Li Yong, Liu Ze, Miao Yu, Yuan Wei, Liu Zheliang
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing, China.
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing, China.
Ultrasonics. 2020 Dec;108:106169. doi: 10.1016/j.ultras.2020.106169. Epub 2020 May 29.
The novelty of this paper is that a spiral-coil EMAT (electromagnetic acoustic transducer) is applied to rail subsurface inspection. To study the spiral-coil EMAT for rail subsurface inspection, the dominant mechanism is investigated emphatically. The interaction between the Lorentz-force mechanism and the magnetostriction mechanism is analyzed corresponding to the magnetic flux density and the frequency which has a significant effect on the magnetostriction mechanism. The effect of frequency on beam divergence is further discussed about the rail subsurface inspection using spiral-coil EMAT as well. A 2D FEM (finite element model) of spiral-coil EMAT is established and the simulation is carried out to analyze these issues. Besides, the experiments to inspect the subsurface crack of steel plate are carried out at various frequencies to verify the feasibility of the application. The experimental results demonstrate that the rail subsurface inspection by using the spiral-coil EMAT is feasible and the high frequency can contribute to distinguish the echo signal from the rail subsurface crack.
本文的新颖之处在于将螺旋线圈电磁超声换能器（EMAT）应用于铁轨表面下检测。为了研究用于铁轨表面下检测的螺旋线圈EMAT，着重研究了其主要机制。对应于对磁致伸缩机制有显著影响的磁通密度和频率，分析了洛伦兹力机制与磁致伸缩机制之间的相互作用。还进一步讨论了频率对使用螺旋线圈EMAT进行铁轨表面下检测时波束发散的影响。建立了螺旋线圈EMAT的二维有限元模型（FEM）并进行了模拟以分析这些问题。此外，在不同频率下进行了检测钢板表面下裂纹的实验，以验证该应用的可行性。实验结果表明，使用螺旋线圈EMAT进行铁轨表面下检测是可行的，并且高频有助于区分来自铁轨表面下裂纹的回波信号。
