基于交流电磁场裂纹缺陷识别仿真研究

为了研究基于交流电磁场裂纹缺陷识别问题，调研了交流电磁场检测的国内外现状，结合交流电磁场技术，利用有限元分析软件ANSYS Maxwell构建常见的裂纹缺陷模型，进行仿真分析。研究了缺陷尺寸的识别以及不同缺陷簇群对交流电磁场(Alternating Current Field Measurement，ACFM）检测信号特征的影响，对提取的Bx和Bz（沿坐标轴X方向和Z方向的磁感应强度）特征信号的影响进行了分析与探讨，得到影响ACFM技术的核心参数，并建立了缺陷深度和长度的测量评估方法。研究结果表明:通过测量Bz曲线的峰谷间距可初步确定缺陷长度； Bx曲线检测同时受缺陷深度和缺陷长度的影响，对于缺陷深度检测灵敏度较低；ACFM技术虽能够实现对缺陷个数的识别，但难以准确识别缺陷尺寸的大小，当缺陷间的距离足够大时，才能准确实现缺陷的定量识别。

Simulation research on crack defect identification based on alternating current electromagnetic field

In order to study the problem of crack defect identification based on the alternating current (AC) electromagnetic field, the current status of AC electromagnetic field detection at home and abroad was investigated. Combined with the alternating electromagnetic field technology, a common crack defect model was constructed by using the finite element analysis software ANSYS Maxwell to carry out the simulation analysis. The identification of defect size and the influence of different defect clusters on the characteristics of alternating current field measurement (ACFM) detection signals were studied. The influence of extracted Bx and Bz (magnetic flux density along X axis and Z axis) characteristic signals were analyzed and discussed, then the core parameters influencing ACFM technology were obtained, and the measurement evaluation method of defect depth and defect length was established. The results showed that the defect length could be determined preliminarily by measuring the peak to valley spacing of the Bz curve. The Bx curve detection were affected both by the defect depth and defect length, and the sensitivity for the detection of defect depth was low. Although ACFM can realize the identification of the number of defects, however, it is difficult to accurately identify the defect size, and the quantitative identification of the defect can be accurately achieved only when the distance between the defects is sufficiently large.