Further investigation on nearly constant strain-rate loading in SHPB tests for brittle materials using a pulse-shaping technique

Based on SHPB experiments and numerical simulations, this paper appraises the necessity of achieving a nearly constant strain-rate loading in split Hopkinson pressure bar (SHPB) tests of brittle materials. It is found that the inertia-induced lateral confinement of the brittle material specimens is still significant even the shaped incident stress pulse can generate a nearly flat plateau in the reflected pulse in SHPB tests. Therefore, the application of the techniques like pulse-shapers in SHPB tests on brittle materials may not change the nature of the observed transition strain rate, which represents the transition of the stress states from the uniaxial stress state to the multiaxial stress state. The inertia-induced lateral confinement effect needs to be considered in the interpretation of any SHPB results for brittle materials even though the techniques such as pulse-shapers are used.