Instrumented Taylor impact test for measuring stress-strain curve through single trial

Abstract

In our previous study, a modified Taylor impact test instrumented using a Hopkinson pressure bar and high-speed imaging was proposed to obtain the stress-strain curve at any moment. In this method, only a linear change in the internal force with respect to the axial position in the plasticity-dominant region of the specimens was assumed. Basically, the Taylor impact test measures the impact yield stress through large non-uniform plasticity in deformed specimens and has been widely expanded, such as verifying the models used to express the mechanical behavior. However, there are no crucial methods for obtaining the stress-strain curve although the proposed method is more effective. This is because the method has not been verified experimentally or discussed sufficiently. In this study, the validity of the proposed method and the intrinsic time for obtaining the stress-strain curve are discussed through an experiment and finite element simulation at different impact velocities. The intrinsic time can be selected from the time period of phase 2 after the three phases deformation is confirmed via high-speed imaging. The reliable stress-strain curve in a low strain range at the intrinsic time can be obtained successfully using an actual experiment based on the proposed method without repeating the tests many times.