An investigation of interfacial stresses in adhesively-bonded single lap joints subject to transverse pulse loading

Debonding in adhesively-bonded lap joints is a detrimental failure mode contingent upon the level of stresses develped in the adhesive. In this work, an analytical model is developed to estimate the peel and shear stresses in an isotropic elastic adhesive in a single lap joint subjected to transverse pulse loads. The proposed analytical model is an extension of the mathematical models developed by He and Rao (Journal of Sound and Vibration 152 (3), (1992) 405–416, 417–425) to study the coupled transverse and longitudinal vibrations of a bonded lap joint system. The adhesive, in this work, is modelled as an elastic isotropic material implemented in Abaqus 6.9−1. The interfacial stresses obtained by finite element simulations were used to validate the proposed analytical model. The maximum peel and shear stresses in the adhesive as predicted by the analytical model were found to correlate well with the maximum stresses predicted by the corresponding numerical models. The peel stresses in the adhesive were found to be higher than shear stresses, a result which is consistent with intuition for transversally loaded joints. The analytical model is able to predict the maxium stresses in the edges where debonding initiates due to the highly asymetrical stress distribution as observed in the finite element simulations and experiment. This phenomenon is consistent with observations made by Vaidya et al. (International Journal of Adhesion & Adhesives 26 (2006) 184–198). The stress distribution under uniformily distributed transverse pulse loading was observed to be similarly asymetric.