Development of the Transient Simulated Laminate (TSL) Methodology for Moisture Ingression Studies Using Unsymmetric Laminates

This article presents a non-destructive method to examine a graphite/epoxy composite under hygrothermal conditions. By applying the transient simulated laminate (TSL) technique, a methodology was developed to evaluate the effects of water ingression on the laminates based on the changes in curvature of laminates. The absorption-desorption-resorption cycle of laminates was evaluated in situ by measuring both moisture content and curvatures of unsymmetric laminates [02/902] T . Curvatures of laminates decreased as more water diffused into the laminate until a high moisture content was reached. During hygrothermal cycling, the curvature of a laminate was affected not only by absorption temperature, but also desorption temperatures. This work demonstrated that curvature measurements in addition to moisture measurements could be an effective tool for relating physical state changes to hygrothermal cycling history in composite laminates.

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