Week - 5 - 2D meshing for Plastic components
Aim:
To extract the mid-surface of the given plastic component and geometry cleanup for the 2D mid surface meshing.
Procedure:
1.Import the given plastic model into ANSA workspace.
To import the model, go to FILE > OPEN > select the model and ok.
The given plastic component is shown in below image.
After the model import switch on all the cons in the model by switching on all the options in the FACES DRAW bar. This will help in viewing the surface connection in a deatail.
2.Geometry check and mid surface extraction.
It is time consuming to check the surfaces of the model manually, so to speed up the geometrical check up checks option from tools is used TOOLS > CHECKS > GEOMETRY > EXECUTE
The model has some minor errors which can be fixed automatically fixed.
SELECT THE ERRORS > RIGHT MOUSE CLICK > FIX, this will clear the errors, if errors still exist, manual cleanup needs to be carried out by releasing the cons and fixing the damaged face and performing the topo to fix the free edges.
Mid surface extraction.
Before mid-surface extraction check the thickness of the component if it has a varying thickness, then the best way to extract the mid-surface is by manual mid-surfacing.
When the model has varying thickness ANSA algorithm fails to capture the proper geometry, hence the manual mid-surfacing is carried out.
To measure the thickness go to UTILITIES > MEASURE > select the points.
The given model is a plastic component that has a varying thickness, hence manual mid-surfacing is performed, by extracting individual mid-surface form faces of different thicknesses.
It helps in cutting the faces passing through each other, it creates a cut on the faces which are intersecting each other
For parts with varying thickness, cons are used to create the middle curve and using the middle curve mid face is generated using FACES > NEW
After creating the mid surface, divide the mid surface and apply the appropriate property with thickness to both the faces
final mid-surface with varying thickness property cards apllied to the mid-surfaces.
Geometry cleanup for meshing the generated mid-surface, Run the geometry check again on the mid-surface and fix the issues
3.Property ID’s creation and application of property id’s
To create property go to LISTS > PROPERTIES > RIGHT MOUSE CLICK > NEW > PSHELL > PSHELL.
Since the elements used are 2D shell select PSHELL.
Apply the thickness value and select the faces to apply the property to the faces.
4. Quality criteria setup and Meshing.
set up the quality criteria for the meshing, go to UTILITIES > QUALITY CRITERIA
To start the meshing switch to Mesh module bar in the modules menu bar
some of the most used options in meshing process are highlighted in the below image.
Using these common parameters repeatedly a 2D mesh passing all the quality can be generated, to start meshing the surface go to MESH GENERATION > BEST and select the surface to be meshed.
the number of tria elements in the model is below the threshold value of 15% with just 135 tria elements in the model.
5.Quality check.
The meshed part can be checked for quality criteria by switching the drawing styles to hidden modehe meshed part can be checked for quality criteria by switching the drawing styles to hidden mode, at some areas where two different triple cons are present the elements fail due to minimum element length which can not be solved, hence there are some off elements present in the mode
cons too near to eachother elements failuer can not be avoided in thses areas.
final element quality.
total of 5 elements have failed for the quality criteria which accounts to 0.05% of total elements.
Drawing shell as solid and checking the applied thickness to the master model.
from the above images it can be seen that the entire geometry has been captured with proper thickness values.
Learning outcomes:
Mid-surfacing of plastic components, manual mid-surfacing, varying thickness application
Conclusion:
Generated mid-surface for the given plastic component and 2D meshing is performed on the midsurface and property cards with different thickness are created and applied to the appropreate faces.