Chemical kinetic model of interfacial degradation of adhesive joints

Mechanical properties of adhesive joints are degraded in the presence of wa ter. The progressive decrease in strength has been attributed to propagatio n of interfacial crack. Water diffusion and stress distribution within adhe sive joint as a function of time has been modeled using finite element in t his study, The stress history at the interface displayed spatially invarian t characteristics similar to that of interfacial water concentration variat ion as a function of diffusion. The water-stress history along the interfac e 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 litera ture.