Polyconvex hyperelastic modeling of rubberlike materials

Abstract In this work a number of selected, isotropic, invariant-based hyperelastic models are analyzed. The considered constitutive relations hyperelasticity include the model by Gent (G) and its extension, so-called generalized (GG), exponential-power law (Exp-PL) power (PL). material parameters under study have been identified for eight different experimental data sets. As it has demonstrated, much celebrated Gent’s does not always allow to obtain an acceptable quality approximation. Furthermore, is observed that best curve fitting usually achieved when experimentally derived conditions were proposed Rivlin Saunders fulfilled. However, shown in contradiction with mathematical requirements stored energy polyconvexity. A polyconvex function assumed order ensure existence solutions properly defined boundary value problem avoid non-physical response. It found case analyzed application polyconvexity leads only slight decrease quality. When assumed, approximation obtained PL model. Among non-polyconvex models, results most frequently GG both G problematic due presence locking effect.