Fatigue research of metro car body based on operational loads  

作　　者：Xihong Jin Feng Guo 

机构地区：[1]State Key Laboratory of Heavy-Duty and Express High-Power Electric Locomotive,Product Research and Development Center,CRRC Zhuzhou Locomotive Co.,Ltd.,Zhuzhou,China

出　　处：《Railway Sciences》2024年第5期558-574,共17页铁道科学（英文）

基　　金：the CRRC Zhuzhou Locomotive Co.,Ltd.and Shanghai Railway Certification(Group)Co.,Ltd.This research was funded by the Major Research Project of CRRC(No.2022CYY007 and No.2020CCA094).

摘　　要：Purpose–The principle of infinite life design currently directs fatigue resistance strategies for metro car bodies.However,this principle might not fully account for the dynamic influence of operational loads and the inevitable presence of defects.This study aims to integrate methods of service life estimation and residual life assessment,which are based on operational loads,into the existing infinite life verification framework to further ensure the operational safety of subway trains.Design/methodology/approach–Operational loads and fatigue loading spectra were determined through the field test.The material test was conducted to investigate characteristics of the fracture toughness and the crack growth rate.The fatigue strength of the metro car body was first verified using the finite element method and Moore–Kommers–Japer diagrams.The service life was then estimated by applying the Miner rule and high-cycle fatigue curves in a modified form of the Basquin equation.Finally,the residual life was assessed utilizing a fracture assessment diagram and a fitted curve of crack growth rate adhered to the Paris formula.Findings–Neither the maximum utilization factor nor the cumulative damage exceeds the threshold value of 1.0,the metro car body could meet the design life requirement of 30 years or 6.6 million km.However,three out of five fatigue key points were significantly influenced by the operational loads,which indicates that a single fatigue strength verification cannot achieve the infinite life design objective of the metro car body.For a projected design life of 30 years,the tolerance depth is 12.2 mm,which can underscore a relatively robust damage tolerance capability.Originality/value–The influence of operational loads on fatigue life was presented by the discrepancy analysis between fatigue strength verification results and service life estimation results.The fracture properties of butt-welded joints were tested and used for the damage tolerance assessment.The damage tolerance life can be effectiv

关 键 词：Metro car body Field test Structural integrity Damage accumulation Damage tolerance 

分 类 号：U27[机械工程—车辆工程]