【作者】 孙保苍；

【导师】 周传荣；

【作者基本信息】 南京航空航天大学 ， 机械设计与理论， 2002， 博士

【摘要】 旋转机械广泛应用于机械、动力、航空航天等工程技术领域。当前，随着科学技术的不断进步，旋转机械的设计正日益朝着大功率、高转速及柔性等方向发展。使用中也出现了许多用传统的线性理论无法解释的现象(如混沌现象，概周期运动等)，并导致了许多严重的事故。本课题“轴承—转子系统非线性动力学若干问题研究”来源于东南大学火电机组国家振动研究中心。在此背景下，以轴承—转子系统为研究对象，利用数值积分法和Poincare映射并结合谱分析，研究了转子动力学中的若干非线性问题，所得结果为有关旋转机械的设计及故障监测与诊断提供了一定的依据。 论文首先介绍了非线性转子动力学中常用的有关基本理论及本文采用的一种非线性非稳态油膜力模型，并利用该模型从多个角度研究了轴承—刚性转子的非线性动力学行为。结果表明，在这一非稳态油膜力模型下，在转速、无量纲偏心及一包含诸多因素的综合参数的变化过程中，在很大的范围内，系统运动都会出现由不断倍周期分岔导致的混沌现象和概周期运动。 以轴中间存在弓形裂纹的Jeffcon弹性转子为研究对象，考虑转轴涡动对裂纹开闭规律的影响，建立了轴承—弹性裂纹转子的非线性动力学模型。在此基础上研究了非线性油膜力和裂纹共同作用下系统某些参数的变化对系统的非线性动力学行为的影响。在特定的参数组合下，也会导致系统的混沌运动等复杂动力学行为。所得结果对于同类型旋转机械的故障监测与诊断具有一定的指导意义。 鉴于工程中广泛使用有限宽轴承，而对于这种轴承的油膜力的计算，采用数值方法计算工作量很大，而解析法又无能为力的情况，本文引入了一种适用于工程精度要求的平均本征值法。利用这种非线性油膜力模型研究了轴承—转子系统的非线性动力学行为并得到了一些有益的结果。所得结果对于工程实际同类型转子的设计与计算具有一定的借鉴意义。 最后对全文研究工作的创新之处进行了总结，指出了今后需进一步研究的方向和任务。更多还原

【Abstract】 The rotational machinery are widely used in many engineering fields such as mechanism, power , aviation and spaceflight. With the rapid advances of engineering and technology, the designs of rotating machinery are increasingly developing towarg to large power, high speed and flexibility. Meanwhile,many phenomena such as chaotic and quasi-period movement that are not interpreted by linear theory appear and bring about a lot of serious accidents.This task-a number of problems researches for nonlinear dynamics of bearing-rotor system,comefrom National Engineering Research Center of Turbo genetator Vibration. Based this background, this paper studies the some non-linear dynamic problems existing in bearing-rotor system using numerical integral method. The results give some theoretical basis to the designs of similar systems and have specified engineering signifance.First.the paper introduces basical nonlinear theory frequently used in the study of bearing-rotor systems and a accurate model of nonlinear oil-film force. The nonlinear dynamic behaviors of bearing-rigid rotor system are extensively investigated. The results show that there exists such nonlinear dynamical phenomena as chaos ang quasi-period movement when the rotational speed , mass eccentric and a synthesizing parameter of the system change. From different point of view,the chaotical phenomenen induced by double period bifurcation is found.In this paper, the dynamical model of bearing-elastical rotor with a cross-section of crack is estabilished. The influence of whirling motion of the shaft to opening regularity of crack is considered. The nonlinear dynamical behaviors on some parameters are studied. The results have certain sigfinance to the inspection and diagnose of troubles of similar rotational machinery.In fact, the bearing with finite width are widely used in rotational machinery. But the calculation of oil-film force of this kind of bearing needs a large mount of time,and analytical method is powerless to this problem. Considering of above reasons, this paper leads into averageing natural value method that can meet the requirment of engineering. Using this method ,the paper investigate the some nonlinear dynamical behaviors of bearing-rotor system.At the end of this dissertation ,research works to bring forth new ideas for this dissertation are sumarried ,and nesrssary research problems to go a step further are pointed out too.更多还原