The split Hopkinson bar bulge setup: a novel dynamic biaxial test method

Abstract

In sheet metal forming, very often, large plastic deformations are imposed to a thin plate. An accurate description of the material’s elastoplastic response is therefore of paramount importance to perform finite element (FE) simulations of an actual forming operation. Reliable stressstrain data till significantly larger strains compared to tensile tests can be identified by means of bulge test. In this work, a dynamic hydraulic bulge test is proposed. The novel split Hopkinson bar bulge setup, combines features of classical split Hopkinson pressure bar (SHPB) and hydraulic bulge tests. The special configuration of the Hopkinson bars leaves the sample surface fully accessible. As such, high-speed optical measurements can be performed on the sample surface allowing the application of, for instance, digital image correlation (DIC) for full-field displacement strain mapping. The potential of the facility is explored by performing experiments on 0.8mm thick Al2024-T3 sheet.