Learning Forum

[Elmano6]

Dear experts,

I have the following problem: I created CAD-Models of TPMS structures (Gyroid, Schwarz-p and Schwarz-D) with Creo Parametric. Each model is 50x50x29 mm with cells of roughly 9x10x10 mm and wall size 0,8 mm. I exported them as stl-file to use them in Ansys. After importing the model in Spaceclaim, I did the automatic Facet-Repair and Facet Check. It showed no errors and only the hint that there is one joined knot. I turned the model into a solid body (Volumenkörper) and chose the "merge surfaces option". I got a large .scdoc file, which I imported to Workbench. Now I am having trouble meshing it for future analysis.

The automatic mesh does not work.

The method "Tetraeder" with algorithmus "flächenunabhängig" and max size of elements (0.005m), min element size (0.002m) and angle of 13.5 degrees gives me errors of negative jakobi-determinante.

Are there parameters, that you would not change and others, that you would recommend adjusting?

I appreciate your help.

BR

Elmano

[peteroznewman]

If possible, generate the Gyroid as a zero-wall-thickness surface. Bring that STL file into SpaceClaim. Use tools on the Facet tab to regularize the triangular mesh. You might want to create some Planes on the Design tab. You can slice the Facet surface into smaller pieces to apply the Skin Tool to generate surface geometry (not facets) that will be easily meshed with shell elements that you can assign the 0.8 mm thickness to.
If you stick with a closed facet body, you can try some of the auto-skin techniques I have used in the videos shown below.
https://www.youtube.com/watch?v=Gj3bTd0aN8I
https://www.youtube.com/watch?v=d4ZXSFjIAII
https://www.youtube.com/watch?v=Y8uFzkQxmaA

[Elmano_6]

Thank you very much for your help.
Unfortunetaly, I do not know how to turn the Creo TPMS structure into zero-wall-thickness. Can the alert "Facets have a joined knot" in Spaceclaim cause a problem for the meshing in Mechanical? Since it is not an error but just a hint. After checking the facets, I do not have errors, so I turn the model into a solid by merging the surfaces.
What element type, minimum and maximum size, and angle do you recommend to mesh gyroid cells of 10x10x9 mm?
I would really appreciate your help. Thank you in advance.