Hello there,

I wanted to ask, whether it’s possible to define a SymbolicEnergy for solving an almost incompressible nonlinear elasticity problem. For that I would like to try out a penalized energy function of the type

Psi(C,p) = Integrate(NeoHooke(C) + p * Theta(J) - 1/2*kappa * p^2)

where C = F^T . F (like in the elasticity demo in the docs), J = sqrt(det(C)), Theta(J) = Log(J).

If i do the directional derivatives wrt p i get the side constraint

Integrate((Theta(J) - 1/kappa * p)*q) = 0

Can I do this in NGSolve?

Cheers

Elias