Experimental and numerical study of adhesively bonded glass fibre-reinforced polymer - to-steel double-shear lap splices

This study investigates, experimentally and using finite element analysis, the adhesive bond between glass fibre-reinforced polymer (GFRP) and steel. Seventeen double-shear lap-splice were fabricated and tested in tension. The results show that the methacrylate adhesive used had higher bond strengths than the epoxy adhesive. A finite element model for selected test specimens was developed to analyze the stress within the adhesive. The model was verified by comparison with strain data from the shear lap-splice tests. The model was used to determine the maximum principal stress in the epoxy adhesive and the maximum shear strain in the methacrylate adhesive at failure, and thus quantify the characteristic strength of these adhesives. It was shown that the ductility of the methacrylate adhesive allowed it to yield at locations of stress concentrations, providing higher splice capacity, despite having a lower nominal shear strength as compared with the epoxy adhesive.