Ultrasonic method for determining attenuation coefficients in plate-shaped materials

Abstract

Measurements of elastic wave transmission through a fluid-loaded plate are usually employed for studying acoustic properties of materials. In this work an experimental method has been introduced for investigating the attenuation effect on plate transmittivity of ultrasonic waves at normal incidence, and for determining the attenuation coefficient as a function of frequency in plate-shaped materials. The method, based on the well-known transmission selective properties of layers, has been developed by resorting to swept frequency techniques analogous to those usually employed for network analysis. A simplified theoretical formalism is also developed, whose predictions are compared with the experimental results, showing good agreement.