Zhou, Tingting and Zybin, Sergey V. and Liu, Yi and Huang, Fenglie and Goddard, William A. III (2012) Anisotropic shock sensitivity for β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine energetic material under compressive-shear loading from ReaxFF-ℓg reactive dynamics simulations. Journal of Applied Physics, 111 (12). Art. No. 124904. ISSN 0021-8979 http://resolver.caltech.edu/CaltechAUTHORS:20120731-094128604
- Published Version
See Usage Policy.
Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20120731-094128604
We report here the predictions on anisotropy of shock sensitivity and of chemical process initiation in single crystal β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (β-HMX) using compressive shear reactive dynamics (CS-RD) model with ReaxFF-ℓg reactive force field. Analysis of resolved shear stress induced by uniaxial compression along three shock directions normal to (110), (011), and (010) planes leads to identify eight slip systems as candidates for shear deformation. For each of the eight slip systems, non-equilibrium reactive dynamics simulations were carried out to determine thermal, mechanical, and chemical responses to shear deformation. Shock direction normal to (010) plane exhibits large shear stress barriers arising from steric hindrance between molecules of adjacent layers leading to local dramatic energy and temperature increases under shear flow that in turn accelerate chemical bond breaking and initial product formation processes, promoting further molecular decomposition and eventually transition to detonation. This suggests that single crystal β-HMX is sensitive to shocks in direction normal to (010) plane. Shock directions normal to (110) and (011) planes reveal significantly less steric hindrance, leading to more modest energy and temperature increases followed by slower chemical reaction initiation. Thus, shock directions normal to (110) and (011) planes are less sensitive than shock direction normal to (010) plane, which agree with interpretations from currently available plate impact experiments on HMX. This validation of CS-RD and ReaxFF for characterizing sensitivity of single crystal energetic materials indicates that these methods can be applied to study sensitivity for more complex polymer bonded explosives and solid composite propellants having complex microstructures, corrugated interfaces, as well as defects.
|Additional Information:||© 2012 American Institute of Physics. Received 1 August 2011; accepted 15 May 2012; published online 20 June 2012. This work was supported by the U.S. Army Research Office (W911NF-05-1-0345 and W911NF-08-1-0124; Ralph Anthenien program manager) and by Office of Naval Research (N00014-09-1-0634; Cliff Bedford program manager). It was also supported by the National Natural Science Foundation of China (Grant No. 10832003) and by the Open Grant of State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, P. R. China (Grant No. KFJJ12-6M). Some computations in this work were carried out on the Army HPC system (the Arctic Region Supercomputer Center) (we thank Dr. Betsy Rice and Larry Davis for assistance).|
|Subject Keywords:||bonds (chemical), compressive strength, detonation, explosives, polymers, propellants, reaction kinetics, shear deformation, shear flow, shock waves, slip, thermomechanical treatment|
|Other Numbering System:|
|Classification Code:||PACS: 82.40.Fp, 62.20.F-, 81.40.Gh, 81.40.Lm, 82.20.Wt, 82.33.Vx|
|Official Citation:||Anisotropic shock sensitivity for β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine energetic material under compressive-shear loading from ReaxFF-lg reactive dynamics simulations Tingting Zhou, Sergey V. Zybin, Yi Liu, Fenglei Huang, and William A. Goddard, III J. Appl. Phys. 111, 124904 (2012); http://dx.doi.org/10.1063/1.4729114|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||31 Jul 2012 17:24|
|Last Modified:||26 Dec 2012 15:46|
Repository Staff Only: item control page