Description: The parallel network viscoelastic model allows realistic simulation of viscous materials that may undergo large deformations, such as polymers. The model consists of multiple elastic and viscoelastic networks as depicted in Figure 6–4. In the model one of the networks is purely elastic, and the remaining networks are viscoelastic. The elastic response is specified using one of the hyperelastic material models, and the viscous response is governed by a flow rule derived from the Mises stress potential and the strain-hardening or the hyperbolic-sine evolution laws.