The Characteristics of Explosives Initiated by Precursor Shock Waves in Shaped Charge Jet Penetrating a Bulkhead at DifferentTemperatures

doi:10.3969/j.issn.1000-1093.2021.01.005

Abstract

Abstract: The reaction mechanism and response law of ammunition under the impact of shaped jets are of great significance to the study of ammunition safety. The initiation caused by shock waves formed in bulkhead and the effects of explosive temperatures in experiment and numerical simulation are mainly researched. An experimental device was designed for the large-sized shaped-charge jet penetrating the different thick bulkheads to initiate heated explosives. The upper and lower ends of explosive charge are heated, and its side keeps warm to achieve the uniform heating and temperature control of the charge. Jet-penetrating initiation experiments of RDX-based aluminized explosives (mass ratio of RDX, Al and adhesivein explosive formulation is 61%∶30%∶9%) were performed under the conditions of different temperatures and bulkhead thicknesses. Flash X-ray high-speed radiography was used to observe the jet penetration process and detonation wave. A temperature-dependent simulation model of jet initiating explosives was established, and large quantities of numerical simulations were made on the initiation caused by shock waves, which were formed in jet penetrating the bulkhead. It is found that the precursor shock waves are formed in bulkhead by jet penetrating the thick bulkhead, and reach the surface of the explosive earlier than the jet does, and the explosive is detonated after the shock waves propagate in the explosive at a certain depth. When the incident pressure is between 3.1 GPa and 5.13 GPa, the explosive is detonated by shock waves formed in bulkhead. When the incident pressure is higher than 5.13 GPa, the impact initiation occurs. The explosive temperature has a great influence on the precursor shock wave initiation mechanism. It is suggested that the shock sensitivity of the explosive to the jet decreases with the increasing temperature at 25-110 ℃, mainly because of binder softening. However, at 110-170 ℃, the influence of the soften binder is weak, and the shock sensitivity increases when the temperature exceeds a certain value, which depends on the increasing sensitivity of RDX.

Key words: heatedRDX-basedaluminizedexplosive, shaped-chargejet, shockinitiation, initiationbyshockwavesformedinbulkhead

CLC Number:

ZHAO Pin， CHEN Lang， LI Jinhe， LU Jianying， WU Junying. The Characteristics of Explosives Initiated by Precursor Shock Waves in Shaped Charge Jet Penetrating a Bulkhead at DifferentTemperatures[J]. Acta Armamentarii, 2021, 42(1): 45-55.

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