Scattering-induced attenuation of an ultrasonic beam in austenitic steel

Abstract

The scattering-induced attenuation coefficient of a beam of longitudinal waves propagating through an austenitic steel plate is measured as a function of the texture angle. The experimental data were obtained by mapping the incident and the transmitted ultrasonic field, and by evaluating the energy loss experienced by each plane wave component of the beam. Contrary to the behavior of data obtained by means of conventional techniques, that of the data reported in this work agrees qualitatively with the theoretical predictions. The reasons for the disagreement between theory and data obtained by means of conventional techniques are also discussed.

Longitudinal wave attenuation measurements by means of a diffraction-insensitive large-aperture PVDF hydrophone

“…Scattering at the boundaries between the sample and its surrounding medium is another problem, because these energy losses are corrected by means of reflection and transmission coefficients based on the approximation that the interrogating finite ultrasound beam is a plane wave. In previous studies, the application of conventional measurement techniques in conjunction with the aforementioned corrections failed to estimate the intrinsic attenuation in anisotropic structures correctly [11][12][13] .…”

“…In the so-called conventional energy method (CEM), the receiving transducer is replaced by a needletype hydrophone and the ultrasound field, both with and without the sample, is mapped over a large area to intercept the entire field. The approach works well both in isotropic and anisotropic structures [9,13] , but the data acquisition is cumbersome and dedicated software tools are needed to process them. Firstly, the recorded fields have to be represented in terms of plane waves requiring the application of a two-dimensional fast Fourier transform (FFT) algorithm to obtain the spectra in the Fourier space domain.…”