大型重载支承轴隐蔽部位由于发生不可观测的突发性疲劳断裂，严重影响正常生产，给企业带来重大经济损失；分析这类支承轴的结构特点与振动信号特征之间的关系，运用时序分析方法对振动信号进行建模，并采用残差${\sigma }_a^2$和归一化残差平方和NRSS作为识别疲劳裂纹状态的特征指标，有效诊断出了支承轴的疲劳裂纹程度。实验结果表明，采用${\sigma }_a^2$和NRSS作为特征指标的时序分析方法对大型重载支承轴隐蔽部位的疲劳裂纹状态进行诊断，比常规的时频幅值特征分析法更为敏感有效、简便易行，且具备很强的实用性。

Because of the unobserved sudden fatigue failure of the large-scale and heavyburden supporting shafts, the normal product line is affected seriously. Based on analyzing the relation ship between this type of supporting shafts construction characteristics and vibration signal characteristic, the model of the vibration signal is established by the method of time series.Residual (${\sigma }_a^2$) and normal residue square sum (NRSS) are adopted to identify the fault state, and the degree of supporting shafts' fatigue crack is diagnosed effectively.The result of experiment shows that the method of time series using ${\sigma }_a^2$ and NRSS as the index to diagnose the fatigue crack of large-scale and heavyburden supporting shafts is more sensitive and effective than the normal method using time-frequency domain of amplitude, and has very strong practicability.