GMR array uniform eddy current probe for defect detection in conductive specimens
GMR array uniform eddy current probe for defect detection in conductive specimens
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DOI：
10.1016/j.measurement.2013.06.050
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发表时间：
2013-12-01
期刊：
影响因子：
5.6
通讯作者：
Geirinhas Ramos, H.
中科院分区：
文献类型：
--
作者：
Postolache, Octavian;Ribeiro, Artur Lopes;Geirinhas Ramos, H.
涡流探头（ECP）与单个磁场传感器的使用代表了用于导电样品中的缺陷检测的常见解决方案，但是当要检测大表面样品时，这是一个耗时的过程，需要大量的扫描步骤。为了加快无损检测过程，包括单个激励线圈和传感线圈阵列的涡流探头提供了一个很好的解决方案。本文研究的解决方案取代了巨磁阻（GMR）的传感线圈，由于其高灵敏度和宽带响应。因此，ECP激励线圈可以在较低的频率比传统的允许缺陷被检测在较厚的structure.In这项工作中，一个优化的均匀涡流探头架构，包括两个平面的激励线圈，一个矩形磁场偏置线圈和GMR磁强计传感器阵列。交流电流被施加到探头的平面螺旋矩形线圈，而一组GMR磁力计传感器检测被测样品中的感应磁场。矩形线圈提供直流均匀磁场，确保探头的GMR磁力计的适当偏置，在线性区域上和GMR静态特性的相同分支处设置功能点。如果所有传感器都偏置在相同的工作点上，则每个GMR的相同样本所获得的图像上的差异减小。的自动化测量系统的元素，用于检查下使用建议的涡流探头，包括基于2D模板匹配算法和相应的实验结果的验证程序的测试板包括在文件中。(C)2013爱思唯尔有限公司保留所有权利。
The usage of eddy current probes (ECP) with a single magnetic field sensor represents a common solution for defect detection in conductive specimens but it is a time consuming procedure that requires huge amount of scanning steps when large surface specimens are to be inspected. In order to speed-up the nondestructive testing procedure, eddy current probes including a single excitation coil and an array of sensing coils present a good solution. The solution investigated in this paper replaces the sensing coils for giant magneto-resistors (GMRs), due to their high sensitivity and frequency broadband response. Thus, the ECP excitation coil can be driven at lower frequencies than the traditional ones allowing defects to be detected in thicker structures.In this work an optimized uniform eddy current probe architecture including two planar excitation coils, a rectangular magnetic field biasing coil and a GMR magnetometer sensor array is presented. An ac current is applied to the planar spiral rectangular coil of the probe, while a set of GMR magnetometer sensors detects the induced magnetic field in the specimens under test. The rectangular coil provides the DC uniform magnetic field, assuring appropriate biasing of the GMR magnetometers of the probe, setting-up the functioning point on the linear region and at the same branch of the GMR static characteristics. The differences on the images obtained for the same specimen for each GMR are reduced if all sensors are biased on the same working point. Elements of the automated measurement system used to inspect the plate under test using the proposed eddy current probe, including a validation procedure based on a 2D template matching algorithm and the corresponding experimental results are included in the paper. (C) 2013 Elsevier Ltd. All rights reserved.