航空发动机双转子系统非线性动力学分析与故障传递特性研究

With highly integrated system and intense structure of aeroengine, fault features pass a long and complex transmission path before they reach the vibration measurements installed on the casing. Therefore, analysis of fault transmission characteristics is important for fault detection in dual rotor system of aeroengine. To study fault transmission characteristics, this project firstly analyze the dynamics of key components in the dual rotor system, including: (1) nonlinear features of intershaft bearing and squeeze film damper which connect the low pressure rotor and the high pressure rotor, coupled dynamics between the bearing and the rotors are studied through analysis of fluid-structure interaction in oil film, bearing and rotors; (2) nonlinear dynamics of the system with dual rotors, disk, blade, and casing, where the interaction between the components are modeled and analyzed and responses under multi-source excitations are studied. Then, fault transmission characteristics and sensitivity of fault features are studied through analysis of fault modeling and dynamics of system with faults, with the purpose of obtaining fault features on casing. Finally, experiments on test rig of intershaft bearing and squeeze file damper and test rig of dual-rotor system with rotors, disk, blade, and casing are carried out to study the fault transmission characteristics. This project will expand the research on nonlinear dynamics of dual rotor system and resolve the fault transmission characteristics, which can advance the theoretical basis on the reliability of the dual rotor system.

航空发动机结构紧凑、系统高度集成，部件故障经过复杂路径传递到布置振动测点的机匣上。为此，分析故障在双转子系统中的传递特性对故障识别十分重要。本项目为研究故障传递特性，首先研究双转子系统中关键部件的动力学特性，包括：（1）连接低压、高压转子的中介轴承和挤压油膜阻尼器的非线性特性，通过流固耦合分析油膜流动特性及其与转子的耦合动力学特性；（2）双转子-轮盘-叶片-机匣系统的非线性动力学特性，研究叶片、轮盘与转子间耦合作用，分析多源激励载荷下系统的响应特性。在此基础上，分析典型故障建模方法和动力学特性，研究故障在不同部位的传递特性，获得故障在机匣上的特征表达，并开展参数敏感性研究。最后，搭建中介轴承和挤压油膜阻尼器模型实验台和双转子-轮盘-叶片-机匣模型实验台，通过实验研究故障传递特性。本项目的实施将促进双转子系统非线性动力学研究，解析双转子系统故障传递特性，为提高双转子系统的可靠性奠定理论基础。

针对航空发动机结构紧凑、系统高度集成的特点，分析部件故障经过复杂路径传递到布置振动测点的机匣上的特性，对于故障识别与诊断十分重要。本项目聚焦典型故障在双转子系统中的振动传递特性，首先，研究双转子系统中关键部件的动力学特性，建立了考虑中介轴承和挤压油膜阻尼器非线性的双转子系统动力学模型，比较了利用不同单元系统的动力学特性，研究了双转子-轴承-机匣系统的动力学、机匣支撑轴承与中介轴承的故障特性、故障振动特征的传递特性，研究了挤压油膜阻尼器的非线性阻尼对双转子系统的动力学特性产生的影响，以及对典型转子故障特征在双转子-轴承-机匣结构中的传递产生的影响。其次，研究了多源激励下双转子-轮盘-叶片-机匣的非线性动力学特性，考虑机匣支撑轴承、中介轴承特点，分析了双转子-轴承-机匣系统动力学系统的振动特征，开展了不同载荷作用下双转子-轮盘-叶片-机匣系统耦合振动动力学特性分析。再次，研究了不对中、松动、碰摩、轴承故障等典型故障在双转子系统中的动力学原理，以机匣支撑轴承、中介轴承故障为出发点，在双转子-轴承-机匣系统动力学模型中探讨故障特征的传递特性，采用基于符号动力学的时空模式网络模型对转子-轴承-机匣系统的振动传递特性进行分析，研究了振动故障特征传递特性。最后，利用已有的转子-轴承-轮盘-叶片-机匣耦合振动实验台，开展了典型转子故障、轴承故障、振动传递特性等实验研究；改造了双转子-轮盘-叶片-机匣系统实验台，开展了各种典型故障的模拟实验研究，包括转子质量不平衡、叶片-机匣碰摩、叶片飞出和轮盘机匣碰摩故障；建立了双转子-轴承-机匣系统实验台，开展了机匣支撑轴承故障实验和中介轴承故障实验。通过本项目的研究，进一步理解了双转子系统的耦合非线性动力学特性和故障传递特性，为双转子系统的故障诊断奠定理论基础。