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建立了基于钢轨螺栓孔残余应力分布规律和局部应变，并考虑残余应力衰减的疲劳裂纹萌生寿命预测模型。分析了冷扩张对疲劳裂纹尖端应力强度因子分布的影响。结合实验探讨了冷扩张过程对钢轨螺栓孔疲劳寿命的影响方式和效果。结果表明，冷扩张过程所引入的切向残余压应力能保持足够的强度，以对钢轨螺栓孔起到显著的防裂和止裂作用。
The prediction model of fatigue crack initiation life based on the rule of residual stress distribution and local strain of rail bolt hole is established, and the fatigue crack initiation life prediction model considering residual stress attenuation is established. The effect of cold expansion on the stress intensity factor distribution at fatigue crack tip is analyzed. The effect of cold expansion process on the fatigue life of rail bolt hole was discussed with the experiment. The results show that the tangential residual compressive stress induced by cold expansion can maintain sufficient strength to play a significant role in crack prevention and crack arrest of rail bolt holes.