Detection of Moisture in Graphite/Epoxy Laminates by X-Ray Diffraction

Abstract

The objective of this study was to determine if X-ray diffraction could be utilized to detect moisture non-destructively in graphite/epoxy laminates. CuKα1 X-rays were diffracted from 333 + 511 planes of Al particles em bedded between the first and second plies of [0 ± 60] s lamiantes during layup. Diffracted peak positions were quite sensitive to environmental moisture, decreasing 0.624 ° ± .015 °2θ on going from a completely dry to a completely wet state at 50°C. The changes were reversible. Correlations be tween in-plane, residual particle strains and both average and local moisture content of the laminate were obtained. Annealing effects were investigated.