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?