Effect of humidity on the mechanical properties of adhesively bonded aluminium joints

摘要

The presented work focuses on the effects of water degradation on the long-term behaviour of adhesive joints. The objective of this study is to measure the evolution of various mechanical properties such as tensile stress and fracture toughness as a function of humidity for two distinct adhesives, using bulk adhesive and double cantilever beam specimens in unaged and aged conditions in order to understand the influence of humidity on the adhesive properties. A mathematical equation that allows the prediction of each property degradation as a function of water is proposed and validated, which takes into account various parameters such as the diffusion coefficient, resulting in a general equation for mechanical property degradation prediction of potentially any adhesive. It was also found that the distinct adhesive properties such as strength, stiffness and fracture toughness all decreased due to water degradation with the exception of the strain that increased, concluding that water reduces the joint strength and lifespan of the studied adhesives, although in different ways.