Is it reasonable, to do linear natural frequency analysis for a plastic part of uniform thickness?

[ninjaz]

A plastic component with uniform thickness which purpose is to protection of surroundings.
Is it okay to consider the plastic as linear material and do modal analysis for the shape?

 

[Mustaine3]

In a frequency analysis you have no other choice than using the linear elastic behavior of the material, since it is a pure linear procedure.

The only thing you could do, is doing a nonlinear step before, to change the stiffness of the material.

 

[kan123]

Mustaine3 is correct that only linear elastic behavior is used in a frequency analysis. If you feel it is important to account for nonlinear behavior, you could do a full (direct) transient solution to find the response to a particular loading condition.