Energy absorption characteristics of thin aluminium plate against hemispherical nosed projectile impact

The energy absorption characteristics of monolithic and layered aluminium plates made of aluminium 1100-H12 were investigated against hemispherical nosed projectile impact both experimentally and numerically. The span diameter of 1 mm thick monolithic plates were varied as 68, 100, 150, 200, 255, 350, 450, 550, 650 and 750 mm whereas the effect of target configuration were studied for monolithic (1 mm), layered in contact (0.5+0.5) and spaced target (0.5+0.5) of 150 mm free span diameter. The spacing between thin layers was varied as 4.5, 10, 20, 30, 40, 50 and 60 mm. Each target was impacted normally by 19 mm diameter hemispherical nosed projectile. Some of numerical results were validated with experimental results with varying target span diameter (68, 100, 150, 200 and 255 mm), layered in contact target and the target with 4.5 mm spacing. Numerical results were found to be quite close with experimental results. A pressure gun was employed to carry out the experiments while the numerical simulations were performed on ABAQUS/Explicit finite element code. Further numerical simulation results were used to calculate the energy dissipation in plastic deformation. The energy was further disintegrated in stretching in radial, circumferential, axial and tangential directions. Both the ballistic performance and energy absorption characteristics were significantly influenced by target span and configuration. The ballistic limit has been found to be significantly increased with an increase in the span diameter of the target. The monolithic target was found to be superior followed by layered in contact and spaced target.