Modelling the tensile fracture behaviour of CFRP scarf repairs

An experimental and numerical study concerning the tensile behaviour of adhesively-bonded carbon–epoxy scarf repairs is presented, using scarf angles ranging from 2° to 45°. A mixed-mode cohesive damage model adequate for ductile adhesives was used to simulate the adhesive layer. The cohesive laws of the adhesive layer, composite interlaminar and composite intralaminar (in the transverse and fibre directions) in pure modes I and II, necessary to simulate numerically the experimental failure paths, were previously characterized using an inverse method. Validation of this methodology was accomplished in terms of repair initial stiffness, maximum load and the corresponding displacement, as well as the failure mode. A good agreement between the numerical predictions and the experiments showed that the proposed methodology can be successfully applied to joints or repairs bonded with ductile adhesives.