Learning Forum

[Nikos Zoupas]

Hello,

I'm using Ansys for the topology optimization of an object in order to be printed. So after the topology optimization, I want to fill the object with a lattice structure through spaceclaim. After this process I'm trying to mesh the model but, the minimum element quality is too low (near to zero). For the mesh I use tetrahedron method with element size of 2mm, note that the programm doesn't let me use the previous settings of the first static analysis. How can I improve the mesh, if someone has any ideas please let me know.

[mjmiddle]

Are you using the patch independent tetrahedral mesher? I think that's probably the only one that will work well with the latticed, facetted geometry from a topology optimization. There are not clearly defined surface patches so the patch dependent tetrahedral mesher will normally fail on this type of geometry. It sounds like you have just set a body size. You should try to get as much as you can from the global mesh settings, such as using the curvature sizing and maybe also proximity. Set an appropriate minimum curvature size. Use mesh defeaturing to merge node across small problems, and you can experiment with that value also. Set the quality to standard mechanical rather than the default aggressive mechanical:

If you have defined face patches, you can set more local sizes, like face and edge sizing at the problem location.

Also, when you set a mesh metric, it will show a histogram. You can change the X and Y axes to see the lowest bar best and adjust that lowest bar to just have a few elements using the "Controls":

Then select that lowest histogram bar. It is always important to visualize why those worse elements are forming that way. You must undertsand what's happening in those locations. Then you can use a different mesh size in that location (vertex/edge sizing or sphere of influence body sizing), or modify geometry, or maybe use Virtual Topology or different defeature size, etc...