基于DIHPB技术的高应变率剪切测试方法

在测试材料动态力学性能时，直接撞击式霍布金森压杆（direct impact Hopkinson pressure bar，DIHPB）实验系统相对于分离式霍布金森压杆（split Hopkinson pressure bar，SHPB），往往能获得更高的应变率。本文中采用一种新型双剪切试样，在DIHPB系统下对603钢进行了动态剪切测试。获得了603钢在应变率1 500～33 000 s?1的剪应力-剪应变曲线，并与SHPB系统下的测试结果进行了对比。结果表明，由两种测试方法获得的流动应力具有较好的一致性，但曲线的上升沿存在明显区别。采用数值模拟对DIHPB方法的准确性进行了验证，并对该实验方法的适用条件进行了分析。采用DIHPB方法，可以观察到603钢的流动应力存在明显的应变率效应，但在较高的加载速度下材料的失效应力随着加载速度的增加而呈降低趋势。

A high-strain-rate shear testing method based on the DIHPB technique

Compared to the split Hopkinson pressure bar (SHPB) technique, the direct impact Hopkinson pressure bar (DIHPB) method can usually obtain a higher strain rate in dynamic tests of material properties. Based on the DIHPB system, a new double shear specimen was used to measure the shear stress-shear strain curves of 603 steel at strain rates ranging from 1 500 s?1 to 33 000 s?1. Through comparison with the testing results achieved in a SHPB system, it is found that the flow stresses determined by the two methods have a good consistency, but a difference exists in the rising parts of the flow stress curves. Numerical simulation was carried out to validate the DIHPB method, and the proper testing condition of this method was analyzed. With this method, it was observed that the flow stress of 603 steel showed an obvious strain rate effect. At higher loading speeds, however, the failure stress of the material presented a decreasing tendency with the increase of the loading speed.