Material Characterization of Armor Steel and Investigation of Its Ballistic Performance

Dynamic behavior of armor steel grade has been investigated by implementing Johnson-Cook plasticity and failure models. The stress and strain curves obtained from the experiments at different strain rates (10−4-1550 s−1) and temperatures (25-600 °C) were used to calibrate the parameters of Johnson-Cook plasticity model. Parameters of Johnson-Cook failure model were obtained by combining finite element modeling with tensile tests. Validation of Johnson-Cook material parameters is performed using finite element simulations and digital image correlation experiments performed on notch specimens of radii between 2 and 6 mm under uniaxial tension. The ballistic impact tests were performed on 6 mm thick armor plate against 7.62 × 39 mm hardened steel core and 7.62 × 54 mm armor-piercing projectiles. The armor plate when impacted against 7.62 × 39 mm projectile exhibits indentation, while the plate undergoes complete penetration when impacted against 7.62 × 54 mm projectile. Results of ballistic tests at different incident velocities were compared by carrying out numerical simulations on armor steel plate. The ballistic limit of the plate, when impacted against 7.62 × 54 mm projectile, is obtained from numerical simulation and estimated as 825 m/s. The plate experiences a high strain rate and hence a temperature rise during the impact. The present work investigates the increase in temperature in the plate during the ballistic impact at different incident velocities. The temperature of the plate was estimated to increase up to half of its melting temperature, 810-952 K, when impacted against the 7.62 × 54 mm projectile at varying velocities between 820 and 950 m/s.