Influence of Moisture Absorption and Elevated Temperature on the Dynamic Behavior of Resin Matrix Composites: Preliminary Results

The objective of this research is to experimentally determine the effects of moisture absorption and elevated temperature on the dynamic flexural behavior of resin matrix composite beams. Trend information obtained under two limiting environmental conditions—dry at room temperature [25°C, 77°F] and fully moisture-saturated at 93°C (200°F)—is presented for graphite/epoxy beams of three distinct layups. The data have been obtained by transient excitation of the fundamental vibration mode of cantilever specimens. The results indicate that stiffness is reversibly altered in matrix-controlled modes of deformation and that damping characteristics are altered substantially in both fiber and matrix-controlled modes due to environmental conditioning.