hhdias:
However, after fining all the mid-surfaces and expanding the faces, I noted that some lines were present in the shell, due to how the command works in SolidWorks (for I beam, I select the upper bigger surface and one of the small faces, so the middle line is offset.
Is there any way to fix this? With the current setup I cannot create a compound part in PrePromax.
Compounding may fail with shells due to small misalignments or no sufficient partitions:
For the compound feature to work, the geometry must fit perfectly. In your case, the flanges have planar faces in contact with the cylinder, and so the geometry cannot be correctly fused.
You can try to fix the geometry - you can also combine the parts inside the CAD software that you are using. Elongate the flanges to penetrate the cylinder wall.
Or, you can use multiple tied connections between all parts using the Search contact pairs function.
Orthogonal shell mesh model - #6 by FEAnalyst - like here in your case:
It’s usually better to merge stuff in CAD software before export in such cases. I would try the Fuzzy boolean union tool from the Defeaturing add-on workbench in FreeCAD followed by Part → Convert to Solid.
That’s the idea of this tool, it’s not a midsurface extraction. It only removes the volume from solid parts.
Check this page: https://wiki.freecad.org/FEM_Geometry_Preparation_and_Meshing#Choice_of_the_type_of_geometry
