单向L(0,2)超声导波EMAT结构设计
Structural design of one-way L(0,2)ultrasonic guided wave EMAT
赵云伟 1王悦民 1汤槟晖 1许鉴鉴1
作者信息
- 1. 海军工程大学动力工程学院,湖北武汉 430033
- 折叠
摘要
超声导波在管道中传播时双向传播的特性以及端面反射回波的影响导致检测回波信号复杂难以分辨.依据电磁声换能器(EMAT)激发机理和纵向超声导波的波结构特性,设计了一种周期性永磁铁增强径向偏置磁场,从而增大洛伦兹力轴向分量、减小径向分量来控制激发单一L(0,2)导波;同时依据波叠加原理,通过控制相邻线圈线间距、激励电流方向和延迟时间等来选择纵向超声导波的激发方向.研究结果表明:当相邻激励线圈电流相反、线间距为λ/4,且延迟时间为T/4 时,采用优化设计的周期性永磁铁可以实现管道中超声导波的方向控制,使得回波信号容易分辨,提高了管道的检测效率.
Abstract
The characteristics of two-way propagation of ultrasonic guided waves in pipeline and the influence of the end-face reflected echoes make the detection echo signals complex and difficult to distinguish.According to the excitation mechanism of electromagnetic acoustic transducer(EMAT)and the wave structure characteristics of longitudinal ultrasonic guided waves,a periodic permanent magnet is designed to enhance the radial bias magnetic field,thereby increase the axial component of the Lorentz force and reduce the radial component to control the excitation of a single L(0,2)guided wave;at the same time,according to the principle of wave superposition,the excitation direction of the longitudinal ultrasonic guided wave is selected by controlling the distance between adjacent coil wires and the direction of excitation current and the delay time.The research results show that when the adjacent excitation coils have opposite currents,the line spacing is λ/4,and the delay time is T/4,the optimally designed periodic permanent magnet can realize the direction control of the ultrasonic guided wave in the pipeline,which makes echo signal easy to distinguish,and improves the detection efficiency of the pipeline.
关键词
非铁磁性管道/纵向导波/洛伦兹力/方向控制/电磁声换能器Key words
non-ferromagnetic pipe/longitudinal guided wave/Lorentz force/direction control/electromagnetic acoustic transducer(EMAT)引用本文复制引用
出版年
2024
NETL
NSTL
万方数据