International Journal of Applied Electromagnetics and Mechanics - Volume 74, issue 4

Authors: Theodoulidis, Theodoros

Article Type: Editorial

DOI: 10.3233/JAE-249002

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 287-287, 2024

Authors: Park, Won-Kwang

Article Type: Research Article

Abstract: Several researches have confirmed the possibility of localizing small anomalies via Kirchhoff migration (KM); however, when the background information is unknown, small anomalies cannot be satisfactorily retrieved. This fact can be examined through the simulation results; however, related theoretical result to explain the reason of such phenomenon has not yet been investigated. In this contribution, we show that the imaging function of the KM can be expressed by an infinite series of the Bessel function of the first kind, material properties, and antenna arrangement, and applied alternative value of the background wavenumber. Based on the theoretical result, we explain why …the exact location and shape of anomalies cannot be retrieved. The simulation results with synthetic data exhibited to support the theoretical result. Show more

Keywords: Kirchhoff migration, scattering matrix, background information, microwave imaging, simulation results

DOI: 10.3233/JAE-230113

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 289-297, 2024

Authors: Long, Cai | Wang, Yuanyuan | Dong, Haoran | Tao, Yu | Ye, Chaofeng

Article Type: Research Article

Abstract: It is still a challenging problem to detect small defects for eddy current array probes, which requires the probes to possess excellent sensitivity, as well as high spatial resolution. This paper presents a novel high-resolution magnetic field imaging probe with two rows of tunneling magnetoresistance (TMR) array sensors. The bare die sensors are integrated on a printed circuit board by golden wire bonding technology. The two rows of sensors are placed staggered with each other. The data of the two arrays are merged into a matrix, in which way the image pixel pitch is increased to 0.25 mm. The probe employs …a differential scheme to suppress the noise, so as to detect the weak signal of small defects. To highlight the weak defect indications, feature extraction and segmentation algorithms are developed. The experimental results confirm that the proposed method can inspect a small defect with dimensions 1 mm (length) × 0.1 mm (width) × 0.1 mm (depth) on a stainless-steel sample. Show more

Keywords: Array probe, differential measurement, eddy current testing (ECT), image segmentation, tunneling magnetoresistance sensor

DOI: 10.3233/JAE-230115

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 299-306, 2024

Authors: Mottola, Vincenzo | Corbo Esposito, Antonio | Piscitelli, Gianpaolo | Tamburrino, Antonello

Article Type: Research Article

Abstract: In this paper we present a first non-iterative imaging method for nonlinear materials, based on Monotonicity Principle. Specifically, we deal with the inverse obstacle problem, where the aim is to retrieve a nonlinear anomaly embedded in linear known background. The Monotonicity Principle (MP) is a general property for various class of PDEs, that has recently generalized to nonlinear elliptic PDEs. Basically, it states a monotone relation between the point-wise value of the unknown material property and the boundary measurements. It is at the foundation of a class of non-iterative imaging methods, characterized by a very low execution time that …makes them ideal candidates for real-time applications. In this work, we develop an inversion method that overcomes some of the peculiar difficulties in practical application of MP to imaging of nonlinear materials, preserving the feasibility for real-time applications. For the sake of clarity, we focus on a specific application, i.e. the Magnetostatic Permeability Tomography where the goal is retrieving the unknown (nonlinear) permeability by boundary measurements in DC operations. This choice is motivated by applications in the inspection of boxes and containers for security. Reconstructions from simulated data prove the effectiveness of the presented method. Show more

Keywords: Monotonicity principle, non-iterative algorithms, magnetostatic permeability tomography, inverse problems, nonlinear materials

DOI: 10.3233/JAE-230129

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 307-312, 2024

Authors: Kyrgiazoglou, Athanasios | Gerardis, Stefanos | Loizos, Dionisis | Politis, Panagiotis-Avgerinos | Theodoulidis, Theodoros

Article Type: Research Article

Abstract: Machining technology plays a major role in modern manufacturing industries due to the growing demand for equipment and products for aerospace, automotive, precision machinery sectors etc. A key issue associated with any type of machining operation is the accelerated tool wear which leads to shorter tool life, thus to low machining precision and decreased productivity. In this paper an electromagnetic Non-Destructive Testing method (NDT), and in particular Eddy Current Testing (ECT), is used to detect the wear of used cutting tools vs a new one.

Keywords: Eddy Current Testing, machinery tools, non-destructive evaluation

DOI: 10.3233/JAE-230130

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 313-319, 2024

Authors: Skarlatos, Anastasios | Reboud, Chritophe

Article Type: Research Article

Abstract: A new approach for the solution of transient eddy-current problems involving pieces with one direction of symmetry is presented. The approach is applicable to pieces with translational or rotational symmetry. A Fourier series decomposition of the solution is introduced in the direction of symmetry, which converts the original 3D numerical problem into a series of independent 2D problems. The decomposition has significant benefits in terms of computational time and numerical noise reduction, and is inherently parallelisable.

Keywords: Transient response, pulsed eddy-current, hybrid formulation, spectral method

DOI: 10.3233/JAE-230131

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 321-326, 2024

Authors: Wu, Tong | Wang, Yuanyuan | Li, Xiaoguang | Tao, Yu | Ye, Chaofeng

Article Type: Research Article

Abstract: The reliability of thimble tubes plays a critical role for maintaining the safety of a nuclear power plant. The defect depth needs to be quantified and predicted to support the operational decision-making. This paper presents a method to quantify the defects on thimble tube wall based on the analyzation of eddy current testing (ECT) data. Then, a method using artificial neural network (ANN) to predict the detect depth is studied. The tubes are divided into 2 shapes and four regions according to their positions and the data of each region and each shape is expanded by mean interpolation. A prediction …model based on ANN is constructed for each shape in each region. The experimental results show that the model can predict the signal of the next year according to the signal of the previous three years with mean absolute percentage error less than 16%. Show more

Keywords: Thimble tube, eddy current testing, artificial neural network, quantification, prediction

DOI: 10.3233/JAE-230132

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 327-334, 2024

Authors: Tamburrino, Antonello | Sardellitti, Alessandro | Milano, Filippo | Mottola, Vincenzo | Laracca, Marco | Ferrigno, Luigi

Article Type: Research Article

Abstract: This paper introduces Buckingham’s 𝜋 theorem in the context of Non-Destructive Testing & Evaluation (NDT&E). Its application leads to easier problems to handle by reducing the number of variables involved. In this sense, dimensional analysis can provide the foundation for in-line, real-time and low-cost inspection methods that are fully compatible with the requirements of the Industry 4.0 and NDE 4.0 paradigms. In order to show the impact of the Buckingham’s 𝜋 theorem in NDT&E, we consider a practical case of interest, i.e. the simultaneous estimation of thickness and electrical conductivity of metallic plates via Eddy Current Testing. An initial numerical …analysis is carried out with the aim to show the metrological performance of the method. The results obtained show that the method combines good accuracy with low computational costs. Show more

Keywords: Dimensional analysis, Buckingham’s 𝜋 theorem, non-destructive testing & evaluation, eddy current testing, multi-parameter simultaneous estimation, thickness estimation, electrical conductivity estimation, NDE 4.0

DOI: 10.3233/JAE-230133

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 335-341, 2024

Authors: Baskaran, Prashanth | Ramos, Helena Geirinhas | Ribeiro, Artur Lopes

Article Type: Research Article

Abstract: Probability of Detection (PoD) models, in general, take into consideration one or multiple flaw parameters such as its length, maximum depth, and/or maximum surface area, and one flaw signal. However, due to correlation between the response signals, it might be necessary to consider multiple flaw response signals simultaneously. Hence, in this work, we demonstrate the possibility of including multiple correlated flaw signals, features, towards the construction of a PoD curve. The flaw features considered are the 3 components of the magnetic flux density. This is a simulation based PoD estimation for a narrow opening notch type flaw located in the …sub-surface of a two-layer geometry. The inspection is carried out by an uniform eddy current probe that induces a spatially uniform fields into the conducting space, around the region of interest. The analysis was performed using the semi-analytical boundary element method (BEM). Show more

Keywords: Boundary element method (BEM), electric dipoles, magnetic-electric Green’s functions, Probability of Detection (PoD)

DOI: 10.3233/JAE-230134

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 343-349, 2024

Authors: Campos, Lucas Braga | Camerini, Cesar Giron | Fernandes, Daniel Mendes | Silva, Vitor Manoel | Santos, Rafael W.F. | Pereira, Gabriela Ribeiro

Article Type: Research Article

Abstract: With the development of non-destructive inspection techniques, more and more challenging situations have arisen and the correct choice of operating parameters can be decisive for a good detection sensitivity. Based on that, an algorithm was developed to obtain the best combination of an eddy current sensor operation parameters. The results obtained demonstrate the improvement in the cracks detection in welded parts after optimization.

Keywords: Optimization, eddy currents, fatigue crack, weld

DOI: 10.3233/JAE-230136

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 74, no. 4, pp. 351-356, 2024