基于实测应力的动车组制动盘盘毂服役特性

针对仿真或仅考虑紧急制动状态下动车组制动盘盘毂安全性分析中存在的不足,基于盘毂应力在线测试,分析动车组高速运行和不同制动方式下盘毂的频谱特性和成分特性;考虑应力集中,根据静力等效原则进行毂齿根部的应力线性化,分析不同制动方式对盘毂疲劳损伤的影响;采用指数模型拟合和核密度估计相结合的方法,推理97.5%置信度下的盘毂实测应力谱,并考虑车轮镟修前后盘毂损伤演化和材料强度退化,评估盘毂服役安全性。结果表明:盘毂载荷振动频率主要分布在0~71 Hz和341~680 Hz频带,车轮镟修可有效降低341~518 Hz频带内的载荷振动、消除518~680 Hz频带内的载荷振动;动车组高速运行和车轮状态不良是造成盘毂损伤的主要原因;若按盘毂服役寿命为1500万km计算,盘毂疲劳薄弱区的等效应力为37.4 MPa,累积损伤为0.61,该结果可为盘毂的结构设计和检修维护策略制定提供依据。

Service Characteristics of EMU Brake Disc Hub Based on Measured Stress

In order to make up for the shortcomings in the safety analysis of EMU brake disc hub mostly through virtual simulation or only considering emergency braking,the spectral characteristics and composition properties of EMU disc hub were analyzed under high speed operation and different braking modes based on the online test of hub stress.Considering the stress concentration,the stress at the root of hub tooth was linearized according to the principle of static equivalence,and the influence of different braking modes on the fatigue damage of disk hub was analyzed.The measured stress spectrum of the hub was inferred on the confidence level of 97.5%based on the combination of exponential model fitting and kernel density estimation.The service safety of the hub was evaluated considering the damage evolution of the hub and the strength degradation of the material before and after wheel reprofiling.Results show that the load vibration frequency of the hub is mainly distributed in the frequency band of 0~71 Hz and 341~680 Hz.Wheel reprofiling can effectively reduce the load vibration in the frequency band of 341~518 Hz and eliminate the load vibration in the frequency band of 518~680 Hz.The main causes of disc hub damage are the high speed operation and poor wheel condition of EMU.If the service life of disk hub is 15 million kilometers,the equivalent stress in the fatigue weak area of the hub is 37.4 MPa,and the cumulative damage is 0.61.The results can provide the basis for the structural design and maintenance strategy of the disk hub.