FEM Mesh has no Volumes

Mods FEM
1

Hi there,

I’m trying to run a FEM analysis on a model based from an STL file.

My process:

  1. repair mesh if needs
  2. create shape from mesh
  3. refine shame
  4. convert to solid.

Then in FEM when creating a mesh it refuses to create any volumes. Only surfaces.

File attached

Thanks in adavnce
fcthingy.FCStd (147 KB)

2

I’m on the way … Jus two hints … Have you run Part check geometry on it? Is is really a valid solid?

3

yep, Part → check geometry shows there are holes in the Shape, thus it is not a valid Solid, because the Shell is not closed …


Screenshot_20180610_055512.png

4

BTW: which version of FreeCAD do you run? You should have at least 0.17 Release Roland !

5

Aha,

I’ll try to fix this and give it another go.

Thanks again

6

Because of the sheetmetal like structure, it will be better to go not for a solid but for a shell.

shell.png
repaired.FCStd (387 KB)
done with:
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.13892 (Git)
Build type: Release
Branch: master
Hash: 23f58f1afc710c6189ac44414c8696e8e838535c
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: German/Germany (de_DE)


workflow:

  • downgraded your “solid”
  • deleted unneeded faces (all the tiny ones)
  • repaired some gaps
  • upgraded to shell
  • ready to FEM :smiley:
7

I’m interested why you recommend the shell over solid? Presumably you can still set the shell thickness to model sheet metal?
Is it more accurate?

As a side note I found the model error in autocad and smoothly sailed into fem (solid). So thank you all for your help. didn’t notice the error