Rotating Eddy Current Testing: a Probe Optimization Analysis to Improve Test Performance

Rotating Eddy Current (REC) techniques have been widely adopted to improve defect detection capabilities in Non-Destructive Testing (NDT). However, the integration of ferromagnetic structures into REC-based probes remains an underexplored approach to further improve detection sensitivity. This paper presents a numerical analysis investigating the impact of different ferromagnetic structures (i.e. air-cored, ferromagnetic-shielded, ferromagnetic-cored and pot-cored) on the performance of REC probes. Finite element analysis (FEA) simulations were performed with COMSOL Multiphysics ®, evaluating each probe configuration in terms of reaction magnetic flux concentration and defect detectability. The study considered superficial and buried cracks in an aluminium alloy sample, analyzing variations in defect response, in terms of reaction magnetic flux, according to crack size and depth. The results indicate that the optimal probe design depends on defect location: while ferromagnetic-cored structures offer superior performance for surface cracks, pot-cored structures improve the detection of buried defects. These results highlight the potential of ferromagnetic structures adopted in REC methods, suggesting the need for further optimization adapted to the specific inspection scenario.