Enlever sigma et epsilon de Fenics2DRVE

    def epsilon(self, u):

        return mat.epsilon(u)



    def sigma(self, eps):

        return mat.sigma(self.C_per, eps)



    def StrainCrossEnergy(self, sig, eps):

        return mat.strain_cross_energy(sig, eps, self.mesh, self.rve_area)