Can a quasilinear viscoelastic model describe the nonlinear mechanical behavior of unfilled elastomers?

摘要

An extensive set of linear and nonlinear mechanical experiments, including nonlinear stress-strain behavior, stress relaxation, and creep/recovery, have been carried out on a lightly crosslinked styrene-butadiene rubber (23.5 wt% styrene) for a wide range of temperatures, extension rates and extension ratios. The linear viscoelastic response determined via tensile creep and dynamic shear experiments was analyzed via time temperature superposition to obtain the relaxation spectrum. The extensive nonlinear experimental data was used to critically evaluate a class of constitutive models consisting of an additive combination of a hyperelastic term and a single integral quasilinear viscoelastic term. For moderate deformations the model quantitatively described all the features of the observed mechanical behavior. The dependence of the model parameters on temperature and crosslink density was determined.