A novel full-view split Hopkinson pressure bar technique for flexural testing

This paper presents the design concept of a ring-on-ring test configuration arranged in a novel split Hopkinson pressure bar (SHPB) inspired setup. It is a generic design, but in this case, intended for investigating the equibiaxial flexural strength of small circular soda-lime-silica glass specimens at high strain-rates. As these kinds of results for glass are rare to find in the literature, this concept will add new knowledge to the field. It is a widely used practice to apply setups like a SHPB for dynamic material characterisation. However, the novelty in the design of the presented SHPB setup consists of a transmission bar transformed into a tube having the incident bar going through. This reduces the total length of the setup considerably and provides the opportunity to apply high-speed cameras for recording the fracture process together with digital image correlation, as the tensile side of the specimen is visible during the tests. A numerical assessment of the experimental setup is provided, indicating the overall applicability of the concept. This includes an analysis of the possibility of obtaining dynamic load equilibrium between the incident bar and the transmission tube, which is a required load condition for evaluating the tested specimens.