ABSTRACT
Adhesive-bonded joints use an intermediate layer that adheres to the faying surfaces of the parts to be joined. Initially, applications of adhesive-bonded joints were limited to the solution of specific problems, such as the reinforcement of a basically wooden wing structure by means of adhesive-bonded aluminum alloy spar caps or doubler plates. An adhesive-bonded joint must be considered as a chain consisting of a number of individual links, the weakest of which finally determines the strength of the chain. To understand the complete mechanism of the strength and durability of adhesive-bonded joints and structures it is necessary that each link be analyzed in depth. Because the quality of adhesive-bonded structures is the result of an intricate manufacturing process, tight quality control is of utmost importance. The best operational results for metal-to-metal bonded structures were obtained when chromic acid anodizing had been incorporated in the surface treatment process of the aluminum adherends and phenolic resin-based adhesives were used.
