I'm learning how to do Finite Element calculations using Comsol Multiphysics.
In Comsol, Linear Elastic Material and Nonlinear Elastic Material are available as material models:
Using Linear Elastic Material, you can add Plasticity, and define Initial yield stress as well as the tangent modulus:
I'm wondering, if we have plasticity, doesn't that make our material model immediately nonlinear? Plasticity implies change in the elastic modulus, and being able to define separate Young's modulus and tangent modulus produces a nonlinear stress-strain curve.
What is the difference between defining Linear Elastic as material model and then adding plasticity, versus using a Non-linear material model?
I did a simple cantilever calculation with point load at the tip (right edge):
Taking the stress at a cross section along the beam shows the stress gradient change around 30MPa: