Constitutive Behavior and Ballistic Performance of Aerospace 2A16 Aluminum Alloy under Different Impact Velocities

Abstract

2A16 aluminum alloys possess outstanding mechanical characteristics such as high specific strength and remarkable heat-resistance capacity. Figuring out the dynamic mechanical performance of 2A16 aluminum alloy over a large range of strain rates is beneficial to further broaden its application as crucial civil and military structures under extreme loading. This paper mainly focused on the mechanical properties and ballistic impact capacity of 2A16 aluminum alloy under different strain rates. Firstly, the quasi-static, intermediate strain rates and high strain rate mechanical experiments of 2A16 aluminum alloy specimens were conducted using an electronic universal testing machine, a high velocity hydraulic servotesting machine, and a split Hopkinson pressure bar (SHPB) at room temperature, which aims to acquire its dynamic mechanical properties at different strain rates and the fracture behaviors under different stress conditions. Then, the modified Johnson-Cook constitutive model and the Johnson-Cook fracture model were fitted based on the stress-strain relationships obtained from the tests. Finally, the ballistic impact experiments were carried out by a spherical nosed projectile striking on square 2A16 aluminum plates with the incident velocities ranging from 150–190 m/s. Numerical simulations based the nonlinear explicit finite-element (FE) code Ls-dyna were conducted to reproduce the ballistic impact tests. The ballistic limit velocity of 2A16 aluminum was obtained through the Recht-Ipson empirical model and the predicted results agreed well with the numerical results. The results obtained from this study can contribute to the design and optimization of 2A16 aluminum aerospace engineering structures with better impact protection capacity.