Nlgeom missing from the dynamic step


maybe it’s not a bug in a typical sense but I’ve noticed that the essential Nlgeom parameter is missing from the dynamic step definition window in v1.4.0 dev:

I guess that it’s just a matter of setting




in ViewDynamicStep.cs. I could try to send a merge request but is this parameter currently disabled in the dynamic step for a reason or was it just overlooked ?

Hmm, I disabled it on purpose since I think it is not possible to have a dynamic analysis without nonlinear effects. So I thought it makes no sense to show it to the user.

But it seems that currently Nlgeom is not added to the *Step keyword before *Dynamic, meaning that it’s disabled by default and all dynamic analyses are performed without geometric nonlinearity.

Personally, I would prefer to have it enabled by default for dynamic analyses but still with an option to disable it for some benchmark/verification studies. In Abaqus, Nlgeom is even disabled by default for implicit dynamics and enabled by default (with an option to disable it) for explicit dynamics. I recall a few cases when I had to disable it for some more thorough investigations regarding the solver’s behavior.

I was not aware of this possibility. So I think my assumption was wrong, and I will enable the activation of the Nlgeom parameter to the user. I will have to do some tests about it to see how it affects the results.

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