Determination of the properties of composite interfaces by an ultrasonic method

Abstract The feasibility of using a recently developed ultrasonic technique to determine certain macroscopic properties of the interface zones of composite laminates is studied. The strong influence of the elastic properties and the thickness of the interface zone on the phase velocity of guided waves is demonstrated by means of a simple model of a single fiber embedded in a layer of the matrix material. The overall dynamic elastic moduli of a unidirectional graphite-epoxy composite laminate are determined through inversion of guided wave dispersion data obtained by the leaky Lamb wave experiment. The thickness and elastic properties of the interlaminar interface zone in a cross-ply graphite-epoxy laminate are also estimated by the same approach.