Abstract
A resonant phenomenon of the circumferential (C-) Lamb wave generated by eight transducer elements located evenly on the circumference was shown. The eight transducer elements on a pipe surface are none other than the sensor system for transduction of axial guided waves. Because the resonant condition of the phenomenon depends on the wall thickness, we proposed a novel method for estimating the wall thickness. In this paper, the principle, theoretical background and experimental verifications were shown. The experimental investigations using several modes of the C-Lamb waves were carried out. The estimations of the wall thickness coincided well with the theoretical predictions.
