HMX晶体摩擦特性的近场动力学模拟研究

The high energy crystal HMX is extensively utilized in military and defense applications due to its high energy density, thermodynamic stability and exceptional stability. However, during processes such as manufacturing and transportation, HMX can be subjected to frictional stimuli, leading to ignition, explosions or other safety incidents. Interfacial friction has been shown to be a significant factor in localized heating and even explosions in HMX crystals. But the friction mechanism associated with HMX crystal interface has yet to be fully understood. In addition, most of the existing numerical simulation methods are based on continuum mechanics and face challenges in modeling discontinuities, such as internal damage in HMX crystals. Conversely, the peridynamic (PD) theory, which can simulate the natural initiation and propagation of cracks, has unique advantages in studying the friction behavior of HMX crystals and serves as an effective method for investigating the friction mechanisms of HMX. In light of this, a friction model that considers frictional effects between damaged cracks for HMX crystals is developed based on the thermo-mechanical PD theory to investigate how factors such as load, scratching velocity, and initial crack defects influence the frictional behavior of HMX crystals. It has been demonstrated that increasing the normal load exacerbates surface damage to the HMX crystal and deepens the damage inside the HMX. Increasing the scratching velocity leads to a rapid rise in the surface temperature of the HMX crystals, thereby enhancing interfacial friction. Increasing the scratching velocity also suppresses crack initiation and propagation. For HMX crystals containing initial cracks, the friction coefficient first decreases, then increases as the indenter passes through the cracks, before decreasing again and gradually stabilizing. It also creates a local stress concentration that induces a crack propagation path, with the induction influenced by the stress value at the crack tip. And the surface temperature near the initial crack is influenced by friction and heat conduction between the cracked interfaces, exhibiting a tendency to first increase and then decrease when approaching the crack. The results will help further elucidate the friction mechanism of high energy HMX crystals, which is crucial for maintaining the stability throughout the life cycle.