六硝基六氮杂异伍兹烷/2, 4, 6-三硝基甲苯共晶冲击起爆过程的分子动力学模拟

多尺度冲击技术可以准确的再现含能材料冲击起爆过程中冲击波阵面及反应区内的热力学和化学反应路径. 文本利用反应力场分子动力学(ReaxFF-MD)对六硝基六氮杂异伍兹烷/2, 4, 6-三硝基甲苯(CL20/TNT)1:1共晶沿<110>方向以6–10 km·s^-1的冲击速度进行冲击压缩模拟. 产物识别分析显示当冲击速度≥7 km·s^-1时, 冲击激发化学反应发生, 并且利用Rankine-Hugoniot守恒关系求得冲击起爆压力为24.56 GPa. 再者, 比较了冲击速度与粒子速度, 冲击速度与冲击诱发形变的关系, 当冲击速度为7–8 km·s^-1时, 冲击起爆发生, 系统经历弹- 塑性相变, 初级化学反应及次级化学反应, 并且相变与化学反应同时进行, 对于较高的冲击波速度(≥9 km·s^-1), 共晶系统内为过驱响应, 热力学参数均出现陡峭的梯度变化, 冲击波压缩材料直接阶跃至塑性变形阶段, 并且此阶段出现大量的碳原子.

Molecular dynamics simulations of sho ck initiation of hexanitrohexaazaisowurtzitane/trinitrotoluene co crystal

Multiscale shock technique (MSST) has been shown to accurately reproduce the thermodynamic and chemical reaction paths throughout the shock wave fronts and reaction zone of shock initiation of energetic materials. A 1:1 cocrystal of hexanitrohexaazaisowurtzitane/trinitrotoluene (CL20/TNT) is shocked along the <110> orientations under the conditions of shock velocities lying in the range 6–10 km·s^-1 in ReaxFF molecular dynamics simulations. Products recognition analysis leads to reactions occurring with shock velocities of 7 km·s^-1 or stronger, and the shock initiation pressure is 24.56 GPa obtained from the conservation of Rankine-Hugoniot relation. Comparisons of the relationships are carried out between shock velocity and particle velocity, shock velocities and elastic-plastic transition. During shock initiation with the shock velocities lying in the range 7–8 km·s^-1, the shocked systems correspond to an elastic-plastic deformation, primary chemical reactions, and secondary chemical reactions. And the elastic-plastic transition coincides with the chemical reaction at higher shock velocity (≥9 km·s^-1), the cocrystal material response is over-driven, and all the thermodynamic properties show steep gradients, the compressed material by the shock wave steps into the plastic region, and a large number of carbon atoms appear in the early stage of over-driven shock initiation.