Axial distribution characteristics of fragments of the warhead with a hollow core

Fragmentation characteristics are the key parameters to assess the damage efficiency, as well as the risks in potential accidents, of a warhead with a hollow core. However, limited work has been conducted to predict the fragment distributions along the axis of novel warheads with hollow cores. In the present work, the fragment distributions and fragment velocity distributions of warheads with different sizes of hollow cores were determined by the processing of witness plates and a flash-radiography method respectively. It was found that the variation of fragment velocity along the axis of cylindrical casing near the detonation end decreased and the fragmentation along the axis of cylindrical casing near the detonation end became more uniform with the increase of the diameter of cylindrical hollow core. The variation of fragment velocity along the axis of cylindrical casing near the non-detonation end slightly increased, and then decreased with the increase of the diameter of cylindrical hollow core. The fragmentation near the non-detonation end did not change significantly because of the short effect distance of the rarefaction wave from the non-detonation end along the axis of the casing. Based on the fragment velocities along the axis, a modified formula including the effects of the rarefaction waves from the hollow core and the ends of explosive charge was established and validated experimentally and numerically. The results indicate that the proposed formula is accurate and reliable in predicting the fragment velocity distribution along the axis of novel warheads filled with hollow-charge and detonated at one end.