Numerical Simulation on the Initiation of Cylindrical Covered Charge Impacted by Tungsten Sphere Fragment

The interaction of tungsten fragment and cylindrical covered charge with different curvature radius is simulated by using AUTODYN-3D software. The influence of impacting position of fragment on the detonation characteristics of explosive is analyzed, and the “up-down” method is used to obtain the critical detonation velocity. The results show that the impact initiation progress of cylindrical covered charge coincides with that of plane covered charge. The detonation point is at a certain distance from the interface between explosive and casing, and gradually approaches to the interface as the fragment impact velocity increases. The cylindrical covered charge is easy to detonate under the same condition, and its critical detonation velocity increases nonlinearly with the increase in curvature radius. For collision point offset δ=0, the critical detonation velocity is increased by 3.2% for infinite curvature radius r=∞ compared with that for r=40 mm; the critical detonation velocity increases exponentially with the increase in offset δ. For r=40 mm, the critical detonation velocity for δ=0.94r is increased by 35.6% and 31.5% compared to that for δ=0 and plane covered charge, respectively.