Modeling of Ignition in a Single Layer of Impacted Energetic Crystals

Abstract

A thermal‐mechanical model for the ignition of a layer of cyclotetramethylene tetranitramine (HMX) particles under drop‐weight impact was developed. Considering the micro‐particle plasticity, frictional heating, melting, fracture, and chemical reaction at particle level, effects of loading parameters and sample characteristics on ignition and mechanical responses were discussed. The threshold values for ignition to occur under different loading conditions and various material parameters can be predicted. The model was validated by comparing experimental measured and calculated mean pressure‐strain curves, which showed two turning points due to localized fragmentation and melting. Relationships between thermal and mechanical responses at the particle level were examined.

A Hot Spots Ignition Probability Model for Low-Velocity Impacted Explosive Particles Based on the Particle Size and Distribution

“…A micromechanics approach based on heating equations and the kinematic and deformation description for a thin layer of HMX energetic powders under drop weight impact is established; the work focuses on the thermal and mechanical processes that act to transfer the input kinetic energy into the localized high-temperature ignition sites [11]. Wu et al [12][13][14] established some microscopic hot spot model, and they used those model to explain explosives thermodynamic performance under low-velocity impact. In multiple phase processes, interphase heat exchange plays the role of heat losses in homogeneous combustible gas mixtures.…”