A novel flexible eddy-current probe with high sensitivity for NDT

This paper presents a novel flexible eddy-current probe specifically designed to inspect small defect for material with planar or complex geometry. The proposed eddy-current probe has a planar design and a multilayer structure using flexible printing circuit board technology. The fundamentals on the sensor operation are presented and explained in the presence of a metallic part to be inspected with and without defects. A finite element model was used to detail the probe operation and to assess the influence of input current frequency on the probe response. Finally, the simulations were validated experimentally using a prototype probe and an aluminum alloy block with standard defects produced using electro-discharge machining. Experiment shows that the probe has a high sensitivity to small defect with any orientation, and has a good SNR. The probe can be used in QNDE with a precision better than 1mm.