Abstract
Subsurface Corrosion (SSC) has posed a severe threat to the integrity of in-service conductive structures. Although Pulsed Eddy Current technique (PEC) has been proven applicable regarding non-destructive inspection of SSC, it has been found disadvantageous in terms of Signal-to-noise Ratio (SNR) and sensitivity to SSC, etc. In light of this, this paper proposes Pulse-modulation-based Eddy Current technique (PMEC). The advantages of PMEC over PEC have been analyzed via simulations based on analytical modeling and a series of experiments. Through theoretical and experimental investigations, it has been found that PMEC realizes the elaborate inspection of conductive structure, and has higher sensitivity in detection and evaluation of SSC than PEC.