Influence of adverse temperature and moisture conditions on the fracture behaviour of single-strap repairs of carbon-epoxy laminates

The influence of temperature and moisture on the fracture properties of carbon-epoxy bonded joints was studied in this work. Four temperatures and three moisture adverse environments were considered and compared with reference conditions. Fracture characterisation under mode I, mode II and mixed-mode I+II was performed to assess the influence of the adverse conditions on the measured properties. Subsequently, single-strap bonded repairs under three-point bending loading were also analysed under the same environments. Initial stiffness, maximum load and corresponding displacement were the parameters studied. A trapezoidal cohesive mixed-mode I + II zone model was used to predict the mechanical behaviour of the single-strap repairs under the several adverse conditions. The resulting numerical load-displacement curves were compared with the experimental ones.