Constant true strain rate loading under Hopkinson tension bar

• Universal incident wave formulation is deduced for constant true strain rate of SHTB. • Its merits are verified via both experiments and simulations across various materials. • Theoretical relation is proposed to experimental achievement between striker and wave. The Hopkinson tension bar has been widely employed for obtaining the dynamic tensile behavior of materials under high strain rates, and a constant true strain rate is theoretically required for evaluating the potential strain rate effect of materials. However, it actually happens seldom. In this study, a universal incident stress wave equation is theoretically derived based on stress wave theory, which functions to conduct tensional and constant true strain rate loading on various materials. Experiments on different materials are performed to verify its advantages, together with extensive evidence from numerical simulations for true strain rate loading. Experimental achievement is approached by an abnormally shaped striker tube for an ideal incident stress wave, and the quantitative relation between the wave configuration and striker tube shape is also theoretically formulated for actual experimental guidance demonstrated via numerical simulations. The findings facilitate the efficient performance of the Hopkinson tension bar and the evaluation of advanced materials.