Ductile Fracture Characterization of A36 Steel and Comparative Study of Phenomenological Models

摘要

To better predict ductile fracture (DF) of structural steels under complicated stress states, the DF of an A36 steel was experimentally and numerically investigated within a wide range of stress states. Meanwhile, a scanning electron microscope (SEM) analysis was performed to shed more light on the DF microscopic mechanism of the material tested. The correlations between the ductility and the stress states for the A36 steel were identified using four representative uncoupled DF models, which are endowed with different stress triaxiality (rf) and Lode parameter (L) dependence. In addition, the experimental results of an AISI 1045 steel, covering a wider range of stress states (-0.255 ＜ η ＜ 0.986; -1＜ L＜0.571), were revisited. By evaluating the three-dimensional (3D) fracture loci of the A36 and AISI 1045 steels using distinct models, it was concluded that an appropriate model should be featured with flexible η and L dependence as well as the asymmetry with respect to the plane of L = 0.