Initiating insensitive munitions by shaped charge jet impact

Abstract

When it comes to attacking munitions by means of a Shaped Charge Jet Impact (SCJI), various types of reactions are likely to occur, which range from a severe detonation to a simple burning type of reaction. These differences in responses are highly affected by the properties of energetic materials as well as the Shaped Charge (SC) calibre used. This paper aimed at investigating a series of different values of the jet threshold calculated by the jet tip velocities and diameters (V² d), which was obtained using a 38 mm conical SC. The main objective was to underline the critical values of (V² d) responsible for initiating different types of reactions on 81 mm mortar bombs. Several values of the jet threshold were acquired by varying the conditioning steel plate. The jet tip velocities were measured by using two different experimental methods, by means of flash x-ray and by inserting velocity screens that accounted for computing the residual tip velocity after penetration. Explosive formulations used were 2,4,6-trinitrotoluene (TNT) as baseline and reference of conventional high explosives (HE), along with different explosive compositions based on 3-nitro-1,2,4-triazol-5-one (NTO) as insensitive high explosive (IHE) candidates. In addition, the difference between the initiation behaviour of TNT and that of NTO/TNT-based was addressed by analysing the effects of jet tip velocity, tip diameter and reactions corresponding to the impact of each value of V² d. This work focused on providing useful information towards understanding the effect of the jet energy, tip velocity and tip diameter to the response of munitions filled with various explosive formulations.