A micromechanically motivated uncoupled model for ductile fracture prediction

This paper is a contribution to the ductile fracture prediction by the proposal of a new uncoupled ductile fracture criterion. In the new criterion, two typical void deformation models were carefully considered, with the plastic strain increment regarded as a key impetus of the damage evolution and its accumulation. The new ductile fracture criterion was constructed with three model parameters with different physical meanings. A 3D ductile fracture surface model was obtained by transforming the proposed criterion from stress space to the space of stress triaxiality, Lode parameter, and fracture strain, and a parametric study was carried out to better understand their effects. To validate the performance of the new criterion, it was used to construct the 3D fracture surfaces of 5083-O aluminum alloy, TRIP690, and Docol 600DL (a dual-phase steel). Comparisons of the results with experimental observations indicate that the proposed criterion provides good prediction capability over a large range of stress states for various materials, with good flexibility and considerable accuracy.