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 力学学报  2015, Vol. 47 Issue (1): 174-179  DOI: 10.6052/0459-1879-14-141 0

### 引用本文 [复制中英文]

[复制中文]
Liu Hai, Li Qikaiy, He Yuanhang. MOLECULAR DYNAMICS SIMULATIONS OF HIGH VELOCITY SHOCK COMPRESSED TNT[J]. Chinese Journal of Ship Research, 2015, 47(1): 174-179. DOI: 10.6052/0459-1879-14-141.
[复制英文]

### 文章历史

2014-08-13收稿
2014-09-24录用
2014-09-24网络版发表

1. 北京理工大学爆炸科学与技术国家重点实验室, 北京 100081;
2. 清华大学材料学院, 北京 100086

1 模拟及计算细节

 图 1 梯恩梯板内粒子以7 km/s 撞击固定壁面示意图(a) 及梯恩梯单胞(b) Fig.1 Schematic diagram of buttress-like TNT impact on mounting surface with 7 km/s (a) and unit cell (b)
2 结果及分析 2.1 冲击压缩与稀疏拉伸过程的$P$-$V$曲线

 图 2 冲击压缩与稀疏拉伸过程的P-V 曲线 Fig.2 P-V relations of the process of shock compression and tension
2.2 冲击压缩过程密度及粒子速度的一维分布

 图 3 冲击压缩过程的一维密度剖面(续) Fig.3 1-D density profile in shock compression process (continued)

 图 4 冲击过程的一维粒子速度剖面 Fig.4 1-D particle velocity profile in shock process

2.3 冲击压缩与稀疏拉伸过程的物理图像

 图 5 冲击压缩与稀疏拉伸的物理图像 Fig.5 Physical picture of the process of shock compression and tension
2.4 产物识别分析

 图 6 冲击过程中主要产物随时间演化情况 Fig.6 The time evolution of main products during the shock process

2.5 含碳团簇演化分布

 图 7 冲击过程中最大摩尔质量含碳团簇的演化分布(a)以及团簇中原子数量比的波动情况(b) Fig.7 Time evolution of the largest carbon-containing cluster formed (a) and fluctuations in the elemental composition (b) during the shock process
3 结论

 [1] Van Duin ACT, Dasgupta S, Lorant F, et al. ReaxFF: a reactive force field for hydrocarbons. J Phys Chem A, 2001, 105(41): 9396-9409 [2] Strachan A, Kober EM, van Duin ACT, et al. Thermal decomposition of RDX from reactive molecular dynamics. J Chem Phys, 2005, 122: 054502 [3] Agrawalla S, van Duin ACT. Development and application of a ReaxFF reactive force field for hydrogen combustion. J Phys Chem A, 2011, 115(6): 960-972 [4] Nomura K, Kalia RK, Nakano A, et al. Dynamic transition in the structure of an energetic crystal during chemical reactions at shock front prior to detonation. Phys Rev Lett, 2007, 99: 148303 [5] Liu LC, Liu Y, Zybin SV, et al. ReaxFF-lg: correction of the ReaxFF reactive force field for london dispersion, with applications to the equations of state for energetic materials. J Phys Chem A, 2011, 115(40): 11016-11022 [6] Wen YS, Xue XG, Zhou XQ, et al. Twin induced sensitivity enhancement of hmx versus shock: a molecular reactive force field simulation. J Phys Chem C, 2013, 117: 24368-24374 [7] Plimpton S. Fast parallel algorithms for short-range molecular dynamics. J Comp Phys 1995, 117(1): 1-19 http://lammps.sandia.gov. [8] Dremin AN. Shock discontinuity zone effect: the main factor in the explosive decomposition detonation process. Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences, 1992, 339(1654): 355-364
MOLECULAR DYNAMICS SIMULATIONS OF HIGH VELOCITY SHOCK COMPRESSED TNT
Liu Hai, Li Qikaiy, He Yuanhang
1. State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China;
2. School of Materials Science and Engineering, Tsinghua University, Beijing 100086, China
Abstract: We simulate the shock compression behavior of TNT with ReaxFF-MD. When shock compression is complete, all of the TNT molecules are decomposed, and when volume compression is up to the 40% of original volume, pressure of the system reaches a peak. Close behind is rarefaction wave reverse stretching the compressed energetic materials and leading to a large number of atoms or molecules group splash to the downstream, pressure begin to unload at the same time. Density and particle wave velocity profile show a greater density in the compressed region, and the particles in a stationary state, but sharp velocity gradient in the region of compression wave. In the earlier chemical characteristics, TNT molecules shed the H, O atoms under the effect of shock compression, and then the residues aggregate to the larger clusters, and this phase associated with translational-vibrational relaxation processes. The rotational mode is subsequently transferred into vibrational modes with a time scale of 0.5 ps. Fragment analysis shows that a large number of C—H, O＝N bonds rupture to form the OH, H2, H2O, N2 groups and parts of H, O atoms are free in the system. The molar mass of the carbon-containing clusters under the joint actions of compressional wave ahead and rear compression is accumulating gradually from the analysis. Atomic ratio in the carbon-containing clusters tends to balance (O/C=0.680, H/C=0.410, N/C=0.284), but less than the ratio in the initial structure.
Key words: shock compression    TNT    reactive force field    molecular dynamics