Static and cyclic strength properties of brittle adhesives with porosity

This research focuses on a bottom-up adhesive properties characterization and its validation in composite joints. It starts from the characterization of bulk adhesive going through bonded joint specimens and subcomponents. This paper focusses on the levels of the adhesive material itself and of the joint. After an extensive experimental campaign with particular attention to porosity in the adhesive a probabilistic approach is used to identify the most appropriate failure criterion. The strength prediction method considers a statistical size effect in the strength of the material by considering not only the magnitude of the stress distributions, but also the volume over which they act. This approach is subsequently used for the numerical prediction of the strength of joints in simple joints and in spar-cap-shear web subcomponent. The predicted resistance of joints are in agreement with experimental joint tests.