A New Method of Eddy Current Impedance-Extracting and Hardness-Classifying for Valves

This paper describes a new method of eddy current impedance extraction and hardness classification for valves, which is used in online classification. A finite element simulation is conducted to estimate the base magnetic response in specimens with various initial permeabilities, and a scatter diagr...

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Main Authors: Hu Pengfei, Xie Qingsheng, Huang Haisong
Format: Article
Language:English
Published: IEEE 2020-01-01
Series:IEEE Access
Subjects:
Online Access:https://ieeexplore.ieee.org/document/8990102/
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author Hu Pengfei
Xie Qingsheng
Huang Haisong
author_facet Hu Pengfei
Xie Qingsheng
Huang Haisong
author_sort Hu Pengfei
collection DOAJ
description This paper describes a new method of eddy current impedance extraction and hardness classification for valves, which is used in online classification. A finite element simulation is conducted to estimate the base magnetic response in specimens with various initial permeabilities, and a scatter diagram between the hardness calibration and initial permeability is plotted experimentally; thus, the hardness classification model is obtained by using the initial permeability as the intermediate variable. A lock-in amplifier is commonly used to measure the amplitudes of impedance components in conventional eddy current testing. This study replaces the lock-in amplifier with a cross-correlation algorithm with the objective of integrating the impedance processing with the subsequent classification. Moreover, an incremental and decremental support vector machine is used to classify the valve specimens based on the extracted impedance due to its demonstrated excellent performance for both linearly separable and nonlinearly indivisible problems. The cross-correlation algorithm and the incremental and decremental support vector machine are implemented on a field-programmable gate array, which has the advantage of parallel processing and can satisfy the online requirements. A comparison with the traditional impedance comparison method shows that the proposed method not only is suitable for online hardness classification but also achieves good performance in correlating impedance amplitude changes caused by a temperature increase of the coil and various heat treatment conditions with the hardness values.
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spelling doaj.art-c142837b1e5945bb8a6ccb8e2726d5d82022-12-21T22:53:56ZengIEEEIEEE Access2169-35362020-01-018467814679410.1109/ACCESS.2020.29729378990102A New Method of Eddy Current Impedance-Extracting and Hardness-Classifying for ValvesHu Pengfei0https://orcid.org/0000-0002-8959-4313Xie Qingsheng1https://orcid.org/0000-0003-4600-4966Huang Haisong2https://orcid.org/0000-0002-3305-9450Key Laboratory of Advanced Manufacturing Technology of the Ministry of Education, Guizhou University, Guiyang, ChinaKey Laboratory of Advanced Manufacturing Technology of the Ministry of Education, Guizhou University, Guiyang, ChinaKey Laboratory of Advanced Manufacturing Technology of the Ministry of Education, Guizhou University, Guiyang, ChinaThis paper describes a new method of eddy current impedance extraction and hardness classification for valves, which is used in online classification. A finite element simulation is conducted to estimate the base magnetic response in specimens with various initial permeabilities, and a scatter diagram between the hardness calibration and initial permeability is plotted experimentally; thus, the hardness classification model is obtained by using the initial permeability as the intermediate variable. A lock-in amplifier is commonly used to measure the amplitudes of impedance components in conventional eddy current testing. This study replaces the lock-in amplifier with a cross-correlation algorithm with the objective of integrating the impedance processing with the subsequent classification. Moreover, an incremental and decremental support vector machine is used to classify the valve specimens based on the extracted impedance due to its demonstrated excellent performance for both linearly separable and nonlinearly indivisible problems. The cross-correlation algorithm and the incremental and decremental support vector machine are implemented on a field-programmable gate array, which has the advantage of parallel processing and can satisfy the online requirements. A comparison with the traditional impedance comparison method shows that the proposed method not only is suitable for online hardness classification but also achieves good performance in correlating impedance amplitude changes caused by a temperature increase of the coil and various heat treatment conditions with the hardness values.https://ieeexplore.ieee.org/document/8990102/Eddy current testingfinite element modelcross-correlation algorithmincremental and decremental support vector machineimpedance extractionhardness classification
spellingShingle Hu Pengfei
Xie Qingsheng
Huang Haisong
A New Method of Eddy Current Impedance-Extracting and Hardness-Classifying for Valves
IEEE Access
Eddy current testing
finite element model
cross-correlation algorithm
incremental and decremental support vector machine
impedance extraction
hardness classification
title A New Method of Eddy Current Impedance-Extracting and Hardness-Classifying for Valves
title_full A New Method of Eddy Current Impedance-Extracting and Hardness-Classifying for Valves
title_fullStr A New Method of Eddy Current Impedance-Extracting and Hardness-Classifying for Valves
title_full_unstemmed A New Method of Eddy Current Impedance-Extracting and Hardness-Classifying for Valves
title_short A New Method of Eddy Current Impedance-Extracting and Hardness-Classifying for Valves
title_sort new method of eddy current impedance extracting and hardness classifying for valves
topic Eddy current testing
finite element model
cross-correlation algorithm
incremental and decremental support vector machine
impedance extraction
hardness classification
url https://ieeexplore.ieee.org/document/8990102/
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