Affiliations: [a] Indira Gandhi Center for Atomic Research, A CI of Homi Bhabha National Institute, Non-Destructive Evaluation Division, Kalpakkam, TN, India
Correspondence:
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Corresponding author: Arjun A.R., Non-Destructive Evaluation Division, Indira Gandhi Center for Atomic Research, A CI of Homi Bhabha National Institute, Kalpakkam, 603102, TN, India. Tel.: +91 94 9837 5848; E-mail: [email protected], [email protected]
Abstract: Eddy current measurements are prone to edge effects when measurements are carried out near a sample boundary. In order to reduce these edge effects, typically ferrite shields are used which constrain the magnetic field within the shield volume. However, their effects on sensitivity towards changes in conductivity for Sweep Frequency Eddy Current (SFEC) measurements have not been investigated. A 2D axisymmetric Finite Element Model (FEM) has been developed to predict the frequency response of impedance of SFEC probes. The model predicted that the addition of shields minimized edge effect but with reduced sensitivity. A simulation study is carried out to optimize the probe design to increase the sensitivity of shielded ferrite probes. Based on these results, a probe is constructed with a custom ferrite shield and its shielding efficiency and probe sensitivity are compared experimentally with those for the probe with conventional ferrite shields.
Keywords: Sweep Frequency Eddy Current Testing, Finite Element Model, edge effect, probe design optimization and sensitivity
