航空发动机轴承动态接触与界面润滑耦合机理研究

The advanced rolling bearings are the heart parts for keeping aero-engine run with high reliability and long fatigue life, however, the operating environment involving high-speed, high-temperature, large changing load and severe complicated lubrication-contact status, which often cause the early failure of the bearing. In this project, the aero-engine bearing is taken as the research object, and the coupling failure form of fatigue flake is focused on, which have the strong concealment and difficult diagnosis characteristics, and need to be solved urgently. Together with the three main introduced factors: complicated dynamic running conditions, severe interfacial lubrication status and internal material inhomogeneity defect, the coupling mechanism study of dynamic contact and interfacial lubrication of aero-engine bearing is carried on. In the coupling mechanism study, three theories including rolling bearing dynamics, tribology and heterogeneous contact are indispensable, however, the most previous studies only present the detail independent research, simplified coupling or minority coupling analysis. In this project, considering the effect of macro mechanics kinematics properties, micro surface topography, interfacial lubrication status and internal material inhomogeneity defect, the coupling model of rolling bearing dynamic performance—mixed TEHL(thermal elastohydrodynamic lubrication)—heterogeneous thermal elastoplasticity contact is built, the dynamic properties, frictional properties and heterogeneous material properties are predicted, the generation mechanism and evolution law of the coupling failure is revealed, which can provide basic theoretical support for failure diagnosis, design parameters optimization, fatigue life and reliability prediction of domestic aero-engine bearings.

高端滚动轴承是保证航空发动机高可靠性和长寿命稳定运转的心脏部件，而高速高温高变负载工况及苛刻复杂润滑-接触状态等恶劣作业环境常常诱发其发生早期异常失效。本项目将针对航空发动机轴承隐蔽性强、诊断难度大且又急需解决的耦合失效问题—接触疲劳剥落，及其诱导失效的三大主要因素：复杂动态运转工况、恶劣界面润滑状态和内部材料杂质缺陷，开展航空发动机轴承动态接触与界面润滑耦合机理研究。耦合研究中轴承动力学、摩擦学及非均质接触学三大理论缺一不可，而目前的研究多为独立开展、耦合简化或少量耦合。本项目综合考虑轴承宏观力学和运动学特性，真实表面形貌、界面润滑状态及内部杂质缺陷影响，建立滚动轴承动态性能-混合热弹流润滑-非均质弹塑性热接触耦合分析模型，预测轴承动力学特性、摩擦学特性及非均质接触学特性，揭示耦合失效的产生机制及演变规律，为国内航空发动机轴承故障诊断、设计参数优化、疲劳寿命及可靠性预测提供基础理论支撑。

高端滚动轴承是保证航空发动机高可靠性和长寿命稳定运转的心脏部件，而高速高温高变负载工况及苛刻复杂润滑-接触状态等恶劣作业环境常常诱发其发生早期异常失效。本项目将针对航空发动机轴承隐蔽性强、诊断难度大且又急需解决的耦合失效问题—磨损、胶合和疲劳点蚀，及其诱导失效的三大主要因素：复杂动态运转工况、恶劣界面润滑状态和内部材料杂质缺陷，开展了航空发动机轴承动态接触与界面润滑耦合机理研究。.首先，开展了基于航空发动机轴承动力学的界面混合润滑特性建模研究，考虑了典型工况和真实表面粗糙度影响，分析了轴承动力学性能及微观界面润滑状态变化。然后，完成了航空发动机轴承非均质接触特性分析方法研究，揭示了不同非均质材料弹性模量、形状及位置等因素对接触应力状态、应变及位移的影响规律。进一步，发展了航空发动机轴承动态接触与弹塑流润滑耦合分析模型，考虑接触摩擦副弹、塑性变形影响，研究了塑性变形、硬化准则及真实粗糙表面对轴承接触-润滑状态的影响。最后，考虑了流体流变特性以及摩擦热耦合作用影响，发展了轴承摩擦-温升、三维动态应力和寿命预测模型，建立了轴承磨损、胶合和疲劳强度评估方法，基于界面磨损理论模型预测了轴承磨损状态，利用界面温升模型评估了轴承胶合程度，基于三维动态应力分布和寿命预测模型计算了轴承材料的疲劳破坏风险。.项目最终形成一套从轴承动力学性能到界面弹塑性混合润滑特性，再到非均质材料接触应力状态的耦合分析模型，揭示了轴承磨损、胶合和疲劳点蚀耦合失效的产生机制及演变规律，为国内航空发动机轴承故障诊断、设计参数优化、疲劳寿命及可靠性预测提供基础理论支撑。