脉冲压缩技术在高温锻件电磁超声检测中的应用  

Application of pulse compression technology in electromagnetic ultrasonic testing of high temperature forgings

作　　者：汪树民 石文泽 卢超[2] 张琦 程进杰 吴健 WANG Shumin;SHI Wenze;LU Chao;ZHANG Qi;CHENG Jinjie;WU Jian(Jingdezhen Inspection Branch of Special Equipment Inspection and Testing Institute of Jiangxi Inspection and Testing Certification General Institute,Jingdezhen 333000,China;Key Laboratory of Nondestructive Testing of Ministry of Education,Nanchang Hangkong University,Nanchang 330038,China;Jiangxi General Institute of Inspection,Testing and Certification,Nanchang 330200,China;Shangrao Branch of Special Equipment Inspection and Testing Institute of Jiangxi Inspection and Testing Certification General Institute,Shangrao 334000,China)

机构地区：[1]江西省检验检测认证总院,特种设备检验检测研究院景德镇检测分院,江西景德镇333000 [2]南昌航空大学,无损检测技术教育部重点实验室,南昌330038 [3]江西省检验检测认证总院,特种设备检验检测研究院,南昌330200 [4]江西省检验检测认证总院,特种设备检验检测研究院上饶分院,江西上饶334000

出　　处：《压力容器》2023年第8期28-36,共9页Pressure Vessel Technology

基　　金：国家市场监督管理总局科技计划项目(2021MK056);江西省检验检测认证总院科研项目(ZYK202202);江西省青年基金项目(20181BAB216020)。

摘　　要：针对脉冲压缩技术应用于电磁超声检测时,检测系统频谱特性与调制信号带宽不匹配,导致脉冲压缩效果下降的问题,建立了电磁超声检测过程的场路耦合分析有限元模型,比较线性调频(LFM),Barker,LFM+Barker和调幅线性调频(AMLFM)+Barker共4种调制信号对脉冲压缩效果的影响。以高温锻件平底孔缺陷螺旋线圈电磁超声检测为例,对比和验证了同时宽的4种调制信号脉冲压缩技术的应用效果。研究结果表明:采用Barker信号激励时,获得的脉压信号主瓣信噪比最高,但由于时频积较小,空间分辨率差;采用LFM信号激励时,高温锻件中高频成分超声波衰减愈加严重,造成主瓣信噪比下降和波包宽度变大等问题;采用AMLFM+Barker激励时,由于子函数加窗导致主瓣宽度有所增加;基于LFM+Barker复合调制信号的脉冲压缩技术兼具高主瓣信噪比和高空间分辨率的优点。该研究可以为高温环境下铸锻件超声检测提供解决方法。When pulse compression technology is applied to electromagnetic ultrasonic testing,the spectrum characteristics of the detection system do not match the bandwidth of the modulation signals,which leads to the decline of the pulse compression effect.A finite element model for field-circuit coupled analysis of the electromagnetic ultrasonic testing process was established,and the effects of four modulation signals such as Linear Frequency Modulation(LFM),Barker,LFM+Barker,and Amplitude Modulation Linear Frequency Modulation(AMLFM)+Barker on pulse compression performance were studied.Taking the spiral coil Electromagnetic Acoustic Transducer(EMAT)detection for the flat-bottom hole defect in high-temperature forgings as an example,the application effects of pulse compression techniques of four modulated signals with the same pulse width were compared and verified.The research results show that when using Barker signal excitation,the main lobe signal-to-noise ratio(SNR)of the obtained pulse-compressed signal is the highest,but due to the small time-frequency product,the spatial resolution is poor.When using LFM signal excitation,the high-frequency component ultrasonic attenuation in high-temperature forgings becomes more severe,resulting in problems such as decrease in the SNR of the main lobe and increase in the width of the wave packet.When using AMLFM+Barker excitation,the main lobe width is widened due to windows adding to the subfunctions.The pulse compression technology based on LFM+Barker composite modulation signals concurrently possess the advantages of high main lobe SNR and high spatial resolution.This study can provide a solution for ultrasonic testing of castings and forgings in high temperature environments.

关 键 词：高温锻件 电磁超声换能器 场路耦合分析 脉冲压缩 电磁超声检测 信噪比 

分 类 号：TH49[机械工程—机械制造及自动化] TB559[理学—物理]