Initiation of Explosive Transformation of High Explosives under Low-Velocity Mechanical Impacts and Weak Shock Waves Due to Formation of Viscoplastic Flows

A key issue for explaining bursts and explosions of high explosives (HEs) under low-velocity mechanical impacts with registered time delays is the formation of local high-temperature regions. It is demonstrated by an example of HMX that the required temperatures should significantly exceed the HMX melting point and can be obtained only due to the work of viscosity forces in the liquid phase. In this case, however, it is necessary to ensure HE flow velocities greater than the primary impact velocities by several orders of magnitude. A mechanism of generation of such velocities is proposed: squeezing of the HE, which is heated on shear strains and plasticized, from the shear layer under the action of the pressure difference along the layer. Conditions of fast decomposition of the HE in the shear layer and conditions of an explosion of the surrounding HE are formulated.