Analysis of acousto-ultrasonic characteristics for contact-type transducers coupled to composite laminated plates

The acousto-ultrasonic (AU) input-output characteristics for contact-type t ransmitting and receiving transducers coupled to composite laminated plates are considered in this paper. Combining a multiple integral transform meth od, an ordinary discrete layer theory for the laminates and some simplifyin g assumptions for the electro-mechanical transduction behaviour of the tran sducers, an analytical solution is developed which can deal with all the wa ve processes involved in the AU measurement system, i.e, wave generation, w ave propagation and wave reception. The spectral response of the normal con tact pressure sensed by the receiving transducer due to an arbitrary input pulse excited by the transmitting transducer is obtained. To validate the n ew analytical-numerical spectral technique in the low-frequency regime, the results are compared with Mindlin plate theory solutions. Based on the ana lytical results, numerical calculations are carried out to investigate the influence of various external parameters such as frequency content of the i nput pulse, transmitter/receiver spacing and transducer aperture on the out put of the measurement system. The results show that the presented analytic al-numerical procedure is an effective tool for understanding the input-out put characteristics of the AU technique for laminated plates. (C) 2001 Else vier Science Ltd. All rights reserved.