双盘转子—电磁轴承系统的碰摩振动特性

Rub-impact vibration characteristics of double-disc rotor system with magnetic bearings

转子系统的非线性振动是工程实际中的复杂问题,尤其转子系统碰摩振动的强非线性动力学特性,诱发倍周期分岔、hopf分岔及混沌等复杂现象。建立一类考虑碰摩故障的主动电磁轴承支撑双盘转子系统的力学模型,基于非线性动力学和转子动力学理论,采用多目标协同、多参数耦合仿真分析,运用变步长4阶Runge-Kutta法数值计算,通过获得的转子系统周期分岔图、碰摩分岔图、轴心轨迹图、Poincaré映射图、最大碰摩力及碰摩占空比曲线图,揭示了转子系统的非线性动态响应。同时研究复杂转子系统的碰摩振动特性与结构参数的关联关系。计算结果表明,系统的间隙阈值越小且转速越低条件下的周期碰摩振动越具复杂性和多样性,且系统因碰摩故障引发的最大碰摩力及碰摩占空比曲线峰值也较高。系统的定子刚度比越大,其表现出的各类周期碰摩振动的振动幅值和冲击速度越高;最大碰摩力越大。系统的偏心比值越大,系统的周期碰摩振动模式类型越多样化且混沌窗口越多;系统的各类周期碰摩振动产生的最大碰摩力和碰摩占空比也越高。同时,进一步分析了基本周期振动、亚谐振动、概周期振动和混沌的发生区域及转迁规律。研究结果可以有效地为该类转子系统动态匹配设计、大数据诊断与协同优化提供实际指导意义。

Nonlinear vibration of rotor system is a complicated problem in engineering practice,especially the strong non-linear dynamic characteristics of rub-impact vibration of rotor system,which induces complex phenomena such as period-doubling bifurcation,Hopf bifurcation and chaos.A mechanical model of active magnetic bearing supporting double-disc rotator system considering rub-impact was established.On the basis of theory of non-linear dynamics and rotator dynamics,multi-parameter coupling and multi-objective co-simulation analysis were adopted.The dynamic behavior of the system was reflected by the periodic bifurcation diagram,rub-impact bifurcation diagram,axis track map,Poincarémap,maximum rub-impact force and duty cycle diagram obtained by numerical calculation of the variable step 4-order Runge-Kutta.The relationship between rub-impact vibration characteristics and structural parameters of complex rotor system was studied.The calculation results are drawn.The smaller the clearance threshold of the system and the lower the speed,the more complex and diverse the periodic rub-impact vibration,and the higher the peak value of the maximum rub-impact force and duty cycle curve caused by rub-impact.The larger the stator stiffness ratio of the system,the higher the vibration amplitude and impact speed of all kinds of periodic rub-impact vibration.The greater the maximum rubbing force.The larger the eccentric ratio of the system,the more diverse the types of periodic rub-impact vibration modes and the more chaotic windows of the system.The maximum rub-impact force and duty cycle of the system due to various periodic rub-impact vibrations are also higher.The occurrence area and transition law of basic periodic vibration,subharmonic vibration,almost periodic vibration and chaos are further discussed.The research results can effectively provide practical guidance for dynamic matching design,large data diagnosis and collaborative optimization of this type rotor system.