A (GCM) is proposed to investigate 3D ductile fracture accounting for the void growth, coalescence, and complete failure phenomena. The proposed model idealizes the ductile fracture process as continuum damage evolution, cohesive crack initiation, nonlinear softening along the crack surface, and complete failure. The Gurson model is employed to describe continuum damage with void growth, while the cohesive zone model is utilized to introduce discontinuous cracks and represent nonlinear softening behavior. The transition from the continuum damage to discontinuous crack is taken into account systematically using a porosity-based crack initiation criterion considering stress triaxiality. The computational results successfully reproduce the experimental results of fracture tests with 15–5 PH steel and structural carbon steel 20 within the unified modeling framework. Furthermore, strong and stable convergence of both global and local responses (e.g., load-displacement curve, area reduction, crack tip location) are demonstrated under the mesh refinement without the aid of any characteristic length scale parameter in the simulations.

中文翻译：

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用于 3D 延性断裂模拟的 Gurson-Cohesive 建模 (GCM)

建议使用 A (GCM) 来研究 3D 延性断裂，以解释空隙增长、聚结和完全失效现象。所提出的模型将延性断裂过程理想化为连续损伤演化、内聚裂纹萌生、沿裂纹表面的非线性软化和完全失效。 Gurson 模型用于描述空洞增长的连续损伤，而内聚区模型用于引入不连续裂纹并表示非线性软化行为。使用考虑应力三轴性的基于孔隙率的裂纹萌生准则系统地考虑从连续损伤到不连续裂纹的转变。计算结果成功地再现了统一建模框架内15-5 PH钢和结构碳钢20断裂试验的实验结果。此外，在网格细化下，在模拟中无需任何特征长度尺度参数的帮助下，证明了全局和局部响应（例如，载荷-位移曲线、面积减小、裂纹尖端位置）的强而稳定的收敛。