STP674: A Model for Correlating Damage and Ultrasonic Attenuation in Composites

    Hayford, DT
    Graduate student and professor, Virginia Polytechnic Institute and State UniversityBattelle's Columbus Laboratories, BlacksburgColumbus, Va.Ohio

    Henneke, EG
    Graduate student and professor, Virginia Polytechnic Institute and State UniversityBattelle's Columbus Laboratories, BlacksburgColumbus, Va.Ohio

    Pages: 17    Published: Jun 1979


    Abstract

    Ultrasonic attenuation data measured by the pulse-echo technique have been obtained versus load for two different graphite-epoxy laminates, [0, ±45, 90]s and [0, 90, ±45]s, and are presented here. The attenuation-load data display distinct changes at load values associated with the initiation of transverse cracks in the weakest plies and with the knee in the bilinear stress-strain curve. It was the objective of the work presented here to determine if a simplified diffraction model could be used to account for the attenuation changes. The basis of the diffraction model is that transverse cracks or delaminations, or both, initiating and progressing in the specimen under the area covered by the ultrasonic transducer would serve to cause diffraction of the ultrasonic beam and thereby appropriate changes in the measured attenuation. Trends in the numerical results obtained from this model correlate with the experimental observations indicating in a preliminary fashion that the model might be an appropriate one for describing the damage-attenuation interaction.

    Keywords:

    composite materials, ultrasonic attenuation, diffraction, damage, composite laminates, graphite-epoxy, nondestructive tests


    Paper ID: STP36910S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP36910S


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