Shock initiation characteristics of four-component HTPB solid propellant containing RDX

In order to investigate the characters of the four-component HTPB solid propellant containing RDX initiated by shock waves and evaluate its adaptability to low temperature, Lagrange analytical experiments were carried out in normal and low temperature conditions. In the Lagrange analytical experiments, sensors were embedded in different locations of the material, and the dynamic mechanical behavior of the material was obtained by analyzing the variation of some mechanical parameters (such as stress or pressure, particle velocity, strain or specific volume and temperature) measured by the sensors. Since the thickness of gap affected the initiation pressure, the manganese-copper sensors were used to measure the pressure changes in different positions of the propellant with the gap thicknesses of 40, 45 and 50 mm, respectively. When the gap thickness was 40 mm, the propellant detonated. In contrast, the propellant burned for the gap thicknesses of 45 and 50 mm. The ionization probes were used to collect the detonation velocity of the propellant. In normal temperature conditions, the detonation velocities with the gap thicknesses of 10 and 40 mm were measured. In low temperature conditions, the detonation velocities with the gap thicknesses of 10, 30 and 40 mm were measured. The growth laws of the detonation were analyzed, and the parameters such as detonation pressure, detonation velocity and detonation distance of the solid propellant were obtained. Numerical simulation was carried out to calculate the shock initiation process of the propellant, and the parameters of the ignition and growth model and the JWL state equation of the nonreactive propellant were determined by fitting the experimental data. The results show that the detonation pressure of the solid propellant is about 12.5 GPa, the critical initiation pressure is 5.16−5.61 GPa, the detonation distance is about 13.3 mm, and the detonation velocity is 5.719−6.013 km/s. The research results indicate that the low temperature has little effect on the shock initiation characteristics of the solid propellant.