The impact of various waveform shapes on the response signal in pulsed eddy current NDE

Abstract

This paper focuses on the pulsed eddy current (PEC) excitation in nondestructive evaluation (NDE). In conventional eddy current NDE, where the harmonic excitation is used, the optimal inspection frequency for detection and evaluation of expected defects depends on material thickness and its electromagnetic properties. In PEC a single pulse can, in principle, generate a wide range of frequency components. This study concerns evaluation of pulse shape and its width on resolution of defects with different depths. Different excitation waveforms contain wide spectrum of frequencies, therefore the resolution of defects could vary. Resolution of defects with various depths based on difference signal is then investigated for various pulsed waveforms while the width of pulses is varied as well. The presented results show the dependencies on pulse width and shape.