A study on squeal noise reduction considering the pad shape of the disc brake system for urban railway vehicles

Journal of Mechanical Science and Technology - In this paper, to help reduce the squeal noise produced during the braking of urban railway vehicles, the shape of the disc brake pad was investigated...     

摩擦副组合对摩擦磨损性能的影响

在1：1惯性力矩制动试验台上研究了两种不同石墨形态的铸铁制动盘与两种混杂纤维增强的酚醛基制动闸片配副时的摩擦磨损性能。结果表明，对于某一配方的制动闸片，使用灰口铸铁盘的摩擦副具有较高的摩擦系数，但制动盘表面温度较高，闸片磨损量较大；对于某一种制动盘，使用B配方制动闸片时，制动盘表面的温度较高，但闸片的磨损量较小；在所有四种组合中，B配方制动闸片与灰口铸铁盘配副的瞬时摩擦系数能够完全满足有关技术要求。     

Advanced Friction–Wear Behavior of Organic Brake Pads Using a Newly Developed System

The objective of this study was to investigate the influence of an advanced performance system on the tribological behavior of brake pad material using a specially designed brake pad tester system following standard SAE J-661. The tribological behavior and friction and wear characteristics of the organic brake pad samples were evaluated. During braking tests, the samples, in contact with a cast iron disk, were studied at different disc speeds, temperatures, and braking cycles under a constant pressure. In order to understand the friction and wear behavior, the unworn surfaces, worn surfaces, and wear debris were characterized by means of scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). Furthermore, the surface characteristics and differences in the wear modes of the brake pad samples were examined. Wear debris was permitted to deform the brake pad surfaces, leading to friction layers and enabling the estimation of the friction behavior of the brake pads. The results showed that the best friction–wear behavior was obtained with lower braking cycles at low speeds and temperature. Thus, the newly developed brake pad tester system proved very effective in evaluating the performance of the brake pad samples.     

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.     

Semi-analytical approch for brake squeal of a rail pad

Journal of Mechanical Science and Technology - In this study, a semi-analytical pad model was developed to analyze the causes and mechanism of brake squeal of a rail pad in a railway brake system....     

踏面制动尖叫噪声的有限元分析

利用ABAQUS软件建立铁路货车车轮踏面制动系统有限元模型,对其进行制动摩擦尖叫噪声的有限元复特征值分析.根据复特征值实部的正负判断系统发生尖叫噪声的可能性,如果有实部为正的特征值,则可判断系统有发生尖叫噪声的趋势.在ABAQUS建模方法中,闸瓦与车轮之间的法向力根据接触计算确定,不需假设接触弹簧,可以方便处理非平面滑动接触尖叫噪声问题.利用该模型,研究滑动摩擦因数、闸瓦压力角、闸瓦压力和转动方向对尖叫噪声的影响.研究结果显示,闸瓦压力角对制动尖叫噪声有重要影响,当闸瓦压力角α=5°时,制动系统发生尖叫噪声的影响.研究结果显示,摩擦因数越大,系统发生尖叫噪声的趋势就越大;闸瓦压力越大,尖叫噪声发生的趋势就越大.车轮逆时针转动比顺时针转动更容易引起尖叫噪声.     

稳恒磁场作用下摩擦制动尖叫发生率及其预测分析

为了研究稳恒磁场作用下制动尖叫发生率随制动工况的变化规律,提出一种基于长短时记忆(LSTM)网络的摩擦制动尖叫发生率的预测模型。设计制动尖叫信号的测量方案,并开展大量的模拟制动试验;通过LSTM门控循环单元的深度学习网络,构建对不同制动工况下制动尖叫发生率的智能预测模型;通过预测模型及摩擦界面的微观特性分析稳恒磁场对制动尖叫行为的影响规律及机制。结果表明：建立的模型可以实现对制动尖叫发生率的准确预测;稳恒磁场可有效降低制动尖叫发生率,但当磁感应强度增大到一定阈值后,磁场对摩擦行为的影响程度趋于饱和,制动尖叫发生率也逐渐趋于稳定。研究结果为探索发展基于磁场的制动器制动尖叫主动抑制技术提供了理论基础和数据模型。     

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。     

Analytical formulation of mode-coupling instability in disc-pad coupled system

This paper describes the mode-coupling-type squeal mechanism in a disc brake system. The mode shapes of a disc and a brake pad (an annular sector plate) are obtained using the component eigenvalue analysis and the Rayleigh-Ritz method, respectively. The disc-pad coupled system subject to friction-couple is discretized by the truncated set of system component modes. Mode-coupling instability is determined in closed form resulting from a reduced-order friction-coupling model, which subsequently defines the modal stability index. The proposed index parameter determines the necessary condition for flutter instability without solving system complex eigenvalues. The numerical investigation shows that the disc-pad modal interaction has a strong squeal tendency when two pads are not identical.     

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。