A new transducer holder mechanism for efficient generation and reception of Lamb modes in large plates

A new transducer holder mechanism is described in this paper. This mechanism is very useful for inspecting large plates by Lamb waves. The new mechanism allows water coupling between the ultrasonic transducers and the specimen but requires neither a water jet nor a big water tank for immersing the specimen into it. This mechanism allows the transducers to rotate for changing the angle of strike of the incident beam and avoids undesirable multiply-reflected signals between the transducer and the specimen. An aluminum plate with fabricated internal defects has been inspected by the Lamb wave technique using the new transducer holder mechanism. The experimental results clearly show the superiority of the new design when compared with the conventional designs available today. (C) 1998 Acoustical Society of America. [S0001-4966(98)04609-8]