Conductivity invariance phenomenon of eddy current testing- analytical modeling and physical interpretation

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International Pub Date : 2025-10-06 DOI:10.1016/j.ndteint.2025.103568

Fenglong Wang , Yating Yu , Cheng Sun , Haipeng Yang , Guiyun Tian

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引用次数: 0

Abstract

The Conductivity Invariance Phenomenon (CIP) has been previously discovered in our previous work—in multilayer structures, when the alien material layer in the conductivity invariance point changes suddenly in electrical conductivity, the eddy current testing signal remains unaffected [1, 2]. The CIP has been proven to potentially eliminate the coupling effects between electrical conductivity and magnetic permeability in Eddy Current Testing (ECT). However, current research on CIP primarily focused on controlling materials within the conductivity invariance point, lacking a deep understanding of the underlying physical mechanisms, which limited the application of CIP in engineering. Therefore, this paper conducts an in-depth investigation of CIP, establishing an analytical model to efficiently calculate the conductivity invariance point and validating it through numerical simulation and experiments. Additionally, this paper finds that the CIP arises from the combined effects of electromagnetic field coupling interference in multilayer structures and the electromagnetic interaction of the alien material layer itself. When the alien material is within the conductivity invariance point, the two effects cancel each other out, demonstrating CIP. On the other hand, the physical mechanism of CIP is demonstrated by the equivalent conversion method. This research provides a theoretical foundation for the future application of CIP in decoupling electrical conductivity and magnetic permeability issues in eddy current testing, facilitating precise measurement of magnetic permeability.

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查看原文本刊更多论文

涡流检测的电导率不变性现象——解析建模与物理解释

导电性不变性现象（Conductivity Invariance Phenomenon， CIP）在我们之前的多层结构工作中已经被发现，当导电性不变性点处的异质材料层的导电性突然发生变化时，涡流测试信号不受影响[1,2]。在涡流测试（ECT）中，CIP已被证明可以潜在地消除电导率和磁导率之间的耦合效应。然而，目前对CIP的研究主要集中在将材料控制在电导率不变性点内，缺乏对其潜在物理机制的深入了解，限制了CIP在工程中的应用。因此，本文对CIP进行了深入研究，建立了高效计算电导率不变性点的解析模型，并通过数值模拟和实验对其进行了验证。此外，本文还发现CIP是多层结构中电磁场耦合干扰和外来材料层本身电磁相互作用的综合作用。当外来物质在电导率不变点内时，这两种效应相互抵消，证明了CIP。另一方面，用等效转换法论证了CIP的物理机理。本研究为未来CIP在涡流检测中解耦电导率和磁导率问题的应用提供了理论基础，便于磁导率的精确测量。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Ndt & E International 工程技术-材料科学：表征与测试

CiteScore

7.20

自引率

9.50%

发文量

121

审稿时长

55 days

期刊介绍： NDT&E international publishes peer-reviewed results of original research and development in all categories of the fields of nondestructive testing and evaluation including ultrasonics, electromagnetics, radiography, optical and thermal methods. In addition to traditional NDE topics, the emerging technology area of inspection of civil structures and materials is also emphasized. The journal publishes original papers on research and development of new inspection techniques and methods, as well as on novel and innovative applications of established methods. Papers on NDE sensors and their applications both for inspection and process control, as well as papers describing novel NDE systems for structural health monitoring and their performance in industrial settings are also considered. Other regular features include international news, new equipment and a calendar of forthcoming worldwide meetings. This journal is listed in Current Contents.