Influence mechanism of tantalum foil on the fracture behavior of cylindrical shells under detonation loading

To overcome the strength reduction problem caused by shell grooving, a pre-control method involving bonding high-impedance tantalum foil onto the outer surface of the shell was proposed. The influence of tantalum foils with different shapes and effective lengths on the fracture of cylindrical shells under inner explosion was investigated through experiments. It was found that bonding tantalum foil to the outer surface could significantly enhance the controllability of shell fragmentation, resulting in the generation of more large-mass fragments with regular shapes and high integrity. The microscopic characteristics of the fragments indicated that the tantalum foil played a shielding role in crack generation on the outer surface of the fragments, thereby reducing internal damage within the fragments. Moreover, shear fracture was the predominant mechanism for shell fragmentation. The evolution process of shell fracture was revealed through shock wave theory and numerical simulation. It was found that the rectangular tantalum foil first separated from the shell, followed by a collision, and then cracks propagated towards the inner surface. The fenced tantalum foil mainly dominated the shell fracture through a cutting action, and the cracks originated from the intersections of shear bands. In addition, the numerical simulation results also indicated that externally bonding tantalum foil could effectively reduce the peak tensile stress of the shell. When the effective length of the rectangular tantalum foil was 1.3, the shear cracks precisely converged on the inner surface of the shell, and the fragments formed exhibited the best uniformity.