J0420207 Efficient generations and detections of the Lamb waves by a pair of Line-focus type air-coupled transducers

Abstract

Efficient transduction of a circumferential (C-) Lamb waves by a pair of noncontact air-coupled ultrasonic transducers (NAUT) was presented. A line focus type (LFT-) of the NAUT was employed for the efficient transduction of the C-Lamb wave, which was designed so as to take an almost same angle of the incident longitudinal beam on the circular pipe surface. Outstanding characteristics of the LFT-NAUT for the C-Lamb wave transduction were theoretically and experimentally shown in comparison to those of the conventional plane type (CPT-) NAUT.