Acoustic material signature for a cracked surface

Abstract

A model of the acoustic material signature for a line-focus scanning acoustic microscope, based upon a boundary-element calculation and an electromechanical reciprocity identity, is described. The electromechanical reciprocity identity is used to relate the voltage at the terminals of the transducer of the microscope to the acoustic wavefields at the interface between the specimen and the coupling fluid. The wavefields scattered from the surface of the specimen, including the leaky Rayleigh wave, are calculated. Both a defect-free elastic surface and one broken by a crack are considered. Knowing the wavefields incident and scattered from the specimen, the acoustic signature is calculated using the reciprocity relation. Further, the results for a defect-free surface are compared with an experimental measurement. >