Characterizing the shock sensitivity of HMX using laser-driven flyers

Abstract. Improving the safety of the shock initiation of energetic materials is an advantage brought by the use of laser-driven flyers. The implementation of this technique into a usable detonator requires a rigorous characterization of the energetic material’s shock sensitivity. Using a Nd:YAG laser (1064 nm, 550 mJ, 6 ns pulse duration) in confined interaction to generate flyers with a diameter of 1 mm punched out of metallic coatings deposited onto 1 mm-thick H-K9L glass windows, go no-go tests were conducted on a HMX explosive charge. Flyer velocity was recorded using Photon Doppler Velocimetry (PDV) and critical initiation curves were obtained for different flyer thicknesses. Experimental results were compared to several energy criteria. Results showed better correspondence with Bowden’s criterion. Better results were achieved for all criteria when excluding thicknesses where the flyer behaves as rod. Only one-dimensional and two-dimensional criteria were used in this work. Knowing that most laser-driven flyer exhibit some form of curvature, further studies will be necessary to determine the consequences of flyer curvature on shock initiation by laser-driven flyers.