航空轴承全寿健康状态演变规律及其可测性研究

Aircraft bearing, the key transmission and supporting components in aircraft engine, severs as not only the core power units but also the fatal bottleneck of the performance and life of a whole engine. Therefore, it is significant to investigate the life-lengthy heath evolution of aircraft bearings to improve the condition monitoring and health management of an aircraft engine. Centered on the stage evolution mechanism of aircraft bearing’s tribo-performance, this project proposes the characterization of this tribo-system degradation with three evolution stages. First is the boundary lubrication induced by initial lubricating film broken; second is the wear during the rolling-sliding contact between solid surfaces; and the third is the structure vibration induced by the enlarged constraint clearance. Correspondingly, on-line monitoring techniques for ultro-sonic oil film thickness, wear debris and vibration are employed to extract the stage features and evolving principles. Eventually, the health evolving model and real-time evaluation method can be established for aircraft bearing. Specific researches focuses on four aspects: ①boundary lubricating oil film identification by ultra-sonic signal,② the initiation of wear by particle characterization,③Characteristic spectrum extraction of the clearance- and surface-induced vibration,④ health evaluation model based on stage evolution principles. The distinguishing contribution of this research is to provide the life-lengthy health evaluation of aircraft bearing tribo-system by establishing on-line wear state identification. The outcomes of this project will break through the existing health evaluation pattern from the aspect of physical mechanism.

作为关键传动和支撑部件的航发（航空发动机）主轴轴承不但是主机的动力核心，也是整机性能和寿命的致命瓶颈。为此，开展其全寿命健康状态演变规律研究将对航发的状态监测和健康管理具有重要的意义。本课题以航空轴承的摩擦学性能的演变机理为核心，从油膜破裂导致的边界润滑、固体滚滑接触导致的典型磨损以及运动间隙变化导致的结构振动三个演变阶段，表征该摩擦学系统的衰变规律；分别采用超声油膜厚度在线监测、磨粒在线监测，以及宏观振动监测方法提取上述阶段的特征及演变规律，建立其健康状态演变模型及实时评估方法。具体研究内容包括：①基于超声检测的润滑油膜厚度边界润滑特征识别；②在线磨粒特征表征早期磨损的方法；③轴承间隙、及表面变化诱导的振动频谱特征提取方法；④基于阶段演变规律的健康状态评估模型。本研究的特色在于通过建立基于航空轴承摩擦学系统的磨损状态在线辨识方法，从机理层面给出其全寿命健康状态的评价机制。

以航空滚动轴承摩擦学系统为研究对象，本项目构建了油膜厚度、磨损、振动的融合监测体系，揭示了摩擦学性能的阶段演变规律，形成了多信息融合的航空轴承健康状态评估方法。主要成果包括：1）提出了综合考虑接触微区变形及油膜刚度分布特性的射线模型，实现了滚动接触摩擦副接触区域内的膜厚提取；2）提出了基于神经网络的典型磨粒辨识方法，构建了融合磨粒宏观量化和微观机理结合的磨损分析模型；3）开发了基于光度立体视觉原理的三维显微图像重构系统，实现了曲面表面磨损形貌的原位测量与表征；4）阐明了磨损程度与摩擦振动之间的相互诱导关系，揭示了滚滑接触下的摩擦振动机理；5）提出了基于油膜厚度和摩擦振动的早期润滑衰变及严重磨损阶段表征方法，建立了基于磨损表面形貌和磨粒形态的磨损状态演变模型，形成了多信息融合的摩擦学性能退化表征体系；6）提出了综合考虑作用机理和监测数据的状态评估方法，实现了摩擦学系统性能退化的系统建模；7）开发了可模拟复合工况条件的全轴承试验台架，完成了滚动轴承热特性试验与全寿命可靠性试验。项目成果形成了摩擦学系统健康评估的基本方法体系，为实现航空滚动轴承的全寿命健康分析提供理论基础和技术依据。