Qindong Lin

Studying the interplay among mechanical response, damage propagation, heat accumulation, and chemical reaction is essential for predicting the initiation and detonation of polymer bonded explosives (PBX). A simulation framework is proposed in this study to investigate the mechanical response and energy evolution characteristics of PBX, aiming to facilitate the research on the non-shock ignition mechanism. First, a mechanics-energy-heat simulation framework (MEHSF) is established by coupling the Continuum-Discontinuum Element Method (CDEM) and the energy-heat statistics method (EHSM). CDEM involves numerical simulation of mechanical response, EHSM focuses on numerical simulation of energy evolution and heat accumulation. An optimization algorithm for crystal-binder mesh is proposed to prevent computational termination due to the negative volume of high-aspect-ratio elements and to enhance the computational efficiency. Subsequently, the accuracy of EHSM in the dynamic case is verified based on a benchmark of a high-speed sphere hitting the smooth rigid wall. Finally, a split Hopkinson pressure bar test on PBX is simulated, and the mechanical response, energy evolution and heat accumulation characteristics of PBX are investigated. The results indicate that the crystal-binder interface undergoes the most severe damage, and the change trends of various energy components are closely related to the mechanical response characteristics of PBX.

Studying the interplay among mechanical response, damage propagation, heat accumulation, and chemical reaction is essential for predicting the initiation and detonation of polymer bonded explosives (PBX). A simulation framework is proposed in this study to investigate the mechanical response and energy evolution characteristics of PBX, aiming to facilitate the research on the non-shock ignition mechanism. First, a mechanics-energy-heat simulation framework (MEHSF) is established by coupling the Continuum-Discontinuum Element Method (CDEM) and the energy-heat statistics method (EHSM). CDEM involves numerical simulation of mechanical response, EHSM focuses on numerical simulation of energy evolution and heat accumulation, and the data is automatically transferred between algorithms. An optimization algorithm for crystal-binder mesh is proposed to prevent computational termination due to the negative volume of high-aspect-ratio elements and to enhance the computational efficiency. Subsequently, the accuracy of EHSM in the dynamic case is verified based on a benchmark of a high-speed sphere hitting the smooth rigid wall. Finally, a split Hopkinson pressure bar test on PBX is simulated, and the mechanical response, energy evolution and heat accumulation characteristics of PBX are investigated. The results indicate that the crystal-binder interface undergoes the most severe damage, and the change trends of various energy components are closely related to the mechanical response characteristics of PBX.