作者：赵云伟, 王悦民, 汤槟晖, 许鉴鉴

作者单位：海军工程大学动力工程学院，湖北 武汉 430033

关键词：非铁磁性管道;纵向导波;洛伦兹力;模态控制

摘要：

超声导波在管道中传播时具有多模态特性，导致超声导波检测的回波信号复杂难以分辨。依据EMAT激发机理和纵向超声导波的波结构特性，设计一种周期性永磁铁组以增大洛伦兹力轴向分量、减小径向分量，激励纯净的L(0,2)模态导波。研究永磁铁宽度对L(0,1)模态抑制效果的影响规律，得到控制效果较好的永磁铁宽度。结果表明：相比传统EMAT，新型EMAT对L(0,1)模态抑制效果显著，L(0,2)模态与L(0,1)模态峰值之比是传统EMAT的7.62倍。

Design and optimization of EMAT structure for excitation of L(0,2) guided waves in pipelines
ZHAO Yunwei, WANG Yuemin, TANG Binghui, XU Jianjian
School of Power Engineering, Naval University of Engineering, Wuhan 430033, China
Abstract: Ultrasonic guided waves have multi-modal characteristics when propagating in the pipeline, which makes the echo signals detected by ultrasonic guided waves complex and difficult to distinguish. According to the excitation mechanism of EMAT and the wave structure characteristics of longitudinal ultrasonic guided waves, a periodic permanent magnet group is designed to increase the axial component of the Lorentz force and reduce the radial component to excite the pure L(0,2) mode guided waves. The influence of the permanent magnet width on the L(0,1) mode suppression effect is studied, and the permanent magnet width with better control effect is obtained. The results show that compared with the traditional EMAT, the new EMAT has a significant suppression effect on the L(0,1) mode, and the ratio of the L(0,2) mode to the L(0,1) mode peak is 7.62 times that of the traditional EMAT.
Keywords: non-ferromagnetic pipe;longitudinal guided wave;Lorentz force;modal control
2024, 50(3):97-102  收稿日期: 2021-12-02;收到修改稿日期: 2022-02-05
基金项目:
作者简介: 赵云伟(1997-),男,山东青岛市人,硕士研究生,专业方向为舰船动力装置状态检测、故障诊断与维修技术。
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