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 mec hanism is very useful for inspecting large plates by Lamb waves. The n ew 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 transdu cers to rotate for changing the angle of strike of the incident beam a nd avoids undesirable multiply-reflected signals between the transduce r and the specimen. An aluminum plate with fabricated internal defects has been inspected by the Lamb wave technique using the new transduce r holder mechanism. The experimental results clearly show the superior ity of the new design when compared with the conventional designs avai lable today. (C) 1998 Acoustical Society of America. [S0001-4966(98)04 609-8]