Effects of a Flaw on Acoustic Wave Propagation by an EMAT System

Application of electromagnetic acoustic transducers (EMATs) to nondestructive testing has a potential advantage over conventional ultrasonic testing, because EMATs require no contact between a transducer and a test specimen. So far there have been various studies dealing with theoretical basic analysis for understanding physical phenomena of EMATs[1], numerical approaches for design optimization of EMAT systems [2], and their industrial applications [3]. Though flaw detection by using ultrasonic waves generated by either conventional transducers or EMATs usually utilizes only echoes from flaws as detected information, noncontactness of EMATs, leading to easy theoretical formulation of wave generation or detection, can make EMAT testing a promising method of flaw identification through thorough inverse analysis of detected wave signals