STRENGTH AND DURABILITY OF GRAPHITE/EPOXY COMPOSITES UNDER HYGROTHERMAL CONDITIONS

摘要

As composites are being increasingly used in marine environments, the necessity to understand the effects of hygrothermal exposure on the strength and durability of composite materials has become a critical issue. While much work has been done to evaluate the moisture absorption behavior of composite materials, relatively little work has been done to explore the effects of combined moisture and elevated temperature conditions on the durability of composite materials. Weitsman et al.(1,2) have shown that moisture can either enhance or reduce the fatigue life and fatigue damage of polymer composite specimens depending on test conditions. In the current study, the effect of moisture and temperature, combined and individually, on fatigue damage and durability of cross-ply graphite/epoxy composite specimens will be evaluated. Results from fatigue testing in ambient and elevated temperature water will be presented as well as corresponding dry fatigue testing results. Fatigue damage in each of the cases will be assessed and compared and the results will be used to gain an understanding of how such conditions may be incorporated in fatigue life prediction.