Although mechanical fatigue is considered stochastic in nature and there is a trend in industry towards reliability-based design, most popular high cycle stress-based fatigue models applied by industry still relies on deterministic methods. This is evidenced by the absence of integral probabilistic approach for predicting local and global probabilities of failure of structures in fatigue analysis commercial codes. In this paper, a probabilistic extension of the classical Basquin linear and bi-linear fatigue models, which are the most commonly promoted by standards (ASTM, UNE…) and Guidelines (FKM, DNV GL, VDI…), is proposed. The proposed models include the scale effect and the probabilistic character of the S-N field. This seems to be a judicious and recommendable option for the practicing engineer to face the real fatigue design of components under varying loading while ensuring safety requirements. The proposed enhanced model is implemented into the NCode2020 software to illustrate the possible implementation in general commercial codes focused on fatigue design. Finally, the applicability of the procedure proposed is illustrated by means of a practical example that includes the evaluation of experimental results and the prediction of failure for an Open-Hole-Plate.

尽管机械疲劳本质上被认为是随机的，并且工业上存在基于可靠性设计的趋势，但是工业上最流行的基于高循环应力的疲劳模型仍然依赖于确定性方法。这可以通过在疲劳分析商业法规中缺乏用于预测结构失效的局部和全局概率的积分概率方法来证明。本文提出了经典Basquin线性和双线性疲劳模型的概率扩展，这是标准（ASTM，UNE…）和指南（FKM，DNV GL，VDI…）最常推广的。提出的模型包括尺度效应和SN场的概率特征。对于实践中的工程师来说，这是明智的和可取的选择，它可以在确保安全性要求的同时，面对变化载荷下的组件的真实疲劳设计。提议的增强模型已在NCode2020软件中实现，以说明集中于疲劳设计的通用商业代码的可能实现。最后，通过一个实际示例说明了所提出程序的适用性，其中包括对实验结果的评估和对开孔板失效的预测。