M.S. (Master of Science)
Department of Mechanical Engineering
Split Hopkinson Bar (SHB) methods are widely used to experimentally characterize the mechanical properties of materials such as metals, concrete, and ceramics undergoing rapid deformation. NIU had a split-Hopkinson tensile apparatus that can conduct coarse tensile test, but it can’t output the useful signal. The aim of this thesis is to optimize the existing apparatus, so the high strain rate tensile tests for the stainless steel 304 can be conducted and useful signal can be got. The alignment of the bars is critical for a good signal that has less noise. To eliminate the noise signal, some accurate fixture is designed. A new reflective tensile test apparatus is used to get better data. Based on the one-dimensional wave propagation theory, when compression wave arrives at the interface of the two identical bars, it will propagate almost totally. However, a tension wave will still pull the bars to be split. A new specimen is also designed corresponding. This new specimen not only has no influence to the propagation of the compression wave, but also can bear the tensile wave. By testing with some samples, the feasibility of this device is proved. An open-source MATLAB code is immigrated to analyze the data outputted by the oscilloscope. The procedures and tips about the using of the code is introduced in the thesis.
Ji, Jiale, "Optimize The NIU Split Hopkinson Pressure Bar Apparatus For Conducting High Strain Rate Tensile Test on S304 Foils" (2022). Graduate Research Theses & Dissertations. 7231.
Northern Illinois University
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