The effects of disbonds on the stress intensity factor of aluminium panels repaired using composite materials

Bonded composite patching has been recognized as an efficient and economical method to extend the service life of cracked aluminum components. The stress intensity factor is considerably reduced by the bonded composite repair. In this work, the finite element method is applied to analyse the behavior crack emanating from semi-circular notch root repaired by a boron/epoxy composite patch. The stress intensity factor (SIF) was computed for cracks repaired using a composite patch, taking into account of the disbond. In this case, the increase of patch thickness reduce the negative effects of disbond. The maximal reduction of composite patch of orientation (1) is the order of 56% more important with regard to patch of orientation (2). The minimal SIF in the presence of the disbond is obtained when the crack length is the order of 2ρent. It reaches its value maximal for a crack length equal to 2ρent/5.