Determination Of Length To Diameter Ratio In Torsional Split Hopkinson Bar

Determination Of Length To Diameter Ratio In Torsional Split Hopkinson Bar

Split Hopkinson bar (SHB) is a well-known device for mechanical characterization of materials under dynamic loading. The device can be compressive, tensile, torsional or shear. The effect of dimensions of SHB in particular the length to diameter ratio, L/d, of the bars has been the subject of numerous investigations over the past several decades. However, little work has so far been performed on the forgoing ratio in torsional Hopkinson bar (TSHB). In this work, the length to diameter ratio of the input or output bar, L/d, is studied by numerical simulation and theory through Lagrange diagram of the TSHB. It is found that for L/d>80, the incident, reflected and transmitted wave lengths obtained from simulations and Lagrange diagram are the same. This value of L/d is quite consistent with that usually recommended for compressive and tensile versions of SHB. The numerical model of TSHB is validated by Lagrange diagram and experiment.