Week 4

Plastic Bottle Cap Meshing

Objective : To mesh the bottle cap model for the given quality criteria.

The model is imported on to the GUI of ANSA.

Quality Criteria :

Target Element Size: 1

S.No	Quality Criteria	Value
1	Min Length	0.5
2	Max Length	3
3	Aspect	3
4	Warpage	15
5	Skewness	45
6	Jacobian	0.7
7	Min angle Quad	45
8	Max angle Quad	135
9	Min Tria Angle	30
10	Max Tria Angle	120
11	Tria Percentage	15

Procedure :

Step 1 : Import the model onto the ANSA GUI.

Step 2 : Check for topological errors in the model. We can resolve the topological errors automatically.

Step 3 : Now we can go for Mid Surface Extraction. The Mid surface extraction can be done automatically or manually . Whichever suits best for the model. This factor is based on the complexity of the model.

Reason for extracting the mid surface -> If we mesh entire component in 3D the number of elements , number of nodes will increase which in turn increases the time frame in processing because of the increased complexity which makes it difficult for the engineers to analyze the model.

For this model the mid surface was extracted manually.

• Generally the plastic models will be having multiple thickness in different areas of the model.
• The mid surface is extracted manually by using offset option from the faces module buttons.
• After extracting the mid surface we check of for topological errors through check geometry from tools and fix the errors if there are any.
• Triple coons will be formed on the surface.

Step 4 : Assign the property to each component based on the thickness of the parent geometry of the component.

Step 5 : To start meshing.

Reason for meshing -> Discretization process is done to convert the infinite number of points to a finite number of nodes.

To carry out meshing there certain quality criteria that are necessary for the meshing to be good , so we assign those quality criteria’s as mentioned above.

• The “best” meshing option is used in meshing the components from the mesh generation module buttons.
• The “best” is chosen because it chooses the best suitable meshing algorithm available from ANSA and deploys it on the components.
• The meshing is carried out by area to area to keep the possible errors at minimal.
• After the completion of we try and resolve the errors and reduce the number tria elements.

• We also use reconstruct , smooth , split , join ,reshape options from shell mesh module buttons to resolve the elemental errors present on the mesh.

There will be few off elements present in the mesh because of the triple coons in some areas and the complexity of the model.

Observation : The modeling and meshing of the Bottle Cap is done with minimal possible off elements and low trias concentration.