轴承不对中-碰摩耦合故障下双转子系统非线性振动特性分析

ANALYSIS OF NONLINEAR VIBRATION CHARACTERISTICS OF DUAL⁃ROTOR SYSTEM UNDER BEARING MISALIGNMENT⁃RUB⁃COUPLING FAULT

为揭示因轴承不对中导致的故障转子系统振动特性,基于坐标变换关系,推导了轴承不对中下转子偏转位移表达式。在此基础上,建立了综合考虑碰摩力、油膜力等外激励影响下双盘转子轴承不对中-碰摩耦合故障系统动力学模型,采用数值方法研究了转速及质量偏心对系统动态特性的影响。结果表明,轴承不对中故障会增加系统碰摩发生可能性、恶化轴系振动并加大系统非稳态运动范围。虽然不对中量的加入可在一定程度上延缓系统因参数变化引起的失稳运动,但据此产生的振幅增加与系统安全运行目标相悖,故应采取必要措施对轴承不对中故障加以控制。相关结论可为转子-轴承系统振动状态识别及稳定性分析提供有益借鉴。

In order to reveal the vibration characteristics of fault rotor systems caused by the bearing misalignment,the expression of the rotor deflection displacement under the bearing misalignment was derived through the coordinate transformation relation.On this basis,the dynamic model of the double disk rotor system with the coupled bearing misalignment⁃rub⁃impact fault,considering the influence of external excitation including the rub⁃impact force and the oil film force was established.The effects of rotational speed and mass eccentricity on the dynamic response of the system were studied by means of the numerical method.The results show that the bearing misalignment fault can increase the possibility of rub⁃impact,worsen the shafting vibration and magnify the unsteady motion range of system.Although the addition of misalignment can delay the instability movement induced by parameter changes to a certain extent,the enlargement of amplitude is contrary to the safe operation goal for system,therefore,the necessary measures should be taken to control the bearing misalignment fault.The relevant conclusions can provide useful references for the vibration state identification and the stability analysis of rotor bearing systems.