A differential planar eddy currents probe: Fundamentals, modeling and experimental evaluation

This paper presents a new eddy current probe specifically designed to inspect imperfections along Friction Stir Welding joints. The proposed probe has a planar design and a differential operation introducing several innovative aspects in eddy currents generation and sensing. The fundamentals on the probe 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 several operational parameters on the probe response. Finally, the simulations were validated experimentally using a prototype probe produced in printed circuit board and an aluminum alloy block with standard defects produced using electro-discharge machining.