Control of Condensed-Phase Explosive Behaviour by Means of Cavities and Solid Particles

Controlling the sensitivity of condensed-phase explosives is a matter of safe handling of the materials and a necessity for efficient blasting. It is known that impurities such as air cavities or solid particles can be used to sensitise the material by reducing the time to ignition. As the ignition of the explosive is a temperature-driven event, analysing the temperature field following the interaction of a shock wave with these impurities gives a measure of the effect of the impurity on the sensitisation of the material. Air cavity collapse in explosives has been extensively studied and recently focus has shifted on the accurate recovery of the temperature field during the collapse process. The interaction of a shock wave with solid particles or with a combination of cavities and particles, has been studied to a lesser extent. In this work, we assess the effect of the different impurities in isolation, in a multi-cavity and a multi-bead configuration and as a combined particle-cavity matrix. Results indicate that the beads have a more subtle effect on the sensitisation of the material, compared to cavities. An informed combination of the two (leading order by cavities and marginal adjustment by particles) could result to a fairly accurate control of the explosive.