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Terminal ballistic performance of high-strength projectiles penetrating into metallic targets is mostly concerned by both weapon and armor designers. Most existing works are concentrated on the rigid-eroding penetration regime, and limited studies have addressed the rigid-deforming-eroding penetration regime. In this paper, nineteen shots of hemispherical nosed D6A steel projectiles penetration test on 5A06-H112 aluminum targets is conducted with a wide range of velocities (696 m/s–1870 m/s). The non-monotonic dependence of depth of penetration (DOP) on the impact velocity is observed, which successively corresponds to the three penetration stages, i.e., rigid projectile penetration, deforming projectile penetration without eroding and eroding projectile penetration. Then, for the non-monotonic rigid-deforming-eroding projectile penetration regime, the applicability of the existing six classical theoretical models for both rigid and eroding projectile penetrations is evaluated. Furthermore, the transition velocities (the upper limit of rigid penetration and the lower limit of eroding penetration) are discussed and an empirical judgement criterion for the occurrence of non-monotonic dependence is proposed. Finally, by conducting the dynamic compression test, quasi-static tension test under varying temperature, etc., the Johnson-Cook model parameters for the present target and projectile are calibrated and validated by numerically simulating the present test. [ABSTRACT FROM AUTHOR]

Highlights: [•] The effect of layering depends on the strength and nose shape of projectiles. [•] The change in strength leads to the failure of projectiles. [•] The strength of projectiles affects the ballistic resistance of targets. [•] The number of layers affects the ballistic resistance of targets. [•] The different layering effect due to the transitions of failure models of targets. [Copyright &y& Elsevier]

Abstract: In this paper, the ballistic behavior of single, double-, three-, four- and six-layered plates impacted by hemispherical-nosed projectiles were experimentally investigated. Ballistic limit velocity for each multi-layered target was obtained based on the investigation of the effect of the air gap between layers, the number, order and thickness of layers on the ballistic resistance. The results showed that the monolithic thin targets presented more effective than multi-layered targets when the dominant response of monolithic targets were dishing and bulging which involved bending and stretching, and the ballistic limit velocities of multi-layered plates increased with the increase of the number of layers, although the multi-layered targets were less effective than monolithic targets. However, the monolithic targets had lower ballistic resistance than multi-layered targets if the total thickness above a specific value, the dominant target response changed from shearing to bulging and dishing when using multi-layered targets instead of monolithic targets. Moreover, the air gap decreased the ballistic resistance of multi-layered targets, but the air gap size had slight influence on the ballistic resistance. The order of layers affected the ballistic resistance of multi-layered targets, the multi-layered targets of two equal thick plates had the highest ballistic resistance followed by multi-layered targets of a thicker front plate and a thinner back plate, multi-layered targets of a thinner front plate and a thicker back plate. [Copyright &y& Elsevier]

Abstract: The present paper presents an experimental and numerical study concerning the deformation and failure behavior in the Taylor impact test. Projectiles manufactured from a commercial high strength and super-hard aluminum alloy 7A04-T6 with a nominal diameter of 12.6mm and a length of 50.8mm were fired against a hardened tool steel plate by a one- and two-stage compressed gas gun within the velocity range of 175–370m/s. Three different deformation and failure modes were observed from the test: mushrooming, shear cracking and fragmentation. Individual velocity ranges and the transitions between the deformation/failure modes are identified by both experiments and numerical simulations. Slightly modified Johnson–Cook models of strength and accumulative damage failure are employed in 3D numerical simulations to describe material behavior of the striking cylinders. Good agreement between the numerical simulations and the experimental results was found. Detailed computational results of each scenario are offered to understand the deformation and failure mechanisms. [Copyright &y& Elsevier]

Abstract: In this paper, perforation of single and three layered metallic targets by hemispherical-nosed cylindrical projectiles are studied experimentally. The circular targets of Al 1100 have a diameter of 220mm and the hemispherical-nosed projectiles are silver steel cylinders with a mass of 12.15g which are hardened to 56RC. The single layer target is 3mm thick and the thicknesses of layers of the three layered targets are 0.5, 1 and 1.5mm. The multi-layered targets are tested both when the layers are in-contact and spaced (with air gaps). Tests are carried out using a one stage gas gun. The ballistic limit velocity is obtained and the effects of order of layers and the width of air gaps between them on the ballistic limit velocity are investigated. The results show that the single layer targets have greater ballistic limit velocities than multi-layered targets. Furthermore, the ballistic limit velocity of in-contact layered targets is greater than that of spaced layered targets. [Copyright &y& Elsevier]

Abstract: This paper presents the ballistic behavior and penetration mechanism of metal–metal and metal–fabric layered structures against 7.62armour piercing projectiles at a velocity of 840±15m/s at 30° angle of impact and compares the ballistic results with that of homogeneous metallic steel armour. This study also describes the effect of keeping a gap between the target layers. Experimental results showed that among the investigated materials, the best ballistic performance was attained with metal–fabric layered structures. The improvements in ballistic performance were analyzed in terms of mode of failure and fracture mechanisms of the samples by using optical and electron microscope, X-ray radiography and hardness measurement equipments. [Copyright &y& Elsevier]