动车组设备舱冷却单元铝合金立柱开裂成因研究  

Study on causes of cracking in aluminum alloy columns of cooling unit in EMU equipment cabin

作　　者：王文静[1,2] 董子钰 李博 杨广雪[1,2] 张延蕾[3] WANG Wenjing;DONG Ziyu;LI Bo;YANG Guangxue;ZHANG Yanlei(School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China;Key Laboratory of Vehicle Advanced Manufacturing,Measuring and Control Technology,Ministry of Education,Beijing Jiaotong University,Beijing 100044,China;CRRC Dalian Institute Co.,Ltd.,Dalian Liaoning 116021,China)

机构地区：[1]北京交通大学机械与电子控制工程学院,北京100044 [2]北京交通大学载运工具先进制造与测控技术教育部重点实验室,北京100044 [3]中车大连机车研究所有限公司,辽宁大连116021

出　　处：《北京交通大学学报》2023年第5期91-97,共7页JOURNAL OF BEIJING JIAOTONG UNIVERSITY

基　　金：中央高校基本科研业务费专项资金(2020JBM032);国家自然科学基金(52075032);中国铁路总公司科技研究开发计划课题(K2022J003)。

摘　　要：为探究动车组冷却单元铝合金立柱开裂原因,对其结构框架及立柱开展线路测试,获得底板气动载荷、振动加速度及立柱关键部位动应力时频域特征,结合模态分析得到立柱开裂原因,并计算立柱开裂处1500万km等效应力幅值及疲劳损伤值.研究结果表明:列车高速运行下,底板气动载荷主频、振动加速度主频与立柱裂纹附近动应力主频及冷却单元框架大、小底板变形的固有频率相近,即气动载荷作用下大、小底板发生共振,使铝合金支撑立柱在吊耳焊缝处出现应力集中,并从疲劳薄弱部位的凹侧焊趾处开裂;立柱裂纹附近测点1500万km损伤值大于1,表明结构在设计寿命周期内存在疲劳失效风险.To investigate the causes of cracking in the aluminum alloy columns of the EMU cool-ing unit,on-track tests are carried out on the unit frame and columns.This study obtains time and frequency domain characteristics of aerodynamic loads and vibration acceleration on the bot-tom plate and dynamic stress at key locations of the columns.Combining this with modal analy-sis,the reasons for column cracking are identified.Furthermore,the equivalent stress amplitude and fatigue damage value at 15 million km at the column's crack location are calculated.The re-sults show that when the train is running at high speed,the main frequencies of the aerodynamic load and vibration acceleration of the bottom plate are close to the main frequencies of dynamic stress near the column crack and the natural frequencies of the bottom plate deformation of the cooling unit frame.This suggests that the resonance of the bottom plate under aerodynamic load causes stress concentration at the welding seam of the lifting lug on the aluminum alloy support column,leading to cracks initiating from the concave weld toe of the fatigue-prone region.The damage value near the column crack at 15 million km exceeds 1,indicating a fatigue failure risk within the design lifecycle.

关 键 词：动车组 时频分析 线路测试 冷却单元 气动载荷 振动加速度 疲劳损伤 

分 类 号：U266[机械工程—车辆工程]