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Transient buckling analysis under temperature loading

Transient buckling analysis under temperature loading

Transient buckling analysis under temperature loading

(OP)
Hi,

I'm working on a thin shell model with temperature loading (Input from another odb via *TEMPERATURE, FILE).
Due to high thermal gradients and buckling of thin walls, the analysis has lots of convergence problems. I tried to solve the calculation with *STATIC, STABILIZE and *CONTACT CONTROLS, STABILIZE as well as with *DYNAMIC (explicit and implicit). It's still impossible to get through all 50 steps (transient heating up with a maximaum temperature change of 50°C from step to step).

Can anyone help me to get the analysis running? Validation would be possible by checking the dissipated energy due to stabilization.

Best regards,
Frank

RE: Transient buckling analysis under temperature loading

It is hard to recommend something, without knowing the exact reason for the nonconvergence.

RE: Transient buckling analysis under temperature loading

(OP)
Hi Mustaine3,

some steps abort due to a too high displacement correction at nodes in the structure (buckling?). In other steps, the contact constraints do not converge -> too much SDIs.

RE: Transient buckling analysis under temperature loading

And why is Explicit not working?

Have you also tried *Dynamic, Application=Quasi-Static?

RE: Transient buckling analysis under temperature loading

(OP)
Hi Mustaine3,

*Dynamic, Application=Quasi-Static leads also to convergence issues.
Explicit is not working at the moment due to modelling issues. I'm currently working on some contact redefinition to get an explicit analysis running.

RE: Transient buckling analysis under temperature loading

Is it possible that you convergence issue is because you actually have a bucking instability? Have you considered a Riks analysis to evaluate post-buckling?

RE: Transient buckling analysis under temperature loading

(OP)
Hi TGS4,

I'm quite sure that the instabilities cause my convergence issues. Unfortunately, a riks analysis isn't possible with temperature loading sadeyes

RE: Transient buckling analysis under temperature loading

Then you issue is structural/mechanical and not analytical, correct?

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