Laser-induced air shock from energetic materials (LASEM) method for estimating detonation performance: Challenges, successes and limitations

Abstract

Recently, a laboratory-scale method for measuring the rapid energy release from milligram quantities of energetic material has been developed based on the high-temperature chemistry induced by a focused, nanosecond laser pulse. The ensuing exothermic chemical reactions result in an increase in the laser-induced shock wave velocity compared to inert materials; a high-speed camera is used to record the expansion of the shock wave into the air above the sample surface. A comparison of the characteristic shock wave velocities for a wide range of energetic materials revealed a strong linear correlation between the laser-induced shock velocity and the reported detonation velocities from large-scale detonation testing. This has enabled the use of the laser-induced air shock from energetic materials (LASEM) method as a means of estimating the detonation performance of novel energetic materials prior to scale-up and full detonation testing. Here, we report new applications of the LASEM method including conventional energetic materials with metal additives, novel energetic materials, porous silicon impregnated with oxidizers, and aged energetic material samples. We also discuss the challenges and limitations of the technique such as sample preparation, shot-to-shot reproducibility, and reaction propagation. While the extension of LASEM to novel high-nitrogen energetic materials and aged conventional energetic material samples has been quite successful, non-organic and other highly reactive samples present some unique challenges.