摘要
在考虑影响焊接接头疲劳强度影响因素和小应力对损伤影响的基础上,利用残余应力系数将焊接接头应力比R=0.5的S-N曲线修正为对称循环(即R=-1)下结构的S-N曲线。根据平均应力敏感系数将雨流计数分级的线路实测非对称循环应力谱转化为对称循环下应力谱,基于铁道车辆焊接结构疲劳强度评估原理和Palmgren-Miner线性疲劳累积损伤准则,提出焊接结构疲劳寿命预测方法,求得变幅应力谱的线性累积损伤和,以及由此导出指定寿命下的等效应力,评估车体结构的疲劳寿命是否满足设计要求。对车体结构典型测点I和测点II的分析结果表明:车体结构的疲劳寿命满足设计要求,同时将线路测试应力谱外推到考虑小应力影响确定的许用损伤和,得出车体结构的最大运营里程数,为达到设计寿命的重载电力机车车体结构进一步延长使用寿命提供了理论依据。
In this paper,based on the influence factors affecting the fatigue strength of welded joints and the influence of small stress on the damage,the residual stress coefficient is used to modify the S-Ncurve of the welded joint stress ratioR=0.5 to theS-Ncurve which stress ratioR=-1.Then the rainflow counting result of the line measured unsymmetrical stress needs to be adjusted to symmetrical stress spectrum.Based on the fatigue strength evaluation principle of the welded structure of railway vehicles and the linear fatigue cumulative damage criterion of Palmgren-Miner,the fatigue life prediction method of welded structure is proposed,and the linear cumulative damage sum of the variable amplitude stress spectrum is obtained.Furthermore a derivation of equivalent fatigue stress under constant fatigue life is made to evaluate whether the fatigue life of a vehicle body satisfies design life.The analysis results of typical measurement points I and II of the vehicle body structure indicate that the fatigue life of the vehicle body structure meets the design requirements,and the test stress spectrum of the line is extrapolated to the allowable damage sum determined by considering the small stress effect,and the vehicle is obtained.The maximum operating mileage of the vehicle body structure provides a theoretical basis for the body structure of the heavy-duty electric locomotive that has reached the design life to further extend the service life.
作者
金希红
曾燕军
李祥涛
王泰
JIN Xihong;ZENG Yanjun;LI Xiangtao;WANGTai(State Key Laboratory of Heavy Duty AC Drive Electric Locomotive Systems Integration,Zhuzhou 412001,China;R&D Center,CRRC Zhuzhou Locomotive Co.,Ltd.,Zhuzhou 412001,China;School of Mechanical Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《重庆理工大学学报（自然科学）》
CAS
北大核心
2020年第1期44-50,共7页
Journal of Chongqing University of Technology：Natural Science
基金
国家重点实验室开放课题项目“大功率交流传动电力机车系统集成”(2017ZJKF02
2017ZJKF04)
关键词
重载电力机车
车体结构
线路试验
Miner准则
疲劳寿命
heavy electric locomotive
carbody structure
line test
criterion of Palmgren-Miner
fatigue life
