Overlay patch repair of scratch damage in carbon fiber/epoxy laminated composites

In this paper we present a numerical and experimental study on the overlay repair of scratch damage in carbon-fiber/epoxy composite laminates. The scratch damage severs several load bearing plies and results in a lack of symmetry in an originally symmetric multidirectional laminate. The ply-by-ply p-version finite element model is used to investigate the effects of the repair patch variables on the overall efficiency of the repair procedure and the lamina level stress states. The results show that interlaminar crack propagation in the direction parallel to the surface can be retarded with careful selection of repair parameters.