Determination of length to diameter ratio of the bars in torsional Split Hopkinson bar.

• Novel methodology for obtained length to diameter ratio (L/D) in TSHB. • L/D is validated by experiments and obtained from FEM and Lagrange diagram are the same. • The difference between the theoretical value of velocity and numerical was 0.9%. • The shear strain compatibility was satisfied by the numerical wavelengths gained for L / D > 80. • Measurement uncertainly and repeatability are important factors in the analysis. Split Hopkinson bar is a well-known device for mechanical characterization of materials under dynamic loading. The device can be compressive, tensile, and 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 some investigations over the past several decades. However, no work has so far been performed on the forgoing ratio in torsional Split Hopkinson bar (TSHB). In this work, the length to diameter ratio of the input or output bar, L / D , is studied by numerical simulation, theory through Lagrange diagram of the TSHB and experiment. It has been found that for L / D > 80 , the incident, reflected and transmitted wavelengths 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. [ABSTRACT FROM AUTHOR]