Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (11): 2024-2034.doi: 10.3866/PKU.WHXB201409192

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Microscopic Physical and Chemical Responses of Slip Systems in the β-HMX Single Crystal under Low Pressure and Long Pulse Loading

SONG Hua-Jie1, ZHOU Ting-Ting1, HUANG Feng-Lei2, HONG Tao1   

  1. 1. Institute of Applied Physics and Computational Mathematics, Beijing 100094, P. R. China;
    2. State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, P. R. China
  • Received:2014-06-25 Revised:2014-09-19 Published:2014-10-30
  • Contact: ZHOU Ting-Ting, HUANG Feng-Lei E-mail:zhou_tingting@iapcm.ac.cn;huangfl@bit.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (11372053, 11172044, 11221202) and Opening Project of the State Key Laboratory of Explosion Science and Technology (Beijing Institute of Technology), China (KFJJ14-06M).

Abstract:

From the viewpoint of the elastic-plastic microscopic mechanisms of explosives, we investigated the microscopic physical and chemical responses of seven dominant slip systems in the β-octahydro-1,3,5,7- tetranitro-1,3,5,7-tetrazocine (β-HMX) single crystal under low pressure and long pulse loading using the ReaxFFforce- field-based molecular dynamics method. The simulation results suggest that the seven slip systems exhibit different physical and chemical responses for loading orientations normal to the (001), (101), (100), (011), (111), (110), and (010) crystal planes. The shear stress, energy, temperature, and chemical reaction strongly depend on the loading direction. For the (010) plane, the shear stress barrier is very high, which leads to fast energy accumulation and temperature increment that contribute to the early bond-breaking process, making it the most sensitive direction. For the (001) plane, the small shear stress barrier results in slow energy accumulation and temperature increase, and thus little bond dissociation, making it the least sensitive direction. The reaction sensitivity of the slip system is suggested to be significantly related to the intermolecular contacts on the two sides of the slip plane (i.e., steric hindrance) and the reaction activity of contacted atoms or groups. Directions with large steric hindrance and high reaction activity lead to high reaction sensitivity, whereas directions with small steric hindrance or low reaction activity result in low reaction sensitivity. The slip system with relatively high chemical reaction sensitivity is suggested to be associated with the origin of“hot spots”in energetic single crystals. This study provides theoretical support for developing a more reasonable and reliable sensitivity evaluation method for high explosives.

Key words: HMX, Elastic plasticity, Slip system, Sensitivity, ReaxFF, Molecular dynamics

MSC2000: 

  • O642