基于高频振动的天线梁疲劳研究

 蔡川东,邬平波

(西南交通大学 牵引动力国家重点实验室,四川 成都 610031)
摘要:针对地铁线路运营过程中频繁出现的天线梁疲劳失效问题开展动应力和振动加速度测试研究。根据动应力测试数据,分析天线梁薄弱处的疲劳寿命,对天线梁进行PolyMAX法模态识别找出其低阶固有频率以及振动频谱分析找出其振动特性传递规律。分析结果表明:天线梁ATP吊座与主管连接的焊缝处发生共振而出现高应力循环,其应力水平和作用频率远高于设计水平,在运营中极易发生疲劳失效。同时基于工程应用方案,对天线梁应力集中部位增加加强筋进行结构优化,测试结果表明,加强筋增加了结构强度、有效减小了动应力的幅值,但没有避开共振。最后基于试验数据和仿真结合,提出了减轻质量提高固有频率以及动力吸振装置来降低振动。结合实际振动环境,要求天线梁的设计应该有效的避开工作模态,而不是仅仅优化局部强度,为动态结构的设计提供新思路。
关键词:天线梁;动应力;疲劳损伤;高频振动
中图分类号:U270.1 文献标志码:A doi:10.3969/j.issn.1006-0316.2018.11.001
文章编号:1006-0316 (2018) 11-0001-06
Research on Fatigue of Antenna Beam Based on High Frequency Vibration
CAI Chuandong,WU Pingbo
( Traction Power State Key Laboratory, Southwest Jiaotong University, Chengdu 610031, China )
Abstract:In view of the fatigue failure of the antenna beam occurring during the operation of the subway line, the research on the dynamic stress and vibration analysis are carried out. According to the dynamic stress data, the fatigue life of the weak spot of the antenna beam was analyzed. The PolyMAX modal identification method is used to identify the low order natural frequency of antenna beam and use the vibration spectrum analysis to find out the law of the vibration transmission. The analysis result shows that: high stress cycles occurs in the weld joint of the antenna beam between ATP hanger and main pipe because of the resonance. The stress level and the frequency of action are higher than the design level, and fatigue failure is easy to occur in the operation. At the same time, the reinforcement is added to optimize the structure on the concentrated stress parts. The test result shows that the reinforcement increases the strength of the structure and reduces the amplitude of the dynamic stress effectively, but it don’t avoid resonance. Finally, based on the experimental data and simulation, using the reduction of the quality to improve the natural frequency and the vibration absorption device are proposed to reduce vibration. Combining vibration environment into dynamic stress analysis, it is required that the antenna beam should avoid the working mode rather than optimize the local strength. It provides a new idea for the design of dynamic structure.
Key words:antenna beam;dynamic stress;fatigue damage;high frequency vibration
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收稿日期:2018-03-16
基金项目:国家重点研发计划资助(2016YFB1200505);牵引动力国家重点实验室课题项目(2015TPL_Z03)
作者简介:蔡川东(1992-),男,四川南充人,硕士研究生,主要研究方向为车辆系统疲劳强度。
 

 

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