Method for Removing Secondary Peaks in Remote Field Eddy Current Testing of Pipes

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• 作者：Qingwang Luo ; Yibing Shi ; Zhigang Wang ; Wei Zhang…
• 关键词：RFEC testing ; Secondary peaks ; Defect assessment ; Dual receivers ; Wiener deconvolution filter ; ANSYS
• 刊名：Journal of Nondestructive Evaluation
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：36
• 期：1
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Structural Mechanics; Characterization and Evaluation of Materials; Vibration, Dynamical Systems, Control; Classical Mechanics;
• 出版者：Springer US
• ISSN：1573-4862
• 卷排序：36

文摘

In the remote field eddy current (RFEC) testing of pipes, because the remote eddy current penetrates the pipe’s wall twice, the testing results exhibit two peaks (primary peak and secondary peak) that originate from both the transmitter and receiver passing by the same place in the pipe. The secondary peaks have the same features as the primary peaks that are used to assess defects, and if there is no separation between primary peaks and secondary peaks, incorrect evaluations of defects will be obtained. Considering the benefits of removing secondary peaks in RFEC testing, dual receivers are taken into account. Dual receivers are set in remote fields and are set coaxially to the transmitter to obtain differential signals at the same time. In the proposed method, position dependent response of the differential signals from the dual receivers is calibrated, a Wiener deconvolution filter is used to identify secondary peaks and filter testing noise, and the factors that affect results of removing secondary peaks are also analyzed. To validate the feasibility of the proposed method of RFEC testing, ANSYS is made use of when setting up the analysis model, and an experimental pipe is designed to be identical to ANSYS model. The results of the analysis of ANSYS and experiments both validate the practicality of the proposed method and show the benefits of simplifying the analysis of RFEC signals.