The Spallation of Metal Plates under Short Pulsed Loading

Aluminum, brass and steel plates with thickness of 2.0~7.8 mm were impacted by thin mylar flyers at velocities 0.714~2.24 km/s, driven by an electric gun. The pressure pulse duration was about 40~80 ns. It is found from metallographic observations of the target samples that the fracture and spallation mechanism is just the same as that under longer pressure pulse loading. 1 D and 2 D numerical simulations were performed and three spallation criteria, maximum tensile strength, stress gradient and cumulative damage, were employed in elastic-plastic-hydrodynamic codes SSS and WSU. Comparison of calculated and experimental data shows that above criteria are basically appropriate even for such short loading pulse.