Mechanics of dwell and post-dwell penetration

This article presents test data, analysis and computed results for gold rods impacting silicon carbide targets. This work focuses on the dwell phenomenon, but also investigates the penetration response. Experiments are presented for several target configurations including targets that use a small diameter copper buffer, targets that use a large diameter copper buffer, and targets that use no buffer. The dwell-penetration transition velocity for a silicon carbide target with no buffer is 822±46 m s-1 and increases to 1538±12 m s-1 when a buffer is used. The results demonstrate the significant effect a buffer has on interface defeat and that silicon carbide can resist extremely large surface stresses (24 GPa) without the use of any confinement or prestress. A significant finding is the non-linear 'erratic' penetration velocity that occurs when dwell is not maintained. Computations are also presented that reproduce the effect of using a buffer including the effect of buffe r separation. Of particular interest is the non-linear penetration velocity produced in the computed results.