Influence of Macrocracks Extending along the Propagation Direction of Detonation Wave on the Detonation Velocity of Explosives

ABSTRACT When detonation encounters macrocracks extending along the propagation direction of the detonation wave in explosives, steady detonation velocity may decrease, and the detonation may fail. We investigate the impact of macrocracks on detonation velocity by simulation. Cracked explosives are modeled as gap‐containing plane explosives with confinement, characterized by two independent variables: explosive thickness and gap width. The variation of detonation velocity under different combinations of explosive thickness and gap width is obtained statistically, and divided into three subregions in a diagram. Analysis results show that there is a critical gap width. When gap width exceeds the critical value, only explosive thickness affects detonation velocity, while failure explosive thickness remains constant. Conversely, if gap width falls below the critical value, both explosive thickness and gap width significantly affect the detonation velocity, with failure explosive thickness decreasing as gap width diminishes. Furthermore, for a fixed gap width, an empirical formula of detonation velocity for cracked explosives is proposed, which incorporates an additional parameter compared to that for cylindrical charges. Finally, stable detonation may occur when the distention ratio of cracked explosives is below a certain value, but the distention ratio alone cannot uniquely determine the detonation velocity.