傅里叶分解在航空发动机复合故障诊断中的应用研究

Application of Fourier Decomposition Method in Composite Fault Diagnosis of Aero-Engine

针对航空发动机转子振动信号的非线性、非平稳特性,应用傅里叶分解方法(Fourier Decomposition Method,FDM)实现航空发动机转子复合故障诊断。首先应用傅里叶分解方法将振动信号分解为一系列固有频带分量,然后计算每个固有频带分量与原信号的互相关系数及峭度值,将互相关系数与峭度值的阈值作为判断准则,提取信号的主要固有频带分量,重构信号,并且生成边际谱,实现主要频谱成分的分析。最后通过互相关系数与峭度值相结合的准则,实现谐波分量与冲击分量信号的提取,实现复合故障类型进一步分析与诊断。应用此方法对航空发动机转子试验器的松动-碰摩-不对中复合故障信号进行诊断,可将不对中、松动、碰摩的故障特征有效分离出来,证明了FDM在复合故障特征分离与诊断中的有效性。

Based on the nonlinearity and nonstationarity of vibration signal of aero-engine rotor,Fourier decomposition method(FDM)is applied to the diagnosis of composite faults of aero-engine rotor.First,the vibration signal was decomposed into several Fourier intrinsic band functions(FIBFs)by FDM.Then the kurtosis value of each FIBF and the cross-correlation number between each FIBF and the source signal are calculated of each FIBF.The main FIBFs are extracted and the signal is reconstructed by combining the cross-correlation number threshold and kurtosis threshold.According to the main FIBFs,the marginal spectrum is generated to realize the analysis of the main spectrum components.Finally,the harmonic component and impulse component of the signal are extracted by combining the cross-correlation number and kurtosis value,and the composite fault can be further judged and analyzed.This method is applied to the diagnosis of the composite fault signal of the aero-engine rotor tester,and the fault features of misalignment,looseness and rubbing are separated.It is proved that this method can realize the feature separation and diagnosis of the composite fault.