为克服变幅载荷疲劳裂纹的预测中受到的实验成本、时间、载荷谱型等诸多因素的限制,在常幅载荷下S-N曲线与疲劳裂纹扩展曲线关系的基础上,研究了变幅载荷下两曲线之间的关系,并结合疲劳累积损伤理论,推导了块谱载荷裂纹扩展裂纹长度的预测方法,同时考虑了超载迟滞效应的影响,最后进行了实验研究.实验与计算结果表明该方法有效、便于工程应用,该方法可用于结构设计阶段对疲劳裂纹扩展寿命的预测. In order to overcome the limitations of experimental cost, time, load profile and so on, which are used in the prediction of the fatigue crack of the luffing load, on the basis of the relationship between the SN curve and the fatigue crack growth curve under the normal amplitude load, And the theory of fatigue cumulative damage, the prediction method of crack propagation crack propagation in bulk spectrum is deduced, and the influence of overload hysteresis is considered. Finally, experimental studies are carried out.The experimental results show that this method is effective, Which is convenient for engineering application. The method can be used to predict the fatigue crack growth life span in the structural design stage.