Influence of Mass Ratio on Forward and Reverse Ballistic Impact Equivalence: Experiments, Simulations, and Mechanism Analysis

Reverse ballistic impact tests are widely used for studying dynamic responses because they provide more comprehensive and quantitative projectile/rod response results than forward impact tests. To examine equivalent forward and reverse conditions, a series of 8-cm length oxygen-free copper rods with varying length-diameter ratios was used in forward and reverse ballistic Taylor impact experiments with velocities and strain ratios of 104-215 m/s and 1.25 x 10(3)-2.5 x 10(3) s(-1), respectively. Digital image correlation (DIC) and traditional optical measurements were used to determine instantaneous responses at the mu s level. Based on DIC, transient structural deformation, and plastic wave propagation, the forward and reverse length difference at similar velocities ranges from 2 to 6.95 %. Rules governing deformation from the perspective of energy, along with rules for changes in energy and plastic wave propagation were determined. The relative deformation energy error was below 5 % for target projectile mass ratios above 20.