Mechanical behaviour of bonded joints including viscoelasticity for the adhesive under triangular pulse loading and harmonic loading

Abstract

The constitutive law of the interface is a prime issue when evaluating the strength of adhesively bonded joints. The polymer-based adhesives exhibit loading rate sensitivity and damping properties owing to their viscous nature, especially at high temperatures or under water. This paper aims to establish a shear-lag model to elucidate the mechanical behaviour of adhesively bonded joints under triangular pulse loading and harmonic loading. The extended shear-lag model is focused on improving the previous shear-lag models by including viscoelastic behaviour using the Kelvin model for the adhesive. Analytical expressions of the slip and interfacial shear stress distribution have been respectively presented for pull-push joint and pull-pull joint under triangular pulse loading. Compared with finite element simulation, the predictive model shows an excellent agreement with the FEA results. The damping properties including the storage modulus, loss modulus and loss factor for these two bonded joints subjected to harmonic loading are theoretically derived. Finally, results obtained from the predictive model are presented to illustrate how the bond length, loading rate and loading frequency affect the behaviour of such bonded joints.