Quantitative assessment of damage growth in graphite epoxy laminates by acousto-ultrasonic measurements

The acoustoultrasonic NDT method proposed by Vary (1976, 1978) for composite laminate damage growth quantitative assessment can both respond to the development of damage states and furnish quantitative parameters that monitor this damage development. Attention is presently given to data obtained for the case of quasi-static loading and fatigue testing of graphite-epoxy laminates. The shape parameters of the power spectral density for the ultrasonic signals correlate well with such other indications of damage development as stiffness degradation.