Ignition mechanism and chemical reaction of the micro-damage polymer-bonded explosives under different inertial loading conditions

Understanding the impact-induced ignition properties and energy release behavior of polymer-bonded explosives (PBXs) is critical for the safety of explosive systems. In this study, a new impact test component was designed using a light gas gun to quantify the ignition mechanism and chemical reaction of micro-damaged PBXs under different inertial loading conditions. A constitutive model was developed to describe the mechanical-thermal-chemical response of the PBXs. This model was employed to further investigate the correlation between microcracks, debonding, hot spots, and chemical reactions. The results show that the stress state of the material is not uniformly distributed due to the micro-inhomogeneities and structural defects of PBXs. The shear friction of the microcracks contributes to localized hot spots, thereby inducing ignition. The critical loading condition for ignition is the length of the steel pillar is 32 mm. The damage and hotspot temperatures of the anterior lateral and posterior lateral regions are greater than those of other locations. The ignition response is accentuated with longer steel pillars, resulting in a more violent release of energy.