SCATTERING OF LONGITUDINAL-WAVES BY A CYLINDRICAL CAVITY IN AN ATTENUATING SOLID

This paper deals with the scattering of plane longitudinal elastic waves incident normally on a cylindrical cavity in a solid medium with attenuation. The scattered fields are found by introducing complex wave numbers whose imaginary parts are given by the attenuation coefficients of the solid medium. The impulse responses of the scattered displacement field at various positions of the receivers are obtained. It is seen that the impulse responses in an attenuating medium are different from those in a medium with negligible attenuation. To verify the accuracy of predicted impulse responses, experiments have been carried out for aluminum and acryl specimens as a typical nonattenuating medium and an attenuating one, respectively. Experimental results are in good agreement with predicted ones. Using the results of this study, once the input waveform and the attenuation coefficients are known, it is possible to predict the waveforms of longitudinal waves scattered by a cylindrical cavity. It is also found that the impulse responses of scattered waves can be applicable to finding the size and the position of the cylindrical cavity in a solid.