Assembly analysis and the meshing methods

[SofieneFEA]

Hi every body,

I’m actually working with CatiaV5R15. I have some questions about the assembly analysis and the meshing methods. So:

- Given a volume (solid) form, how can I do a manual, regular and trustful meshes without utilising the automatic mesh generation (the only purpose of the automatic mesh is to fill in the famous TETRAHEDRON elements….)?
- Given an assembly, and supposing that I have done a regular mesh for each component, how can I assemble these different meshes?
- After doing a mesh, How I can apply load to: a specific point? in a segment portion of one line?. How applying a "pre-stressing"?

 

[JacobL]

What is your analysis purpose? and experience?
catia has not real good solid meshing - considering tet mesh not a really good one.
for hex meshing you need other software - ansys, msc, and the rest.

loads are applied as specified in the catia help system. again, it all depends on your current level of expertise and the need for the analysis.

 

[SofieneFEA]

Thank you JacobL for warning me about such things,

I have done finite element simulations for different structures and I found that some results can be improved by doing a regular mesh. These simulations were done for simple geometrical form (rectangular volumes…). I tried many times to do a good surface mashing with the “Catia Advanced Meshing Tool” and to extrude (or operate) this surface mesh to obtain a good solid HEX mesh…but it seems to not work for more complicated geometries(because you have to define a surface, to give it a shell!!! Property, to define group of entities.....!!). So, I asked if there is a clear procedure to utilise Catia to manualy mesh a solid.

The second question was about the assembly design. I used the different called “analysis connections” and compared them to an assembly (of two solids) done in one solid “.part” document. The results are different and the automatic meshing increases the incoherence of these results. So I asked if I can done the mesh of the different parts separately and to assemble them.

It is true that ANSYS (for example) is more appropriate, but I encountered some problems in converting some parts.
I think that there are some Add-On that can ameliorate the Catia performance.

Best Regards.

 

[enthu1980]

Hi SofieneFEA ,
You can use 3Dsweep for generating hex meshes. Of course, the functinality is not so easy to use and difficult in complex geometry. You may have to vary the tolerance everytime to capture mesh. But the mesh you would get by this functionality is quite good.

Also, you can use second order tets for solid meshing or even for tet filling. You could notice the significant difference in the result.
Use global error sensor or compare discontinuous and continuous image to know the error and quality of mesh

2)Use connections for assembling different meshes. For this you may require to use groups because there will be no geometrical support in case of sweep3D.

3) For loads application also, You can use group (box group or sphere or groups by neighborhood) as per requirement.

4) Also While viewing the result images, you can use this groups in selection part of dialog box of image

Hope this might help you,
enthu