Improving Defect Detection in Eddy Current Testing using Multi-Frequency Rotating Eddy Current Strategy

The detection capability of small defects, such as cracks, with arbitrary orientations, using eddy current testing techniques, is affected by both the direction of the eddy current path respect to the main defect orientation and the depth of the defect to be detected. To give an answer to this problems Rotating Eddy Current (REC) techniques and multi-frequency excitation have been proposed by the scientific community. In this paper, these two solutions have been applyed together in order to improve the detection performance for buried and superficial defects with any orientation. The developed probe together with the novel REC multi-frequency excitation strategy are detailed described and experimentally characterized in various scenarios, including surface and buried cracks, demonstrating the effectiveness of the proposed solution.