Normal and oblique impact of APM2 bullets on AA6082-T4 aluminum plates

摘要

Normal and oblique impact of hard core APM2 bullets on 20 mm thick AA6082-T4 aluminum plates have been investigated both experimentally and numerically. The bullets were fired from a long smooth-bore Mauser rifle, and impacted the target plates at 0°, 15°, 30°, 45° and 60° obliquity. The impact velocity was about 830 m/s in all tests. During testing, the initial and residual bullet velocities were measured by various laser-based optical devices, and two synchronized high-speed video cameras were used to photograph the penetration process. The experimental results show that the velocity drop during perforation is almost unaffected by oblique angle to about 30°. At higher oblique angles, a strong velocity drop is observed. For this particular material the critical oblique angle, i.e. the angle where the penetration process changes from bullet perforation to ricochet, is about 60°. At higher oblique angles the bullet was not able to perforate the target plate. A material test programme was also conducted for the AA6082-T4 plate to calibrate a modified Johnson-Cook constitutive relation and the Cockcroft-Latham fracture criterion, while material data for the bullets mainly were taken from the literature. 3D non-linear finite element simulations with detailed models of the bullet were finally run, and good agreement between the numerical results and the experimental data was in general obtained.