Numerical Study of Material Degradation of a Silicone Cross-Shaped Specimen Using a Thermodynamically Consistent Mooney-Rivlin Material Model

Abstract

At present multiplicative plasticity theories are used to model material degradation of hyperelastic materials within the framework of finite-strain elastoplasticity. The theories assume that the intermediate configuration of the body is unstressed and that such multiaxially stretched bodies do not have compatible unstressed configurations. As a result, there does not exist a motion whose material gradient could define the plastic deformation gradient. The assumption is however not consistent with the theory of nonlinear continuum mechanics and the related theories are not continuum based. In this paper material degradation of a silicone cross-shaped specimen in biaxial tension is studied using a thermodynamically consistent Mooney-Rivlin material model. The material model is based on the first nonlinear continuum theory of finite deformations of elastoplastic media which allows for the development of objective and thermodynamically consistent material models within the framework of finite-strain elastoplasticity. Such material models are independent of the model description and the particularities of the model formulation and moreover they can relate the internal power density of the model to the internal power density of the specimen coming from the tensile test of the modelled material. In this paper a few analysis results are presented and briefly discussed.