电工技术学报2024，Vol.39Issue(8)：2371-2387,17.DOI:10.19595/j.cnki.1000-6753.tces.230249
基于Barker码脉冲压缩技术的钢板多阵元Lamb波电磁超声换能器设计与优化
Design and Optimization of Multi-Array Lamb Wave EMAT for Steel Plates Based on Barker Code Pulse Compression Technology
摘要
Abstract
Traditional Barker code pulse compression technology is constrained by rated parameters of pulse power amplifiers(duty cycle,maximum pulse width),resulting in reduced pulse compression effectiveness and detection speed.Amulti-element Lamb wave Electromagnetic Acoustic Transducer(EMAT)based on Barker code pulse compression technology is proposed.In this multi-element EMAT,the combination of a permanent magnet and a meander line coil is considered an independent element,and the direction of the Lorentz force is controlled by the magnetic field direction of the permanent magnet and the current direction of the meander line coil in each group of array elements.In this way,the excited Lamb wave phase{0,180°}is consistent with the Barker code sequence{1,-1},ultimately generating Lamb waves in Barker code form.A finite element model for the multi-element Lamb wave EMAT detection process is established based on Barker code pulse compression technology with tone-burst excitation.The influence of factors(permanent magnet configuration,array element sequence length,excitation signal cycle count,and meander line coil turns)on peak-side lobe ratio and main lobe width after pulse compression is analyzed. The results show that configuring external permanent magnets improves the signal-to-noise ratio(SNR)of pulse-compressed signals after side lobe suppression when the multi-element Lamb wave EMAT is excited by tone-burst signals.The SNR of the detection echo can be increased by 9.8 dB when the multi-element EMAT with a four-turn meander line coil and a 13-bit Barker code sequence length is configured with three pairs of external permanent magnets.As the number of excitation signal cycles increases,the main lobe width of the pulse-compressed signal after sidelobe suppression exhibits a continuously increasing trend,and the SNR initially increases and then decreases.As the length of the Barker sequence increases,the SNR of the pulse-compressed signal after sidelobe suppression shows a continuously increasing trend.Considering the spatial resolution and SNR of the detected echo,the optimal parameters of the multi-element Lamb wave EMAT area 10-turn meander line coil,11 excitation signal cycles,a 13-bit Barker sequence,and a configuration with three pairs of external permanent magnets. The new multi-element EMAT successfully generates Lamb waves in Barker code form when excited with a tone-burst signal.After the pulse compression,the Lamb wave signal effectively suppresses sidelobes by calculating delay time and performing sidelobe suppression.The multi-element Lamb wave EMAT based on tone-burst excitation and Barker code pulse compression technology improves ultrasonic signals'SNR and spatial resolution.When applied to guided wave detection inmetal plates or pipes with varying thicknesses,maintaining consistent spacing between array elements is crucial for pulse compression effects.Ensuringuniform and consistent magnetic field distribution for each array element is also beneficial.关键词
电磁超声换能器/Barker码脉冲压缩/多阵元Lamb波EMAT/信噪比/空间分辨率Key words
Electromagnetic ultrasonic transducer/Barker code pulse compression/multi-element Lamb wave EMAT/signal-to-noise ratio/spatial resolution分类
矿业与冶金引用本文复制引用
石文泽,李淇鑫,卢超,胡博,刘远..基于Barker码脉冲压缩技术的钢板多阵元Lamb波电磁超声换能器设计与优化[J].电工技术学报,2024,39(8):2371-2387,17.基金项目
国家自然科学基金(52065049,12064001)、国防基础科研计划(JCKY2022401C005)、江西省主要学科与技术带头人培训计划(20204BCJL22039,20225BCJ23023)、江西省杰出青年基金(20212ACB214010)、江西省重点研发计划(20212BBE51006,20223BBE51034)和南昌航空大学研究生创新专项资金(YC2021-S694)资助项目. （52065049,12064001）
