COMPOSITE SCARF REPAIRS USING VACUUM INFUSION AND BONDLINE VEILS

摘要

A soft-patch scarf repair approach, i.e. in situ vacuum assisted resin infusion of repair patches, is investigated for repairing damaged composite laminates. A polyetherimide (PEI) veil was introduced at the parent-patch interface (i.e. resin-rich region or bondline) in resin infused scarf patches to examine the role of interface toughening mechanisms. The effect of moisture ingress was examined on scarf repairs with and without PEI veils along the parent-patch interface. Scarf repairs produced by a hard-patch approach (i.e. secondary adhesive bonding of a cured patch with a film adhesive) were used for comparison. Tensile failure test results from resin infused scarf joints with/ without PEI veils were compared to that of scarf joints bonded with the film adhesive. Fractography studies were conducted using optical and scanning electron microscopy. The fracture surfaces revealed that the scarf joints did not fracture cohesively in the bondline, but failed in the composite adherend with a mode-II dominant fracture. Moreover, the moisture degradation is observed to be higher in the scarf joints with the bondline veil when compared to the joints without the veil.