Study of Parametric Transducer Operation in Pulsed Eddy Current Non-Destructive Testing

In this article is considered the experimental results of the using the parametric type of an eddy current transducer at two excitation modes - pulsed and harmonic. The flat samples from aluminum alloy and steel with artificial crack-like defects on them were selected as testing objects. The estimation of the amplitude, decrement and natural oscillation frequency of the eddy current transducer signal as informative parameters was performed according to the results of the analysis of experimental signals of the parametric transducer. The results of the comparative analysis of the eddy current transducer signals at harmonic and pulsed excitation are presented by estimating of changes in the signals amplitude values from the crack depth in the testing object. It is shown that the signals of parametric eddy current transducer in the form of damped harmonic oscillations obtained by pulse excitation of the transducer can be used in the eddy current non-destructive testing to estimate the depth of surface cracks. The types of the dependences of the attenuation and the natural oscillation frequency of the eddy current transducer signal from the change in the crack depth in the testing object were established using the experimental data. The analysis of the sensitivities of the informational parameters of the eddy current transducer at pulsed excitation to the crack depth in the testing objects is performed.