A constitutive model for understanding the mechanical response of energetic polymers to the strain rate and temperature

In this study, we proposed a constitutive model for describing the strain rate and temperature dependence of glycidyl azide polymer (GAP) elastomers during the whole deformation process, based on a series of mechanical experiments under various conditions. The experimental results show that the tensile stress is linearly related to the logarithm of the strain rate ε in the rate range of 0.5^∼500 mm/min, and an obvious thermal softening effect is observed from −40 to 40 °C. The new idea about modeling is that, using five Maxwell elements to describe the rate dependent behavior, the relaxation time (θ) for each unit and the intervals of logθ between units were determined according to the linear region of σlogθ. For the thermal softening effect, a new approach involving polynomial multiplier-containing temperature function was used to capture the effect clearly. Moreover, a simple, efficient method concerning time-temperature equivalence was put forward to predict the yield stress of the elastomers. By comparisons, our calculated results agree well with the experimental data, demonstrating the feasibility of our model and method.