nonconvergence issue

[Derya Deniz]

Hi,

In my code, I am trying to do several incremental dynamic analyses for an inelastic structure. For convergence issue, I used the related part of the given examples. I just wonder how I can understand that I am having a collapse (instability of the structure), or which convergence warning let me know that I am having a non-convergence issue because of collapse/instability of structure , NOT any numerical analysis reason.

While reading the forum, I learnt that the convergence warnings that came up during my run do NOT mean real warnings just indications of trying another method in the analysis solution (for ex: Modified Newton instead of Newton). As I remember, Sylvia told in one message, if there is an error like “the deformations/stresses/forces could NOT be calculated for member X”, then that means demands are high. Can we say that it is an indication of collapse if that member X is critical in the global response of the structure?

Thanks,
Derya