DYNAMIC TENSILE TESTING OF SHEET MATERIAL USING THE SPLIT-HOPKINSON BAR TECHNIQUE

We have described an experimental method based on the SHPB technique which allows dynamic tensile testing of 1.0-mm-thick sheet material. The test method employs a framing camera to make strain measurements based on direct observation of the deforming test sample. Stress in the sample is determined using traditional SHPB wave analysis. This information is used to construct engineering stress-strain behavior. The stress-strain behavior determined using the test method is shown to be reasonably accurate for annealed tantalum and less accurate for annealed copper. We believe that this phenomenon is related to the constitutive behavior of the test material. Although the stress-strain behavior extracted from the test is in some cases suspect, the test technique is shown to provide highly reproducible results and thus can be employed to examine effects of microstructural features, alloying elements, etc., on dynamic deformation and fracture of ductile materials.