Chemical kinetic model of interfacial degradation of adhesive joints

Mechanical properties of adhesive joints are degraded in the presence of water. The progressive decrease in strength has been attributed to propagation of interfacial crack. Water diffusion and stress distribution within the adhesive joint as a function of time has been modeled using finite elements in this study. The stress history at the interface displayed spatially invariant characteristics similar to that of interfacial water concentration variation as a function of diffusion. The water-stress history along the interface can be modeled as a function dependent principally on water concentration without dependence on position. On this basis, a chemical kinetic model is proposed to explain the joint strength degradation data reported in literature.