抄録
The split Hopkinson pressure bar (SHPB) technique has been often used for determining dynamic stress?strain behavior of materials. Nevertheless, some specific problems still remain regarding effects of specimen size and diameter ratio between the specimen and pressure bars. In our previous study, a model was established by neglecting the kinetic energy from the energy balance and expressing the radial inertia in terms of the time derivative of strain rate and frictional forces acting on both ends of the specimen. From the established model, the actual stress can be expressed by taking sum of the evaluated stress and stress decrement as a function of friction coefficient, Poisson’s ratio and the slenderness ratio of the specimen. The proposed model shows good correspondence with the computed results obtained from the FE model. However, the reliability of the computed results is not high enough, since the assumed constitutive parameters used in the previous study were quoted from literatures. In order to confirm the higher reliability of the model, the constitutive parameters are identified from the experimental results for an Al alloy 7075-T6 by one of the authors. The FE simulations are then performed to investigate the effects of specimen slenderness ratio and diameter ratio between the specimen and the pressure bars on the evaluated stress.
