基于U形磁轭探头的交流漏磁检测法机理研究  

Mechanism study of AC-MFL method using U-shape inducer

作　　者：宋凯[1] 陈超[1] 康宜华[1] 李俊江[1] 任吉林[1] 

机构地区：[1]南昌航空大学无损检测技术教育部重点实验室,南昌330063

出　　处：《仪器仪表学报》2012年第9期1980-1985,共6页Chinese Journal of Scientific Instrument

基　　金：无损检测技术教育部重点实验室基金(ZD201029003);江西省教育厅科技项目(GJJ12406;GJJ12444)资助

摘　　要：交流漏磁检测法常采用U形磁轭探头,但由于正弦波励磁信号引起了涡流,缺陷区域的漏磁场和扰动涡流场共同作用使其检测机理易导致混淆。建立了直流漏磁检测有限元模型,提出了评判检测原理的信号准则。在此基础上,对U形磁轭探头进行了仿真和试验。结果表明,当探头的一次磁场方向、探头移动方向与裂纹走向平行时,裂纹中心处的磁感应强度的水平分量比无缺陷处小,该分量与信号频率和励磁强度无关。依据评判准则,U形磁轭探头检测纵向裂纹时其机理并非源于交流漏磁效应。The alternative current magnetic flux leakage （AC-MFL） method using a U-shape inducer is one of the advanced MFL methods. Because sine wave excitation signal causes eddy current, so the MFL field and disturbance eddy current field in the defect area of a conductor can lead to the confusion in the detection mechanism. Aiming at this problem, a 3D finite element model of DC MFL testing is developed. A judgment criterion of detection principle is presented according to simulation results. On this basis, simulation and test are carried out for U-shape inducer. The results show that horizontal component （By） of magnetic leakage flux density at the crack center is smaller than that in the case without defect when the crack direction is in parallel with the magnetic field direction and probe moving direction. Moreover, the horizontal component （Br） is independent of signal frequency and excitation intensity. Finite element analysis （FEA） and experiment results indicate that according to the judgment criterion, the mechanism using a U-shape inducer to detect longitudinal crack is not primarily originated from AC-MFL effect.

关 键 词：U形磁轭探头 有限元分析 交流漏磁检测 涡流场 

分 类 号：TM154.2[电气工程—电工理论与新技术]