钢轨踏面低频超声表面波传播模式研究  

Research on low-frequency acoustic surface wave propagation mode in rail treads

作　　者：门平 董世运[1] 卢超[3] 康学良 程志远 Men Ping;Dong Shiyun;Lu Chao;Kang Xueliang;Cheng Zhiyuan(National Key Laboratory for Remanufacturing, Academy of Army Armored Forces, Beijing 100072, China;92601 Troops, People＇s Liberation Army Navy, Zhanjiang 524009, China;Key Lab of Nondestructive Testing Ministry of Education, Nanchang Hangkong University, Nanchang 330063, China)

机构地区：[1]陆军装甲兵学院装备再制造技术国防科技重点实验室,北京100072 [2]中国人民解放军海军92601部队,湛江524009 [3]南昌航空大学无损检测技术教育部重点实验室,南昌330063

出　　处：《仪器仪表学报》2018年第3期13-20,共8页Chinese Journal of Scientific Instrument

基　　金：国家重点研发计划重点专项(2016YFB1100205);北京市科技专项(Z161100004916009);北京市科技计划(Z161100001516007)项目资助

摘　　要：钢轨轨头滚动接触疲劳引起钢轨踏面表面及近表面裂纹是目前高速铁路运行的重要威胁之一,铁路部门目前采用的检测技术无法对此类缺陷进行有效监、检测,可采用低频超声表面波对钢轨踏面裂纹进行检测。钢轨轨头异形波导结构使得低频超声表面波传播具有频散特性,这就需要对其传播模式进行有效识别。基于ABAQUS有限元方法建立钢轨踏面简化三维模型,采用二维快速傅里叶变换（2D-FFT）的分析方法得到低频超声表面波在钢轨踏面传播的频率-波数频散曲线,并通过搭建实验系统,对自由状态下60型钢轨低频超声表面波传播模式进行模式识别,研究表明300 k Hz频率点是低频超声表面波在钢轨踏面传播频散分界点;数值模拟采用中心频率为200 k Hz信号单点对称激发,表面波传播模式主要有5种对称模式,激发频率为500 k Hz时,传播模式出现混叠;实验结果显示,激励信号中心频率为500 k Hz,采用斜楔技术在钢轨踏面中轴线上激发低频超声表面波存在4种主要对称传播模式,实验频散曲线分辨率比数值模拟频散曲线分辨率高。Surface and near surface tread cracks induced by rolling contact fatigue in rail heads are serious threats to the current highspeed railway transport.The current detection technology employed by railway technology department are not be effective to monitor and test such defects.The low-frequency acoustic surface wave for solving this problem is proposed in this study.The complex waveguide structures make the low-frequency acoustic surface wave with the characteristics of dispersion.Thus,it is necessary to effectively identify the propagation modes.Based on ABAQUS finite element method,a simplified 3D model of rail tread is formulated.The frequency-wave number dispersion curve of low-frequency acoustic surface wave is obtained in rail head by 2D-FFT.By setting up experimental system,the low-frequency acoustic surface wave modes can recognize 60 types of free rails.According to the research,300 kHz frequency is the critical dispersion point on acoustic surface wave propagation in the rail tread.In the numerical simulation,there are five symmetry modes for surface wave propagation when a single point symmetric excitation is used at 200 kHz.When the excitation frequency is 500 kHz,the propagation modes are overlapped.The experimental results show that there are four symmetric propagation modes of acoustic surface wave excited by wedge technique on the axis of the rail tread at 500 kHz.The experimental dispersion curve resolution is higher than the numerical simulation result.

关 键 词：钢轨轨头 低频超声表面波 二维快速傅里叶变换 有限元方法 传播特性 

分 类 号：TH878[机械工程—仪器科学与技术] U213.43[机械工程—精密仪器及机械]