A NUMERICAL ANALYSIS OF THE EFFECT OF EROSION STRAIN ON BALLISTIC PERFORMANCE PREDICTION by D. Nandlall

This memorandum examines the effect of the erosion strain parameter on the numerical simulation results of the penetration of two different projectile/target systems. This parameter permits the failure of the material and numerically allows the penetration of the target. The first system examined consists of the SS109 5.56-mm bullet striking a 10.8-mm 6061-T6 aluminium target while the second system consists of the M80 7.62-mm bullet striking a 76.2-mm semiinfinite aluminium target. For the SS109 5.56-mm case, it was found that the ballistic limit increased significantly as the erosion strain is increased above 0.4, but as it reaches about 1.3, it becomes less and less dependent on the erosion strain. In the case of the M80 7.62-mm projectile, both the depth of penetration and crater volume were examined as a function of the erosion strain. For erosion strains ranging from 0.5 to 3.0 a significant dependence of the penetration results on the erosion strain was observed. For erosion strains above 3.0, most of the penetration results were observed to be within an acceptable range of the experimental value.