【作者】 周杰；

【导师】 徐道临；

【作者基本信息】 湖南大学 ， 机械工程， 2015， 硕士

【摘要】 隔振降噪是一个长期被关注而重要的研究领域。线性隔振理论的研究已经趋于完善,并得到广泛的工程应用。由于线性隔振系统受限于隔振频率必须大于其固有频率2倍时才能发挥功效,因此对于低频隔振问题,人们积极探索非线性隔振解决方案。本文基于准零刚度概念和形成原理,提出了一种新型的碟形橡胶准零刚度隔振器的设计。准零刚度隔振器是由负刚度元件碟形橡胶(内含钢材料的筋)与正刚度元件竖直橡胶柱并联组合而成,具有低频隔振的特性。设计准零刚度隔振器的关键步骤是获得正、负刚度的完美匹配,达到平衡点处的零刚度特性。借助Abaqus有限元仿真分析,设计了符合负刚度条件的加筋碟形橡胶模型,提出了微凸面的加筋方法并数值分析了设计的可行性。进一步应用Abaqus有限元方法,分析了正刚度橡胶原件的设计模型。经过反复修正模型设计参数,得到了正、负刚度匹配的碟形橡胶准零刚度模型。通过Abaqus分析,获得模型的力与位移曲线和刚度曲线。通过两种方法可界定该模型系统的隔振特性曲线。方法一是将Abaqus的力与位移的关系拟合成一个近似的非线性替代模型,并建立隔振系统的动力学方程,通过Matlab仿真得到系统的力传递率曲线,讨论其阻尼、刚度、和激振力幅值对准零刚度隔振系统的影响;方法二是在Abaqus有限元模型基础上,继续通过Abaqus进行动力学仿真分析,通过采集不同激励频率下的系统响应得到系统的力传递率。这两种方法都证实了碟形橡胶准零刚度系统具有低动刚度、高静刚度的特点,可实现低频隔振。与相同条件下的线性隔振比较,不仅拓宽了隔振频带,还降低了共振频率和峰值。设计制造了膜片弹簧准零刚度隔振器的实验样机,搭建了测试平台,对膜片弹簧准零刚度隔振器进行了静力学实验,获得了力与位移关系曲线,证实了隔振器的准零刚度特性。动态实验数据证实了准零刚度隔振器比线性隔振器有更好的隔振效果。更多还原

【Abstract】 Vibration and noise reduction is one of the most important research areas nowadays in which linear vibration isolation theory is hull-fledged and has wide applications in engineering. According to classical theory of vibration isolation, we know that linear vibration isolator can perform its function only when excitation frequency is larger 2 times than isolator’s natural frequency. If we broad frequency region, especially for low frequency region, of vibration isolation via decreasing the nature frequency, the system ma y meet stability problem. Thus the nonlinear vibration isolation theory need s further exploration.A new type design of disc rubber vibration isolator with quasi-zero-stiffness(QZS) characteristic is proposed based on the theory and design principle of the QZS. The QZS isolator was devised by assembling a reinforced disc rubber with negative stiffness property with a vertical rubber cylinder with positive stiffness characteristic in parallel which has characteristic of low frequency vibration isolation.The key design procedure is choosing perfect matching of positive and negative stiffness which achieves zero stiffness property at balance position. A qualified model of reinforced disc rubber with negative stiffness property is designed b y means of Abaqus simulation. The micro-convex reinforcement form is proposed and the feasibility of this design is analsized. Next, the rubber model with positive stiffness is also analsized and the whole model of disc rubber with quasi-zero-stiffness characteristic is built with revising model parameters repeatedly. The stiffness characteristic of the QZS system was analyzed by means of Abaqus simulation and zero stiffness property is observed. Next, two methods is adopted to get the force transmissibility of QZS vibration isolation system. One is numerical simulation in which the force-displacement relationship of QZS system was replaced by a approximate nonlinear model by fitting the FEA simulations data. Then governing equation of the vibration isolation system is formulated and the force transmission curve of the system is obtained by Matlab simulation. We analysize the effect of damping 、 stiffness and excitation amplitude on QZS characteristic of vibration isolation system. The other method is dynamic simulation by Abaqus. The force transmission curve of the system is obtained by the response under different excitation frequency. The two methods have demonstrated that the QZS isolator has the superior characteristic of low-dynamic-high-static stiffness and may realize low-frequency vibration isolation. Compared with the corresponding linear vibration isolation with the same system parameters, the QZS isolator not only broadens the isolation frequency band, but also reduces the resonance peak.Finally, an experimental bench of diaphragm spring vibration isolator with QZS characteristic is set up. The static experiment of diaphragm spring vibration isolator was carried out, and a force-displacement curve is obtained and demonstrated the QZS characteristic of the vibration isolator. The results of dynamic experiment revealed that the QZS isolator has better isolation performance compared with the corresponding linear one.更多还原