中文摘要：

分析了理论临界冲击拉伸速度。指出率相关的Karman-Taylor塑性波传播理论、完全热耦合的高应变率本构关系以及绝热升温方程确定了理论临界冲击拉伸速度。对于高导无氧铜,采用典型的两类高应变率本构关系计算了理论临界冲击拉伸速度。研究结果表明：与Johnson-Cook关系对应的理论临界冲击拉伸速度明显小于与Zerilli-Armstrong关系对应的理论临界冲击拉伸速度。该文也强调指出,理论临界冲击拉伸速度仅对应于塑性波速趋于0,而实验临界冲击拉伸速度不仅与应力波效应有关,而且与杆的动态颈缩、损伤演化致断裂有关。

英文摘要：

The theoretical critical impact velocity in tension is analyzed. It is indicated that the rate-dependent Karman-Taylor theory of plastic wave propagation, the complete thermal coupling constitutive relation at high strain rates and the equation of energy balance applicable to adiabatic heating are essential to determining the theoretical critical impact velocity in tension. For oxygen-free high-conductivity copper, the theoretical critical impact velocities in tension are calculated with two typical constitutive relations at high strain rates. The numerical results show that the theoretical critical impact velocities in tension calculated with Johnson-Cook constitutive relation are smaller than that calculated with Zerilli-Armstrong constitutive relation. It is also noted that the theoretical critical impact velocity in tension is defined by the plastic wave trapping, while the experimental critical impact velocity in tension is determined by the wave effect, by the necking phenomenon and by the micro-damage evolution of a high-velocity tension bar.