ABSTRACT
We developed a micro-mechanically based model of nonlinear behavior of elastomers under different strain-rates. The model is based on the concept of local relaxation of polymer chains in a phantom polymer network. The concept has been further used to describe the decay of stiffness of the polymer chains and eventually creep. Accordingly, the time-dependent damage in one polymer chain is derived with respect to the time and deformation history. The concept is based on experimental data that suggests the time dependent behavior of network is mostly resulted due to the sliding or partial breakage of physical links over time, which results in different distribution of chain lengths over time. The proposed model includes a few number of physically motivated material constants and demonstrates good agreement with experimental data.
