Mid-Surface Generation of Plastic Bottle Cap Model

Taking measurements of thickness in random parts of the model gives random values of thickness, which concludes that it is a plastic model. So we have to try manual mid-surface generation techniques for the model. Based on the shape and conveniences, we have to use different techniques for the mid-surface generation. Each part needs a different kind of operation for the extraction of the mid-surface.

• Faces >> Middle >> Single/Multi >> Selecting faces according to the order gives us the mid-surface of that part
• Faces >> Offset >> Selecting the faces and the offset value
• Faces >> Extend >> Selecting CONS and faces will extend the CONS to that face.
• Utilities >> Rotate >> Copy and it can be used where symmetrical macros are aligned in a circle.

These are the main tools used in this model for the extraction of mid-surface. Also Cut, Project, Curve >> Middle, Points >> ON COG, Delete, New, Topo and other tools are used in the process. By combining and using these tools the mid-surface of the model gets extracted.

Fig 3: Mid-Surface of Plastic Bottle Cap Model

Step 3: Adding Quality Criteria and Meshing

After the mid-surface generation, we have to add target/average length and other quality parameters in ANSA. Try a suitable mesh generation mode for the meshing operations. In this case, Best, Spot, and Free Mesh techniques are used.

Fig 4: Quality Criteria and Mesh Parameters

Try a suitable mesh generation mode for the meshing operations. In this case, Best, Spot, and Free Mesh techniques are used. As a result,

Fig 5: Meshing

Here, 60-off elements cannot be fixed, because of the presence of triple cones between the surfaces.

Step 3: PID Setting and Thickness Assignment

Because it's a plastic model, the thickness assignment and PID setting should be carried out. Every mid-surface should have PID based on its thickness. Also, compare it with parent geometry with the help of the 'Draw Shell As A Solid' option in the quality criteria tab.

No.	PID	Thickness
1	36030	1.22
2	36031	1.34
3	36032	1.58
4	36033	1.53
5	36034	1.78
6	36035	2.25
7	36036	1.05
8	36037	1.14
9	36038	0.83
10	36039	0.63
11	36040	0.86

Fig 6: Final Result

4. Result

• The meshing of the Plastic Bottle Cap Model is completed and every element/shell in the mesh is.
• Proper PID Setting and thickness assignment are completed.
• The mesh consists of a total of 8127 no. of shells and it includes 7850 quads and 277 trias.

5. Conclusion

• The given Plastic Bottle Cap Model meshing is completed as per the quality criteria mentioned. The meshing is done after the successful geometric clean-up and proper mid-surface generation for the Plastic Bottle Cap Model. Also Completed the comparison between the parent geometry and the mid-surface.