High Strain Rate Impact Response of Graphite/Epoxy Composites with Polycarbonate Facing

Abstract

Impact damage is of critical concern in structures using laminated fiber reinforced composites. Thermoplastic polycarbonate offers high impact resistance and finds application in windshields, canopies of aircraft and building structures. In several situations the impact threat results in high strain rate (HSR) loading of the structure. In the current study, two constituent advanced materials have been studied as a hybrid construction for their survivability to HSR impact. A laminated graphite/epoxy composite with polycarbonate facing has been investigated. A compression Split Hopkinson Pressure Bar (SHPB) with 0.7500 (19.05 mm) incident and transmission bars is used to study the HSR impact response on eight, sixteen, thirty-two and forty-eight layers (8, 16, 32 and 48 - of 1.6, 3.0, 6.4 and 9.4 mm thickness respectively) of graphite/epoxy cross-ply [0/90]s laminates bonded to polycarbonate facing. Tests were conducted both in the plane of the laminate, and through the thickness. The HSR impact tests were performed by considering three strain rates of 109, 327 and 544 s-1. The results of the investigation showed that a significant portion of the incident energy is absorbed by the polycarbonate and results in lesser extent of impact damage to the graphite/epoxy laminate. The use of polycarbonate is especially useful for thin laminates (8-16-plies).