An overview of vibration effects on energetic materials

Abstract. This work presents an overview of the most significant literature exploring the vibration effects of energetic materials, emphasizing the thermal energy derived from friction and viscoelastic behavior from stress concentrations in localized regions that can trigger ignition or material structure degradation. The mechanical and thermal actions on energetic materials can induce structural damage, cracks, and even decomposition or explosion. These phenomena are preceded by changes in the structural and physicochemical characteristics of the material, which can affect the mechanism and kinetics of decomposition reactions. Therefore, they are of significant scientific and technological interest because of the necessity to predict safe regimes during production, processes, transport, and operation. Notable findings include the transition from thermal decomposition to explosion of RDX crystals subjected to vibrational loading at 110 Hz and compression of 200 MPa, as well as changes in RDX crystal structures observed via X-Ray and IR spectroscopy. Two ignition mechanisms, hot spot and cook-off, are discussed: the former occurs when cooling relaxation time exceeds one stress cycle, while the latter involves an overall material temperature increase due to friction and viscoelastic effects. The existing literature suggests that, despite high temperatures, hot spots contribute only marginally to bulk heating, except under plastic deformation or high-frequency loading conditions. Recent studies on HMX crystals indicate that binder adhesion significantly influences localized temperature rise, with dynamic loading resulting in substantial thermal responses. This concise review underscores the necessity of comprehending localized heating phenomena in energetic materials to mitigate the risk of ignition, emphasizing the crucial role of incorporating vibration tests in safety validations.