【作者】 王峰；

【导师】 王文健；

【作者基本信息】 西南交通大学 ， 机械工程（专业学位）， 2017， 硕士

【摘要】 制动盘与闸片作为保障高速列车运行安全的基础组成部分,其摩擦制动行为对列车安全运行具有重要的意义。因此高速盘形制动界面摩擦与振动行为研究对于保障高速制动系统的可靠性具有重要意义和应用价值。利用MM-1000高速摩擦制动试验机开展高速制动试验,研究了初始制动速度、制动压力、水介质等对高速摩擦制动界面制动行为的影响。使用MATLAB软件将制动振动信号处理为时频图像,结合瞬时摩擦系数曲线阐明了制动过程中水介质对摩擦制动行为的影响。借助于ABAQUS/Standard模块,采用热-机耦合方法计算了摩擦制动界面温度场的分布,进一步解释了不同工况下摩擦制动界面行为的变化规律。论文研究主要结论如下:(1)干态工况下,平均摩擦系数随制动初速度的增加先上升后下降,随制动压力增加而明显降低;瞬时摩擦系数的波动随制动压力的增加而减小,在制动过程中呈先减小后增加的趋势。(2)在中低速工况下,水介质对制动过程影响较明显,制动过程中瞬时摩擦系数较低,制动盘转速非线性降低;随制动速度、制动压力、制动温升的增加和水流强度的减弱,摩擦制动界面处的水介质明显减少,形成类似干态制动的工况,水介质对制动过程影响明显减弱。水介质被封闭在摩擦表面的微裂纹中,形成局部高压的水介质膜,导致制动盘与闸片摩擦界面的材料剥落,形成点状凹坑。(3)对原始振动信号进行重采样能够大幅减小计算量,且对低频段振动时频分析没有明显影响。使用Morlet小波处理得到的时频图中振动频率曲线的斜率与摩擦制动过程中转速变化相对应。(4)摩擦制动过程中制动盘表面温度先升高后降低,导致瞬时摩擦系数呈先降低后略微升高的趋势;在制动试验进行至15～25%时,最高温度出现在摩擦副平均摩擦半径处;制动闸片左侧温度明显高于右侧,造成制动闸片的左侧偏磨现象。更多还原

【Abstract】 The brake disk and pad are basic components for ensuring the operation safety of high-speed train.The friction braking behaviors between the brake disk and pad has important significance for train safety operation.Therefore,the study of the friction and vibration behaviors of high-speed braking disk and pad has a great significance and application value for ensuring the reliability of high-speed braking system.A MM-1000 high-speed friction braking machine was used to carry the high-speed braking experiments.The effect of initial braking speed,braking pressure and water on high-speed friction braking interface behaviors were studied.MATLAB was used to transform the vibration signal to the time frequency map.The effect of water on frictional braking behaviors was explained by analyzing both the time frequency map and instantaneous friction coefficient curve.ABAQUS/Standard was used to calculate the temperature field of frictional braking interface using thermal-mechanical coupling method.Furthermore,the simulation result explains the evolvement rule of friction braking interface under different conditions.The main conclusions are as follows:(1)Under the dry condition,the average friction coefficient first increases and then decreases with the initial braking speed increasing.The average friction coefficient decreases with an increase in braking pressure.The fluctuation of instantaneous friction coefficient decreases with the braking pressure increasing.The instantaneous friction coefficient first decreases and then increases in the braking process.(2)Under low and medium initial braking speed conditions,the water has an obvious effect on the frictional braking behaviors.In the braking process,the instantaneous friction coefficient is low and the decrease of braking disk rotation speed is non-linear.With the initial braking speed,braking pressure and temperature increasing and the water flow decreasing,the water on the friction braking interface obviously decreases.The interface condition is similar with the dry condition.Therefore,the effect of water on frictional braking behaviors is significantly weakened.The water sealed up in the cracks leads to partial high pressure point on the friction surface,which results in serious pitting damage on the braking disk and pad.(3)The resample of original vibration signal can reduce the amount of calculation and has no obvious influence on the time frequency analysis of low frequency signal.In the time frequency map disposed by Morlet wavelet transformation,the slope of vibration frequency indicates the variation of the rotation speed of disk.(4)The temperature of friction braking interface first rises and then drops in the frictional braking process,which causes the instantaneous friction coefficient to first decreases and then slightly increase.The highest temperature appears around the average friction radius of braking disc and pad in the 15～25%braking process.The temperature on the left area of pad is higher than that on the right area,which leads to the partial wear on the left area of pad.更多还原