XII - Low Velocity Detonation of Solid Explosives

Abstract

Some authors compare the detonation velocity to the sound velocity of a dense material. They see differences when the detonation velocity is lower or higher than the sound velocity. But such differences are not meaningful. Such supersonic low-velocity detonations (LVDs) are present for solid explosives. At a certain diameter, which depends on grain size and confinement, a discontinuous or a smooth transition to high-velocity detonation (HVD) occurs at detonation velocities > 4,200 m/s and pressures > 65 kbar. No steady transition velocities are found between the lower-LVD and the upper-HVD values, thus creating a velocity gap. The diameter of transition is proportional to the average grain size for monodisperse materials. LVD in high-density solid explosives is a separate unique phenomenon. The essential dynamic precursor interactions of the confinement with the homogeneous liquid explosive, resulting in its cavitation, are well established for LVD initiation to occur. The same situation applies to solid explosives because luminous precursors appear at the interface, but these precursors are different from those of HVD.