Geometrical discontinuities are inevitable in engineering structures due to various functional requirements, which often yield complex stress–strain state and thereby significantly impact their fatigue performances. In this study, crystal plasticity theory is coupled with traditional critical distance theory for notch effect modelling considering microstructural heterogeneity. Specifically, microstructural and geometrical size effects on critical distance and fatigue performance are studied based on Sub-modelling approach. In addition, critical distance theory is coupled with Weibull distribution for probabilistic fatigue life evaluation of notched components. The developed method is verified and compared by using experimental data of GH4169 alloy. The findings demonstrate that the evaluated curves exhibit strong agreement with tested data and geometrical size effect poses larger influence than the grain size effect on critical distance and fatigue life.

中文翻译：

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使用基于微力学的临界距离理论进行尺寸效应下的概率缺口疲劳评估

由于各种功能要求，工程结构中不可避免地会出现几何不连续性，这往往会产生复杂的应力-应变状态，从而显着影响其疲劳性能。在本研究中，晶体塑性理论与传统的临界距离理论相结合，用于考虑微观结构异质性的缺口效应建模。具体而言，基于子建模方法研究了微观结构和几何尺寸对临界距离和疲劳性能的影响。此外，临界距离理论与威布尔分布相结合，用于缺口部件的概率疲劳寿命评估。利用GH4169合金的实验数据对所提出的方法进行了验证和比较。结果表明，评估曲线与测试数据表现出很强的一致性，并且几何尺寸效应对临界距离和疲劳寿命的影响大于晶粒尺寸效应。