Numerical Evaluation of Measurement Accuracy of Non-Coaxial Hopkinson Bar Method

The high measurement accuracy in dynamic tension testing is required for designs and numerical simulations based on the accurate modeling of stress-strain relations at various strain-rates. The non-coaxial Hopkinson bar method (NCHBM) is one of the recently proposed methods for dynamic tension tests. In this study, the accuracy of the stress-strain relations obtained on the basis of NCHBM is investigated by FEM. The finite element models of NCHBM apparatus and plate type specimens of various dimensions are made in detail. The target material employed in this study is mainly the mild steel that is proper for the investigation of measurement accuracy. On the other hand, SUS316 stainless steel and A7075 aluminum alloy are modeled as specimen materials for the comparison with the experiments. The effects of the bending, the constraint condition, the rising time, the size and geometry of specimen, and the strain rate are examined systematically.