A Probabilistic Fatigue Framework to Enable Location-Specific Lifing for Critical Thermo-mechanical Engineering Applications
A Probabilistic Fatigue Framework to Enable Location-Specific Lifing for Critical Thermo-mechanical Engineering Applications
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DOI：
10.1007/s40192-021-00198-4
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发表时间：
2021-01
影响因子：
3.3
通讯作者：
R. Bandyopadhyay;M. Sangid
中科院分区：
文献类型：
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作者：
R. Bandyopadhyay;M. Sangid
本文描述了在不同热机械载荷条件下预测疲劳寿命和失效模式的概率框架。具体地说，研究了镍基高温合金中夹杂物驱动和基体驱动的竞争失效模式。临界累积塑性应变能密度(APSED)被用作预测金属疲劳裂纹萌生的统一指标，这是因为它使用了单一的未知参数，并且它能够预测不同加载条件和失效模式的失效。在这项研究中，我们使用贝叶斯推理框架描述了临界APSED随温度的变化，并预测了RR1000粗晶变种在不同应变范围和温度下的竞争破坏模式。随着温度的升高，临界APSED似乎沿着垂直反射的S型曲线减小。此外，(A)失效模式的预测，(B)与最小寿命相关的失效模式，以及(C)随着温度的升高和应变范围的减小，与基体驱动的失效模式相关联的位置的变化与RR1000以及文献中记录的其他镍基高温合金的实验观察趋势一致。最后，对于每个模拟加载条件，疲劳寿命的不确定性被量化为基于临界APSE的可信度计算的预测区间和从模拟计算的APE。整个框架向基于微观结构的部件疲劳寿命确定迈出了有希望的一步，并实现了特定位置的寿命方法。
The present paper describes a probabilistic framework to predict the fatigue life and failure mode under various thermo-mechanical loading conditions. Specifically, inclusion- and matrix-driven competing failure modes are examined within nickel-based superalloys. The critical accumulated plastic strain energy density (APSED) is employed as a unified metric to predict fatigue crack initiation in metals, which is favorable due to the usage of a single unknown parameter and its capability to predict failure across loading conditions and failure modes. In this research, we characterize the temperature-dependent variation of the critical APSED using a Bayesian inference framework and predict the competing failure modes in a coarse grain variant of RR1000 with varying strain range and temperature. The critical APSED appears to decrease along a vertically reflected sigmoidal curve with increasing temperature. Further, (a) the prediction of a failure mode, (b) failure mode associated with the minimum life, and (c) the change in the location associated with the matrix-driven failure mode with increasing temperature and decreasing strain range are consistent with the experimentally observed trends in RR1000, as well as other Nickel-based superalloys, documented in the literature. Finally, for each simulated loading condition, the uncertainty in the fatigue life is quantified as a prediction interval computed based on aconfidence level of the critical APSED and the computed APSED from simulations. The overall framework provides a promising step towards microstructural-based fatigue life determination of components and enables a location-specific lifing approach.