In this study, a probabilistic model based on Monte-Carlo theory is applied to predict the fatigue behavior of cast aluminum alloys. The objective of the proposed approach is to investigate the effect of porosity (i.e. the defect size distribution and spatial density) on the fatigue strength and its associated scatter for uniaxial fatigue loads with the load ratio R = 0.1. The proposed model is applied to two cast aluminum alloys with very different defect characteristics. The results for these two alloys confirm that the model can be used to predict the average fatigue strength with a relative error <5%. It also accurately reproduces the experimentally observed trends concerning the scatter in fatigue strength. The scatter is underestimated but is of the same order of magnitude as the experimental values. It is believed that this is because the proposed model considers that the porosity is the only source of scatter. It is demonstrated that the model is well adapted for the prediction of the volume or scale effect in fatigue. This approach can also be used to estimate the Representative Volume Element in Fatigue for cast aluminum alloys.

在这项研究中，基于蒙特卡洛理论的概率模型被用于预测铸造铝合金的疲劳行为。提出的方法的目的是研究孔隙率（缺陷尺寸分布和空间密度）对单轴疲劳载荷（载荷比R = 0.1）的疲劳强度及其相关散射的影响。该模型适用于两种具有非常不同缺陷特征的铸造铝合金。这两种合金的结果证实了该模型可用于预测平均疲劳强度，相对误差<5％。它还准确地再现了实验观察到的有关疲劳强度散布的趋势。散射被低估了，但与实验值的数量级相同。可以认为这是因为所提出的模型认为孔隙率是唯一的散射源。结果表明，该模型非常适合预测疲劳中的体积或比例效应。该方法也可用于估算铸造铝合金的疲劳代表性体积元素。