中介轴承局部缺陷故障机理及复杂路径下特征提取方法研究

The inter-shaft bearing is widely used in high performance aero-engine. It works between the high and low pressure rotors with high speed, high temperature, high load and poor lubrication problems, causing aero-engine malfunctions. At present, the local fault mechanism of the inter-shaft bearing is not clear and the fault feature extraction method under complex path is still not perfect. In order to solve the two problems mentioned above, this paper studies from the following three aspects: theoretical research, experimental research and numerical simulation. At first, establish the local defect dynamic model of inter-shaft bearing considering the influence of lubrication oil film, then obtain the influence of local defect size, position, load, speed and lubricating oil film parameters on the fault characteristic parameters combined with simulation and experiment results, finally the local fault mechanism for inter-shaft bearing under complex path would be clarified. Through theoretical analysis and formula derivation, information exergy theory would be improved. The internal relationship between the local fault form of the inter-shaft bearing and the information exergy will be made clear. Information of Acoustic emission and vibration signals for local defects of inter-shaft bearing is integrated. A method of feature extraction for local defects of inter-shaft bearing under complex path is established. The methods of this project would provide theoretical basis for the realization of inter-shaft bearing fault diagnosis in the engine state and the development of engine condition monitoring technology.

高性能航空发动机支承方案中普遍采用中介轴承结构。中介轴承工作于高、低压转子之间，具有高转速、高温度、高负荷和润滑不良等特点极易发生故障。目前，中介轴承局部缺陷故障机理尚不明了，复杂路径下故障特征提取非常困难。本项目针对上述两个问题，从理论分析、实试验研究和数值模拟三方面开展研究。建立考虑油膜润滑影响的中介轴承局部缺陷故障动力学模型，结合动力学仿真分析和实验结果获取局部缺陷尺寸、位置，载荷、转速和润滑油膜参数对故障特征参数的影响规律，阐明中介轴承局部缺陷故障机理。通过理论分析和公式推导完善信息（火用）理论。理清中介轴承局部缺陷故障形式与信息（火用）之间的内在联系。实现中介轴承局部缺陷故障声发射和振动信号的信息融合。建立基于信息（火用）的复杂路径下中介轴承局部缺陷故障特征提取方法。本项目的研究成果将为实现发动机整机状态下的中介轴承故障诊断和状态监测提供理论基础和新方法。

中介轴承工作于高、低压转子之间，是航空发动机支承传动系统的关键部件。其具有高转速、高温、高负荷且润滑不良等问题极易发生故障。中介轴承一旦发生故障将对发动机造成灾难性后果。对于中介轴承局部缺陷故障机理认识不清和复杂路径下故障特征提取困难是造成发动机在中介轴承设计和使用阶段无法避免和识别故障的主要原因。本项目针对上述两个问题，从理论分析、实试验研究和数值模拟三方面开展研究。首先建立考虑润滑影响和时变位移激励的中介轴承局部缺陷故障动力学模型，基于该模型进行仿真分析,并结合局部缺陷模拟实验研究中介轴承典型故障的时域参数和频域故障特征。采用所建立模型分析了中介轴承微弱故障的演变规律，获取了不同工作状态下故障特征参数的变化规律，揭示中介轴承局部缺陷故障机理。其次，从信息熵与热力学熵关系出发，进一步推导并完善了信息㶲的概念，系统的建立了小波能谱㶲的计算方法，并将其应用到中介轴承故障信号的故障特征提取中，理清中介轴承局部缺陷故障形式与信息㶲之间的内在联系。最后，搭建了中介轴承故障模拟试验台，开展了中介轴承正常状态、内圈故障、外圈故障和滚动体故障的模拟实验，并采集多转速和多测点的振动及声发射信号。基于信息㶲理论，建立了多源异构信息融合的复杂路径下中介轴承局部缺陷故障特征提取方法。本项目获得的理论研究成果能够为复杂路径下中介轴承故障诊断技术研究奠定理论基础。建立的特征提取方法实现在发动机不分解状态下对涡扇发动机中介轴承故障的进行诊断，对提高涡扇发动机可靠性和安全性具有重要意义。