首页|仅线圈式电磁超声检测方法与提离特性研究

仅线圈式电磁超声检测方法与提离特性研究

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针对传统永磁体式或脉冲电磁铁式电磁超声换能器(Electromagnetic Acoustic Transducer,EMAT)易吸附铁磁性颗粒导致换能效率下降甚至功能性损坏、难与铁磁性金属材料实现快速分离或移动、探头体积大、难以实现狭小区域等探头不可达区域的检测等难题,提出了一种仅线圈式电磁超声检测的技术实现与建模方法.建立了集仅线圈式EMAT的激励等效电路和检测过程的场路耦合分析有限元模型,分析了仅线圈式EMAT的纵波激励和接收机理,研究了提离对EMAT线圈的等效阻抗、放电电流的高频成分和类直流成分、检测回波的幅值和中心频率的影响.研制了仅线圈式EMAT检测电路,验证了提离的影响规律.研究结果表明:所研制的仅线圈式电磁超声检测系统可以在 80 mm厚的铝合金试样中激励和接收纵波,且在0.1 mm 提离时,一次底波的信噪比为 28.10 dB.当提离由 0.1 mm增加至 1.0 mm时,二次底波的信噪比由 22.21 dB减小至8.01 dB,其中心频率由 1.35 MHz下降为 1.27 MHz.
Study on Coil-Only Electromagnetic Ultrasonic Testing Method and Its Lift-Off Characteristics
Traditional permanent magnet or pulse electromagnet electromagnetic acoustic transducer(EMAT)has some problems,such as being easy to absorb ferromagnetic particles,resulting in the reduction of energy conversion efficiency and even functional damage,difficul-ty in achieving rapid separation or movement with ferromagnetic metal materials,a large volume of the probe,and being challenging to achieve the detection of the inaccessible areas of the probe such as small narrow areas.A technique realization and modeling method of coil-only electromagnetic ultrasonic testing is proposed to solve the above problems.A finite element model for field-circuit coupling analy-sis of the excitation equivalent circuit and the detection process of the coil-only EMAT is established.The mechanism of longitudinal wave excitation and reception of the coil-only EMAT is analyzed,and the effect of lift-off on the equivalent impedance of the EMAT coil,the high-frequency and DC-like components of the discharge current,and the amplitude and center frequency of the detection echo is also studied.A coil-only EMAT detection circuit is developed,and the lift-off effect is verified.The results show that the coil-only electromag-netic ultrasonic testing system can excite and receive longitudinal waves in an 80 mm thick aluminum alloy sample.The primary bottom wave's signal-to-noise ratio(SNR)is 28.10 dB at 0.1 mm lift-off.When the lift-off increases from 0.1 mm to 1.0 mm,the SNR of the second bottom wave decreases from 22.21 dB to 8.01 dB,and its center frequency decreases from 1.35 MHz to 1.27 MHz.

ultrasonic testingcoil-only EMATcircuit-field coupled analysislift-offlongitudinal wave

石文泽、胡力萍、卢超、胡博、沈功田、张路根、张琦

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南昌航空大学 无损检测教育部重点实验室,江西 南昌 330063

中国特种设备检测研究院,北京 100029

江西省检验检测认证总院特种设备检验检测研究院,江西 南昌 330036

超声检测 仅线圈式EMAT 场路耦合分析 提离 纵波

国家自然科学基金项目国家自然科学基金项目江西省杰出青年基金项目江西省主要学科学术和技术带头人培养计划项目江西省主要学科学术和技术带头人培养计划项目江西省重点研发计划项目江西省重点研发计划项目国家市场监督管理总局科技计划项目江西省检验检测认证总院计划项目南昌航空大学研究生创新专项资金项目

520650491206400120212ACB21401020204BCJL2203920225BCJ2302320212BBE5100620223BBE510342021MK056ZYK202202YC2021-081

2024

10.3969/j.issn.1004-1699.2024.10.004

传感技术学报
东南大学 中国微米纳米技术学会

传感技术学报

CSTPCD北大核心
影响因子：1.276
ISSN：1004-1699
年,卷(期)：2024.37(10)