Week 5

                                                                                                                          WEEK-5 PROJECT

                                                                                                          SOLID MESHING OF RARE VIEW MIRROR

OBJECTIVE:

• Import the CAD geometry of Rare View Mirror assembly
• Clean up the geometry until no topological error is found
• Mesh geometry with target/average length of 1mm with no errors.
• Assign closed volume and generate volume mesh using the given quality criteria.

ABSTRACT

     A rear-view mirror is a flat mirror in automobiles and other vehicles, designed to allow the driver to see rearward through the vehicle's rear window (rear windshield). In this project I am going to generate volume mesh for rare view mirror using tools of ANSA. There is no need to generate any mid-surface for this geometry. The given geometry must be meshed on the surface and then the model should be assigned as a closed volume to generate volume mesh. Also, we need to remove tetcollapses after generating volume mesh.

METHODOLOGY

1. Import the CAD Geometry and do Geometry clean-up with no topological error.
2. Assign the property ID (PID) for each part
3. Setup Quality criteria and generate mesh.
4. Assign closed volume for the given geometry.
5. Generate volume mesh.

INTRODUCTION:

In cars, the rear-view mirror is usually affixed to the top of the windshield on a double-swivel mount allowing it to be adjusted to suit the height and viewing angle of any driver. A swivel is a connection that allows the connected object, to rotate horizontally or vertically. Rear-view mirror consists of mirror top, base and ball type swivel joint which connects both top and base.

                                                                                                                             Rear-View Mirror

                                                                Ball Type Swivel Joint                                                                   Rear-view Mirror Mechanism

PROCEDURE:

Geometry Clean-up

• After importing the geometry into ANSA there will be many topological errors. In order to prevent this, we do a geometry clean-up which is in the check’s manager.

                                                                                                                  Cheks Manager Dialog box

• The errors in the above figure can be fixed automatically using FIX option or if the errors are not rectified, we must clear them manually.

                                        Cheks Manager Dialog box                                                                                    Cheks Manager Dialog box

• After all the error are rectified,if you check the geometry the exceution will be 100% then you can move forward.

ASSIGN PROPERTY ID (PID)

• Every part in the geometry has it’s own property. We can assign PID using ANSA. We have to select the part and click Apply, then we have to select the whole part using window selection to apply the PID.

                                                                                                                               PID Manager

                                                                                                                       PID's assigned for Geometry

MESHING AND IMPORVEMENT OF THE MESH

• After assigning all the quality criterias and mesh parameters,one has to do meshing for geometry.
• Meshing should be done at smaller regions in the beginning and continue on to the falt areas, so that kinks and raised edges can be avoided.

                                                                                                                 Meshing at smaller regions

• We can use align option in order to remove kinks and raised edges. First select the node wich is to be moved and then select three points on the surface in order to move that selected load to the same surface. In this way the surface will be smoother for the geometry.
• Isolate each part for better meshing and spotting erros.

                                                                                                            Isolated Ball Joint Meshed

                                                                                                                       Mesh generated at some regions

                                                                                                            Mesh done for whole geometry

Generating Volume Mesh

• Volume mesh can be created in ANSA only if it recognizes the geometry as a closed volume. Therefore, we must manually update our model to closed volume.
• To convert our model to closed volume one must define volume.

                                                                                                                             Defining Volume for Geometry

• ANSA might crash if you generate volume mesh for the whole geometry. So, define individual closed volumes for different PID’s.
• Defined volumes can be checked under list option under volume dialog box.

                                                                                                                      Defined Volumes

• One can give either Tetra Rapid or Tetra FEM under unstructured mesh dialog box for closed volume.

                                                                                                        Selecting type of mesh for closed volume

• Images of geometry after generating mesh for closed volume.

                                                                                                 Unstructured Mesh in Closed Volume

                                                                                                               Unstructured Mesh in Closed Volume

• After the completion of volume mesh, 1)tria elements-108882.2)Tetra elements-506273.There are no tetcollapses,kinks,raised edges.

                                                                                                              Volume Mesh done for Rear-view mirror

Learning Outcomes:

• Able to do topological clean-up with no errors.
• Aware of all the quality criterias and quality parameters during mesh generation. Understood about mesh generation and implemented mesh generation for complex geometry.
• Learned how to define closed volume.
• Generated tetra rapid mesh for closed volume.

  Conclusion:     

        Solid meshing is successfully generated for rear-view mirror using the given quality criterias mentioned under the challenge. There are no raised edges,kinks and tetcollapses. From this project i know how volumes are defined and meshed. Volume mesh concepts are also understood.

Rear-view Model of ANSA file link :

https://drive.google.com/file/d/1qPI_U4HszWPYRCbKdmlniC4V4Q-xodBf/view?usp=sharing