轮轨曲线尖叫噪声有限元预测方法的研究

利用ABAQUS有限元软件,对车辆经过小半径曲线时的尖叫噪声进行有限元预测分析.建立了包括车轮、钢轨和钢轨支撑弹簧的有限元动力学模型.根据车轮通过小半经曲线时横向蠕滑力饱和的实际情况,假设横向蠕滑力等于摩擦因数乘以法向力,通过摩擦力耦合建立车轮和钢轨耦合的动力学方程.对此动力学方程进行稳定性分析,得出耦合系统动力学特征方程的复特征值.根据是否存在实部为正的复特征值,从而判断系统是否有发生曲线尖叫噪声的趋势.计算结果显示,当轮轨摩擦因数比较大时,系统存在实部为正的复特征值,说明此时轮轨系统存在发生曲线尖叫噪声的可能性.此外,钢轨端部不同约束条件对曲线尖叫噪声预测结果有一定的影响.     

摩擦尖叫噪声有限元预测分析的可靠性研究

使用相同的制动系统,分别建立了基于ABAQUS和NASTRAN的制动摩擦尖叫噪声有限元预测分析模型.基于ABAQUS的摩擦尖叫噪声模型利用接触耦合关系计算法向力,不需要在接触界面假设接触弹簧.基于NASTRAN的摩擦尖叫噪声模型根据罚函数法计算法向力,需要在接触界面假设接触弹簧.比较了这2种模型的计算结果,发现即使这2个模型采用相同的有限元网格,计算预测到的不稳定频率(即实部为正的复特征值虚部)通常不同,且NASTRAN建模方法只能部分预测到中高频尖叫噪声.计算结果显示,当接触弹簧刚度大于等于3.2×109 N/m时,NASTRAN模型的预测结果基本相同;有限元网格尺寸和单元类型对计算结果也有较大的影响.     

约束对盘形制动摩擦噪声影响的有限元研究

建立了铁路车辆盘形制动装置的三维实体有限元模型，分别为该模型中的制动盘、闸片和夹钳等部件设置了不同的材料特性。利用线性弹簧力模拟制动摩擦面间的法向力，摩擦力取为线性弹簧力与摩擦因数的乘积。通过对系统有限元运动方程进行复特征值分析，根据复特征根实部为正值判断系统发生失稳的模态，这也是可能产生摩擦噪声的模态。仿真结果显示，系统的约束条件对摩擦噪声的形成有显著的影响。改变模型的约束条件，可以抑制制动系统的摩擦噪声发生趋势，说明通过优化设置约束条件来提高摩擦系统的运动稳定性从而抑制摩擦噪声的发生是可行的。     

盘式制动器复模态摩擦耦合制动稳定性分析

为研究影响汽车制动噪声的因素,以通风盘式制动器为研究对象,应用有限元软件ABAQUS,建立制动尖叫有限元模型,通过自由模态试验及制动尖叫台架试验验证了模型正确性,进行复特征值分析和自由模态分析,探讨系统部件自由模态与摩擦耦合模态的关系,摩擦系数及制动系统关键部件刹车盘刹车片的弹性模量对制动稳定性的影响,结果显示在摩擦耦合作用下,系统中固有频率接近的部件产生模态耦合,导致系统不稳定振动;系统摩擦系数越大,摩擦耦合程度也越大,系统不稳定性越大,但主振频率不变;刹车盘和刹车片弹性模量增大分别起到增强和削弱摩擦耦合对系统不稳定性的影响。     

接触网-受电弓系统摩擦振动的初步研究

利用ABAQUS建立接触网和受电弓系统的有限元模型,对其进行运动稳定性的有限元复特征值分析,研究摩擦因数、升弓力矩以及承力索和接触线张力对弓网系统运动稳定性的影响.结果表明:随着摩擦因数μ的增大,系统的不稳定性增加;升弓力矩增大,弓网系统的不稳定性也增加;承力索和接触线的张力越大,弓网系统发生不稳定振动的趋势越大;当摩擦因数μ≥0.35时,系统出现模态耦合现象.     

CRH2盘形制动系统制动尖叫噪声研究

为了研究高速动车组的制动尖叫噪声,建立CRH2拖车盘形制动系统的摩擦耦合有限元模型,对其进行运动稳定性和制动自激振动的瞬态动力学分析,研究了摩擦因数、闸片以及制动盘弹性模量对制动系统尖叫噪声的影响。结果表明：随着摩擦因数μ的增大,盘形制动系统发生制动尖叫噪声的趋势增加;随着闸片弹性模量的增大,制动系统发生制动尖叫噪声的趋势增加,并且激发的噪声频率也明显变大;随着制动盘弹性模量增大,制动系统发生制动尖叫噪声的趋势先降低后增大。     

高速铁路车轮多边形磨耗影响因素仿真研究

基于摩擦自激振动可能导致车轮多边形磨耗的观点,建立由1个轮对和2根钢轨组成的轮轨系统摩擦自激振动模型,应用有限元软件ABAQUS提供的复特征值功能分析该模型的摩擦自激振动发生趋势,讨论摩擦因数、扣件刚度、阻尼对摩擦自激振动发生趋势的影响。结果显示,随着摩擦因数的减小和扣件阻尼的增大,轮轨系统摩擦自激振动发生趋势减小,而仅通过改变扣件刚度不能达到抑制车轮多边形磨耗的目的。根据仿真结果,指出减小摩擦因数和增大扣件阻尼是可行的控制车轮多边形磨耗的措施。     

水润滑橡胶轴承不同结构的摩擦噪声分析

利用ABAQUS软件对水润滑轴承系统进行了噪声分析,利用有限元复特征值分析方法,依据复特征值实部的正负判断轴承系统发生噪声的可能性,如果有实部为正的特征值,则可判断系统有发生噪声的可能性.分别研究了水润滑轴承不同结构,包括水润滑轴承过渡圆弧半径大小、水道槽半径大小、水道槽数量及橡胶厚度对摩擦噪声的影响.研究表明,对于中...     

转向节特性对盘式制动器尖叫影响的研究

考虑到目前关于盘式制动器尖叫噪声的仿真研究通常忽略了转向节的影响,建立包含转向节部件的盘式制动器有限元模型,利用复特征值分析法对该制动器的振动尖叫特性进行预测分析,重点探讨了转向节的特性对制动尖叫行为的影响.结果表明增大摩擦因数会增强制动系统产生尖叫的倾向和强度,转向节对制动系统不同部件之间的耦合具有重要影响,其模态将会诱导制动尖叫噪声的产生.当模型忽略转向节时,尖叫预测结果可能出现"过预测"和"欠预测"的现象.转向节刚度增大会诱导更多频率的不稳定振动产生,同时增大系统的振动尖叫强度.由于转向节和盘毂之间并没有存在明显的摩擦运动,因此转向节-盘毂连接处的摩擦因数并不会对系统的制动尖叫行为产生重要的影响.以上研究结果为认识制动尖叫的产生机理及提出合理改善尖叫措施提供依据.     

摩擦片偏磨引起的汽车制动低鸣噪声

建立后盘式制动器有限元模型,对其进行制动低鸣噪声的有限元复特征值分析。根据系统的负阻尼比预测系统出现制动噪声的趋势。利用该模型,研究摩擦片切向偏磨对制动噪声的影响。研究结果表明,切向偏磨是引起制动低鸣噪声的主要原因。当偏磨量大于0.5 mm时,系统的负阻尼比突变,说明发生制动低鸣噪声的可能性极大;同时该噪声的出现与制动压力、摩擦滑动方向、摩擦因数有特定的关系。该计算结果与噪声试验结果完全一致,为消除该制动低鸣噪声提供了理论依据和指导。     

Evaluation of Disc Brake Materials for Squeal Reduction

A nontraditional evaluation tool is introduced to examine the effects of different materials, in practical applications, that are used in fabricating disc brake components for commonly used or special requirements such as heavy-duty performance and racing cars. As an extension to earlier finite element (FE) disc brake models, a detailed FE model of the whole disc brake corner that incorporates the wheel hub and steering knuckle is developed and validated using experimental modal analysis. Stability analysis of the disc brake corner using the finite element software ABAQUS is carried out to predict squeal occurrence also taking into account the negative and positive damping effects and friction material real surface to increase the accuracy of prediction. A Taguchi method–based design of experiment is used to better assess the contributions of different materials and its interaction effects for effective reduction of brake squeal. The results showed that the pad friction material contributes 56% to the total system instability (squeal generation). The rotor material contributes 22% of the system instability. Caliper and bracket materials participate 11 and 11%, respectively.     

摩擦噪声有限元预测

发展一种利用商业有限元软件进行摩擦系统全模型摩擦噪声预测的方法,可以对包括摩擦力和真实边界条件下的摩擦系统的复特征值进行分析,提出进行摩擦噪声预测的主要步骤.该方法能够大大提高摩擦噪声预测分析的精度和效率.利用该方法分析往复滑动摩擦系统的噪声发生趋势,获得系统特征方程的特征根及其变化特性,据此可判断摩擦系统自然频率和可能发生摩擦噪声的频率.计算结果表明,摩擦因数和滑动方向对系统摩擦噪声的形成有重要影响,摩擦噪声发生时摩擦系统具有振动模态重合的特点.将计算得到的系统可能发生摩擦噪声的频率与系统的试验噪声频率进行比较,发现有比较好的一致性.     

A numerical investigation into the squeal instability: Effect of damping

Between the NVH issues, brake squeal is a harmonic acoustic emission (between 1 and 20 kHz) caused by friction induced vibrations. The onset of squeal is due to an unstable behaviour of the system leading to limit cycle vibrations. A general approach used by several authors to determine the system instabilities is the CEA: Complex Eigenvalues Analysis. This work presents a numerical investigation into the squeal instability on a simplified disc-brake system addressed to analyse the effect of damping on the squeal instability.The mode lock-in instability is reproduced by a parametrical analysis. The relationship between the distribution of damping on the system components and the propensity of the brake to develop squeal is investigated. The numerical results are validated by the experimental ones, presented in a previous work. The behaviour of the system eigenvalues highlights that, while a homogenous distribution of damping stabilizes the system, a non-uniform repartition of damping can increase the squeal propensity.     

Squeal analysis of gyroscopic disc brake system based on finite element method

In this paper, the dynamic instability of a car brake system with a rotating disc in contact with two stationary pads is studied. For actual geometric approximation, the disc is modeled as a hat-disc shape structure by the finite element method. From a coordinate transformation between the reference and moving coordinate systems, the contact kinematics between the disc and pads is described. The corresponding gyroscopic matrix of the disc is constructed by introducing the uniform planar-mesh method. The dynamic instability of a gyroscopic non-conservative brake system is numerically predicted with respect to system parameters. The results show that the squeal propensity for rotation speed depends on the vibration modes participating in squeal modes. Moreover, it is highlighted that the negative slope of friction coefficient takes an important role in generating squeal in the in-plane torsion mode of the disc.     

Improvements for reduction of the brake squeal noise at Seoul metro rolling stock on tracks

Experimental and theoretical methods were applied to find and understand the phenomenon of brake squeal noise of the Seoul Metro rolling stock on tracks. Generally, it is well known that brake squeal noise is strongly related to stick and slip between brake pad and disk. In most cases for rolling stock on tracks, trailer cars needed more particular attention through the tests, because they were the major sources of brake noise due to frictional braking. There are two types of rolling stocks in Seoul Metro: chopper and VVVF. Both types of rolling stocks for lines 1 and 3 in the Seoul Metro were used for experimental analyses. To study brake squeal noise under various braking conditions, dynamometer tests were performed at the S&T Brake, Co., which is one of major manufacturers of brake pads for rolling stock on tracks. For measuring brake squeal noise, acoustic tests were performed with a microphone in the Gunja depot. And modal tests for brake parts, which consisted of brake lining, brake lining pad, and back plates, were executed to obtain the natural frequencies related to the brake squeal noise. Also, modal tests of the whole brake assembly and lining block were performed at the heavy maintenance shop of the Gunja depot. The mode analysis using an ANSYS was simulated to determine the relations between the mechanisms of brake squeal noise. As the results of the tests and the simulations, it was found that specific natural frequencies of the brake parts affected squeal noise, and also, the reason to create squeal noise. Finally, improvements for reducing squeal noise were proposed, and applied to lines 2 and 3 at Seoul Metro rolling stock on tracks. This paper was recommended for publication in revised form by Associate Editor Yeon June Kang Seong Keol Kim received his B.S. in Mechanical Design and Production Engineering from Seoul National University, Korea, in 1986. He then received his M.S. and Ph.D. degrees from Seoul National University in 1988 and 1994, respectively. Dr. Kim is currently an Assistant Professor at the School of Mechanical Design and Automation Engineering at Seoul National University of Technology in Seoul, Korea. Also, he works as an Executive Director of R&BD division of Seoul Technopark. Dr. Kim’s research interests include reliability of Micro System Packaging and mechanical vibration.     

闸片沟槽织构对盘式制动尖叫的影响

为研究制动闸片沟槽织构对盘式制动系统制动尖叫的影响,基于摩擦自激振动理论,建立盘式制动系统普通闸片和沟槽闸片有限元模型,采用复特征值分析法研究该盘式制动系统的摩擦自激振动特性。利用该有限元模型开展沟槽的宽度和深度的参数化分析,获得其对制动尖叫的影响规律。结果表明：制动闸片与制动盘间的摩擦自激振动是导致制动尖叫发生的主要原因,沟槽型闸片对抑制制动尖叫具有明显效果;当闸片沟槽深度在5~20 mm区间内,盘式制动系统的稳定性随沟槽深度的增大而呈现逐渐降低的趋势,表明沟槽深度越小,发生摩擦自激振动的可能性越小;在沟槽宽度5~20 mm范围内,随沟槽宽度的增大,盘式制动系统的稳定性先增大后降低,在沟槽宽度为10 mm时,系统发生制动噪声的可能达到最大。     

Disc brake squeal characterization through simplified test rigs

This paper presents a review of recent investigations on brake squeal noise carried out on simplified experimental rigs. The common theme of these works is that of approaching the study of squeal noise on experimental set-ups that are much simpler than commercial disc brakes, providing the possibility of repeatable measurements of squeal occurrence. As a consequence, it is possible to build consistent and robust models of the experimental apparatus to simulate the squeal events and to understand the physics behind squeal instabilities.     

鼓式制动器振动与啸叫的研究

对于干摩擦引 分析汽车制动啸叫噪声,提出了鼓式制动器啸叫时振动的特性仅取决于制动鼓和蹄征 的观战建立了一种三种解析模型,用以分析制动鼓的固有模态及其稳定性,判 断动器是否发生啸叫。理论分析和试验结果吻合良好,表明该方法具有足够的准确度和工程实用性。