Numerical evaluation of ballistic limit velocity and experimental ballistic response of 25 mm thick aluminium 7075 alloy targets

Abstract

The numerical ballistic limit velocity and experimental ballistic response of 25 mm thick AA7075-T651 and solution-treated AA7075 targets were investigated in this paper. In a numerical model, the ballistic limit velocity of 25 mm thick AA7075-T651 and solution-treated AA7075 targets against varied striking velocities in the range of 100–1500 m/s deformable bullets was determined. An experimental ballistic response of 25 mm thick AA7075-T651 and solution-treated AA7075 targets against 7.62 × 51 mm Full Metal Jacket (FMJ) bullets at a high velocity impact of 850 m/s was conducted. Both conditioned targets' tensile, hardness, and impact properties were evaluated. Fracture surface morphology and micrographs of post-ballistic tests were observed using a scanning electron microscope. A numerical model predicted that the optimised ballistic limit velocity of AA7075-T651 and solution-treated AA7075 targets would be 675 and 445 m/s, respectively. Spall fragmentation and the formation of an irregular cavity were observed in AA7075-T651 condition targets, whereas petalling and uniform hole morphology were observed in solution-treated AA7075 condition targets. Experimental ballistic test targets' depth of penetration results show a good correlation with numerically predicted results. A micrograph reveals that there were noticeable changes in the microstructures of solution treated AA7075 condition targets.