Project 1 : CFD Meshing for Tesla Cyber Truck
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For the given model, check and solve all geometrical errors and Assign appropriate PIDs. Perform meshing with the suitable Target length and element Quality criteria.
Target lengths for the different parts of a model can be decided by your own. Finer mesh will give good results and will compromise with the longer processing time. - Objective - To Perform CFD Meshing for Tesla Cyber Truck with the suitable Target length and element Quality criteria.For the given model, check and solve all geometrical errors and Assign appropriate PIDs.
- CFD meshing applies a numerical grid to the fluid body and boundary.
- The main importance of meshing in CFD or FEA lies in the ability to solve the governing partial differential equations in the assigned cell.
- Meshing is done to discretise the given model into finite number of elements
- Meshing is one of the most important steps in performing an accurate FEA simulation.
- A mesh consists of elements that contain nodes (coordinate locations in space that can vary by element type) that represent the shape of the geometry.
- When Mesh length is small, the number of nodes should be high.
- when Mesh length is small, the number of nodes should be low.
- Mesh length is the distance between two nodes.
- Surface Meshing -An area mesh is a representation of a surface that consists of vertices, edges, and faces.
- A surface mesh consists of a set of polygonal surfaces, often triangles, which together form the surface covering of an object.
- There are currently two distinct alternatives for surface representation in the deformable mesh literature, namely triangular and simplex meshes.
- Triangular meshes consist of triangular faces that share each of their edges with exactly one other triangular face. Simplex networks are topological duals of triangular networks.
- Procedure
- Cad model
- Topo clean up
- Geometry checks
- Assigning PIDs
- Meshing
- Target length 3mm for body pid
- Tyres Mesh with target length 5mm
- Lights with target length 2mm
- Windows with target length 3mm
- Results
- Stepwise Explaination
- The geometry is imported into ANSA . Since the car is symmetrical, a cut was made in the track along the YZ plane. Views of the car he checks from all four sides to ensure the cut is perfect.
- Upon closer inspection, the error is mainly is of three types (single cons, overlapping faces, and additional faces).
- These bugs have been fixed in the TOPO sidebar and all bugs have been fixed.
- Geometry check tool was run (Check -> Geometry) after all issues were fixed. The default checks are selected to check for the car errors: Click the Run button to start the verification process.
- Models were supplied with existing PIDs and these were created or modified/renamed.
- Preprocessing to the actual meshing process was completed. A surface mesh is first generated with a classic mesh model.
- For convenience, the PIDs are grouped by mesh size. For each size, we defined outlines, macros, mesh parameters, and quality criteria as follows: You can go to Outline -> Length -> Outline and select all geometry with the selection tool. After selection, press the middle mouse button and enter the mesh length for each pid.
- The same process is repeated for macros.
mesh is generated for the following parameters using a point mesh. This is done in Generate Mesh -> Point Mesh -> Display. - Mesh element quality criteria checked by switching to hidden view: determined from analysis of selected detail geometry
Network quality is defined here. This is done in: Network parameters. The target length is entered and the element type is set to Tria. You can go to Perimeters -> Length -> Perimeters and select all geometry with the selection tool. After selection, press the middle mouse button and enter the mesh length - The quality criteria of mesh elements are checked by switching to invisible. The half body surface is now already meshed. The body should be mirrored. To do this, go to Transform -> Copy -> Entities.
- Follow same steps for all pids with appropriate traget length
The car surface mesh is complete.
- Conclusion
- ANSA is a powerful meshing tool and meshing a complex geometry like this truck requires a suitable workstation.
- There were several instances during this project where ANSA would freeze for 10-20 minutes while meshing arbitrary surfaces.
- SpotMesh produces a lot of bad elements, this was fixed in the Reconstruct tool, which took a lot of time and memory.