Abstract The goal of this study was to examine the fracture behavior of advanced high strength steel (AHSS) sheets in bending. For this purpose, 3-point bending (3 PB) tests were conducted on DP980 and TRIP1180 sheet samples. The test specimens were prepared in different orientations with respect to the rolling direction of the sheets. The onset of fracture and fracture strains were determined through digital image correlation technique. The fracture regions of the deformed specimens were observed at different magnifications to understand the crack initiation mechanism. Apart from fracture characterization, a finite element study was performed for both steels using an Abaqus/Explicit solver. The parameters required for the constitutive equations were obtained based on mechanical characterizations carried out on these sheets in a previous work. Finally, an uncoupled fracture model was adopted to predict the fracture location and onset of cracking during the 3 PB test. The predicted results were found in reasonable agreement with the experimental data when the fracture model was calibrated using an appropriate set of mechanical tests.

中文翻译：

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三点弯曲过程中双相和相变诱导塑性钢的断裂评估

摘要 本研究的目的是检验高级高强度钢 (AHSS) 板在弯曲过程中的断裂行为。为此，对 DP980 和 TRIP1180 片材样品进行了 3 点弯曲 (3 PB) 测试。相对于板材的轧制方向以不同的取向制备试样。通过数字图像相关技术确定断裂的开始和断裂应变。在不同的放大倍数下观察变形试样的断裂区域，以了解裂纹萌生机制。除了断裂表征外，还使用 ​​Abaqus/Explicit 求解器对两种钢进行了有限元研究。本构方程所需的参数是根据先前工作中在这些板材上进行的机械表征获得的。最后，采用非耦合断裂模型来预测 3 PB 试验期间的断裂位置和开裂的发生。当使用一组适当的机械测试校准断裂模型时，发现预测结果与实验数据具有合理的一致性。