Respected Sir,

I am having an issue of solution non-convergence when trying to carry out the non-linear buckling analysis of two rectangular plates (10mm and 20mm) , simply supported on all 4 edges. As soon as the material gets fully yielded (250MPa) the solution has problems converging. Material plastic behaviour was defined as bilinear isotropic hardening.

Can somebody please explain why the solver can't converge on the solution as soon as the entire material gets yielded although I have defined the tangent modulus.

I am on student license.

Thank you