Week- 8 - Solid meshing

OBJECTIVE- To mesh the given rearview mirror component in both 2D and 3D, after checking the model for geometrical errors and fixing them. Also, to ensure the generated mesh follows the given quality criteria.

Quality Criteria for Shell elements is as follows

SR NO	QUALITY CRITERIA	VALUE
1	Target/Average Length	1
2	Minimum Length	0.5
3	Maximum Length	2

Quality Criteria for Solid elements is as follow

SR NO	QUALITY CRITERIA	VALUE
1	Collapse	0.2

CAD MODEL

PROCEDURE-

1.Firstly, we need to use the topo tool to take care of all the single cons and to ensure that are no free edges and they are properly stitched with each other.To perform the TOPO Operation we need to use this command in TOPO Module FACES>TOPO.All the cons are selected and the algorithm takes care of all the single cons.

2.Then We can need to change the orientation of the CAD Model.to change the orientation of the model we need to use this command in TOPO Module FACES>ORIENT

3.Also Delete the Unnecessary Hot Points from the model. in order to do that we need to use this command in TOPO Module HOT POINTS>DELETE

4.After that, as is the norm with meshing on ANSA and before we carry out any other actions, we need to carry out a geometry check and fix all abnormalities.That is done via CHECKS>GEOMETRY.where we Perform the checks operation & after detection if there are any errors we can select all the defects and Auto-fix them by selecting all at once and then right click of the mouse shows fix option.after clicking on that all errors are autofixed

5.Now we can go ahead and work on meshing the surface of the model. As part of this, we need to assign the mesh properties and quality parameters. We need to assign the target length. To do this, we can go to the mesh module and PERIMETERS>LENGTH. This lets us adjust the target length effectively, the resolution of the cons to be finer. here target length required is 1mm.

6.After that we need to assign mesh parameters and quality parameters with the values given in the question

7.Here we have asssigned target element length as 1 mm & min length as 0.5 mm in Mesh parameters and Similarly in quality criteria we have assigned min length as 0.5mm and max length as 2 mm as given in the question.there are several parameters present by default in quality criteria as we are not using them here we can simply uncheck them from the screen by usinb edit criteria visibility option at the bottom of the screen

8.Now we can go ahead and mesh the component. The spot mesh tool in CLASSIC MESH model is used (MESH GENERATION>SPOT MESH).For regions that are flat we need to mesh them with the tria elements. The option to switch to tria is in the bottom left options section after selecting the spot mesh tool & for more complex or curved regions (such as fillets and hemmings),we need to mesh them using ortho elements,The option to switch to ortho is in the bottom left options section after selecting the spot mesh tool

Here we can see the difference between two mesh mesh using Tria elements on flat surfaces and mesh using Ortho elements on the curved surfaces

9.After each mesh iteration, we will need to reconstruct the mesh using SHELL MESH>RECONSTRUCTION. For this to be effective, the neighbouring mesh is selected as well. This ensures the reconstructed mesh is of good quality and flow. The mesh type will need to be changed before using this tool according to the type of surface that is being resconstructed ie. for flat surfaces Tria Elements should be used & for Curved surfaces Ortho elements should be used

10.After meshing all regions and ensuring there are no off elements, we have to put quality criteria for solid Tet Collapse as 0.2 in the Quality criteria tab in the solid section as after defining the geometry component will be converted into a solid volume

now we can proceed to the next step of assigning volumes manually to each set of closed-shell elements. This is done by using VOLUMES > DEFINE > VISIBLE Option

11.Further after the volume is defined by clicking OK window shown as below appears in there we can rename the volume & we have to select the type of mesh we want for the components,we can select either one from TETRA FEM or TETRA RAPID

12.After selecting the type of mesh and cicking ok we need to remesh the component as per the quality criteria of Tet collapse for solid which is beinhg given as o.2mm

13.In This Model there are four components with four different PID'S. we have to perform the mesh according to the type of surface and define and remesh them seperately as discussed above

14.Four different volume PID's will be present after defining and remeshing all the 4 components seperately

15.We need to check whether any element is failing for quality criteria or if there are any off elements.we can tackle this issue with using different tools such as improving mesh quality or reconstructing mesh both of which are available in Volume mesh module in IMPROVE>FIX QUALITY,IMPROVE>IMPROVE MESH,IMPROVE>RECONSTRUCT

16.Final Model images are as shown below

LEARNING OUTCOMES

1.Learnt about the concept of solid meshing as a whole 2.Number of Total elements after volume mesh are significantly higher than the shell mesh 3.Learnt about assigning volumes for closed shell elements 4.Learnt to fix tet collapse failures after meshing 5.Familiarized with the ortho tria and tria mesh types through the spot mesh tool.

RESULT

The given component was geometrically fixed and meshed as per the given mesh requirements and criteria and the generated shell mesh was used to create the solid mesh.Quality and flow were achieved and care was taken to ensure that there were no deformations of any kind on the surface