Shock initiation characteristics of expired single-base propellants

The continuous detonation velocity test, the shock wave sensitivity test and the critical initiation pressure test were developed, respectively, with reference to the GJB772A-97 card gap test. Based on the above tests, the detonation establishment process in the expired single-base propellant was investigated, and the critical gap thickness and the critical initiation pressure were obtained. In the continuous detonation velocity test, the building-up process of the reactive shock wave was observed at the PMMA gap thickness of 50 mm and it developed into a normal detonation at the PMMA gap thickness of 90 mm. The critical gap thickness was 50-52 mm obtained from the shock wave sensitivity test. And the critical initiation pressure was 1.35-1.49 GPa obtained from the critical initiation pressure test. According to the above tests, the numerical simulations were conducted to calibrate the parameters of the reactive rate equation in the ignition-and-growth model for the expired single-base propellant.