Critical velocity criterion of explosive charges initiated by fragment impact considering impact angle and charge radius.

The initiation criterion is utilized to predict the critical detonation condition of explosives and plays a dominant role in the fields of survivability, vulnerability, and safety. In order to predict the threshold criterion of explosives initiated by fragment impact in three-dimensional scenarios, the detonation threshold velocities of Comp B (61% Hexahydro-1,3,5-trinitro-1,3,5-triazine, 39% 2,4,6-trinitrotoluene) explosive charges with different radii under the fragment impact at different polar angles and azimuth angles were obtained by numerical calculations, and further, a three-dimensional initiation criterion was established. The results show that when the impact polar angle of the fragment is fixed, the critical velocity under the same azimuth angle scenario increases as the radius of the charge decreases. When the impact azimuth angle of the fragment is fixed, the critical velocity under the same polar angle scenario is almost unaffected by the charge radius. The maximum error between the three-dimensional initiation criterion and the simulation is 3.09%, indicating the high accuracy of the established initiation criterion.