Francesco Ascione

Failure Criteria for FRP Adhesive Lap Joints: A Comparative Analysis

In this paper the debonding of adhesive lap joints between FRP adherents is analyzed with regard to the influence of the chosen interface failure criterion. In particular, the results obtained by using the well-known criteria of Hutchinson and Suo, Xu and Needleman, and Camacho and Ortiz, are compared. Due to the mathematical formulation of such cohesive interface models, the examined mechanical problem is non linear, although the adherents are supposed to be linear elastic up to failure. Furthermore, shear deformability of the adherents is taken into account. The numerical results of a finite element analysis are presented and discussed. Suggestions for the design of adhesive lap joints are also given.

Axial/Bending Coupled Analysis for FRP Adhesive Lap Joints

In this paper a finite element analysis of the behavior of adhesive joints between FRP (fiber-reinforced polymers) adherents is presented. In particular, double-lap joints, in the case of both normal and shear/flexure stresses, are considered. The problem is nonlinear due to the mathematical formulation of the cohesive laws introduced to model the interfacial interactions. On the contrary, the adherents are supposed to be linear elastic up to failure. The common approach of analyzing shear/flexure behavior separately from extensional behavior, as well as disregarding the mutual effects between the normal and tangential stresses acting at the joint interfaces, has been updated. The paper takes into account the coupling effects between shear/flexure and extensional equilibrium problems. As highlighted in literature, only a coupled analysis can be considered correct when the mechanical characteristics of the adherents are quite different, as usually occurs in practice. Furthermore it also has been assumed that the adherents are shear deformable. The numerical results obtained by such an approach are presented, discussed and compared with others available in literature.