Constitutive Behavior of a Twaron®/Natural Rubber Composite

Abstract

The constitutive behavior of a Twaron CT709R fabric/natural rubber (Twaron R /NR) composite is studied using the fourparameter Burgers model (composed of a Maxwell element and a Kelvin-Voigt element in series), a proposed five-parameter model (consisting of a Maxwell element and a generalized Maxwell [GM] element in series), and a newly developed para-rheological model (comprising a GM element and a stress network element in parallel). The new model makes use of the affine network-based molecular theory of rubber elasticity. The uniaxial stress-strain relation of the Twaron R /NR composite is experimentally determined at two constant strain rates of 0.00001 s −1 and 0.01 s −1 . The values of the parameters involved in the three viscoelasticity models are extracted from the experimental data. It is found that both the Burgers model and the five-parameter model significantly under-predict the stresses for large strain values at both the strain rates. In contrast, the constitutive response at each strain rate predicted by the newly developed para-rheological model is seen to be in good agreement with the measured stress-strain curve over the entire strain range studied. It is shown that the new model also predicts the elastic moduli and ultimate stresses of the Twaron R /NR composite well.

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