Study on the Specimen Size-Effect of Hopkinson Tensile Bar Experiments

Split Hopkinson Bar (SPHB) is the main method to study the mechanical behaviors of materials under high strain-rate loadings. Restricted by loading conditions, generally only small-sized specimens were used in SPHB experiments. Therefore, work-hardening effect which occurs in the machining process could influence the experiments and the results could not reflect the true mechanical properties of materials. To study this effect, Vickers-hardness variation of the material along the cross-section of small-size stainless steel specimens were measured by indentation experiments, and the work-hardening effects on the properties of materials were obtained. By investigating the influence of work-hardening on the tensile property theoretically, the correction method of dynamic tensile results of split Hopkinson tensile bar was given accounting for the quasi-static tensile test results of specimens with different dimensions.