Development of differential hall sensors for Pulsed Eddy Current Testing using Gaussian pulse excitation

• Published in: Sensors and actuators. A. Physical. 2024-12, Vol.379, p.115998, Article 115998
• Main Authors: Dung, Tran Thi Hoai, Trung, Le Quang, Kasai, Naoya, Le, Minhhuy, Luong, Van Su
• Format: Article
• Language: English
• Subjects: Differential Hall sensors; Gaussian pulse excitation; Lift-off distance; Pulsed Eddy Current Testing; Signal noise reduction
• ISSN: 0924-4247
• DOI: 10.1016/j.sna.2024.115998

This study presents the use of differential Hall sensors in Pulsed Eddy Current Testing with Gaussian pulse excitation. This method was selected for its ability to effectively distribute energy across the frequency spectrum, thereby enhancing inspection depth and precision compared to the conventional rectangular pulses. The design of the differential Hall sensors, which includes two Hall sensors, greatly minimizes interference from the primary magnetic field, resulting in improved accuracy in detecting defects, particularly corrosion, across varying lift-off distances. 3D-FEM simulations and experimental results demonstrate that differential Hall sensors outperform traditional single Hall sensors in reducing noise and maintaining corrosion signal. Compared to traditional single Hall sensors, the differential Hall sensors exhibit a significantly improved signal-to-noise ratio, particularly at larger lift-off distances. Additionally, the study employs the Full Width at Half Maximum method to accurately estimate the size of corrosion, offering a precise and non-invasive approach to assessing structural integrity. [Display omitted] •The differential Hall sensor significantly enhances the sensitivity and accuracy in corrosion detection.•The Gaussian pulse is more effective than the rectangular pulse, improving both penetration depth.•Effective noise reduction safeguards corrosion signals even at large lift-off distances.•The experimental results confirm the superiority of the differential Hall sensor in maintaining a clear signal.•The FWHM method allows for accurate prediction of corrosion area size without the need for direct measurement.