An interface constitutive model which accounts for both reversible elastic, as well as irreversible inelastic separation-sliding deformations at the interface prior to failure has been developed and implemented in a finite-element computer program. A set of experiments has been conducted to determine the constitutive parameters in the interface model for adhesively-bonded components made from an aluminum alloy and a ductile polymeric adhesive. The constitutive model and the computational capability are shown to reasonably well predict the macroscopic deformed geometries and the load–displacement curves in: (a) T-peel experiments; (b) four-point bend experiments on bonded bi-layer edge-notch specimens; (c) lap-shear experiments.