Initiation Thresholds and Dynamic Characteristics of an Explosion for Thin Samples of PETN-Al Composites under Laser Irradiation

Abstract

In this paper, we measured thresholds H_cr of explosive decomposition of thin (h = 1 mm) samples of PETN-Al composites with densities in the range of ρ = 0.9–1.7 g/cm³ and variations in the concentration of aluminum inclusions in the range of 0.025–1.0 wt % upon exposure to pulses of a neodymium laser (λ = 1064 nm, 14 ns). For each ρ, inclusion concentrations n_opt, at which the threshold for explosive decomposition of H_cr is minimal, are obtained. The velocities of air shock waves (ASWs) were determined depending on sample density ρ, and the times of the start of explosive decomposition were determined depending on the inclusion concentration. The amplitude (in relative units) and time shift of the maximal pressure of an ASW at the piezodetector are determined depending on sample density. It is concluded that the explosion is governed by the SW mechanism at high densities. As sample ρ decreases, the completeness of the explosion increases, with the most likely mechanism for small ρ being explosive burning. The efficiency of explosive decomposition is higher for samples with lower densities.