Pulse shaping with soft material for SHPB

Abstract

In the split Hopkinson pressure bar (SHPB) experiment, the state of dynamic stress equilibrium should be achieved over most of the test duration. Therefore, pulse shaping techniques which can modify the profile of the incident pulse are usually needed. In this paper, a new method for SHPB incident pulse shaping is presented. The vacuum cement material of which the strength can be ignored is used as the pulse shaper. The experimental results show that, with this method, satisfactory shaping effect can be obtained in a wide application scope. Combining the adjustment of the impact velocity and the amount of the vacuum cement, different shaping results such as sinusoid, slow-rise trapezoid can be obtained. This result would meet the needs of the dynamic stress equilibrium or constant strain rate loading in SHPB experiments. The numerical simulation result indicates that the shaping function of the material is mainly due to the radial inertial effect in the high velocity deformation process of vacuum cement.