Abstract—Strengthening by bonding composite patch is an easy method and showed its reliability especially on aluminium alloys. But the glue that enables secure the reinforcement substrate is still the weak point of the reinforcement of composite materials. Indeed, the majority of the deficiencies found in the structures and repaired are due to the glue. These failures are mainly due to stress transfer from the substrate to the composite patch. Zone transfer effort leads indeed to a peak shear stress near the free edge of the patch. The calculation of stress distributions is therefore important to provide a suitable strengthening solution. The fatigue study allows us to highlight the influence of the distribution patch on the extended life of pre-cracked mechanical structures. Moreover, for a full analysis we must study the influence of various considered parameters set during repair by bonding composite patch.