Ignition and Combustion Developments of Granular Explosive (RDX/HMX) in Response to Mild‐Impact Loading

Abstract

The experimental analyses of ignition and burning responses of mild‐impacted granular explosive, namely, cyclotrimethylene trinitramine (RDX) and cyclotetramethylene tetranitramine (HMX), were performed based on an optimized drop‐weight system equipped with a High‐Speed Camera (HSC). It has been found that jetting phenomena observed by HSC is the result of the energy released by gaseous products, which push the pulverized or melted explosives to splash radially. Jetting is the only and the most obvious difference between reactive and inert particles prior to combustion so that it can be regarded as the sign of ignition more accurately than other ways. For RDX sample, the molten phase plays an important role in the hot‐spots formation. After a piece of waxed paper is put on the glass anvil, the jetting of molten‐phase RDX will be limited due to the high‐roughness of waxed paper. Moreover, ignition growth to burning probability of RDX particles is increased compared with the non‐waxed paper case. Radial deformation velocity, jetting velocity, and flame propagation velocity have been estimated via image processing, making it possible to quantify the violence of mechanical deformation and chemical reaction.

Influence of Particle Size of Explosive on Ignition Mechanism Under Low Velocity Impact

“…Under the same loading conditions, the sample also showed a long-term, large-scale light transmission phenomenon. After the experiment, the researchers observed the wax paper under a microscope and found evidence that the sample melted into the wax paper and solidified in the "groove" of the wax paper [20][21][22]. The experimental process images of 700 μm small particles are very similar to the experimental images of RDX, which have experienced the process of fragmentation, slow radial expansion, and light transmission loading.…”

Effect of aging on damage properties and reaction characteristics of typical 2,4‐dinitroanisole (DNAN)‐based melt‐cast explosives under low‐velocity impact

“…Only 1 % of the material particles producing microcracks will significantly promoted the combustion behavior of the sample. SEM analysis results indicated that the combustion rate sensitivity of the DNAN‐based MCEs was directly related to the microstructural damage of the HMX particles [26, 34].…”

Effect of temperature on ignition mechanism of Ammonium Perchorate (AP) particles under drop weight impact

“…Wu et al. [11, 12, 13] modified the traditional drop hammer device and combined with the high‐speed camera to carry out the drop hammer impact loading experiment on HMX, RDX and other energetic particles, and recorded the plastic deformation, melting, ignition, combustion and extinguishing process of energetic particles. The effects of drop weight height and energetic particle looseness on hot spot formation and ignition were studied.…”

“…Perry et al [9,10] embedded silica spherical sand particles into the contact surface of energetic materials sample and anvil to prove the conclusion that friction mechanism induces ignition of energetic materials. Wu et al [11,12,13] modified the traditional drop hammer device and combined with the high-speed camera to carry out the drop hammer impact loading experiment on HMX, RDX and other energetic particles, and recorded the plastic deformation, melting, ignition, combustion and extinguishing process of energetic particles. The effects of drop weight height and energetic particle looseness on hot spot formation and ignition were studied.…”