In ANSYS Classic (Mechanical APDL), is it possible to ...

> model a frame, like say, a portal frame with beam elements

> apply vertical loads

> switch on stress-stiffening SSTIF

> do non-linear analysis, so the SSTIF will lower the stiffnesses of the columns (stress-softening due to compression)

> do a modal analysis to determine the frequencies and mode shapes in the stress-softened state?

* if i do modal analysis on the as-it-is model, i get a set of frequencies

* if i am able to do modal analysis on the as model analysed with SSTIF, i should getting a set of frequencies that's lower than those obtained from the as-it-is model, due to lowering of stiffness by stress-softening during the SSTIF analysis.

So, can i do a modal analysis in the stress-softened state of the model?