Numerical simulation of split Hopkinson torsional bars on incremental strain rate test
Ikeda Shushi; Kishida Keizo; Nakano Motohiro
Abstract:Numerical simulation of incremental strain rate test on pure copper has been executed to examine whether shear stress and shear strain can be evaluated precisely in the split Hopkinson torsional bars (SHTB). The shear stress calculated from transmitted waves as a nominal value over the gage length of the specimen shows good agreement with the value evaluated directly from the element of thin walled part of the specimen. On the other hand, the nominal shear strain and shear strain rate calculated on the basis of the relative motion at the both ends of the specimen tend to be larger than the directly evaluated values. This overestimation of shear strain and shear strain rate is due to the strain concentration and the spread of the plastic deformation near the reentrant corners of the specimen. The experimental results of shear strain measured directly by the strain gages cemented on the specimen agree well with the analytical results. Key Words:torsional impact, Hopkinson bars, incremental strain-rate, finite element method, pure copper, constitutive relation, strain concentration