Hi everyone, I’m new here and i hope not to miss the correct discussion.
My goal is to perform a simple modal dynamics analysis of a cantilever beam, Step 1 computes the first three modes with a Frequency step, then Step 2, a Modal dynamics analysis, should be supposed to compute the response to a surface traction orthogonal to the free edge, with a tabular amplitude.
When i run the analysis it computes effortlessly Step 1 but not Step 2, and it does not throw errors.
When i deactivate Step 1, it throws an error because the .eig file is not found, indeed I have the “Storage” value set to “Yes” in Step 1. I could upload the .pmx file if needed.
Thanks in advance to anyone reaching out.
Please do, it’s hard to say and we can only guess what’s wrong without it.
Modal dynamics step can’t work without frequency step because it’s based on modal superposition and requires mode shapes to compute linear dynamic response.
It tells me that new users can’t upload attachements ! I copy here the WeTransfer link.
Thanks a lot
Now you should be able to upload directly.
Regarding the issue, CalculiX has some problems with shells in linear dynamics: Utilities to handle ccx issues with shells in steady state dynamics
In this case, the workarounds from that thread didn’t help and even simplifying the model to the minimum did nothing. The only way I’ve found to be working for now is to use the Thicken Shell Mesh tool to run this with solids instead of shells.
You should also increase the maximum number of increments because the default 100 is not enough in your case.
Beam mod.pmx (3.1 MB)
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Thanks a lot Jakub ! It works well now. I’ll use it for more complex models!
