低频交流漏磁可视化检测方法研究

At present,ferromagnetic components such as carbon steel are widely used in key equipment of industry and military. Its integrity is mainly evaluated by magnetic flux leakage testing. Thismethod, however, cannot meet the requirements of quality control and safety maintenance due to low sensitivity and efficiency. In view of the above problems, this project study magnetic flux leakage and magneto optical imaging in-depth. A method of visual magnetic flux leakage testing and evaluation using low frequency excitation is proposed. This project has three key points: 1) Based on low frequency excitation and magnetic dipole model,advantages ofmagnetic flux leakage and magneto optical imaging are fusedto improve testing sensitivity of deep defects; 2) Based on optical flow method, magnetic domain wall is extracted from the magneto-optic image sequence, thus a high quality of image is reached; 3)Though analyzingcoupling between themagnetic domain and leakage magnetic field,analgorithm is proposed to map the leakage magnetic field,andinverse it frommagneto-optic image.Successful implementation of this project canpush the testing field from point to area. It is not only highlight the sensitivity and efficiency of ferromagnetic material evaluation, make testing visual, but also put a milestone for defect quantification and structure health state evaluation.

目前，碳钢等铁磁性构件被广泛应用于工业、国防等重要领域，其结构完整性主要采用漏磁检测方法进行评估。然而，漏磁检测方法灵敏度和效率较低，检测结果不直观，难以满足现代化重大装备质量控制和安全维护的需求。针对以上难题，本项目深入研究漏磁和磁光成像检测机理，提出一种低频交流漏磁可视化检测方法。该新方法：1）基于低频交流激励模式和磁偶极子模型，融合漏磁与涡流检测优势，提高深层缺陷检测的灵敏度；2）基于光流法处理单周期多帧磁光图像，消除磁光薄膜磁畴壁干扰噪音，提高磁光成像质量；3）研究磁光薄膜磁化场与漏磁场耦合规律，提出漏磁场信号分离算法，进而实现磁光图像到缺陷漏磁信号的反演。本项目的成功实施将传统漏磁检测的“点”检测扩展为“面”检测，在大大提高铁磁性构件检测的灵敏度和效率的同时，还可为缺陷的量化重构和构件的健康状态评估提供丰富的信息。

目前，碳钢等铁磁性构件被广泛应用于工业、国防等重要领域，其结构完整性主要采用漏磁检测方法进行评估。然而，漏磁检测方法灵敏度和效率较低，检测结果不直观，难以满足现代化重大装备质量控制和安全维护的需求。针对以上难题，本项目深入研究漏磁和磁光成像检测机理，提出一种低频交流漏磁可视化检测方法。该新方法：1）基于低频交流激励模式和磁偶极子模型，融合漏磁与涡流检测优势，提高深层缺陷检测的灵敏度；2）基于光流法处理单周期多帧磁光图像，消除磁光薄膜磁畴壁干扰噪音，提高磁光成像质量；3）研究磁光薄膜磁化场与漏磁场耦合规律，提出漏磁场信号分离算法，进而实现磁光图像到缺陷漏磁信号的反演。本项目的成功实施将传统漏磁检测的“点”检测扩展为“面”检测，在大大提高铁磁性构件检测的灵敏度和效率的同时，还可为缺陷的量化重构和构件的健康状态评估提供丰富的信息。