Shock activation theory for aluminum nano-particles outside high explosives

Abstract

Recent research has revealed that aluminum nanoparticles (ANPs) can also be activated by shock waves when positioned outside high explosives. To explore the shock activation of the ANPs in the composite explosive (where ANPs are placed outside high explosives), the shock activation theory for ANPs is proposed. According to this theory, ANPs heat up from initial state to a critical reaction state due to both shock work and plastic work. To verify this theory, we conducted four rounds of explosion experiments in an enclosed space, varying ANP layer thicknesses and measuring quasi-static pressure to estimate the activation efficiency of the ANPs. The experimental results show that, as the ANP layer thickness increases from 0.44 mm to 0.94 mm and 1.90 mm, the activation degree of ANPs decreases from 59.4% to 44.8% and 46.5%, respectively. This indicates that thicker ANP layers result in lower activation efficiencies. Notably, all experimental results fall within the range of theoretical predictions, confirming the reliability of the shock activation theory for ANPs. Further research indicates that the activation efficiency of ANPs can be regulated by increasing the detonation velocity of the inner explosive and adjusting the fill ratio of the ANP layer, thereby enhancing the total energy of the composite charge. Our study provides a new perspective on the activation mechanism of ANPs outside high explosives and offers theoretical references for regulating energy output in explosive charges.