Integrated Ultrasonic Technique for Characterization of Composite Materials

Abstract

In this paper, an ultrasonic technique, previously developed by the authors for simultaneous wave speed and attenuation measurements [1], is applied to characterize composites. The amplitudes of tone-burst signals generated over a selected frequency range were measured to determine attenuation. For the determination of the wave velocity , a number of frequencies are selected at which a zero crossing of the tone-burst signal coincides with a zero crossing of a continuous reference sine wave. Various configurations of ultrasonic transducers for integrated measurements have also been investigated. A selected configuration of the ultrasonic and electronic system has been applied to characterize the porosity content in 200-ply unidirectional graphite/epoxy composite laminates.