一种宽频动力吸振器的设计研究

发布时间：2018-03-14 20:47

本文选题：结构振动　切入点：动力吸振器　出处：《北方工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：现代工业的发展使得人们的生活水平有了大幅度的提高,与此同时,工业设备产生的振动及噪声污染也带来了很多危害,其对于环境、人身健康、设备寿命及精度等方面都造成了不良的影响。动力吸振作为减振方法的一种,由于结构简单、控制方便、价格低等优点,因此在工程实践中的应用十分广泛。本文作者提出了一种动力吸振器的结构,该动力吸振器一方面通过压缩或拉伸C型弹簧组来实现弹簧刚度的连续可调,进而控制动力吸振器固有频率的调节；另一方面,通过更换可调质量块的大小,可以实现动力吸振器工作频带范围的调节。本文建立了动力吸振器弹簧组的物理模型,分析出弹簧组在竖直方向上的刚度系数与两个直线螺母间的跨距的平方成正比例关系,并且通过能量法推导出弹簧的有效刚度表达式,得知弹簧的有效刚度仅与其截面宽度、厚度和弯曲半径有关。通过理论计算和数值仿真,得到了两个直线螺母间的跨距与动力吸振器固有频率之间的线性关系,以及动力吸振器的移频特性,其频带变化率最大可以达到77%。为了检验动力吸振器的减振效果,本文以平板结构作为振动基体并施加简谐激励,通过有限元方法仿真计算了动力吸振器的减振效果,结果表明：该动力吸振器在频带范围内的最大减振效果达到9dB,并且当动力吸振器安装在距离振源越近的安装位置时减振效果越好。为了使动力吸振器能够达到最大的减振效果,对动力吸振器的主要参数进行了分步优化设计：首先建立了动力吸振器减振系统的运动学微分方程,获得了稳态位移的数学表达式；利用小步长搜索法编程对动力吸振器系统参数：质量比μ,激振频率比g,阻尼比ξ固有频率比f进行了最优化设计；然后以这四个最优参数为基础,通过ANSYS Workbench有限元软件对动力吸振器的尺寸参数进行了二次优化,最终获得了动力吸振器各个参数的最优解。经过优化后的动力吸振器的最大减振效果达到11.8dB,性能提升了近30%。为使动力吸振器获得更好的宽频减振能力,使用HyperWorks有限元软件对动力吸振器进行了拓扑优化设计,并对优化后的动力吸振器减振效果进行了仿真计算,仿真结果表明：拓扑优化后的动力吸振器在0-200Hz的频带范围内比之前具有更多的模态分布；动力吸振器在50Hz-200Hz频带内的平均减振效果为5dB,比优化前的性能提升了约25%；在0-50Hz频带内的减振效果较优化前略有提升。
[Abstract]:With the development of modern industry, people's living standards have been greatly improved. At the same time, the vibration and noise pollution caused by industrial equipment has also brought a lot of harm to the environment and human health. Dynamic vibration absorption is a kind of vibration absorption method which has the advantages of simple structure, convenient control and low price, so it is widely used in engineering practice. In this paper, a structure of dynamic vibration absorber is proposed. On the one hand, the dynamic vibration absorber realizes the continuous adjustment of spring stiffness by compressing or stretching C-type spring group, and then controls the adjustment of the natural frequency of dynamic vibration absorber, on the other hand, By changing the size of the adjustable mass block, the range of the working frequency band of the dynamic vibration absorber can be adjusted. In this paper, the physical model of the spring group of the dynamic vibration absorber is established. It is found that the stiffness coefficient of the spring group in the vertical direction is proportional to the square of the span between the two linear nuts, and the expression of the effective stiffness of the spring is derived by the energy method, which shows that the effective stiffness of the spring is only related to its cross-section width. The thickness is related to the bending radius. Through theoretical calculation and numerical simulation, the linear relationship between the span between two linear nuts and the natural frequency of the dynamic vibration absorber is obtained, as well as the frequency shift characteristics of the dynamic vibration absorber. In order to test the damping effect of the dynamic vibration absorber, the flat plate structure is used as the vibration matrix and the harmonic excitation is applied. The vibration absorption effect of the dynamic vibration absorber is calculated by the finite element method. The results show that the maximum damping effect of the dynamic vibration absorber is up to 9 dB in the frequency band, and the better the damping effect is when the dynamic vibration absorber is installed near the vibration source. In order to achieve the maximum damping effect of the dynamic vibration absorber, the main parameters of the dynamic vibration absorber are designed step by step. Firstly, the kinematic differential equation of the dynamic vibration absorber damping system is established. The mathematical expression of steady-state displacement is obtained, and the parameters of dynamic vibration absorber are optimized by using small step search method: mass ratio 渭, exciting frequency ratio g, damping ratio 尉 natural frequency ratio f. Based on the four optimal parameters, the dimension parameters of the dynamic vibration absorber are quadratic optimized by ANSYS Workbench finite element software. Finally, the optimal solution of the parameters of the dynamic vibration absorber is obtained. After the optimization, the maximum damping effect of the dynamic vibration absorber reaches 11.8 dB, and the performance is improved nearly 30%. In order to make the dynamic vibration absorber obtain better wideband vibration absorption ability, the topology optimization design of the dynamic vibration absorber is carried out by using HyperWorks finite element software, and the effect of the dynamic vibration absorber after the optimization is simulated. The simulation results show that the dynamic vibration absorber with optimized topology has more modal distribution in the frequency range of 0-200 Hz than before. The average damping effect of the dynamic vibration absorber in the frequency band of 50Hz to 200Hz is 5 dB, which is about 25% higher than that before optimization, and the damping effect in the frequency band of 0-50 Hz is slightly higher than that before optimization.
【学位授予单位】：北方工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535

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