Abstract: In order to apply oblique incident line-focusing SV wave for defecting detection of thick-walled aluminum tubes, an optimization design method of curved meander-line coil was proposed, which was used to stimulate SV wave. Three simulation models with plane coil, plane bending coil, and optimized curved coil as main components were studied by taking workpiece with different curvatures as detection objects. The results show that the optimized curved coil has the most obvious improvement effectiveness on the workpieces with large curvature, the directivity accuracy may be increased by 14.53%, and the detection amplitude may be increased by 37.42%. Finally, the experiments were carried out with 4 mm diameter transverse through hole of the thick-walled aluminum tubes as artificial defect. It is found that the detection amplitude of the maximum curvature tube is enhanced by 338.84%.

Key words: electromagnetic acoustic transducer（EMAT）, shear vertical(SV) wave, line-focusing, thick-walled aluminum tube, defect detection

摘要： 为将斜入射线聚焦垂直剪切(SV)波用于厚壁铝管缺陷探伤，提出了用于激励SV波的曲面曲折线圈优化设计方法。以不同曲率工件为检测对象，研究了以平面、平面弯曲及优化曲面的曲折线圈为主要元件的三种仿真模型，结果表明，优化曲面的曲折线圈在大曲率工件中的改进效果最为明显，其指向性精度最高可提高14.53%，探伤幅值最大可增强37.42%。最后以厚壁铝管直径4 mm横通孔为人工缺陷开展试验研究，发现最大曲率管的探伤幅值增大了338.84%。

关键词: 电磁超声探头, 垂直剪切波, 线聚焦, 厚壁铝管, 缺陷检测