Now I am trying to implement Ogden model in Comsol Multiphysics, but I had some problem.
Then I realized that in Comsol, it's possible to implement a nonlinear young's modulus.
But I am a little confused.
If you have a nonlinear Young's modulus, in the stress-strain curve, E is the tangent of this curve.
For hyperelastic material, let's say Ogden material. It's usually a nonlinear stress-strain curve as well.