Exported a deformed shell model to .inp but it becomes a solid when importing it

General Questions
1

Hi there,

I want to run a static analysis using the deformed mesh of a previous shell buckling run. So, I did the initial shell tower model, ran the buckle, got the deformed shape I want and exported it as .inp. Note that this first model is made of surface, with S6 shell elements. Then, I start a new model and import the previously generated .inp and it gets the model with deformed shape, which is great. BUT now the mesh elements are solid C3D15. Why this? Am I doing something wrong? The problem is the shell is thin and I don’t need it in solids. It will make all much slower when refined, adding plasticity and non-linear geometry solution for a buckling/post-buckling run.

This software is great. By the way I’m in Linux, but it works.

Appreciate the help.

First shell model mesh:

image
image812×388 54 KB

After importing deformed .inp in a new model:

image
image811×377 57.7 KB

2

This is because CalculiX internally expands shells to solids. But if you set Output to 2D in the first analysis, you will get the mesh without this expansion and thus you will be able to export/import it as a shell mesh.

output 2D
output 2D884×442 19.1 KB

2 Likes
3

Hi,

thanks for the instructions. It worked!

I’m having now another problem that only nodal outputs come. But I’ll investigate it better before any request.

4

So you don’t get the stresses/strain ? In linear buckling or nonlinear static analysis ?

5

In the nonlinear static, where I imported the deformed mesh.

I’ll try starting from scratch and see if there is something wrong in the reused model.

6

If it’s all gray, it may mean that the analysis failed to converge (especially if the previous frames contain the results).

7

No, it is fine. I made a new model and am getting all stress and even plastic strains. All good. Thanks!