短脉冲载荷下金属材料的层裂破坏

 本文用点炮加载聚酯薄膜飞片撞击金属靶材料，飞片速度0.714~2.24 km/s，脉冲宽度40~80 ns，击靶压力为2.280~11.952 GPa。在回收的铝、铜和钢靶样品上观察到层裂现象。通过金相分析发现它们的破坏方式与在一般较长脉冲加载下的破坏方式相似，铝和铜以延性方式破坏；钢则以脆性方式破坏。一维和二维数值模拟结果表明通常的几种层裂判据在这个应力、应变和应变率范围内也基本上适用。

THE SPALLATIONOF 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 40-80ns. It i.s 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. 1D and 2D numerical simulations were performed and three spallation criteria, maximum tensile strength, stress gradient and cumulative damage, were employed in elastic-piastic-hydrodynamic codes SSS and WSU. Comparison of'calculated and experimental data shows that above criteria, are basically appropriate even for such short loading pulse.