Mechanical behaviour of PVC: model evaluation

The work compares the capability of three simple models to reproduce the nonlinear elastic behaviour of rubberlike materials using experimental data due to Treloar and to Kawabata. These are the Arruda and Boyce eight-chain model, the first stretch invariant model, and the Turner and Brennan composite model. The eight-chain model produces very similar results to those of the first stretch invariant model, and thus it is shown that it cannot be much improved within these limitations. The composite model gives excellent agreement with the extensive data due to Kawabata and it conforms much more closely to the quintessential data due to Treloar than the two other models in focus. Then the composite model is applied to predict the yield stress of oriented PVC. Thereto a set of experiments has been performed to determine the variation of the yield stress with orientations for different pre-stretches. The agreement between the prediction and the experimental results is proven to be quite satisfactory.