柴油机排气弯管与支架断裂故障分析与优化  

Analysis and optimization of fracture failure of exhaust elbow and bracket of diesel engine

作　　者：田玉泰 TIAN Yutai(Shanghai New Power Automotive Technology Co.,Ltd.,Shanghai 200438,China)

机构地区：[1]上海新动力汽车科技股份有限公司,上海200438

出　　处：《柴油机设计与制造》2025年第1期39-44,共6页Design and Manufacture of Diesel Engine

摘　　要：针对某款矿区装载机柴油机排气弯管及其支撑支架出现的断裂故障进行分析。根据实际振动测试数据初步诊断为共振导致此处加速度载荷异常增大;通过有限元分析,消声器排气弯管组件1阶次模态频率为77.8 Hz,与共振频率(78.0 Hz)十分接近,因此确认诊断合理;根据诊断结果,考虑到温度场的影响,计算排气弯管与支架的高周疲劳安全系数。结果表明:排气弯管及其支架疲劳系数不满足设计要求的部位与整车实际断裂位置相吻合。对疲劳系数低于设计要求的部位进行结构优化,并再次进行评估。结果表明,优化后的消声器排气弯管组件1阶次模态频率为88.8 Hz,远离共振区域,且疲劳系数满足设计要求,可以通过整车1 000 h耐久考核。An analysis was conducted on the fracture failure of the exhaust elbow and bracket of the diesel engine of the loader in the mining area.Based on actual vibration test data,it was preliminarily di-agnosed that resonance caused an abnormal increase in acceleration load at this location.Through finite element analysis,the 1st order modal frequency of the muffler exhaust elbow assembly was 77.8 Hz,which was very close to the resonance frequency(78.0 Hz),thus confirming that the diagnosis was rea-sonable.Based on the fault diagnosis results,the high cycle fatigue safety factor of the exhaust elbow and bracket was calculated,considering the influence of temperature field.The results show that the areas where the fatigue coefficient of the exhaust elbow and bracket does not meet the design requirements are consistent with the actual fracture location of the entire vehicle.Structural optimization of the areas with fatigue factors lower than the evaluation requirements is carried out and evaluated again.The optimized muffler exhaust elbow assembly has a 1st order modal frequency of 88.8 Hz,far from the resonance fre-quency,and the fatigue coefficient meets the design requirements.It can pass the 1000 h durability as-sessment of the entire vehicle.

关 键 词：柴油机 排气弯管 支架 模态 高周疲劳 结构优化 

分 类 号：U46[机械工程—车辆工程]