Vault karamba 3d mesh and stress

Hi everyone,

I am trying to analyze gothic vault with karamba 3d, with and without rib.
-First I have a question about the resolution of the mesh, I use mesh to shell as on the picture below and I was wondering if the resolution that I use is ok to get the order of stresses in the vault ? Because I have seen that the values change a lot with the resolution of the mesh.

-Second, I look at the princ stress 2 to get an idea of compression values, and I see some blue parts that seems to bee in small tension, is it because of the mesh ?

Also, the maximum and minimum value seems very hight, I think it is because of the concentration of stress in the support, maybe I could ignore those values for my analysis ?

I’m only architecture student, and I haven’t a lot of experience in those question :slight_smile:
Thanks a lot in advance for your help,

Hi @morgie02,
in case of shell calculations the mesh is fine enough if the results do not change significantly when varying the mesh density.
At the supports you get stress concentrations because of the pointwise supports of the shell elements. You could integrate beam elements into the shell at the supports - e.g. at the free edges near the supports (0<1m). This would create a more realistic stress situation there.
The blue spots at the free edges look wired. Could you post the GH definition? Otherwise it is hard to guess what could be the source of the problem.
– Clemens

Hi @karamba3d,

Thanks a lot for your answer. Here is the gh definition. (88.4 KB)
I am unsure if the mesh is ok.
What do you mean by “wired” for the blue points ?

Thanks in advance

Hi @morgie02,
a refinement of the mesh shows that that there are small regions with tension along the edge in the vicinity of the supports. The reason for this is, that the shell acts there like a V-shaped beam there. The outward bending results in tension at the tip of the cross section.

‘wired’ was a Typo. it should have been ‘weired’.
– Clemens