Week 4
MESHING OF A BOTTLE CAP MODEL
Objective:
To create a 2D mesh for a bottle cap model with the given element quality criteria and to assign mid surface thickness to the shell elements using ANSA.
Methodology:
- Geometry cleanup
- Midsurface extraction
- Meshing as per criteria
- Assigning thickness property
Quality criteria:
|
S.No |
Quality Criteria |
Value |
|
1 |
Target/Average length |
1 |
|
2 |
Minimum Length |
.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 |
Procedure:
As the thickness of the bottle cap model is very less, we can do 2D meshing instead of 3D meshing.
1.Geometry cleanup:
The given model is performed with topology to view the cons properly.
Then it is subjected to geometry cleanup.
The errors are checked and fixed as shown in the figure.
2.Midsurface extraction:
The given model is complex and has variable thicknesses. Hence different mid surface extraction methods are adopted.
- Offset method:
Some of the parts of the model are subjected to an offset method to extract their mid surfaces.
- Multi middle option:
Some of the parts of the model are subjected to the multi middle option method to extract their mid surfaces
- Curve middle option:
The threaded part and some of the side features are captured using the middle option in curves.
While taking the mid surface, separate PID is assigned to the parts which is having various thicknesses value.
Mid surface extraction of bottle cap model:
The final mid surface of the model will look like as shown in the figure below.
3.Meshing:
The given element quality condition is entered into the quality criteria tab and it is saved.
The best mesh algorithm was used for meshing in order to get the proper good quality mesh.
Using commands like split, swap, etc in the elements module the trias in the model was reduced as much as possible.
The meshed model will look like as shown in the figure below:
Finally, the meshed model was viewed as solid using shell as solid option in the presentation tab.
Learning outcomes
- Able to fix the geometrical errors in the model.
- Mid surface extraction by offset and the multi middle option
- Assigning thickness value with the use of relevant PIDS.
- Elimination of all errors under given quality criteria.
Conclusion:
Thus 2D mesh is created for the bottle cap model according to the given element quality criteria using ANSA.