Low-speed bending impact behaviour of adhesively bonded dissimilar single-lap joints

This study investigates the low-speed bending impact behaviour of adhesively bonded dissimilar single-lap joints and the effects of both strength and plastic deformation capability of adherend material on adhesive failure. Dissimilar adhesive single-lap joint specimens, such as Al 2024-T3 (top adherend)-Al 5754-0 (bottom) and Al 5754-0 (top)-Al 2024-T3 (bottom), were tested at two impact energy levels (3 and 11 J) for two overlap lengths (25 and 40 mm). The progressive failure analysis of the adhesive layer was also conducted by the non-linear explicit finite element method. The adhesive layer was modelled with a 3D cohesive layer along with the upper and lower adhesive interfaces and a non-linear continuum adhesive region between two cohesive layers. The continuum adhesive region had elasto-plastic adhesive properties whilst the cohesive layers obeyed 3D cohesive rules. The experimental and predicted contact force-time, contact force-displacement diagrams, axial separation lengths of the failed adhesive region, permanent deflection of the bonded region, fracture surfaces were in good agreement. The strength and plastic deformation capability of adherend materials and impact energy levels affected the progressive adhesive failure behaviour. The proposed finite element model was successful reasonably in predicting the initiation and propagation of the adhesive failure.