Low-temperature dynamic mechanical properties of thermal aging of hydroxyl-terminated polybutadiene-based propellant

Dynamic mechanical properties of thermal aging hydroxyl-terminated polybutadiene (HTPB)-based propellant were tested using split Hopkinson pressure bar (SHPB) under low temperature (− 50 to 25 °C) and high strain rate (800–2000s−1). Relevant test data were obtained. Moreover, microscopic damages of thermal aging HTPB under dynamic conditions were observed through scanning electron microscopy (SEM) and micro computed tomography (CT). The test results demonstrate that the dynamic stress–strain curve of the thermal aging propellant is similar to that of non-aging propellant, and its dynamic mechanical properties show evident temperature and strain rate effects. With the increase in aging time, the dynamic compressive strength of thermal aging propellant increases continuously. Given the same aging time, the dynamic strength of the propellant is negatively related with temperature but positively correlated with strain rate. Moreover, it shows a logarithmic linear relation with strain rate. After low-temperature dynamic loading, the thermal aging propellant mainly presents damages of transgranular fractures, porosity increase, and matrix tearing. Moreover, the thermal aging propellant develops more serious impact-induced damages than the non-aging propellant. Finally, the master curve of the dynamic strength of the thermal aging propellant is obtained based on time–temperature equivalence principle.