Scattering of longitudinal waves by a cylindrical cavity in an attenuating solid

Abstract

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.

Wave scattering from cylindrical fluid inclusions in an elastic medium and determination of effective medium properties

“…Additionally, this value was chosen to compare to the results of Kim et al [17]. The results for the numerical model are shown in Fig.…”

“…Ice itself is highly attenuating to sound and depends upon frequency. As previously stated, others have included the effects of attenuation in their scattering experiment [5,17] by making the wavenumber k a complex quantity.…”

“…The boundary conditions for a cylindrical fluid inclusion in a surrounding elastic matrix are fairly straightforward and have been presented by others [5,17,33]. Since the scattering problem in this thesis deals with a fluid inclusion, only three scattering coefficients are solved for.…”

“…He also derived the scattering equations for a fluid-filled cylindrical bore. Kim et al [17] dealt with scattering from a cylindrical cavity in an elastic medium by taking into account attenuation in the medium. The authors determined the angular distribution of the scattered field and calculated the time domain impulse responses for the scattered displacement field.…”

Ultrasonic Scattered Field Distribution of One and Two Cylindrical Solids with Phased Array Technique

“…Assuming mode conversion in a solid, both scattered longitudinal waves and scattered shear waves were generated simultaneously [16]. Acoustic wave attenuation in the medium was taken into consideration and applied to the scattered field for a cylindrical cavity in an elastic medium [17,18]. Attenuation was found to be universal, depending on the components and interface of the medium [19,20], and the scattering displacement field was recalculated based on the time-domain impulse responses under this condition.…”