In this paper, a new coupled damage‐plasticity model is proposed to predict plastic response and ductile fracture for two hydrostatic‐stress‐insensitive metals. A convenient hybrid experiment–simulation approach is designed to calibrate model parameters. Geometry transferability of model parameters is validated to various notched tensile specimens. With the characteristics of the present constitutive model, the critical damage parameter is demonstrated to be an appropriate fracture criterion, where fracture strains of various notched tensile specimens are in good agreement with experimental data. The study also reveals that there exist complementing mechanisms for the stress‐triaxiality‐dependent damage evolution and strain hardening of effective (undamaged) stress, respectively, that result in the non‐uniform distribution of overall (damaged) equivalent stress–strain curves on the minimum cross section of tensile specimens. Then, it is the combined effect of non‐uniformly distributed overall equivalent stress–strain curves that results in the phenomenon of hydrostatic‐stress insensitivity in metals.

中文翻译：

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耦合损伤-塑性模型的静水压力不敏感金属的延性断裂

本文提出了一种新的耦合损伤塑性模型，以预测两种静水压力不敏感金属的塑性响应和延性断裂。设计了一种方便的混合实验-仿真方法来校准模型参数。模型参数的几何可传递性已针对各种缺口拉伸样本进行了验证。根据本构模型的特征，临界损伤参数被证明是合适的断裂准则，其中各种切口拉伸试样的断裂应变与实验数据非常吻合。研究还表明，存在分别针对有效（未损伤）应力的应力三轴性损伤演化和应变硬化的互补机制，结果导致在拉伸试样的最小横截面上总的（损坏的）等效应力-应变曲线不均匀分布。然后，正是非均匀分布的整体等效应力-应变曲线的组合效应导致了金属中的静水压力不敏感现象。