Pulsed Eddy Current-GRM Insepction and Image Analysis of Multilayer Airframe Structures
- 作者：G.YangZ.ZengY.DengX.LiuL.UdpaT.Chen
- 会议时间：2011-11-11
- 关键词：涡流检测 ; 趋肤深度 ; GMR测试 ; 感应磁场
- 作者单位：G.Yang(Department of Electrical & Computer Engineering, Michigan State University, East Lansing, Michigan48824, USA)Z.Zeng(Department of Aeronautics, Xiamen University, Xiamen, Fujian 361005, China)Y.Deng,X.Liu(Departments of Electrical Engineering, University of Colorado Denver, Denver CO, 80217-3364, USA)L.Udpa(Department of Electrical & Computer Engineering, Michigan State University, East Lansing, Michigan 48824, USA)T.Chen(School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China)
- 母体文献：全球华人无损检测高峰论坛论文集
- 会议名称：全球华人无损检测高峰论坛
- 会议地点：厦门
- 主办单位：中国机械工程学会
- 语种：chi
摘要
Detection of deep hidden cracks under fasteners (CUF) poses a major challenge in traditional eddy current testing (ECT) techniques because the weak eddy current signal due to skin depth or penetration depth of the fields. Reliable subsurface crack detection in multilayer structures using ECT solution has been investigated. Giant magnetore sistive (GMR) sensors are finding increasing applications in directly measuring weak magnetic fields associated with induced eddy currents. Pulsed eddy current testing (PECT) with GMR sensors system has been developed to identify the existing of subsurface cracks around fastener sites inaircraft wing frame. As an improved technique of ECT, the applied PEC-GMR testing generates 2D rasterscan image一C-scan and distinguishes crack and no crack conditions utilizing the asymmetric GMR response observed for crack feature. The built PEC-GMR system has shown the feasibility in detecting sub surface cracks at aluminum fastener sites, where the measured normal component Bz of induced magnetic field isused to identify defective fastener sites. The asymmetry information in the GMR signals along Bz has been exploited. However, detecting cracks under steel fasteners remains a problem since a subsurface crack is dominated by the strong signal from the steel fastener. This paper presents the feasible study of detectingc racks under steel fasteners using the component Bz and additional information contained in the tangentialcomponents By and Bx of induced magnetic fields in conjunction with image processing to detect and estimate subsurface corrosions of multilayer airframe structures. The applied PEC-GMR technique has presented the reliable inspection of the CUFs.