A Novel Striker Configuration for Tensile Split Hopkinson Bar Testing with Dynamic Specimen Recovery

Abstract The split Hopkinson pressure bar (SHPB) is widely used for acquiring high strain rate (HSR) material data. For purposes of exhaustive characterisation, HSR data are required to assess strain rate sensitivity. A notable limitation of a conventional SHPB lies in the control of a test specimen’s ultimate deformation, because specimens are typically subjected to an unknown number of repeated loading events. For this reason, microstructural investigations on SHPB specimens hold little value, as the final specimen state does not correlate with the recorded loading event. In this paper, a tensile split Hopkinson bar (TSHB) arrangement designed to conduct interruptible tests is presented. This includes a pull-off tensile striker and tandem momentum traps in a novel configuration, which allows the input bar to remain supported over its entire length while eliminating the need for precise gap setting between pressure bars and momentum traps, or striker speed control. In addition, a fir-tree tensile specimen fixture design was utilised to secure the specimen to the bars. Results from a series of experiments on DOMEX 550 specimens are presented to demonstrate the effectiveness of the TSHB configuration. Loading histories inferred from strain gauge data are compared to the measured lengths of recovered specimens as verification of the ability of this apparatus to conduct interruptible tests. In addition, tests are compared to those conducted without interruption under the same testing conditions, further demonstrating the capability of this system.