- Frédéric Barlat, Pohang University of Science and Technology, Gyeongbuk, Republic of Korea
Large-scale advanced high strength steel (AHSS) sheet specimens were deformed in uniaxial tension, using a novel grip system mounted on an MTS universal tension machine. After prestrain, the large gauge section yielded a reasonably homogeneous strain distribution. It was then used as a prestrained material to examine the anisotropic response in biaxial tension tests with various load ratios, orthogonal tension tests at 90° from the prestrain axis, and cross-tension tests at 45°. The flow curve and the instantaneous r-value of the prestrained steel in each testing condition were also measured and compared with those of the undeformed steel. A distortional plasticity model was employed to predict the behavior of the prestrained material. The uniaxial flow curves and the yield surfaces after uniaxial prestrain that were predicted by the plasticity model were in good agreement with the experiments; the r-value evolution was qualitatively well predicted.
About the Speaker:
Frédéric Barlat is a professor in the Materials Mechanics Laboratory in the Graduate Institute of FerrousTechnology, Pohang University of Science and Technology.