齿轮—转子—滑动轴承系统时变非线性动力特性研究

本文应用求周期解的数值计算方法－打靶法和判定周期解稳定性的Ｆｌｏｑｕｅｔ乘子研究了齿轮－转子－滑动轴承系统中齿轮啮合时变刚度，滑动轴承非线性特性对转子系统不平衡响应和失稳的影响，并比较了平衡位置失稳和不平均响应周期解失稳，以及按双轴计算与单轴计算结果的差别，为工程设计理论计算提供基础。     

非自治系统用瞬态响应求周期解稳定度的方法

根据Floquet理论关于线性周期系数系统解的性质及稳定性条件 ,定义了衡量非线性非自治系统周期解受扰后的衰减速率指标—稳定度。从动力系统流的概念出发 ,给出了利用非线性非自治系统稳态周期解受扰后的瞬态响应信息计算周期解稳定度的方法。以不平衡滑动轴承 弹性转子系统为例 ,说明了该方法的有效性。将稳定度等于零作为临界判据 ,该方法不仅解决了工频周期解失稳边界的确定问题 ,而且解决了渐进稳定域的估计和抗冲击扰动裕度的计算问题     

挤压油膜阻尼器－滑动轴承－刚性转子系统的稳定性及分岔行为

对挤压油膜阻尼器－滑动轴承－转子系统的稳定性及分岔行为进行了研究，由于该动力系统为一强非线性系统，具有复杂的非线性现象。本文采用Ｆｌｏｑｕｅｔ理论对其周期解的稳定性进行了计算分析：随着系统参数的变化，该系统将出现稳态周期解、准周期分岔、倍周期分岔。文中也对系统平衡点的稳定性进行了分析，讨论了其Ｈｏｐｆ分岔行为     

求非线性转子－轴承系统周期响应的一种计算方法

本文把求非线性转子－轴承系统瞬态响应的分块Ｎｅｗｍａｒｋ方法与打靶法结合求系统的周期解，该方法利用了分块Ｎｅｗｍａｒｋ方法求解速度快的优点和Ｊａｃｏｂｉ矩阵求解时每步不需迭代的特点。本文首先给出周期解的求解公式，然后用一个算例，讨论了周期解的稳定性及失稳后的分岔行为。     

弹性支承滑动轴承不平衡转子系统非线性动力稳定性和分岔的研究

研究弹性支承滑动轴承不平衡转子系统的稳定性及分岔特性。建立了弹性支承-滑动轴承-转子非线性动力系统的力学模型，在油膜力非线性的情况下，应用数值模拟，采用打靶法计算了刚性转子系统的周期解，并与龙格-库塔法计算的结果进行了对比，依据Floquet理论，分析了周期解的稳定性，再结合龙格-库塔法、Poineare映射法作出了系统运动分岔图。最后，讨论了轴的柔性对转子系统运动稳定性的影响。     

阻尼器—轴承—柔性转子系统的稳定性及分岔

本文对挤压阴尼器－滑动轴承－柔性转子系统的稳定性及分岔特性进行了理论分析，首先讨论了系统平衡位置的稳定性及共Ｈｏｐｆ分岔，然后讨论了不平衡响应的稳定性及分岔。分析表明：在一定参数条件下，系统的稳态响应将发生倍周期分岔、二次Ｈｏｐｆ分岔及鞍－结分岔。     

轴承-转子系统Hopf分叉及其后动力学行为研究

采用长轴承解析模型研究滑动轴承支承的平衡单盘柔性转子-轴承系统的自激振动,把结合打靶法的延续算法应用于柔性平衡转子-轴承系统Hopf分叉后周期解的追踪和求解上,基于Floquet理论对周期解的稳定性加以分析.通过持续追踪周期解频率变化并与失稳固有频率进行对比,分析了自激锁相现象,研究了非线性油膜力自激源对系统的作用机理.运用Poincare映射、分叉图、及Lyapnov指数对周期解分叉、混沌及进入和脱离混沌的过程进行了分析.     

挤压油膜阻尼器—滑动轴承—刚性转子系统的稳定性及分岔行为

对挤压油膜阻尼器－滑动轴承－转子系统的稳定性及分岔行为进行了研究，由于该动力系统为一强非线性系统，具有复杂的非线性现象。本文采用Ｆｌｏｑｕｅｔ理论对其周期解的稳定性进行了计算分析：随着系统参数的变化，该系统将出现稳态周期解、准周期分岔、倍周期分岔。文中也对系统平衡点的稳定性进行了分析，讨论了Ｈｏｐｆ分岔行为。     

一种估算外弹性阻尼支承最佳参数的方法

设计参数合理的外弹性阻尼支承可以明显改善轴承－转子系统的固有特性及强迫振动响应。文中以滑动轴承支承的单质量转子系统不平衡响应计算为例，介绍了一种估算外弹性阻尼支承最佳参数的新方法——虚设振幅逆解法，并取得了良好的效果。研究结果表明，按照该方法选择弹性阻尼支承最佳参数是合理有效的，并使系统减振要求与改善系统传递力特性和系统的稳定性得到了内在统一。     

裂纹转子分叉、混沌行为研究中的映射延拓综合法

介绍一种能全面计算周期激励下非线性系统周期响应，拟周期响应和混沌响应的新算法－映射延拓综合法，它可方便地确定拟周期响应和混沌响应对应的系统参数区间。应用此算法对具有非线性刚度的裂纹转子系统裂纹扩展故障特征问题进行了研究，得到了以裂纹深度为分叉参数的系统稳态响应分叉解图。     

A numerical method on estimation of stable regions of rotor systems supported on lubricated bearings

ＩｎｔｒｏｄｕｃｔｉｏｎＷｈｅｎｃｏｎｔｒｏｌｌｉｎｇｔｈｅｄｙｎａｍｉｃｓｔａｂｉｌｉｔｙｏｆｌａｒｇｅｒｏｔａｔｉｎｇｍａｃｈｉｎｅｒｙ ,ｎｏｔｏｎｌｙｔｈｅｐｒｏｂｌｅｍｗｈｅｔｈｅｒｅｑｕｉｌｉｂｒｉｕｍｓｔａｔｅｏｆｔｈｅｓｙｓｔｅｍｉｓｓｔａｂｌｅｍｕｓｔｂｅｓｏｌｖｅｄ ,ｂｕｔａｌｓｏｔｈｅｒｅｇｉｏｎｏｆａｓｙｍｐｔｏｔｉｃｓｔａｂｉｌｉｔｙｎｅｅｄｔｏｂｅｄｅｔｅｒｍｉｎｅｄ .Ｗｈｅｎｔ→∞ ,ｓｏｌｕｔｉｏｎｓｕｎｄｅｒｉｎｉｔｉａｌｃｏｎｄｉｔｉｏｎｓｗｉｔｈｉｎｓｕｃｈｒｅ…     

Unbalanced-bridge Computational Techniques and Accuracy for Automated Multichannel Strain-measuring Systems

While much of the current literature and practice is concerned with balance-bridge strain measurements, this paper outlines a straightforward method for measuring strain using unbalanced-bridge techniques. Exploiting the performance and stability available in today's digital voltmeters and low-cost computers, it will be shown that the use of unbalanced bridges is well suited to automated strain measurements. The paper also presents a method for assessing the accuracy of a strain-measurement system by using the specifications of the individual components. Additionally, a comparison of accuracy for balanced and unbalanced conditions is included in this assessment.     

Effects of axial preload of ball bearing on the nonlinear dynamic characteristics of a rotor-bearing system

This research studies the effects of axial preload on nonlinear dynamic characteristics of a flexible rotor supported by angular contact ball bearings. A dynamic model of ball bearings is improved for modeling a five-degree-of-freedom rotor bearing system. The predicted results are in good agreement with prior experimental data, thus validating the proposed model. With or without considering unbalanced forces, the Floquet theory is employed to investigate the bifurcation and stability of system periodic solution. With the aid of Poincarè maps and frequency response, the unstable motion of system is analyzed in detail. Results show that the effects of axial preload applied to ball bearings on system dynamic characteristics are significant. The unstable periodic solution of a balanced rotor bearing system can be avoided when the applied axial preload is sufficient. The bifurcation margins of an unbalanced rotor bearing system enhance markedly as the axial preload increases and relates to system resonance speed.     

Stability and bifurcation of unbalance rotor/labyrinth seal system

The influence of labyrinth seal on the stability of unbalanced rotor system was presented . Under the periodic excitation of rotor unbalance , the whirling vibration of rotor is synchronous if the rotation speed is below stability threshold, whereas the vibration becomes severe and asynchronous which is defined as unstable if the rotation speed exceeds threshold . The. Muszynska model of seal force and shooting method were used to investigate synchronous solution of the dynamic equation of rotor system. Then , based on Floquet theory the stability of synchronous solution and unstable dynamic characteristic of system were analyzed.     

Poincare型胞映射分析方法及其应用

本文用Poincare型胞映射方法对平衡及不平．衡轴承转子非线性动力系统的全局特性进行了分析研究,同时求得了一定状态空间内系统存在的周期解及其在各不同Poincare截面上的吸引域,得到了一些新的现象和规律,并通过对平衡及不平衡轴承转子系统的全局特性异同的比较,说明了要建立既适用于平衡轴承转子系统又适用于不平衡轴承转子系统的非线性稳定性准则应注意的几个问题     

Nonlinear dynamic behaviors of a rotor-labyrinth seal system

The nonlinear model of rotor-labyrinth seal system is established using Muszynska’s nonlinear seal forces. We deal with dynamic behaviors of the unbalanced rotor-seal system with sliding bearing based on the adopted model and Newmark integration method. The influence of the labyrinth seal one the nonlinear characteristics of the rotor system is analyzed by the bifurcation diagrams and Poincare’ maps. Various phenomena in the rotor-seal system, such as periodic motion, double-periodic motion, quasi-periodic motion and Hopf bifurcation are investigated and the stability is judged by Floquet theory and bifurcation theorem. The influence of parameters on the critical instability speed of the rotor-seal system is also included.     

精细积分法在迷宫密封转子系统非线性动力学特性计算中的应用

基于Muszynska密封力模型,建立了迷宫密封转子系统的非线性动力学模型,将精细积分法推广应用于非线性情况,计算了迷宫密封不平衡转子系统的动力学特性,依据Floquet理论讨论其分岔特性。研究表明：在2^N类算法计算指数矩阵基础上提出的精细积分法和传统的数值计算方法相比,其精度高,在分析中通过取不同步长计算对比,表明该方法在某些情况下可以采取较大时间步长,有效提高了计算速度。     

Controlled synchronization at the existence limit for an excited unbalanced rotor

The synchronization of a controlled unbalanced rotor with a viscoelastically mounted supporting body and force-excitation is studied. The existence and stability conditions for the synchronous regime of motion are derived for a general control law by the method of direct separation of motion. Then a control law is developed using speed gradient method in order to transfer maximum energy from the excitation to the rotor. The free parameters of the control law are derived in such a way that the controlled synchronization is stable at the existence limit.     

About the new method to regulate the eccentric force of mechanical vibrators

Summary This paper deals with a new method for a continuous regulation of a vibratory machine oscillation amplitude, by acting only on the electronic equipment, which can be put at large distance from the machine.The regulation is obtained by the starting transient, with variation of the angular positions of two unbalanced masses.Experimental tests on the analysis of the dynamics and stability of the motion of the rotating unbalanced masses are reported.The influence of the mechanical configuration of the system is examined.

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Sommario Questo lavoro tratta di un nuovo metodo per una regolazione continua dell'ampiezza di oscillazione di una macchina a vibrazioni, agendo solamente sul sistema elettronico di controllo, che può essere posto a grande distanza dalla macchina.La regolazione è ottenuta attraverso il transitorio di avviamento variando le posizioni angolari di due masse non equilibrate.Sono riportate le prove sperimentali sull'analisi della dinamica e della stabilità del moto delle masse rotanti non equilibrate.Si è esaminata l'influenza della configurazione meccanica del sistema.