FABRICATION OF WOVEN CARBON FIBRE POLYCARBONATE REPAIR PATCHES/

In-held repair of composite aircraft is often performed in difficult c onditions and hence needs to be as simple as possible. Current repair techniques generally involve the application of composite patches base d on thermosetting epoxy resin via either wet lay-up, prepreg stacking over a film adhesive, or bonding precured patches. These methods of r epair are very effective, but a complex cure cycle under controlled co nditions is required and the use of epoxy resin means that storage mus t be taken into consideration. Composites patches based on thermoplast ic resins overcome both of these problems; they do not require curing, and have no special storage needs. Thermoplastics can also be thermof ormed and can hence be produced in sheet form and formed to the correc t shape in situ during adhesive bonding to the surface to be patched, using vacuum and heat. With its low thermoforming temperature and good mechanical properties, polycarbonate is a good candidate for use as a thermoplastic matrix, with woven carbon fibre fabric as the reinforce ment to produce patch laminates. The present paper describes the use o f solution impregnation together with him stacking to produce patches of acceptable quality and how these patches were formed without any wr inkling using double diaphragm forming. Copyright (C) 1996 Elsevier Sc ience Limited