Ductile fracture modelling of steel plates under tensile and shear dominated states

The prediction of ductile fracture is highly related to the stress and strain states in the plastic stage. For steel plates in the engineering structure, despite many stress-strain equations based on the von Mises criterion developed, it is found that the finite element (FE) analysis using true stress-strain relation calibrated by the uniaxial tensile tests cannot properly describe the shear behaviour of steel plates. In this paper, the combined linear and power stress-strain law with a shear plastic factor is proposed to characterize the mechanical behaviour of steel plates under shear dominated state. Then, Bao-Wierzbicki (BW) criterion, an uncoupled damage model, is adopted to predict the tensile and shear dominated fracture of steel plates. The uniaxial tensile and shear tests of steel plates are carried out to calibrate relevant parameters in the true stress-strain relation and ductile fracture model. Furthermore, single-bolt connections subjected to tensile and shear dominated states are designed and tested. Parallel FE simulations are performed to validate the ductile fracture model with the calibrated stress-strain relations. FE results regarding these specimens show a good agreement with the corresponding experimental results. The uncoupled damage model integrated with the proposed stress-strain relation is verified to be suitable to simulate the ductile fracture of steel plates under tensile and shear dominated states.