The influence of adhesion defects on the collapse of FRP adhesive joints

In this paper, the debonding of adhesive double-lap joints between FRP adherents is analyzed with regard to the influence of an initial adhesion defect on their ultimate capacity. The analysis is carried out by using the interface cohesive models proposed by Hutchinson & Suo, Xu & Needleman, and Camacho & Ortiz.The mechanical model utilized takes into account the shear deformability of the adherents and the coupling effects between axial and shear/flexure behavior. The model is non-linear due to the hypothesis of a cohesive interface adopted for the adhesive layer. The numerical results, obtained via finite element analysis, have highlighted that the model of Hutchinson and Suo is less conservative than the other two and that joints subjected to axial forces are less sensitive to initial adhesion defects than ones loaded by both axial and shear forces.