Network evolution model of anisotropic stress softening in filled rubber-like materials: Parameter identification and finite element implementation

A purely micromechanical network evolution theory granting new insight into the damage mechanism was proposed previously by the authors (Dargazany and Itskov, 2009).In this follow-up paper, we further formulate the network evolution model for implementation into finite element simulations.To this end, a general internal variable formulation is developed which determines the inelastic response of the microstructure on the basis of the free energy function.The thermodynamical consistency of the network evolution model is then verified analytically.Next, the predictive capabilities of the model are demonstrated by means of several experiments especially designed to capture stress softening, permanent set, and induced anisotropy.Finally, the influence of the filler concentration on material parameters is studied.