Abstract
This paper presents a phenomenological material model for rubber-like solids and its numerical implementation. The model consists of a hyperelastic damage model in parallel with visco-elasto-plastic models, which include strain-dependency of the hysteretic loops. The underlying key feature of the model is an expression of free-energy of the visco-elasto-plastic model, in which the elastic strain energy is multiplied by a function of strain called hardening ratio, in order to reproduce the strain-dependency of the hysteretic loops. The formulation starts from 1D model, and it is extended into 3D models in infinitesimal and finite deformation regimes. Stress integration algorithms and consistent tangent moduli of those 3D models are also developed. Finally, the visco-elasto-plastic models are combined in parallel with a hyperelastic damage model as a new constitutive model for rubber-like solids. By comparing the proposed model with several experimental data of a rubber, it is found that the model could reproduce behavior of the rubber in various multi-axial deformations under several practical strain rates.
