REVIEW ON THE DESIGN OF NON-CONTACT ULTRASONIC TRANSDUCERS USED FOR CONTROL OF MATERIALS

Abstract

Established methods for non-destructive ultrasonic testing of materials include the use of ultrasound transducers. The function of these transducers is to produce directly or indirectly piezoelectric effect to generate and detect ultrasonic signals. The best known is the immersion control technique, when the piece is completely immersed in a water bath. But there are some cases when the piece cannot be immersed in the bath due to its large dimensions such as airplane wing, wind turbine blade, airplane fuselage. Also, the tested specimen can be damaged by direct contact with the ultrasonic transducer, for example electrical scheme, porous materials, sandwich composite materials.