Application of Diffraction Corrections to the Absolute Measurement of Scattering Amplitudes

摘要

Ultrasonic scattering measurements are influenced both by the measurement geometry and the properties of the flaw. This paper discusses a set of correction factors which account for the measurement geometry effects and allow the scattering properties of the flaw to be directly related to the measured data. As shown in the inset of Fig. 1, theories for ultrasonic scattering often assume plane wave illumination and predict the scattering amplitude, A, which defines the far field radiation that would be observed in an unbounded elastic medium. This scattering amplitude is a function of frequency and the angles and polarizations of the incident and scattered fields. The diffraction corrections are designed to allow results of measurements in complex geometries to be related to these unbounded medium scattering amplitudes.