Description: The parallel rheological framework allows you to model the response of materials subjected to large strains that exhibit nonlinear time-dependent behaviors, such as polymers, accurately. An example of a model defined within this framework is depicted in Figure 6–1. The model consists of multiple viscoelastic networks and, optionally, one elastoplastic network. The elastic response in all the networks is specified using one of the hyperelastic material models available in Abaqus. The response of the equilibrium network (network in Figure 6–1) can be purely elastic, or it can include plasticity and Mullins effect to predict softening during unloading. The viscous response in the viscoelastic networks is governed by a flow rule derived from the Mises stress potential and the strain-hardening law, the hyperbolic-sine law, the Bergstrom-Boyce law, or user-defined laws. In addition, thermo-rheologically simple temperature effects can be included in each viscoelastic network by specifying the shift function. The following forms of the shift function are supported: the Williams-Landel-Ferry form, the Arrhenius form, and user-defined forms.