【作者】 侯俊；

【导师】 过学迅； 邓楚南；

【作者基本信息】 武汉理工大学 ， 车辆工程， 2009， 博士

【摘要】 如今随着汽车工业的迅速发展,机动车已经进入了普通老百姓的家庭,方便了人们的日常生活和工作。但汽车的噪声,特别是制动器噪声,已成为现代城市生活不可忽视的一大公害,并引起广大消费者的广泛关注。控制噪声污染已逐渐成为人们行车及生活的迫切要求,因此降低汽车的制动噪声成为了汽车制造商乃至全人类社会强烈共识和亟待解决的重要问题。本文的课题来源是浙江省重点实验室项目“浙江省汽车零部件试验基地计划”,编号2003E10052。文章在查阅大量国内外文献的基础上,以盘式制动器为研究对象,采用在盘式制动器中制动块的底板上粘贴一层阻尼层的做法实现制动器结构减振降噪的目的,探讨了粘弹性材料的阻尼特性对制动器振动与噪声的影响,并达到预期目标。为阻尼技术在制动器减振降噪方面的应用提供了理论依据和试验研究方法。本文首先对问题的工程背景做了详细的介绍,分析了盘式制动器摩擦噪声的产生机理,解释了振动与噪声之间的关系,总结了目前常用的研究振动和噪声的方法。通过一个简化的有限元模型,运用模态分析和相关实验数据,分析了三个主要参数：摩擦系数,制动压力和温度对制动噪声的影响,得出相关结论。建了各零部件的三维几何模型,研究了零部件面向制动噪声的动态特性,得到了它们的各阶实模态,分析探讨了各个部件的动态特性与制动噪声之间的关系。建立制动器总成的CAD装配模型和有限元模型,并对制动器总成进行面向制动噪声的复模态分析,得到总成的动态特性。选取一对新的制动块,通过静态接触试验,用压力显示器测得制动块上的压力分布特性,然后测定制动块摩擦表面的粗糙度。然后将这些测得的真实值和磨损公式进行计算得到结果进行比较,指出用仿真的方法研究磨损特性的可行性,用复模态方法对不同磨损情况下制动器噪声的产生情况进行预测,最后将预测得到的噪声结果与实际噪声实验得到的结果进行对比,说明磨损预测结果与噪声的联系。文中尝试用仿真的方法预测制动块的磨损情况,这是文中的一处创新。对盘式制动器阻尼降噪方法进行了理论研究。首先进行了阻尼层的机理分析,分析了阻尼层在制动系统中的减振机制及衡量阻尼材料特性的主要性能指标。介绍了阻尼结构的有限元分析方法、粘弹性阻尼材料的数学表征及其在动力学方程的求解方法。然后建立了质量集中的盘式制动器参数模型,得到阻尼系数的变化对啸叫特征参数的影响,得出在系统中增加阻尼可以减小不稳定的内部振动模态的结论。最后对于阻尼层结构进行了建模,采用了8节点线性边界单元方法,比较了四种不同结构阻尼层结构,结果证明该方法有着较好的计算精度,且更易操作,大大的提高了计算效率。提出了对阻尼层结构的建模方法,此方法具有一定的通用性,可以为后续对不同厚度,材料组成的阻尼层进行快速分析,这也是文中的一处创新。探讨了阻尼层材料按照ASTM E756-98标准,对于不同阻尼结构的测试方法,并通过厂家所做的测量数据进行总结和计算得到粘弹性阻尼材料的振动阻尼特性参数,包括：损失因子、杨氏模量和剪切模量。通过这种方法测得的材料阻尼特性可以被广泛应用在数学模型中用来设计阻尼系统并预测它们的工作状态。然后对盘式制动器振动和噪声试验进行了介绍,按照SAEJ2521方法对某产生制动噪声的盘式制动器在Link公司的单头噪声惯性制动器试验台上进行了试验。对制动块底板上增加橡胶阻尼层的制动器进行了试验研究,并和未增加阻尼层的同一制动器进行了噪声对比。结果显示,在添加阻尼层后,制动器噪声不管是在分布的频率、产生噪声的概率还是测得的峰值声压级都有不同程度的降低,试验再次验证了阻尼降噪方法可以降低噪声的产生概率。更多还原

【Abstract】 With the rapid development of the automotive industry, motor vehicle has entered the ordinary families, which is convenient for people’s daily life. But the automobile noise, especially the brake noise, has become a big nuisance which we can not be ignored, and catches extensive attention of consumers. Control and reduction of brake noise has become urgent demand of all the people, thus to reduce automobile brake noise becames an important problem to be resolved both by the automobile manufacturers and researchers.This topic comes from "Zhejiang Province Key Laboratory Project for Experimental Bases of Automobile Parts", No.2003E10052. After extensive review of the related literature, the approach of adding an insulator at the back of the disc brake back plate has been realized to reduce the structure vibration and noise. Discussion has been done of the performances of several viscoelastic damping materials which showed good results of reduction of noise. The dissertation reveals damping technology in brake antivibration amd noise reduction applications, and provides theoretical basis and test methods for future studies.First of all, a detailed introduction of engineering background of the noise problem is presented. The dissertation analyzes of the disc brake friction mechanism of noise, explains the relationship between noise and vibration, summarizes the current research of commonly used methods of noise and vibration.3D models of the disc brake parts are established respectively. The dynamic characteristics of the model for each brake parts are studied. This paper also analyzes the relationship of dynamic characteristics and noise of the each part. The CAD model and finite element model of the brake assembly is established, analysis is taken using the complex modal analysis method, and the dynamic characteristic of assembly is calculated.Theoretical research of damping noise reduction method of disc brake is stated. Based on the layer of damping mechanism analysis, this paper analyzes the damping layer in the braking system of the vibration damping mechanism and characteristics of its main performance indexes, introduces the structure of the finite element analysis method of damping of viscoelastic materials, the mathematical representation and the solving method of dynamic equations. And an analytic model is used to get relationship of the damping coefficient and squeal characteristics parameters which indicate that increasing system damping can reduce the unstable vibration modes. For damping layer structure modeling, the 8 nodes linear boundary element method is applied and the result shows that the proposed method has better accuracy, and easier to operate, and greatly improvement of the computational efficiency.According to damping layer materials E756-98 standard ASTM test, different structures of the test methods have been disscussed. the data have been calculated and summed, and then the viscoelastic damping materials vibration damping parameters have been measured, including:the loss factor, young modulus and shear modulus. The method of calculating the damping materials characteristics can be widely used in the mathematical model and forecasting system damping performaces of their working conditions. Then the disc brake vibration and noise tests were introduced, and tests have been done in accordance with J2521 SAE method on the inertia-noise-dynamometer 3900 made by Link company. The increase of rubber damping layer on the brake back plates was investigated, and a comparative study of brake noise with and without the damping layer has been done. Results show that, by adding damping layer, the brake noise in the frequency distribution, noise probability and measured peak values have been reduced at different levels, so the tests verified that damping noise reduction method can reduce the noise generated probability.更多还原