Modeling of AP-HTPB solid propellant viscoelastic behavior using Modified Maxwell model

This research explores the viscous effects present in heterogeneous solid propellants through experimental analysis. The uniaxial tensile tests were conducted at constant strain rate, and the relaxation tests were conducted at different strain levels and temperatures. The viscoelastic behavior of this material was confirmed on the basis of the experimental data. By using the Modified Maxwell model, a mathematical formula was generated to identify the viscoelastic behavior based on Prony series, then the material parameters of the constitutive model are determined numerically by using MATLAB software. High agreement between the calculation results and the experimental results was found, with a maximum error of approximately 5.35%. Finally, numerical modeling of the relaxation tests was conducted to simulate the stress relaxation behavior of the AP-HTPB composite solid propellant by using the ANSYS program, and the maximum difference between the numerical and experimental results was 6.47%.