Learning Forum

[muge]

Hi, i´m working on a project that is necessary to get the bending stress of a shell, but occurs this error:

"For this result, the scoped geometry(s) or named selection should have at least one sheet or a face on sheet or a solid with solid shell mesh."

What I can do to fixe it?

 

[KR]

Hello,nMay be a stupid suggestion - but could you please try and import your geometry directly into the Transient thermal (rather than using the External Model)? Please let us know if this works.nThanks.nKarthikn

[muge]

n

Hello,May be a stupid suggestion - but could you please try and import your geometry directly into the Transient thermal (rather than using the External Model)? Please let us know if this works.Thanks.Karthikhttps://forum.ansys.com/discussion/comment/99348#Comment_99348

I have only .cdb or .db format of model so I used external model section. Even if I use a different, uniform, similar geometry in geometry section, I still get a mesh error at structural part. I do not understand why the error is caused.n

[peteroznewman]

@muge, nAre you working with @SercanKumru, ?n

@SercanKumru The mesh used was very coarse. You should do a mesh refinement study where you reduce the element size and plot how the maximum stress changes as the elements get smaller.It's possible to build geometry that has a sharp interior corner. The theoretical value of stress at that corner is infinity. This is called a singularity. A real corner has a small radius so the stress is finite. It is possible your geometry has a sharp corner and as you make the elements smaller and smaller, the stress will go higher and higher without limit. You would then need to edit the geometry to add a small radius.I suggest you build a very simple geometric model with two bodies that use these two materials. One idea is two spherical shells. Cut through the sphere on 3 planes of symmetry to hold 1/8 of the sphere using Symmetry boundary conditions. Apply a temperature load in a Static Structural analysis to see the stress from the thermal expansion. In this example, there are no stress concentrations, no singularities. You can do a mesh refinement study on this simple model to see how element size affects stress.If you clear the mesh from your model and save a Project Archive .wbpz file, then put that in a zip file and attach it to your reply, I will do this with your materials.https://forum.ansys.com/discussion/comment/99433#Comment_99433

In a nonlinear analysis, when large forces are computed, element distortion occurs. Often, the corrective action is simply to take more substeps so the increment of force is smaller and the element distortion is small enough to be accommodated, and that continues over the many substeps.nOther times, many substeps does not work and a better mesh is required to avoid the element distortion error. For this you need geometry.nWho provided the .cdb file? They imported a geometry file to make the mesh. Ask them to provide the geometry file also.n

[muge]

Hi @peteroznewman ,nYes, I am working with . Unfortunately, the model geometry was not sent to us and the model is old. We are asked to solve with this format but we are constantly getting errors. And yes, highly distorted meshes occurs, we cannot intervene them because of format.nThanks, have a good day.nn

[peteroznewman]

nYou can export a mesh as an STL file, and convert the STL file to geometry using tools in SpaceClaim. There are many videos to help learn how to use those tools. In that way, you will end up with geometry that you can mesh as you want as well as adjust the geometry to help with problem areas.n

[muge]

I also tried this option. However the model consists of 2 parts assembled and after editing it pretends to be one piece. Therefore when applying the boundary conditions, the desired part cannot be selected.nThank you for your response.