Experimental and numerical study on ductile fracture of structural steels under different stress states

摘要

In addition to the stress triaxiality, the Lode angle has recently been recognized as an important parameter influencing the ductile crack initiation, propagation and final failure of structural steels. In this paper, a modified ductile fracture model is proposed to consider the effects of different stress states on the ductile fracture behavior of steels by introducing the deviatoric state parameter. Different stress states, including the tension, compression, shear, tension-shear, and compression-shear states, can be expressed by the stress triaxiality and deviatoric state parameter relating to the Lode angle. Three flat bar tension specimens and eight flat bar shear specimens were designed to model the different stress states, and ductile fracture tests were carried out on these 11 specimens. The parameters of the modified ductile fracture model in this study were determined based on these ductile fracture tests, and the corresponding finite element analytical results regarding these specimens exhibited strong agreement with the tested results. The proposed model was verified as being suitable for simulating the ductile fracture behavior of steels under different stress states. (C) 2019 Published by Elsevier Ltd.