The yielding behavior and plastic deformation of oxygen-free copper under biaxial quasi-static and dynamic loadings

• Published in: International journal of solids and structures Vol. 276; p. 112333
• Main Authors: Jin, Kanghua, Qi, Lin, Kang, Huaipu, Wang, Weibin, Guo, Yazhou, Li, Yulong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2023
• Subjects: Biaxial tensile tests; Electromagnetic split Hopkinson bar; High strain rate; Yield criteria; Yield criteria; Biaxial tensile tests; Electromagnetic split Hopkinson bar; High strain rate
• ISSN: 0020-7683; 1879-2146
• DOI: 10.1016/j.ijsolstr.2023.112333

•True dynamic biaxial tension at various load ratios by biaxial Hopkinson bar.•The quasi-static and dynamic yield surfaces of oxygen-free copper are acquired.•The general von Mises yield criterion including the strain rate effect is verified.•Biaxial tests provide the optimal constitutive parameters for complex loadings. This study investigated the yield behavior of oxygen-free copper under complex stress states and different loading rates. An optimized cruciform specimen and a novel electromagnetic biaxial split Hopkinson bar (EBSHB) were used to perform the dynamic biaxial tension tests at three different load ratios. The non-contact digital image correlation technique was adopted for strain measurement. Quasi-static and dynamic yield surfaces were obtained. Classical yield criteria, including the Tresca and von Mises yield criteria, were evaluated based on the experimental results. The von Mises criterion is found to provide better prediction of the yield surface under both quasi-static and dynamic loadings. The Johnson-Cook model from uniaxial test results provides a moderate prediction for experimental curves, while that from biaxial test results shows better prediction. Dynamic biaxial tests are proven necessary to acquire the constitutive models that can accurately describe the mechanical properties of copper under complex stress states.