Mesoscale modelling of the Shock Detonation Transition of a heterogeneous explosive

Mesoscale simulations of the Shock Detonation Transition (SDT) of heterogeneous explosives provide a means to better understand the SDT at the macroscale. In literature, there has been efforts to determine the formation of hot spots in an explosive microstructure from an impact of a flyer plate. However, studies that focused on hot spot growth and its influence on the shock acceleration are more scarce. In recent experimental studies by Johnson et al. [1-2], hot spots in HMX monocrystals and polycrystals were observed. These studies suggested that hot spots developed mainly on the surface of the crystals and that the grains were consumed by the propagation of a deflagration front. In this communication, mesoscale simulations of an explosive composed of HMX and Viton were performed. Chemical reactions in the explosive were modelled through the propagation of a deflagration front at the surface of the crystals, based on [1-2]. Accordingly, the simulations did not focus on the effects of the explosive microstructure on the hot spot formation, but essentially on their growth and its influence on the SDT. The wedge test configuration was employed on a microstructure generated by a 2D-Voronoï scheme. The shock/detonation position was post-processed from the simulations and used to determine the run-to-detonation distance (RDD) for different impact velocities. The Pop-plot obtained from these RDD was then compared to experimental Pop-plot data.

References

[1] Johnson, B. P., Zhou, X., & Dlott, D. D. (2022). Shock Pressure Dependence of Hot Spots in a Model Plastic-Bonded Explosive. The Journal of Physical Chemistry A, 126(1), 145-154

[2] Johnson, B. P., Zhou, X., Ihara, H., & Dlott, D. D. (2020). Observing hot spot formation in individual explosive crystals under shock compression. The Journal of Physical Chemistry A, 124(23), 4646-4653.