Composite Defects Evaluation Using the Hybrid NDT Methods of PECT and EMAT

In this paper, a hybrid nondestructive testing (NDT) method combined with the pulsed eddy current testing (PECT) method and the electromagnetic acoustic transducer (EMAT) method has been proposed and validated through numerical simulations and experiments. First, a numerical code is developed for the simulation of hybrid EMAT/PECT signals. Second, based on the numerical simulation, the influences of the eddy current induced by the excitation coil and the eddy current due to the velocity effect of the ultrasonic wave are compared and analyzed. Third, several signal separation and extraction methods are proposed on the basis of the spectral analysis and filtering strategies. Finally, hybrid EMAT/PECT experiments are conducted. Based on the numerical and experimental results, the proposed hybrid PECT/EMAT NDT method is demonstrated both high detectability and high efficiency.