Simple and practical solution for characterization of adhesively bonded joints in dissimilar materials

Fiber-reinforced polymer (FRP) composites are increasingly used in structural systems, replacing structural steel and aluminum. It is now well established that adhesive bonding is the most efficient mean of joining composites. Unfortunately, analytical models available in the literature offer design equations mainly applicable to balanced adhesive joints; where the two adherends are identical. In many practical applications, however, FRP composites are used (joined) in conjunction with other materials. This paper presents a simplified model that accurately predicts the behaviour of adhesive joints between different adherends. In this model, exponentially small terms are removed from the analytical solution, greatly simplifying the solution. The resulting design equations provide an accurate method of the design and analyzing of adhesive joints. The model applies to single-lap, single-strap and stiffener-plate joints, where shear and peel stresses are present. Furthermore, the model is easily extended to determine the energy release rate in adhesive joints. Results from the analytical model closely agree with finite element results, which are obtained in a fraction of the time and effort required for a non-linear finite element analysis.