Study on the Microcrack Friction Ignition Mechanism of Explosive Charge

Launching overload rapidly loads the explosive charge and its bottom gaps, pores, and cracks, which will lead to the formation of hot spots in the explosive charge. Therefore, revealing the ignition mechanism of explosive charges containing microcracks under different conditions is of great significance for studying the launch safety of explosive charges. In this paper, a friction ignition model for microcracks of PBX explosive charge in a launch environment has been established to reveal the mechanism of friction ignition for microcracks. The model considers the effects of microcrack friction heat generation process, explosive chemical reaction, heat conduction process, and explosive melting process on explosive temperature during microcrack friction. Based on the microcrack friction ignition model, the effects of microcrack width and loading pressure on the temperature of explosives during the friction process are analyzed. The calculation results show that the increase of microcrack width and loading pressure can lead to the advance of the ignition time, thereby revealing the essential differences in the formation mechanism of microscopic hot spots under impact conditions and launch environments.