Investigation on ignition of an explosive charge in a projectile during penetration based on Visco-SCRAM model

Aimed to the safety of an explosive charge in a projectile during penetration, the visco-statistical crack mechanics (Visco-SCRAM) model was applied to numerically calculate the bulk heat of the explosive charge, the heat produced by the friction between explosive charge cracks, and the heat induced by the friction between the explosive charge and the projectile inner wall. The contribution of the above three mechanisms to the temperature rise of the explosive charge were analyzed, the ignition mechanism of the explosive charge was discussed, and the critical initial penetration velocity of the projectile was obtained corresponding to the ignition of the explosive charge. The investigated results show as follows: (1) the heat induced by the friction between the explosive charge and the projectile inner wall has a certain contribution to the temperature rise of the explosive charge, and this contribution gradually increases as the initial penetration velocity of the projectile increases; (2) the bulk temperature rise produced by the viscosity, damage and adiabatic volume change plays a weak role in the ignition of the explosive charge; (3) the hot spot formation by the friction between the explosive charge cracks is the physical mechanism for the ignition of the explosive charge; (4) the Visco-SCRAM model can be used to predict the ignition responses of explosive charges to low strength and long pulse loads.