Cold Expansion (CE) techniques are extensively used in the aeronautical industry to enhance the fatigue life of open-hole plates. However, the availability of accurate Finite Element (FE) models to simulate the fatigue behavior of this process, particularly Dynamic Cold Expansion (DCE), is limited. This study introduces two novel methods for predicting the fatigue response of DCE and Static Cold Expansion (SCE) open-hole plates. The first method directly estimates the total fatigue life using Continuum Damage Mechanics (CDM) and the Theory of Critical Distance (TCD). The second method separates the prediction of fatigue crack initiation life and propagation life, incorporating CDM, TCD, and the Extended Finite Element Method (XFEM). Moreover, FE models are developed to simulate residual stress, stress under external cyclic loads, and fatigue crack propagation behavior for both DCE and SCE specimens. The proposed methods are evaluated, compared, and the mechanisms behind fatigue life enhancement and fatigue crack propagation modes in CE specimens are discussed. It is found that the prediction accuracy is enhanced by considering stress distributions along the thickness direction and improving the Line Method (LM) in TCD through the introduction of a novel CE parameter. The results demonstrate that both methods achieve good predictive performance, with an average error index within ±30%. Furthermore, it is observed that both DCE and SCE processes primarily improve the fatigue crack initiation life of open-hole plates, with the percentage of crack initiation fatigue life increasing as the expansion size increases. The majority of the fatigue crack propagation life in CE specimens is concentrated in the initial stages of crack propagation. In addition, the effects of DCE and SCE processes on reducing the fatigue crack propagation rate are more pronounced along the thickness direction compared to the width direction, leading to distinct crack propagation modes between CE and non-cold expansion (NCE) specimens.

冷膨胀（CE）技术广泛应用于航空工业，以提高开孔板的疲劳寿命。然而，用于模拟该过程的疲劳行为（特别是动态冷膨胀（DCE））的精确有限元（FE）模型的可用性是有限的。本研究介绍了两种预测 DCE 和静态冷膨胀 (SCE) 开孔板疲劳响应的新方法。第一种方法使用连续损伤力学 (CDM) 和临界距离理论 (TCD)直接估计总疲劳寿命。第二种方法将疲劳裂纹萌生寿命的预测分开，结合了 CDM、TCD 和扩展有限元法 (XFEM)。此外，还开发了有限元模型来模拟DCE 和 SCE 样本的残余应力、外部循环载荷下的应力以及疲劳裂纹扩展行为。对所提出的方法进行了评估、比较，并讨论了 CE 样本中疲劳寿命延长和疲劳裂纹扩展模式背后的机制。研究发现，通过考虑沿厚度方向的应力分布并通过引入新的 CE 参数改进 TCD 中的线法 (LM)，可以提高预测精度。结果表明，两种方法均取得了良好的预测性能，平均误差指数在±30%以内。此外，据观察，DCE 和 SCE 工艺主要提高了开孔板的疲劳裂纹萌生寿命，裂纹萌生疲劳寿命百分比随着扩展尺寸的增加而增加。CE 样品中的大部分疲劳裂纹扩展寿命集中在裂纹扩展的初始阶段。此外，与宽度方向相比，DCE 和 SCE 工艺对降低疲劳裂纹扩展速率的影响沿厚度方向更为明显，导致 CE 和非冷膨胀 (NCE) 样本之间存在不同的裂纹扩展模式。