A Probabilistic Method to Predict the Strength of Adhesively Bonded Joints of Gfrp

Experimental and numerical investigations were carried out on adhesively bonded full-scale double lap joints from pultruded GFRP profiles with relatively thick adhesive layers, needed in infrastructure applications to compensate for tolerances. The influence of different geometrical parameters on the joint strength was investigated, namely the thickness of the adhesive layer (from 5 to 35 mm), the fillet radius (from 2 to 10 mm) and the overlap length (from 100 to 300 mm). A statistically based method for the strength prediction of adhesively bonded double lap joints from pultruded GFRP adherends subjected to quasi-static tensile loading is therefore suggested. The prediction method is based on the experimentally determined material strength and its statistical distribution. It takes into consideration the scale sensitivity of the strength, modelled using Weibull statistics. The developed method considers not only the magnitude of the stress fields, but also the volume over which stress peaks act. The method provided reasonable results for brittle joint failure, while it cannot be used to predict joint strength of quasi-brittle or pseudo-ductile joint failures showing minor statistical scale sensitivity.