冲击加载下20钢中弹性前驱波衰减与应力松弛行为实验研究

 通过改变样品厚度，对平面冲击加载下20钢的弹性前驱波的波幅衰减和应力松弛进行了实验研究。采用激光速度干涉测速仪（VISAR）实测了样品后自由面速度历史，采样频率达到1 ns，保证了实验结果的准确性。实验结果显示：Hugoniot弹性极限随着传播距离呈指数衰减，在所研究的样品厚度范围内，Hugoniot弹性极限减小了44%；应力松弛行为和弹性前驱波的上升沿时间也依赖于传播距离；冲击加载的强度对材料动态屈服行为的影响很小。

Investigation of Precursor Decay and Stress Relaxation in Shock-Compressed 20 Steel

The precursor decay and stress relaxation behavior of 20 steel under shock compression were studied using planar impact experiments with different sample thickness.Time resolved free surface velocity profile measurements are performed by means of a velocity interferometer system for any reflector(VISAR) with the time resolution of 1 ns.The results show an apparent decay in the Hugoniot elastic limit with increasing propagation distance,as well as a stress relaxation behind the elastic wave front,and nearly 44% loss of Hugoniot elastic limit was observed in the present sample thickness range.The rise time of elastic wave fronts as a function of the sample thickness has also been determined accurately.Experiments with different impact velocities are carried out,and indicate apparently the independence of the dynamic yield behavior on the loading stress amplitude.