Pertubation technique in Comsol

Hello all comsol users!

I would like to start using Comsol for structural problems including contact mechanics and non linear material behavior. I would like to know how Comsol assembles matrix for linear perturbation or linearization. There is a little information about this in documentation. Does Comsol linearize and include all non - linearities, for example, in modal/harmonic analysis?

Please, has anyone experienced?

Thank you for any advice!


Petr Henys