不同晶型CL-20冲击分解机理的分子动力学模拟OA北大核心CSTPCD

To deeply understand the impact initiation,impact ignition,detonation process,and detonation product states of en-ergetic materials under extreme conditions,the decomposition reaction processes of α-,β-,γ-and ε-CL-20 crystals under shock loading were studied using self-consistent charge density functional-based tight-binding(SCC-DFTB)in combination with multiscale shock technique.The influence of water molecules on the decomposition of α-CL-20 was also studied because α-CL-20 generally exists in the form of hydrate.The results show that γ-CL-20 has the largest compression ratio among these four CL-20 crystals at the same shock velocity.When the shock velocity is 8 km/s,γ-CL-20 completely decomposes,while the other three crystals do not completely decompose until the shock velocity reaches 9km/s.Moreover,the addition of water mole-cules can significantly increase the activity of CL-20 molecules,and accelerate the decomposition of solid phase α-CL-20.In addition,the initial decomposition path of CL-20 under shock loading is not significantly affected by the crystal forms,but is mainly affected by the shock velocity.When the shock velocity is lower than 8 km/s,the decomposition reaction is triggered by the dissociation of N—NO2 bond.However,when the shock velocity is higher than 9 km/s,the N—NO2 bond is inhibited by high pressure.The H in the C—H bond may preferentially form a five-membered ring with the adjacent NO2,and further produces NO and OH.