A reexamination of high strength steel Q690 plasticity model

The most generally used yield criterion of typical metals, the von Mises yield criterion, shows that the effects of stress triaxiality and Lode angle on the steel plasticity model are negligible. However, recently numerous experimental researches have shown that the influence of the stress triaxiality and Lode angle on the plasticity model of some typical metals should be considered. In the present paper, experiments and finite element analyses are carried out to evaluate the effect of stress triaxiality and Lode angle on the plastic behavior of Chinese high strength steel (HSS) Q690, and the application of von Mises yield criterion of the is reexamined. Results demonstrate that an appropriate yield criterion of HSS Q690 should consider effects of the Lode angle and the influence of stress triaxiality is negligible. Based on experimental and numerical results, a new yield function of HSS is proposed, to essentially simulate the experimental results.