Differential tangential eddy current probe with dual induction for lift-off signal suppression

This paper proposes a passive differential tangential surface probe with dual induction as a means of suppressing lift-off signals in eddy current testing. Simulations and experiments confirmed that the proposed probe is superior to a pancake probe and a self-induction differential tangential probe in its ability to selectively attenuate the lift-off signals. On the other hand, the crack signals of the proposed probe were almost the same as that of the self-induction probe. The results show that the proposed probe can detect minute defects that have been difficult to detect in situations where it is difficult to maintain a constant lift-off, such as when specimens are vibrating.