Dynamic shear fracture of an explosively-driven metal cylindrical shell

Abstract

This work investigates shear fracture behavior occurring in a titanium alloy cylinder internally filled with high explosives through the use of photonic Doppler velocimetry(PDV) array, high-speed framing camera and soft capture tank. The real-time velocity profiles diagnosed by PDV array display from overlapping to scattering, corresponding to the cylinder from uniform expansion to onset of fracture. In addition to the general findings obtained from individual diagnostics, combined analysis from the experimental measurements determines sliding velocity between sheared cracks and the overall adiabatic shear failure process of the metal cylinder is discussed.

Fragment Velocity Characteristics of Warheads with a Hollow Core under Asymmetrical Initiation

“…When the shock wave of the explosive arrived at the test point, the velocity of the point increased dramatically and then the detonation products accelerated the casing to expand gradually. The fragment velocity-time curves exhibited several fluctuations, which was consistent with the experimental results reported in the previous stud- [20,27,28]. In addition, the fragment velocity-time curves exhibited a second time acceleration because the detonation products with higher velocities moved outward to further accelerate the cylindrical casing after the collision of the shock wave or the collision of the detonation products as mentioned above.…”

Acceleration Characteristics of Discrete Fragments Generated from Explosively-Driven Cylindrical Metal Shells

“…2 Error of simulation where the charge is initiated from the center compared to experimental data is 1.02%. 3 Error of simulation with a volume detonation compared to experimental data is 1.52%.…”

“…In the experiment, the cubic preformed fragments fabricated from ANSI 1018 steel had a length of 7.95 mm. The high explosive was Octol with a density of 1.77 g/cm 3 and a detonation velocity of 8200 m/s. The charge had a diameter of 126.04 mm and a length that was twice the diameter, and the ratio of charge mass to metal mass (β) was 0.926.…”

“…Cylindrical shells filled with explosive charges are typical structures in conventional warhead design and can be sorted into the continuous shell and the preformed-fragment shell. After detonation, the metallic shells are driven to accelerate rapidly by the high-intense shock and internal detonation products, followed by large plastic deformations that ultimately lead to disintegration [1][2][3][4]. The acceleration characteristics and final velocity of fragments generated from the disintegrated shells have been of interest to the researchers for decades in the field of the structure protection and weapon effectiveness.…”

“…Note that the application of Photonic Doppler Velocimetry (PDV) arrays and high-speed framing cameras has provided valuable experimental data on the shell acceleration and disintegration [3,4,26,27]. However, to date the exact mechanism for the post-disintegration acceleration of a warhead shell remains to be discovered, this being because of the complicated interaction between fragment acceleration and gas outflow.…”