On the thermodynamic consistency of Quasi-linear viscoelastic models for soft solids

Originating in the field of biomechanics, Fung’s model quasi-linear viscoelasticity (QLV) is one most popular constitutive theories employed to compute time-dependent relationship between stress and deformation soft solids. It simplest models nonlinear viscoelasticity, based on a time-domain integral formulation. In present study, we consider QLV incorporating single scalar relaxation function. We provide natural internal variables state, as well consistent expression free energy illustrate thermodynamic consistency this version model. The formulation highlights striking similarities internal-variable introduced by Holzapfel Simo. Finally, dissipative features compressible materials are illustrated simple tension.