Optimum thickness of joints made of GFRP pultruded adherends and polyurethane adhesive

This paper presents results of experimental and numerical investigations on double-lap joints composed of pultruded GFRP profiles and polyurethane adhesive subjected to quasi-static axial tensile loading. The objective was to investigate the effect of the joint geometry on the structural response of adhesively-bonded joints and, in particular, to seek for experimental evidence of an optimum adhesive layer thickness. The influence of the adhesive thickness (0.3-10.0. mm) and the overlap length (50-200. mm) on the joint behavior was investigated. It was found that there is an optimum adhesive thickness of approximately 1.0. mm and joint strength consistently increases with the overlap length. © 2009 Elsevier Ltd.