冲击加载下 PBX 界面对热点形成和安全性影响

The interfacial structure of polymer-bonded explosive (PBX) has a significant effect on the hot spot formation and impact safety. In order to study the ignition response process of PBX under impact condition, a finite element model reflecting the real internal structural characteristics of the PBX is established by digital modeling and vectorization of images. The model considers the heat generated by friction, the temperature rises caused by crystal deformation, and the exothermic reaction. The hot spot formation under PBX impact load is numerically simulated. Hot spot density is introduced as a basis for determining whether material ignition occurs, and the effects of crystal surface roughness and crystal coating defects on the ignition sensitivity and impact safety of PBX are analyzed. The results show that the internal heat of PBX initially comes from frictional heat generation and crystal deformation during impact loading, and when the temperature gradually raises, the heat mainly comes from the exothermic reaction of crystal. The critical hot spot density for material ignition is 0. 68 mm ^{- 2}. Reducing the crystal surface roughness and improving the coating quality of crystal can help to inhibit the formation of hot spots and reduce the material sensitivity, which can improve PBX safety. This work can be used to evaluate the ignition sensitivity and safety of high explosives and guide their production and processing.