轻质减振降噪方法的设计与分析

发布时间：2018-09-01 11:13

【摘要】：随着汽车工业的迅速发展,消费者对汽车的振动噪声控制水平和整车舒适性的要求越来越高。同时,能源和环保问题也给汽车工业的发展带来了挑战。研宄表明,汽车整车质量减轻,汽车的燃油经济性、操纵稳定性、碰撞安全性等将会得到明显的改善。所以,轻量化已经成为现代汽车设计制造的一项重要目标。在结构表面粘贴粘弹性阻尼材料和附加动力吸振器是工程上常用的两种被动减振降噪措施。具有高阻尼特性的粘弹性材料能在较宽的频率范围内起到很好的减振降噪作用,被广泛地应用在各个工业领域。由质量块、弹簧、阻尼材料构成的动力吸振器(DVA)发明至今已有一百多年的历史,其结构简单,制造成本低廉,可设计性较强,在工业减振降噪方面的作用越来越明显。两种减振降噪措施在实际应用中各有利弊,但每种方法均为原系统带去了一定的附加质量。本文的研究内容重点在于比较在附加质量一定的条件下,粘弹性阻尼材料和动力吸振器对结构的减振效果。研究目标旨在找到有利于实现轻量化目标的减振降噪方法。本文以简支梁的振动为研究对象,主要对比了自由阻尼层(ULD)、约束阻尼层(CLD)和动力吸振器(DVA)三种减振措施减振效果的好坏和附加质量的大小。理论模型部分首先建立了简支钢梁上粘贴自由阻尼层结构(自由阻尼梁)和梁体附加动力吸振器结构(动力吸振器梁)振动响应的解析解力学模型,并在数值计算软件MATLAB中编程求解得到了梁体结构在外界简谐激振力下的稳态位移、速度响应。此外,在有限元软件MSC.NANSTRAN中建立了简支钢梁粘贴约束阻尼层结构(约束阻尼梁)的力学模型,在分析模块中求解其频率响应结果。并将计算得到的速度响应结果导入MATLAB计算软件中与自由阻尼层和动力吸振器的减振方法做了对比分析。然后,通过实验验证了自由阻尼梁、约束阻尼梁和动力吸振器梁振动理论模型的正确性。自由阻尼层和约束阻尼层等粘弹性阻尼材料的减振性能主要由其力学参数决定,而粘弹性阻尼材料的力学参数又是随出厂标准而定的,在实际工业应用并不能做参数优化处理以达到更好的减振效果和更轻的附加质量。通过优化动力吸振器的质量、刚度、阻尼比等重要参数,可以使动力吸振器达到更好的减振效果,并为原系统带去更小附加质量。本文设计了三组动力吸振器,一个质量为10g旨在抑制简支钢梁第1阶自然频率处共振的单动力吸振器,每个质量均为10g分别抑制简支钢梁第1阶、第2阶、第3阶自然频率下共振的三个动力吸振器以及每个质量均为6g的三个动力吸振器,并将这三组动力吸振器的减振效果与自由阻尼层和约束阻尼层作了比较。其中,自由阻尼层重量为30g,约束阻尼层重量为18.4g。结果表明：约束阻尼层比自由阻尼层的减振效果更明显,且附加质量更轻,但后者制造成本较高。重为10g的单动力吸振器在简支钢梁第1阶自然频率处取得了比自由阻尼层和约束阻尼层更好的减振效果。通过对比还发现,自由阻尼层在低频范围内的减振效果不明显,高频减振效果突出,所以动力吸振器在简支梁单模态和低频范围内的减振应用方面更有优势,且附加质量较轻。此外,三个重量均为6g动力吸振器在简支梁前3阶自然频率处都起到了很好减振效果,且优于两种粘弹性阻尼材料。且随着动力吸振器质量的增加,三个重量为10g的动力吸振器的减振效果更为明显,每个动力吸振器可控的振动频带更宽。综合来看,动力吸振器对梁体振动的抑制作用更有针对性,且在较宽频带范围内的整体减振效果也十分理想,并能最大限度地减少在振动控制过程中带来的附加质量。
[Abstract]:With the rapid development of automotive industry, consumers are demanding higher and higher control level of vehicle vibration and noise and vehicle comfort. At the same time, energy and environmental protection problems also bring challenges to the development of automotive industry. Therefore, lightweight has become an important goal in the design and manufacture of modern automobiles. Viscoelastic damping materials and additional dynamic absorbers are two commonly used passive vibration and noise reduction measures in engineering. Noise reduction is widely used in various industrial fields. Dynamic vibration absorber (DVA) consisting of mass block, spring and damping material has been invented for more than one hundred years. It has simple structure, low manufacturing cost and strong designability. It plays a more and more important role in industrial vibration and noise reduction. Each method has its own advantages and disadvantages, but each method brings some additional mass to the original system. The main content of this paper is to compare the damping effect of viscoelastic damping material and dynamic absorber on the structure under the condition of certain additional mass.
In this paper, the vibration of a simply supported beam is taken as the research object, and the vibration reduction effect and additional mass of three vibration reduction measures, namely, free damping layer (ULD), constrained damping layer (CLD) and dynamic absorber (DVA), are compared. Analytical solution mechanics model of vibration response of vibration absorber structure (dynamic vibration absorber beam) is established, and steady displacement and velocity response of beam structure under external harmonic exciting force are obtained by programming in MATLAB. In addition, a simply supported steel beam with adhesive constrained damping layer structure (constrained damping beam) is established in the finite element software MSC.NANSTRAN. The results of the velocity response are imported into the MATLAB software and compared with the vibration reduction methods of the free damping layer and the dynamic vibration absorber. Then, the vibration theoretical models of the free damping beam, the constrained damping beam and the dynamic vibration absorber beam are verified by experiments. The damping performance of viscoelastic damping materials, such as free damping layer and constrained damping layer, is mainly determined by their mechanical parameters, while the mechanical parameters of viscoelastic damping materials are determined by factory standards. In practical industrial applications, it is impossible to optimize the parameters to achieve better damping effect and lighter additional mass. The mass, stiffness, damping ratio and other important parameters of the dynamic absorber can make the dynamic absorber achieve better damping effect and bring smaller additional mass to the original system.
In this paper, three groups of dynamic absorbers are designed. A single dynamic absorber with a mass of 10G is designed to suppress the resonance at the first natural frequency of a simply supported steel beam. Each mass of 10G is used to suppress the resonance at the first, second and third natural frequencies of a simply supported steel beam, and three dynamic absorbers with each mass of 6g. The damping effect of the three groups of dynamic absorbers is compared with that of the free damping layer and the constrained damping layer. The weight of the free damping layer is 30 g and the weight of the constrained damping layer is 18.4 g. The results show that the damping effect of the constrained damping layer is more obvious than that of the free damping layer, and the additional mass is lighter, but the manufacturing cost of the latter is higher. Compared with the free damping layer and the constrained damping layer, the free damping layer has not obvious damping effect in the low frequency range, and the high frequency damping effect is prominent. Therefore, the dynamic vibration absorber is applied in the single mode and low frequency range of the simply supported beam. In addition, the three 6 g dynamic absorbers have a good damping effect at the first three natural frequencies of the simply supported beam and are superior to the two viscoelastic damping materials. The controllable vibration frequency band of the vibrator is wider. Generally speaking, the dynamic vibration absorber has more pertinence to restrain the vibration of the beam, and the overall vibration reduction effect in a wider frequency band is also very ideal, and can minimize the additional mass in the vibration control process.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U465;TB535.1

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