Examination of Dodd and Deeds solutions for a transmit-receive eddy current probe above a layered planar structure

Abstract

Abstract. Exact solutions for the electromagnetic response of a transmit-receive coil pair situated above two parallel plates separated by a gap, were developed using the recently published general model of Desjardins et al. that accounts for all electromagnetic interactions between the voltage-driven probe and the conducting samples. This model was then compared to the well-known model developed by Dodd and Deeds, which assumes a constant amplitude sinusoidal current and an open-circuit pick-up coil. Both models were compared with experimental results that measured the gap -materials simulated the electromagnetic properties of a Zr 2.5% Nb pressure tube and Zr-2 calandria tube, respectively, as found in the fuel channels of CANDU ® reactors. It was observed that while the Dodd and Deeds' model as applied to this work achieved a good shape agreement with experimental data for excitation frequencies at 2 kHz, at the higher frequency of 16 kHz good agreement was not achieved. In contrast, the model of Desjardin's et al., adapted for a transmitreceive probe configuration above two infinite flat plates, achieved an excellent shape agreement at both frequencies.

Measuring Co-Axial Hole Size of Finite-Size Metallic Disk Based on a Dual-Constraint Integration Feature Using Multi-Frequency Eddy Current Testing

“…Luloff et al examined Desjardins et al 's model of a non-coaxial sensor probe above two separated sample plates by utilizing the Dodd-Deeds model. It was found that both methods are matched with the experiments under the low frequency [19]. In [20], by combining the analytical solution and FEM simulations, the ferrite fraction can be inferred with the error typically less than 8 %.…”

Inversion of Distance and Magnetic Permeability Based on Material-Independent and Liftoff Insensitive Algorithms Using Eddy Current Sensor

“…In recent years, the Dodd-Deeds formula [31] has been widely used for the inductance analysis of the air-core coil above the conductive plates [32]- [37]. For the designed eddy current sensor shown in Fig.…”

“…Parameters, including the inversed liftoff distance, LII L 0 , and its corresponded frequency, are used for the inversion of the relative magnetic permeability of the steel using iterative equations from (30) to (32). In Fig.…”

Determination of Surface Crack Orientation Based on Thin-Skin Regime Using Triple-Coil Drive-Pickup Eddy-Current Sensor

“…α and α 1 are related to the wavenumber of the EM plane wave of Transverse electric (TE) mode [17] in the free space and test piece, respectively. α = √ 2 + 2 (5) (3) and h( , )e j( r + ) in (4) are the Fourier transform of the free-space magnetic scalar potential generated by the driving transmitter and pick-up receiver respectively, with h( , ) defined as the following expression.…”