Numerical simulation of drop weight impact sensitivity evaluation criteria for pressed PBXs

Abstract

A thorough understanding of drop-weight impacted responses for polymer-bonded explosives (PBXs) is significant to evaluate their impact sensitivity. The characteristics of the drop-weight impacted pressed PBXs including deforming, fracturing, forming a local high-temperature region and igniting, were simulated using a coupled mechanical-thermo-chemical model integrating micro-defects evolution. A novel evaluation method for impact sensitivity is established using the relation between the input kinetic energy and the output energy due to deformation, crushing energy, local hot spot energy and ignition. The effects of impact velocity on sensitivity were analyzed and the critical local ignition impact velocity is determined as 4.0–4.5 m/s. The simulated results show that shear-crack friction heating is the dominant ignition mechanism. The region along the boundary of PBXs sample is the most hazardous regions where ignition first occur. The propagation of stress wave in PBXs causes shear-crack hotspot and bulk temperature exhibiting an approximate 45° direction evolution path, which is the main reason that dominated damage-ignition region transits from the boundary to the central of sample.

Keywords

• Polymer-bonded explosives (PBXs)
• Drop weight impact
• Numerical simulation
• Sensitivity evaluation criterion
• Hotspot mechanism