Necking in 2D incompressible polyconvex materials: theoretical framework and numerical simulations

We show examples of 2D incompressible isotropic homogeneous hyperelastic materials with a poly-convex stored-energy function that present necking. The construction of the stored-energy function of amaterial satisfying all those properties requires a fine search. We used the software Algencan to perform numerical experiments and visualize necking for the examples constructed. The algorithm is based on minimization of the elastic energy under the nonconvex constraint of incompressibility