Residual thickness measurement method of corroded steel plate using ultrasonic SH array transducer

A residual thickness measurement method for corroded steel plates using ultrasonic waves is presented. In this method, a shear-horizontal (SH) plate wave is transmitted in a steel plate by an SH array transducer, and the echo received by the reflection occurring owing to the cut-off phenomena of the plate wave is utilized. Furthermore, the configuration of the SH array transducer suitable for the method is investigated. With ditching grooves on the surface of a protection plate of the transducer, the sensitivity and variation among array elements can be improved. Experiments are performed to verify the new method using the SH array transducer with grooves. The residual thickness obtained by the new method is consistent with the actual size.