为适应复杂曲面结构的检测,柔性涡流探头得到了越来越多的应用。然而,柔性涡流探头能量较低,如何进一步提高柔性探头的检测能力一直是个问题。针对此,提出了一种基于“八”字形激励的涡流探头结构,并对其检测原理和性能进行了理论和试验分析。通过利用COMSOL仿真软件对探头进行仿真分析发现,相比于常规探头,基于“八”字形激励的探头结构能够减小激励线圈直接耦合磁场对接收线圈的影响,且探头仅对涡流扰动敏感,可有效提高探头信噪比。此外,试验分析发现,当两个激励线圈的夹角为60°时,其对碳钢试件的检测能力最强,同时能够区分不同深度的裂纹缺陷,可在10 mm的提离高度下对宽为0. 5 mm,深为5 mm的裂纹缺陷进行检测。

In order to adapt to the complex curved surface structure detection, flexible eddy current probe has been used. However, due to the low energy of the flexible eddy current probe, further improve the detection capability of the flexible eddy current probe is always a problem. In this paper, a probe based on “八” shape excitation coil was proposed, and its detection principle and performance were studied theoretically and experimentally. Through the simulation analysis of the probe using comsol simulation software, it was found that compared with the conventional probe, the probe structure based on the “八” shape excitation can be used for reducing the directly coupled magnetic field,and it was only sensitive to the eddy current disturbance, so the signal-to-noise ratio can be effectively improved. In addition, through the experimental analysis, it was found that when the angle between the two excitation coils was 60°, its detection ability for the carbon steel specimen used in this paper was the strongest. At the same time, it can distinguish the crack defects of different depths, and can detect the crack defects of 0. 5 mm wide and 5 mm deep under the 10 mm lift-off.