Analysis of Acousto-Ultrasonic Characteristics for Contact-Type Transducers Coupled to an Orthotropic Composite Plate

Acousto-ultrasonic input-output characteristics for contact-type transmitting and receiving transducers coupled to a thin orthotropic composite plate are analyzed in this paper. By introducing the point source/point receiver assumption, the governing equations of the problem, which relates to wave generation, wave propagation and wave reception, are first established. Using the multiple integral transform method, contour integration technique and some complex function theories, a spectral analysis method which is completely different from the present wave path tracing method for this problem is developed. From this approach, the spectral response of the normal contact force between the receiving transducer and the plate, due to an arbitrary input interrogation pulse excited by the transmitting transducer, is expressed in explicit form. Based on this, some physical properties involved with the output of the receiver are examined in the frequency domain. Finally, combining the fast Fourier transform (FFT) technique, some time domain numerical results are calculated to show the input-output characteristics of the AU system considered.