Experimental investigation and constitutive modeling of uncured carbon black filled rubber at different strain rates

Abstract

The tensile behavior of uncured carbon black filled rubber is investigated under different loading scenarios and strain rates. A non-contact optical measurement technique, Automated Grid Method, is applied to the tensile tests to capture the full-field large deformation of uncured rubber samples, and then their accurate stress-strain curves are obtained. Based on the test results, the deformation mechanisms of elastic, inelastic, hysteresis and softening behaviors at different strain rates are revealed and discussed. On the other hand, a three parallel network model comprising a hyperelastic part and two elastic-viscoplastic parts is proposed to characterize the constitutive mechanics behavior of uncured rubber. By using this new proposed model, the distinct characteristics of the cyclic tests can be captured well at four different strain rates. Moreover, the model predictions for the multistep tensile relaxation process are found to be consistent with the experimental observations, which provide a physical framework to describe the underlying deformation mechanisms of uncured rubber.