Ballistic response of double layered 1100-H12 aluminium hemispherical shell structure

Abstract

The ballistic resistance and energy absorption characteristics of the thin hemispherical shells were evaluated against ogive and blunt nosed projectile impact with varying span and configuration of the shell. The span diameter of the 1100-H12 aluminium shell was varied as 68, 100, 150 and 200 mm whereas the configuration of the shell was varied as monolithic and double layered (0.5/0.5, 0.33/0.67 and 0.67/0.33) which was hit at the crown by 19 mm diameter, 50.8 mm length and 52.5 g mass projectile. Three dimensional numerical simulations were carried out through commercially available finite element code ABAQUS. The accuracy of the numerical model was validated by comparing the numerical result of monolithic shell with experimental result conducted through the pressure gun. Numerical simulation result were further employed to extract the total energy absorption in plastic deformation by computing the strain energy in stretching in polar, radial, elevation and shear directions of the shell by using a user defined programme written in python. The influence of projectile nose shape, incidence velocity of the projectile and configuration of the hemispherical shell on the mechanics of failure, ballistic resistance, ballistic limit and energy dissipation characteristics were studied. The double layer hemispherical target showed better performance against ogive nosed projectile however opposite behaviour was observed against blunt nosed projectile.