【作者】 李晓勇；

【导师】 浣石；

【作者基本信息】 广州大学 ， 防灾减灾工程及防护工程， 2011， 硕士

【摘要】 机械设备的周期振动不仅减少仪器的使用寿命、破坏其工作性能、加剧构件的疲劳损伤、降低结构的稳定性和承载强度,而且随着振动的接触传播和噪声的空间传播,还会对周围的环境和人们的生活造成巨大的影响。在这些振动和噪声当中,机械设备工作频率的线谱能量占有主导地位,在振动和噪声污染的传播过程中维持的时间最持久、相应的破坏力也最为突出。目前,振动控制最主要的方法是基于线性理论的隔振技术。随着振动控制要求的不断提高,线性理论已逐渐无法满足现代工程中的实际需要,基于非线性理论的隔振技术研究变得十分迫切。混沌运动是存在于非线性系统中一种特殊的运动现象。混沌隔振的原理就是通过利用混沌运动中其相应的功率谱呈连续分布这一特征,将输入激励的线谱能量分散到较宽的频率范围,以达到改变振动系统的频谱结构,降低振动线谱能量传播的目的。本文以非线性动力学理论为基础对强Duffing模型隔振装置的混沌动力学特性进行了如下几方面的研究:(1)讨论了非线性系统混沌特性的数值研究方法,对强Duffing系统进行了混沌识别和激励参数分岔研究,创新的借助标准差概念建立双参数分岔三维图,得到了系统的动态特性在f?ω平面上的分布情况。从全局角度揭示出系统的混沌分布特性,并进一步研究了阻尼和重力作用对系统动力学特性的分布影响;(2)根据几何非线性的原理设计出了一种参数可调的强Duffing系统非线性隔振装置。根据分析推导和实验得到了装置的动力学参数。并对该非线性装置分别进行了静力和动力实验。实验结果和理论计算的结果对比表明该隔振装置和理论设计较为吻合;(3)利用ANSYS通用有限元分析软件建立了非线性隔振装置的平面实物模型和简化模型,对模型进行了非线性静力和动力的有限元模拟实验。并研究了重力作用、模型误差以及外部激励噪声对强Duffing系统运动状态的影响。论文最后对上述主要研究成果作了总结归纳,并指出了研究过程中存在的缺陷和不足,以及进一步研究的方向和亟待解决的问题。更多还原

【Abstract】 Machine’s periodical vibration does not only cut service life of instrument, but alsodepress its working performance, aggravate constructional element’s fatigue damage, reducestructure’s stability and load capacity. And it can make bad influence on environment andpeople’s living with vibration’s contacting propagation and noise’s space propagation. In thisthe line spectrum energy on machine’s working frequency is on the main position. It has longerduration and more badly destruction power. Nowadays, the most important method ofvibration control is vibration isolation technology based on linear theory. As requisition’simproving of vibration control, it can hardly satisfy the actual need of contemporaryengineering. Therefore vibration isolation technology based on nonlinear theory is becomingbadly needed.Chaos motion is a special phenomena in nonlinear system. The principal of chaoticisolation is to distribute the linear spectrum energy into wide spectrum interval for chaosmotion’s power spectrum is continuous distribution. Then the frequency spectrum of vibrationsystem will be changed, and the aim to depress the linear spectrum energy is achieved.Based on nonlinear dynamics, this thesis is focused on chaotic dynamical characteristicof strongly Duffing model isolation, The main research contents of this thesis are listed asfollows:（1）Numerical research method of nonlinear system’s chaotic characteristic isdiscussed, research of chaos identification and parameter bifurcation based on stronglyDuffing model is conducted. The distribution characteristic of system’s dynamicalcharacteristic on the f ?ωplane is obtained by using standard variance to buildthree-dimension graph of two-parameters bifurcation. The distribution characteristic ofsystem’s chaotic characteristic is showed in global view. Furthermore, damping and gravity’sinfluence on system dynamical characteristic distribution is discussed.（2）A nonlinearisolation mounting with adjustable parameters based on strongly Duffing model is designedaccording geometric nonlinear principle. The dynamical parameters of isolation mounting aregot by analytical derivation and experiment. Static and dynamic experiments on this isolationmounting is conducted. The result of experiment and theoretical calculation showed that this isolation mounting is matched with theoretical design.（3）Plane actual model and simplifiedmodels of nonlinear isolation mounting are built by using ANSYS software．Nonlinear staticand dynamic simulation experiment by finite element method is conducted consideringgravity，model error and external excitation noise’s influence on strongly Duffing system’skinematic state.In the end, main conclusions are summarized and some disadvantage in researchprocedure is picket-out, and some topics for research prospect are presented.更多还原