Identification of nonlinear viscoelastic model

International audienceElastomers are widely used in several engineering applications such as aerospace, automotive and civil engineering applications thanks to their ability to undergoing high strains and strain rates in large temperature range. Several models have been developed in the literature to investigate those nonlinearities. In this work we expose a nonlinear viscoelastic model at finite strain for rubber-like materials based upon the theory of irreversible thermodynamic and the time strain superposition principle. The identification of several model's parameters is highlighted. A systematic identification procedure is used. First, we start by the identification of the shear relaxation module using relaxation tests at low levels of deformation and the identification tools in Abaqus software, then we identify the hyperelastic potential using equilibrium data of simple extension and pure shear experiment and a constrained linear least square minimization with Matlab software, finally we identify the reduced time function using monotonic tests of simple extension for different strain rates and the discretization of the behaviour law. The capacity of the model to predict the behaviour of the material is illustrated via the Cauchy stress relative error