In engineering practice, it is critical to accurately forecast the fracture initiation of ductile metals. Currently, various uncoupled ductile fracture criteria (DFCs) have been constructed to forecast the ductile fracture initiation of sheet metals, and several uncoupled DFCs have been presented to predict the fracture incipience of bulk metals from high to negative stress triaxiality (HNST). However, there is still lack a unified uncoupled DFC that is capable of predicting the fracture initiation of both sheet and bulk metals, efficiently. To deal with the problem and fill the gap above, a simple general uncoupled DFC is proposed in this paper via taking into account multiple void deformation modes and the effects of accelerated void growth and coalescence under high stress triaxiality based on the theoretical analyses of void nucleation, growth and coalescence. Then, the effects of material parameters on the asymmetry of fracture loci, the predictive ability of the new model for the coupling effect of the Lode parameter and stress triaxiality on the ductility of different materials, the number of material constants, and the flexibility of the new model are investigated to fully comprehend the new DFC. In addition, the experimental results of four different metal materials are utilized to verify the effectiveness of the new DFC, and comparative studies with two representative uncoupled DFCs are conducted using the four different metal materials to demonstrate the advantage of the new DFC. Research findings show that the new DFC can accurately forecast both the fracture initiation of sheet metals from equi-biaxial tension (EBT) to shear and bulk metals from HNST, superior to the other uncoupled DFCs. Due to the high prediction accuracy and flexibility of the proposed new DFC, its use in engineering applications and integration with finite element analysis software is recommended.

在工程实践中，准确预测韧性金属的断裂萌生至关重要。目前，已经构建了各种非耦合延性断裂准则 (DFC) 来预测金属板材的延性断裂起始，并且已经提出了几种非耦合 DFC 来预测大块金属从高应力三轴度到负应力三轴度 (HNST) 的断裂起始。然而，仍然缺乏一个统一的解耦 DFC 能够有效地预测板材和大块金属的断裂起始。为了解决这个问题并填补上述空白，本文基于空洞成核的理论分析，通过考虑多种空洞变形模式以及高应力三轴性下空洞加速生长和聚结的影响，提出了一种简单的通用非耦合 DFC , 增长和融合。然后，材料参数对断裂轨迹不对称性的影响，新模型对洛德参数和应力三轴度耦合效应对不同材料延展性的预测能力，材料常数的数量，以及材料的柔性。研究新模型以充分理解新的 DFC。此外，利用四种不同金属材料的实验结果来验证新型DFC的有效性，并使用四种不同的金属材料与两种具有代表性的非耦合DFC进行对比研究，以证明新型DFC的优势。研究结果表明，新的 DFC 可以准确地预测从等双轴拉伸 (EBT) 到剪切的金属板材的断裂起始以及来自 HNST 的大块金属，优于其他非耦合 DFC。由于所提出的新 DFC 具有较高的预测精度和灵活性，建议将其用于工程应用并与有限元分析软件集成。