构架弹性振动对疲劳寿命影响研究

Research on the Influence of Railway Bogie Elastic Vibration to Fatigue Life

近年来国内地铁车辆转向架构架多次发生弹性振动问题,弹性振动对构架疲劳寿命的影响已引起高度关注。现对国内某型地铁车辆转向架构架动应力进行测试并对数据进行时域和频域分析,得到了构架上发生弹性振动测点的动应力特点;在建立构架有限元模型的基础上,计算了构架自由振动频率,结果表明构架实际线路运用中弹性振动频率与其某阶固有频率一致;对测试数据采用去除振动主频率的方法,得到去除弹性振动后测点的动应力时间历程及分布特性,结合雨流计数法、S-N曲线并应用Miner线性疲劳累计损伤理论,得到发生弹性振动和去除弹性振动情况下构架上不同部位测点的等效应力幅值及疲劳寿命,进而获得构架弹性振动对疲劳寿命影响特性。研究结果表明,发生弹性振动后,构架局部位置疲劳寿命将大幅下降,可降至原设计寿命的1/3。

In recent years, the elastic vibration problems has occurred repeatedly in the bogie frame of domestic metro vehicle and its in- fluence on the fatigue life of bogie has been paid high attention. Based on the analysis of dynamic stress test results of the key position points on some type of domestic metro vehicle bogie in time domain and frequency domain, this study achieves the dynamic stress distri- bution characteristics of the vibration test points on bogie frame. And then the FEM model o{ the bogie is established to calculate its free vibration frequency. Results show that the elastic vibration frequency of the bogie in service is consistent with a natural frequency. Adopting the method of removing the domain vibration frequency to process the test data, this study obtains the dynamic stress distri- bution characteristics in time domain of removing the vibration frequency. According to the Rain-flow Counting Method,S N Curve and Miner Linear Damage Cumulative Rules, the equivalent stress amplitude and fatigue life of test points on different parts of the bogie on elastic vibration and removing elastic vibration circumstances are achieved, so that, the structural elastic vibration characteristics of fatigue life can be obtained. The results show that the fatigue life of the test points on local positions of the bogie frame will drop sub- stantially after the elastic vibration occurs and the minimum can be reduced to the original design life of 1/3.