Enhancing Specimen Grip in Torsional Split Hopkinson Bar to Characterize Engineering Materials Under Pure Torsional Load

Torsional Split Hopkinson Bar (TSHB) is the primary apparatus used to generate non-dispersion shear waves and characterize material behavior under dynamic shear stress. However, challenges associated with specimen gripping, especially at high strain rate conditions have limited its application to low strain rates. In this work, a novel connection using a Male-Female built-in Hexagonal Joint (MFHJ) is proposed as an engineering solution to provide a strong connection between the torsional specimen and the input and output bars of the TSHB apparatus. The male hexagon is formed on the specimen tips and the female hexagon is formed on the input and output ends of the torsional Hopkinson bar. This technique is validated numerically and utilized experimentally to study the dynamic material responses of titanium-G5. This work describes the operating principle, numerical validation, and experimental setup of the TSHB apparatus, MFHJ manufacturing, and testing. The results indicate a stable and consistent loading rate in the specimen in addition to providing equilibrium conditions at a high strain rate.