Project 1 - 2D meshing on the instrumental Panel

Aim:

To generate mid surface for the given component after verifying the geometrical errors and to do 2D mesh on the generated mid surface by satisfying the required Quality criteria.

Procedure:

Since the component given has thickness less than 5mm, 2D meshing can be done.

Import Geometry:

Go to File > Open > Select file to import

Topology clean-up:

• Initially when the model is opened, perform Checks > Geometry on each and every component that are present in the model to make sure there are no irregularities present.
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• If any errors occur, we can use Auto fix to solve them or do it manually by using various commands in the Topo deck.
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• After the geometry check is done, Measure command is used to estimate the thickness of the components.
• At times when some of the features are not appearing in their original form, the Auxiliaries > Fine command can be used to increase the resolution at that particular area and check the original shape of the feature.
• Then, the Faces > Orientation command is performed to make sure that all the faces are in same orientation (i.e., positive or negative).

Mid-surfacing:

To generate midsurfaces, various methods are available in ANSA. For this model, I have used Faces > Offset, Faces > Middle and Middle curve options.

Faces > Offset was used for those large and simple surfaces, Face > Middle was used for the ribs and the Middle curves were used to generate midsurface for the doghouses.

Geometry check can be performed once again to eliminate any errors that are present.

Defeaturing:

• Switch to Mesh deck.
• Go to Perimeters > Length and Enter the mesh size as length.
• Perform Measure command at minute edges and make sure it is closer to required mesh size.
• We can use Macros > Cut to split any large surfaces or to simplify the complex surfaces.
• After performing Cut operation, use Hot points > Insert to remove the excess Hot points.
• Always capture the peak of the bead & fillet (using Cut option).

Define Quality Criteria:

Firstly, Open Mesh parameters and enter appropriate values. Then Press F11 to open Quality criteria window. Then, Select and define the required criteria.

Meshing:

For this model I have used 2 different meshing algorithms such as Best Mesh and Batch mesh. It was a trial and error approach. For all the complex areas, I isolated the surfaces and applied batch mesh. If it turned out that the batch mesh had not generated a good quality mesh, then I had proceeded with the Best mesh algorithm. Most of the complex areas were meshed with batch mesh, as it would help save some time by defeaturing the unnecessary macros. All the larger and simpler macros were split into smaller macros and were meshed with Best mesh.

Meshing procedure:

• For meshing the surfaces, Use Best Mesh/Batch Mesh algorithm from the Mesh generation panel.
• Always start meshing from the features.
• To view the mesh quality, Toggle Hidden mode.
• Use Shell mesh > Reconstruct to reform the mesh elements.
• Use Shell mesh > Smooth to smoothen the mesh element structures.
• To copy the mesh generated on the features to other identical features, use Transform > Copy (delete the unmeshed identical features before using Copy option since it'll copy along with the geometric surfaces).
• Perform Topo after copying.

 Some of the basic conditions to be kept in mind while meshing are as follows:

• No Tria elements should be present at the perimeter and the holes.
• No Tria elements should be connected back-to-back or present opposite to each other.
• No Tria elements should be on the features and fillets.
• Max no. of elements should be perpendicular to each other (Minimise wavy mesh flow patterns).

Mesh Flow Correction:

• Use Elements > Split command to move the Tria elements forward.
• Use Elements > Swap command to move the Tria elements sideward.
• Use Grids > Paste command to move the Tria elements backward.
• After meshing, Reconstructing & smoothing operation are completed, Use Macros > Join (change Reconstruct to Keep in options list).
• Stitch all the independent feature meshes using Paste option.

Learning Outcomes:

• Gained better fluency with the ANSA GUI.
• Acquired aptitude on identifying and improving failing and bad quality elements.
• Learnt to use the different midsurfacing and mesh approaches.

 Conclusion:

Thus, the given model is meshed with 2D meshing technique satisfying the required Quality criteria by following all the necessary procedure.