Numerical investigation on ballistic resistance of aluminium multi-layered panels impacted by improvised projectiles

This paper presents a numerical study of perforation of the aluminium multi-layered targets impacted by steel projectiles in the shape of a ball, nut and nail. For the construction of the protective panels arc-, rectangular-, V- and U-shaped sheets of metal were considered. During the tests the panel thickness was constant at 160 mm. The panels were composed of 1.5-mm-thick aluminium sheets, and the initial speed of debris was 500m/s\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$500~\mathrm{m{/}s}$$\end{document}. A comprehensive numerical study indicated the shape of the layer that had superior ballistic resistance and the best strength-to-weight ratio. Computational analyses were also used to investigate the influence of thermal softening and strain rate hardening in the Johnson–Cook constitutive model on the ballistic performance of layered targets. The number of layers required to stop the penetrating objects was compared for the rigid and deformable projectiles. Based on the comparative studies, some guidelines for engineering tasks involving exploration of number of possible technical solutions were proposed.