Interpretation of pulsed eddy current signals for locating and quantifying metal loss in thin skin lap splices

Several key features of pulsed eddy current transient responses from probe coils have been identified and related to specific test parameter and material property changes. While many features are related to flaw size and location, most, such as maximum amplitude, are severely affected by probe lift-off variations and interlayer separations in multi-layered structures. We present several PEC signal features and interpretation techniques for locating and quantifying metal loss in calibration specimens and naturally corroded lap splices exhibiting common noise sources.