Formulation of cohesive failure load for bonded single lap joints using coupled elasto-plastic stress diffusion model

A constitutive elasto-plastic model with moisture diffusion is developed for determining the cohesive strength of adhesively bonded single lap joints with identical adherend materials and thicknesses under tensile-shear loading. Static maximum shear stress failure theory is used for determining the cohesive strength. A Fickian diffusion model is utilized in order to formulate a time- and location dependent shear modulus for the adhesive. The study shows that increased plastic strain due to moisture diffusion would increase the cohesive failure load of adhesively bonded single lap joints.