基于DIHPB 技术的高应变率剪切测试方法

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.