Prediction of ductile fracture for DP590 high-strength steel with a new semi-coupled ductile fracture criterion

This paper is concerned with prediction of the damage evolution and fracture of DP590 by exploring a new semi-coupled ductile fracture criterion. The new semi-coupled ductile fracture criterion uses the DF2010 ductile fracture criterion as the initial damage model with modifying the original fracture strain ε¯fp\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\overline{\varepsilon }}_{f}^{p}$$\end{document} to the initial damage strain ε¯ip\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\overline{\varepsilon }}_{i}^{p}$$\end{document} in the model. In order to further describe the softening phenomenon after damage, this model introduces a damage variable D to measure the cumulative damage and couples the damage variable D to the plastic model to construct a damage evolution model. In order to verify the semi-coupled ductile fracture criterion, the fracture experiment of DP590 was carried out. The resistance method was used to measure the initial damage and fracture of the sample, and the DIC technique was used to measure the strain distribution on the surface of the sample. The initial damage model and damage evolution parameters were calibrated using the experiment–simulation hybrid method and the reverse analysis method, respectively. The VUMAT user subroutine of the calibrated semi-coupled model is implemented into ABAQUS and used to simulate the stretching of each sample. The results show that the semi-coupled ductile fracture criterion can accurately predict the fracture behavior of DP590 materials under different stress states and describe the damage-induced softening phenomenon during the forming process of DP590.