3D ElasticTimoshenkoBeam element with rigid joint offsets about openseespy HOT 6 OPEN

@juancaFS that's an interesting observation. Others will know better, but I suspect it will be difficult to figure out where the difference arises from the information you've given. It might be better to consider a single plane portal frame (3 members), and to check the stiffness matrix from your own calculation with that from OpenSeesPy. You can use printA or the newer gimmeMCK command for this. I reckon it would be easier then to track down where/if the difference arises,.

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Muchas gracias, @juancaFS!
I see the issue, the elasticTimoshenkoBeam element doesn't use the geometric transformation consistently. It's fixable but will take a little time, so thank you for the small example.
In the meantime, can you try using the 'timoshenkoBeamColumn' with elastic shear sections to see if the OpenSees result matches your calculations? https://portwooddigital.com/2022/07/03/elastic-shear-beams-in-opensees/

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I agree 100% with @ccaprani. A minimal working example (portal frame, simple span, or a cantilever), something small and manageable, will go a long way to tracking this down. No one will be able to reproduce what you have shown here.
https://portwooddigital.com/2021/07/01/minimal-working-example/

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@ccaprani @mhscott Of course. Please find attached the script corresponding to a minimal 3D model:

I got the same differences in this model for the case of ElasticTimoshenkoBeam element with rigid joint offsets.

Simple3DFrame.zip

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Dear @mhscott thank you for your advice.
Now I got full agreement using the displacement-based elements with elastic sections in OpenSees.

Simple3DFrameV2.zip

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Good to hear, thanks!

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