Influence of tensile rate on parallel rheological framework model of HTPB propellant

In order to analyze the effect of different combinations of stretching rates of four-component HTPB propellant on the accuracy of the parallel rheological framework model, a nonlinear viscoelastic constitutive model of the propellants was developed based on the parallel rheological framework method. A constitutive model was constructed by combining experiments with different tensile rates, the corresponding constitutive model parameters were obtained and compared with experimental results using finite element models and numerical calculations. The constitutive model errors of the calibration for different rate groups were compared and analyzed. The results show that the model can be calibrated more accurately when a combination of high rate and low rate groups is used, without the need for extensive experiments at intermediate rates. And the high rate propellant tensile test rate can be up to 3000 mm/min, no need to increase the rate. This analysis provides justified suggestions for simplifying propellant material tests and improving the efficiency of the experiments. Concurrently, it paves an effective way to rapidly predict the mechanical properties of propellant materials.