86 / 2019-04-28 10:45:25

Effect of stress triaxiality on the fracture behavior of SENB specimen

管道及储运设施材料 > 管道及储运设施材料

As a key parameter characterizes the triaxial stress state and constraint, stress triaxiality plays an important role in the ductile fracture of metal. At present, the corresponding research is mainly focused on the notched tensile specimens which cover only a small range of possible stress state, while the study for other specimen with complex stress states is inadequate. To solve this problem, a series of finite element models of SENB specimen in reference and numerical simulations, the spatial distribution characteristics of stress triaxiality were analyzed and its variations with equivalent plastic strain at the critical location were quantified. The results indicate that the stress triaxiality ahead of the crack tip symmetrically distributes in the thickness direction and reaches peak value at the center. And its absolute value in the crack propagation direction is symmetrical about the center of ligament. Moreover, the stress triaxiality is not constant during the whole deformation process but increases with the increase of equivalent plastic strain. Furthermore, the fracture locus for SENB specimen with high toughness material is constructed in the space of the equivalent plastic fracture strain and average stress triaxiality considering different specimen sizes, which has both scientific and engineering significance.