Experimental and numerical research on the reaction behavior of PBT propellants under a low velocity impact

The impact sensitivity of propellants is a significant concern during production, application, and storage. To study the impact sensitivity and reaction behavior of 3,3-bis(azidomethyl) oxetane and tetrahydrofuran copolymer (PBT propellants) subjected to a low-velocity impact, 20 sets of Susan tests are performed, and a simulation model is developed. The results show that the reaction is initiated by the impact and extrusion pyrolysis of PBT propellants. For impact velocities ranging from 120 to 300 m/s, the relative released energy of the Susan tests is greater than 20%, increases with the impact velocity, and reaches the maximum value of 57.67%. PBT propellants exhibit severe reactions under a low-velocity impact and are sensitive to crushing impact conditions. According to the simulation results, extruded PBT propellants dominate the reaction behavior of PBT propellants in a projectile of Susan tests under a low-velocity impact, and the reaction behavior of extruded PBT propellants is primarily dominated by coupling of both the impact velocity and confinement. The simulation results are in good agreement with the experimental results. The initiation impact velocity of partial detonation is about 260 m/s, based on experimental and simulation results.