Abstract:
The use of adhesive bonding for airframes and other engineering structures offers significant advantages over the commonly used mechanical fasteners. However, not all adhesives are able to withstand the environmental extremes encountered by a structure over its service lifetime. Therefore, the selection of an adhesive for bonding these structures must include an evaluation of its performance under adverse environments, primarily moisture. Studies of moisture absorption by several adhesives reveal that the adhesives gain the bulk of their water weight within 1 2 days. The effects of this moisture ingress on adhesively bonded joints were evaluated via stress relaxation and fracture analysis. Stress-relaxation results show that some adhesives can retain about half their dry strengths at equilibrium moisture strain, whereas the fracture toughness analysis suggests that ductility decreases with increased duration of exposure. "
