Week - 4 - 2D meshing for Plastic components

AIM:

• To do a pre-processing on a given bottle cap model using ANSA.

OBJECTIVE:

• To check the geometrical error on the Bottle cap model.
• To extract a mid-surface of the Bottle cap model.
• To generate 2D mesh on the components based on the quality criteria given.
• Assigning thickness to the components.

PROCEDURE:

IMPORTING THE CAD MODEL:

• The CAD model is imported into the workspace by using file > open and select the CAD model.
• The model will be imported into the workspace.
• In ANSA we can import all types of CAD software file formats.

GEOMETRY CLEANUP:

• Before working on the model we need to check whether the model has any geometrical errors.
• To check the geometrical errors go to check manager that is available at the tool bar.
• In the check manager select geometry and click execute.

• After clicking on the check geometry the geometrical errors will display.

• The geometrical errors can be fixed manually or automatically.
• In our case we fixed the error automatically by right clicking on the error and click fix.
• Once the model has no error it will show green status in the above image and we can proceed further.

MIDSURFACE GENERATION:

• For extracting Mid surface various tools like Faces > offset, Faces > middle, Faces > mid surface > casting are used to create mid surface automatically and manually.
• The automatic mid surface extraction is not working in this case due to complex features present in the model.
• So in this case manual mid surface extracting tools like offset and middle is used.
• To extract mid manually go to faces > offset

• Select the component faces and give the offset value and click middle mouse button.
• This will convert the solid model into a thin shell components.
• Then the mid surface is extracted by using AND and INOT tools available in ANSA
• The procedure is repeated for all the features to extract midsurface.

PROPERTY ID CREATION:

• Then the property id is created for the mid parts by going to set PID and select the surface and give the thickness value and click ok.
• Then go to property id manager and right click the PID and click apply.

2D MESHING:

QUALITY CRITERIA:

• Go to quality criteria that is available in tool bar.
• The criteria that is given in the question are selected and given the value and clicked apply and ok.

• Then the values of mesh parameters are entered.
• For that go to mesh parameter tool that is available in the tool bar of ANSA.

• Then the meshing is done using mesh generation > best tool. This tool generates the mesh using the best algorithm applicable.
• Then the created mesh is refined using the shell mesh > improve > reconstruct, smooth, reshape tool in mesh module of ANSA.
• It is ensured that there are no rotating quads.
• The trias are kept as low as possible.

• Finally after creating the mesh and clearing the quality criteria the shell element representation is changed by going to utilities> quality criteria> presentation parameters and enabling the draw shell as solid.

• Draw shell as model will add thickness to the model with the thickness that is provided in property ID.
• Then the final model will look like the image as shown below.

RESULT:

• Hence the mid surface has been extracted from the parent geometry.
• Hence there are no surface deformations in the geometry.
• A well connectivity has been established between surfaces.
• The features have been captured properly.
• A good mesh flow has been achieved.

CONCLUSION:

Geometry cleanup, mid-surface extraction and 2D meshing of the given Bottle Cap model were successfully done.