Experiments and modeling of HMX granular explosives subjected to drop-weight impact

Abstract

The drop-weight impacts on a thin layer of cyclotetramethylene tetranitramine (HMX) explosive particles have been performed. The drop-weight impact machine is equipped with high-speed photographic techniques. Effects of drop heights and the amount of particles on compaction, deformation, and thermal responses were investigated. Considering the contact plasticity, friction, melting, fracture, as well as chemical reaction, an analytical model based on heating and kinematics equations for a single layer of explosive particles has been developed. The calculated average pressure, loading time and time-to-ignition agree well with experimental measured ones. Threshold conditions for ignition can be derived from the predicted temperature history curves. Individual particles' pressure-strain exhibited stress-strain-like relationships, from which close relations can be found between experimental phenomena and the material's softening/hardening characteristics.

X‐ray Phase Contrast Imaging of the Impact of Multiple HMX Particles in a Polymeric Matrix

“…These debated interactions are wide‐ranging including defect and pore interactions , particle‐particle interactions , energy dissipation , and frictional heating ; however as this paper focuses on PBX samples with two or more HMX particles, the most relevant factor is the particle‐particle interactions and frictional heating. Zhou et al .…”

“…These debated interactions are wide-ranging including defect and pore interactions [6-9], particle-particle interactions [10,11], energy dissipation [12], and frictional heating [13][14]; however as this paper focuses on PBX samples with two or more HMX particles, the most relevant factor is the particle-particle interactions and frictional heating. Zhou et al looked into the surface roughness and found that there is a "statistically significant" correlation between the surface quality and the shock sensitivity [1].…”

X‐Ray Phase Contrast Imaging of the Impact of a Single HMX Particle in a Polymeric Matrix

“…Other dynamic processes include impact, chemical reaction or ignition, and growth of hot spots. Despite extensive literature on this topic a complete understanding of all the processes and dynamics does not yet exist, especially at the particle or microstructure level [2][3][4][5][6][7][8][9][10][11][12][13]. Studies have examined a variety of sample geometries, materials, and loading conditions.…”

“…It was found that lower density samples build-up to detonation quicker and that age doesn't affect the shock wave profile [6]. Wu et al also considered the sensitivity of HMX particles by performing dropweight experiments [7]. Both single and multiple particles were tested, and it was determined that initiation sensitivity is partially dependent on particle-particle interactions.…”

Theoretical studies on two novel series of energetic cyclic nitramines

“…During the last few decades, high-energy density compounds (HEDCs) with high positive heats of formation (HOFs), high densities (q), excellent detonation properties [detonation velocity (D) and detonation pressure (P)], good thermal stability as well as low impact, and shock sensitivities have been receiving considerable attention to meet the continuing development of national defense and economy [1][2][3][4][5]. Among various types of HEDMs, high energetic cyclic nitramines constitute a unique class of energetic materials and have played an important role in this field.…”