研究了缺口根部强化层中疲劳裂纹的萌生与扩展。结果表明疫劳性能的提高主要归因于喷丸引起的缺口根部残余压应力,其能提高裂纹的闭合力,延缓短裂纹的扩展速率,而对萌生的作用极微。工作应力低时可出现非扩展裂纹。在残余压应力场中长裂纹的扩展可用Newman改进模型进行计算。在残余压应力峰值位置出现最大闭合力和最小裂纹扩展速率,计算和实测值基本一致。 The initiation and propagation of fatigue cracks in the root reinforcement were investigated. The results show that the improvement of the epidemic performance is mainly attributed to the residual compressive stress at the notch root caused by the shot peening, which can improve the closing force of the crack and delay the expansion rate of the short crack, with little effect on initiation. Non-expanding crack may occur when working stress is low. The expansion of long cracks in the residual compressive stress field can be calculated using Newman’s improved model. The maximum closing force and the minimum crack growth rate appear at the peak position of residual compressive stress. The calculated and measured values ​​are basically the same.