Finite element simulation of polymer behaviour using a three-dimensional, finite deformation constitutive model

This paper presents a phenomenological three-dimensional viscoelastic–plastic constitutive model for polymers. The model is based on the assumption that stress can be decomposed into two parts, namely viscoelastic and elastic–plastic. The proposed rate-dependent nonlinear model is then implemented in a finite element program. The validity of the code is assessed by the data from experiments on a specific polymer. The data from three types of tests, namely uniaxial compression, creep, and relaxation, are used to evaluate the validity of the model. Comparisons show that the proposed constitutive model could satisfactorily represent the time-dependent mechanical behaviour of polymers. The model is then used to study the effect of friction in the compression test and the behaviour of polymers under cyclic loading.