Akademik Veri Yönetim Sistemi
5th European Conference on Constitute Models for Rubber, Paris, Fransa, 4 - 07 Eylül 2007, ss.241-242
Rubber-like materials exhibit rate-dependent material behaviour and significant amount of hysteresis upon cyclic loading. Rubber components have a wide range of applications in industrial products. Analysis and design of such components necessitate qualitative and quantitative simulation capabilities. Finite viscoelasticity models with linear evolution laws are bound to small deviations away from thermodynamical equilibrium. One of the recent attempts for the modeling of viscoelastic response of rubber-like materials at finite strains is the Bergstrom-Boyce model. In this contribution, we present the formulation and efficient algorithmic implementation of this model available for the finite element method, which has not been published so far. The formulation is based on the decomposition of the free energy function into volumetric and isochoric parts. The viscous effects are taken to be purely isochoric. The incompressible part of the deformation gradient is multiplicatively split into elastic and inelastic parts. For the update of the inelastic part of the deformation gradient, a predictor-corrector algorithm similar to the elastoplasticity formulation of Simo (1992) is used. In the inelastic corrector step, the elastic finger tensor is integrated with an implicit integration scheme which yields an internal Newton iteration. Furthermore, the computation of the consistent algorithmic moduli is discussed.