考虑弹流润滑影响的表面局部缺陷中介轴承动力学建模

Dynamic modeling for inter-shaft bearings with surface local defect considering elasto-hydro lubrication effects

航空发动机中介轴承位于发动机高、低压转子之间,其内、外环随高、低压转子同向或反向旋转,相对转速高和润滑条件恶劣造成中介轴承故障频发。针对表面局部缺陷中介轴承的振动故障诊断,考虑弹流润滑影响和时变位移激励,提出了一种带局部缺陷的中介轴承动力学建模方法。采用双转子实验台开展中介轴承外圈故障模拟实验,采集振动信号并进行分析。对比动力学模型数值模拟结果和故障轴承实验结果,验证了所建动力学模型的准确性。基于所建立动力学模型对有、无润滑的中介轴承在不同缺陷尺寸条件下的振动响应进行数值模拟。研究结果表明:该模型能够准确模拟中介轴承在不同状态、不同缺陷尺寸下的振动响应变化规律,可用于中介轴承故障机理分析。

Inter-shaft bearings of an aero-engine are located at the place between its high pressure rotor and low pressure one.The inner and outer rings of inter-shaft bearing rotate in the same direction or opposite one with high and low pressure rotors,and their relative rotating speed is high and lubrication condition is bad to cause frequent occurrence of faults.Here,aiming at vibration fault diagnosis of inter-shaft bearings with surface local defect,a dynamic modeling method for them was proposed considering effects of elasto-hydro dynamic lubrication and time-varying displacement excitation.A dual-rotor test platform was used to conduct analog tests for outer ring fault of inter-shaft bearing,and vibration signals were collected and analyzed.Comparing the numerical simulation results of the established dynamic model and the test ones,the correctness of the established dynamic model was verified.Based on the established dynamic model,vibration responses of inter-shaft bearings with and without lubrication under different defect sizes were numerically simulated.The results showed that the model built here can be used to correctly simulate vibration responses of inter-shaft bearings under different conditions and different defect sizes,and analyze the fault mechanism of inter-shaft bearings.