International Science and Technology Journal

The use of adhesive bonds presents numerous advantages such as a more homogeneous stress distribution, higher stiffness, high fatigue strength, low weight, the possibility to join dissimilar materials or corrosion prevention For these reasons, structural adhesive bonding has been increasingly used in industries including construction, automotive and sports The performance of composite joints for aeronautics applications has not been fully achieved in this work. Furthermore, their presence cannot be easily detected by conventional non-destructive tests (NDT). Water diffusion into composite adhesive joints was experimentally studied by means of gravimetric measurements in bond specimens. The main parameters controlling the diffusion in the bond components were obtained from water uptake experiments carried out in bulk specimens of fiber-reinforced composite and epoxy adhesive. The diffusion of water in bonds is a complex mechanism due to the heterogeneous microstructure of the composite and its interface with the adhesive. This process was simulated through micro scale models which represent the microstructure of the composite and of the adhesive joint Structural adhesive joints are adequate for joining aluminum with nearly constant .In terms of fatigue strength,for105 cycles, a decrease about 25%and 39% occurred in specimens immersed during. Water concentration increases in the adhesive while that oil concentration decreases and stabilizes (0.5%), the tests have shown that the water spreads more into epoxy that into polyurethane