Observation of Reverse Jetting from a Semi‐hollow EFP after Perforating a Finite Thickness Composite Armour Panel

Abstract

A jet of material was observed exiting from the rear of the remnants of an initially semi‐hollow explosively formed projectile, which perforated a finite thickness composite armour panel. The observation of this phenomenon was made by means of flash‐X‐ray photography at two different sub‐millisecond times for a copper EFP that impacted the panel at above 2000 m/s. The jet exhibited remarkably similar characteristics to what is typically observed for shaped charge jets for similar liner materials. Progressive necking was observed in the jet and the velocity differences between necked sections were characterized. Simulation of a similar generic event by the ANSYS Autodyn hydrocode showed that reverse jet formation is possible for specific EFP geometries and impact conditions. The relatively low velocities of the jet elements in terms of the laboratory coordinates, holds promise for the soft recovery of the jetted particles.

Study on Forming Law and Penetration of a Spherical Cone Composite Structure Liner Based on the Explosion Pressure-Coupling Constraint Principle

“…The traditional single-cone, double-cone, horn-shaped liners, and hemispherical and spherical missing body liners are common structures, and a shaper is used to adjust the detonation waveform [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Small cone-shaped charge liners form a jet, large cone angle and hemispherical shapes form rod jets, and spherical missing body shaped charge liners form explosive-formed projectiles (EFP) [ 5 , 6 , 7 , 8 ]. The velocity and structure of jet are restricted by the material properties, charge structure, and liner shape [ 9 ].…”

“…The velocity and structure of jet are restricted by the material properties, charge structure, and liner shape [ 9 ]. The velocity of the traditional spherical missing body charge liner after forming is generally less than 3000 m/s, and the penetration depth is less than one times that of the charge diameter, which is difficult to break through [ 5 , 8 ]. Improving the velocity and penetration depth of the spherical missing body after forming is the focus of the current research.…”

“…It has become an important anti-armor weapon [1]. The traditional single-cone, double-cone, horn-shaped liners, and hemispherical and spherical missing body liners are common structures, and a shaper is used to adjust the detonation waveform [2][3][4][5][6][7][8][9][10]. Small cone-shaped charge liners form a jet, large cone angle and hemispherical shapes form rod jets, and spherical missing body shaped charge liners form explosive-formed projectiles (EFP) [5][6][7][8].…”