This paper has shown that the revised form of Fung’s QLV model, proposed recently by the authors (De Pascalis et al.,
2014), offers an effective and efficient way to model nonlinear viscoelastic materials undergoing simple-shear deformation.
The model is able to incorporate a wide range of behaviours through the choice of instantaneous strain measure (modelled
via an effective hyperelastic stress and underlying strain energy function) and relaxation functions. In this paper we examined
two material models, one incorporating incompressibility proposed by Levinson and Burgess, 1971 and the other a neo-
Hookean (incompressible) material, and chose to take a simple one-term Prony series to account for the fading memory of
the deformation history. It was further assumed that rates of deformation are slow enough that inertial effects can be
neglected; hence, as the deformations are spatially homogenous they automatically satisfy equilibrium.
The major simplifying assumption of QLV is that the relaxation functions are independent of the strain. This may lead to
inaccuracies with some types of materials, but can be expected to offer a reasonable model for many practical purposes, such
as when determining small perturbations about a large deformation, e.g. waves on a pre-stressed body. Separating the relaxation
function from the strain measure in the Boltzmann superposition integral allows one to obtain an explicit relation
between the viscoelastic stress T and the strain, or in the present case, the simple shear kðtÞ. For the models employed