Abstract:

The slip and anisotropy of 2, 4, 6-triamino-1, 3, 5-trinitrobenzene (TATB) crystal under shock loading along various directions were investigated using molecular dynamics simulation combined with reactive force field (ReaxFF). The shock strength was approximately 10 GPa, and seven shock orientations normal to the (101), (111), (011), (110), (010), (100), and (001) crystal planes were considered. For these shock directions, the slip systems that are likely to be activated are predicted to be on the {001} plane, whereas others that could not be activated exhibit large shear stress barriers. These slip characteristics are consistent with the layered structure of TATB crystal along the c axis and the planar structure of TATB molecule. The most favorable slip systems are suggested to be (101)/{001}＜100＞, (111)/{001}＜010＞, (011)/{001}＜010＞, (110)/{001}＜010＞, (010)/{001}＜1$\bar 1$0＞, (100)/{001}＜120＞, and (001)/{001}＜010＞. TATB crystal exhibits anisotropic response to shock loading, that is, the shear stress, energy, temperature, and chemical reactivity during shear deformation depend on shock direction. For the (100) and (001) shock planes, the shear stress barrier is relatively high and lasts for a long time, leading to fast energy accumulation and temperature increment, which, in turn, increase the chemical reactivity. In contrast, for the (101) and (111) shock planes, the small shear stress barrier results in slow energy accumulation and temperature rise and, thus, low chemical reactivity. The (011), (110), and (010) shock planes exhibit intermediate responses. The sensitivity of the seven shock planes can be ranked as follows: (101), (111)＜(011), (110), (010)＜(100), (001). This study provides microscale insight into the response mechanisms and structure-property relationship of TATB crystal under dynamic loading and may facilitate designing explosives with high energy but low sensitivity.

Key words: TATB, Shock, Slip, Anisotropy, ReaxFF, Molecular dynamics