高速高压高频动态摩擦的机理研究

With the upgrading of the load capacity and the increasing of the speed of rail transportation in China, the concerns on the safe operation of high-speed trains are growing, and people pay more and more attention to the noise generated by the operation and braking of high-speed trains. The mechanism of high-speed, high-pressure, and high-frequency dynamic friction will be studied in both macro and micro scales in the proposed research. In micro scale, advanced equipment such as atomic force microscope (AFM) and electrochemical - scanning tunneling microscope (EC-STM), will be used to characterize the physical and chemical properties, electromagnetic force, electrostatic force, adhesion, and friction of the contact surfaces with high sliding speed, high-pressure, and high-frequency oscillations. In macro scale, the intrinsic relationship between the friction force or the coefficient of friction and the sliding speed, normal pressure, vibration frequency, and system parameters such as contact temperature and surface roughness will be developed. Constitutive friction laws such as rate-pressure-temperature-state models will be developed in both time and frequency domains, which will be validated by computer simulations. Bayesian statistical theory will be used to predict the friction induced braking squeal, based on the characterization of the physical and chemical properties of frictional surfaces and the dynamic characteristics of braking systems, and solid study on the intrinsic relationship between braking noise and braking environment. This study will provide theoretical guidance to the elimination and control of friction induced vibration and noise.

随着我国铁路运输的载重量增加和速度提升，人们对高速铁路运行安全越来越关注，对高铁运行和制动时产生的噪声也越来越重视。本研究拟从宏观和微观的角度研究高速、高压、高频动态摩擦以及高频摩擦制动噪声的机理。将利用先进的仪器设备，如原子力显微镜(AFM)和电化学-扫描隧道显微镜（EC-STM），从微观上分析研究高速、高压和高频振动工况下摩擦表面的物理和化学特性，以及摩擦表面电磁力、静电力、黏附力、摩擦力的变化规律。从宏观揭示摩擦力与滑移速度、正压力、振动频率、以及摩擦系统参数的内在关系，分别在时间和频率域建立速度-压力-温度-状态数学模型，并用计算机仿真验证并修正理论模型。在对制动摩擦表面的物理和化学特性，摩擦制动系统的动态特性，以及摩擦制动噪声与制动环境内在关系深入研究的基础上，利用贝叶斯统计理论对高频摩擦制动噪声进行预测。本研究将为消去和控制由摩擦引起的振动和噪声提供理论指导。

摩擦引起的声音既能给人们的日常生活带来愉悦，比如小提琴的琴声；但它又常常给人们带来烦恼和环境污染，例如汽车和列车的制动啸叫，刀具加工零件时产生的噪音，等等。因此，深入研究产生摩擦噪声的机理进而有效地抑制和消去摩擦噪声，是国内外很多学术研究人员和企业工程师迫切希望解决的难题。本项目利用缩比列车摩擦制动实验台(TM-1)和常规多功能摩擦磨损实验机(Plint-TE92), 通过大量实验和理论分析揭示摩擦磨损和摩擦高频噪声与相对滑移速度、接触正压力、表面温度、表面形貌、材料、以及摩擦系统结构参数的内在关系。研究发现, 相对滑移速度和正压力对粉末冶金摩擦材料的摩擦磨损性能的影响较复合材料小, 粉末冶金摩擦材料比复合材料的摩擦磨损综合性能优越; 材料的机械和物理性能、接触正压力、相对滑移速度、以及动态摩擦系数是摩擦高频噪声的关键因素。通过激光对摩擦表面进行微织构化处理，可以有效地改善摩擦表面的摩擦磨损和减振降噪性能，这为可靠地控制摩擦表面的摩擦学和声学性能提供了潜在的有效方法。本研究基于贝叶斯统计理论建立摩擦高频噪声的预测和控制模型，对抑制和控制摩擦引起的振动噪声具有重要意义。