ALTERNATIVE STRAIN-RATE DEPENDENT HYPERELASTIC-PLASTIC MATERIAL MODEL

: At present, multiplicative plasticity-based models are used to model material degradation of hyperelastic materials within the framework of finite-strain elastoplasticity. The underlying theory assumes that the intermediate configuration of the body is locally unstressed, and as a result, no plastic deformation field exists that meets the conditions of compatibility. The assumption is; however, neither mathematically nor physically justified and the related material models are not continuum-based. In this paper, an alternative strain-rate dependent hyperelastic-plastic material model is presented. Based on the theory of nonlinear continuum mechanics for finite deformation of elastoplastic media, the model can describe the plastic flow in an objective and thermodynamically consistent manner. Therefore the strain-rate density of the model and the specimen from the uniaxial tensile test of the modelled material can be related. In this paper, the dynamic behaviour of a silicone cross-shaped specimen is studied numerically using a Mooney-Rivlin material model with internal damping.