Optimum thickness of joints made of GFPR 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.