Week - 5 - 2D meshing for Plastic components

2D MESHING OF A BOTTLE CAP MODEL IN ANSA

Aim: To create a Mid-Surface and mesh with the given quality criteria and to make sure the element given is free from geometrical errors.

Objective: 1. To check the geometry error

2. To perform the topology clean up accordingly
3. To implement meshing according to the require quality criteria
4. No. Quality Criteria Value

1 Target/ Average Length 1

2 Minimum Length 0.5

3 Maximum Length 3

4 Aspect Ratio 3

5 Warping 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:

1. Importoing the CAD model from the from the desktop page as follow: Import the model from the file option bar -->new-->select the file from the particular location.
2. after importing the CAD model, first and for most need to check the material. This is done to check the whether the material is defined to model or not. This is done to check whether the material is defined to model or not. In the similar way find any error in geometry of the particular model as follow. There get a few geometry error, which is need to be fix. The geometry occurs due to cons in structure it may be single cons and triple cons. There are some open surfaces that are generating single cons and it is filled by building surfaces in FACES option.
3. Extracting the midsurface: Before extracting the mid-surface for the component, the thickness of each of the surfaces needs to be known. The thickness of the surfaces can be measured using the MEASURE command. By selecting the CONS/Curves option, the distance between two CONS or Curves can be measured and the thickness value is stored. Similarly, the thickness values are measured at various places in the CAD model. The mid-surface for some surfaces can be done using the FACES - > MIDDLE command. This command generally creates a middle face for the selected faces. Upon selecting the faces, the confirmation window will pop up. After accepting, the middle face is created between the two selected faces. This will serve as the midsurface for that part. in some places in case of simple structure FACES -> OFFSET. after extracting the mid surfaces each surfaces has to be assigned a seperate new PID with respective thickness.
4. Meshing the gemoetry using mesh module Meshing: mesh length, macros with mesh parameter and mesh quality criteria must be provided priior to mesh generation but since need to select the entire gemotry at once, need to utilize the same length for all of the geometry. mesh is generated in 1mm size. setting the mesh parameters as follows as shown in below: setting the quality parameters as shown: Best command is used to generate mesh at the sam% and tria element e time Quality check is performed on the generated mesh. mesh is gernated accordingly such that it obeys the required quality criteri. Parallely, mesh clean up is done using the combination of different commands. This way the meshing is done for all the surfaces. While meshing, the components need to be meshed one by one using their PID.
5. Error faced: there are many error faced but they were just simple topological errors and are solved with ease. the main errors are faced while meshing some components. the error are basically between ttriple cons of one features to another features. since ther features arde connected those elements can't be removed are changed. Conclusion - Here we can conclude that the bottle cap is successfully meshed after the geometry topo clean up in FEA software ANSA. Some elements were unable to acquire mesh quality as per the given quality criteria and failed to gain the feature due to minimum length, skewness which can be improved at the further stage before final analysis of the model.