A new ultrasonic technique for the interfacial characterization of adhesive joints

A focused, oblique incidence ultrasonic measurement system for the interfacial characterization of adhesive bonds is presented. The angular spectrum approach is used to model the response of the measurement system. The predictions of the model are compared with measurements on two extreme cases of adhesive bonds, using a specially developed transducer. It is shown that an interference pattern is obtained in the frequency spectrum, depending on the relative distance of the transmitter-receiver pair with respect to the specimen. Results from the two extreme cases suggest that the interference phenomenon increases the sensitivity of ultrasonic waves to the interfacial properties