Influence of Curvature Ratio on Perforation of 2024 Aluminium by Conical Impactor

Abstract

The impact resistance of 2024 aluminium alloy target plate of varying curvature ratio has been studied against conical impactor through numerical simulations using ABAQUS. The curvature ratio (h/r) of the target was varied as 0, 0.25, 0.5, 0.75 and 1.15 and the curvature ratio was calculated as the ratio between apex height (h) and radius (r) of the target. The apex height of the target (h) was varied as 0, 17.1, 34.2, 51.3 and 68.4 mm, whereas, the span (l) and radius (r) of the target are 119 and 59.5 mm, respectively. The material parameters for the Johnson–Cook model were employed to predict the material behaviour of target as well as projectile as available in literature [1,2,3]. The impact velocity of projectile was 605 and 180 m/s, considered against the chosen target configuration to study the influence of varying incidence velocity. The choice of 180 m/s incidence velocity is likely to be equivalent to the ballistic limit of 3.18 mm thick 2024 aluminium target, whereas, the 605 m/s incidence velocity was considered based on the assumption that hand guns were operated in the range of 500–820 m/s incidence velocity. It was observed that when the incidence velocity is 605 m/s, the resistance of target with varying curvature ratio is insignificant. However, the incidence velocity is 180 m/s, the resistance of the target was found to be increased significantly with increasing curvature ratio. Therefore, it is concluded that the incidence velocity is close to the limiting velocity, of 180 m/s, the resistance of the target with curvature ratio of 1.15 was found to be increased by 52% as compared to the target with curvature ratio of 0.