针对铁磁性构件损伤检测的需求，进行了宽带激励下的低频电磁检测技术研究。通过有限元仿真，研究了励磁信号频带对低频电磁场分布的影响；对宽带激励下低频电磁检测信号进行了相似度分析，提出了一种基于宽频响应欧式距离的缺陷表征方法。在以上研究基础上，进行了铁磁性结构缺陷检测试验，结果表明，与传统单频励磁的低频电磁检测技术相比，宽频激励检测技术能够大幅提高低频电磁场的穿透能力，基于宽频响应的欧式距离的表征方法对内部埋藏缺陷的检测能力和空间分辨能力更强。该研究工作为铁磁性构件大范围损伤检测提供了可行的技术方案。

In view of the defect detection in ferromagnetic structure, research is focused on low frequency electromagnetic technique under broadband excitation. Finite element analysis is conducted to investigate the effect of excitation bandwidth on electromagnetic field distribution in structure. The detection signals were analyzed by similarity method, and Euclidean distance was proposed for defect characterization. Low frequency electromagnetic experiments were conducted for defect detection in ferromagnetic structure. The results show that the electromagnetic field penetrability can be improved by broadband excitation, and the spatial resolution and the ability for interior defect detection by low frequency electromagnetic technique are more powerful if using the Euclidean distance of response under broadband excitation. The research provides a potential scheme for a wide range defect detection in ferromagnetic structure.