Experimental and numerical investigation of monolithic and homo-stacked target plates of AA2014-T6 subjected to blunt and hemispherical projectiles

Abstract

In this article, the ballistic response of thin sheets of the aluminium AA2014-T6 in monolithic and homo-stacked configurations was studied experimentally and numerically. Firstly, the experiments were performed on 1 and 2 mm thick monolithic and 1 + 1 mm homo-stacked target plates with blunt and hemispherical nose shape projectiles at different velocities. All experiments were carried out using a single stage gas gun coupled with two ultra-high-speed cameras. Transient response and full-field out-of-plane displacement of the target plates are analysed using 3D digital image correlation technique (3D-DIC). During the investigations the nose shapes of the projectile were found to have a significant influence on both out-of-plane displacement and failure mode of the impacted plates. The target plate is penetrated by shear plugging in the event of a blunt projectile, whereas for a hemispherical projectile impact, penetration occurred from first tensile stretching and then shear plugging. It was also found that the ejected plug and hole size are almost the same and equal to the projectile’s diameter for blunt projectiles. While in case of hemispherical impact both were less than the projectile’s diameter. Secondly, 3D FE simulations for all the configurations were also performed using J-C plasticity and damage criteria. The simulation results were found to be in accordance with the experimental results in terms of failure mode, ejected plug size and plate hole size. Detailed Russel error analysis was also performed to validate the correlation between the experimental and numerical data.