Damage Tolerance and Durability of Fiber-Metal Laminates for Aircraft Structures

2008PDFPresentationsAircraftLaminatesFiber reinforced materialsUnited StatesYang, Jenn-MingUniversity of California, Los AngelesJoint Advanced Materials & Structures Center of ExcellenceUnited States. Federal Aviation AdministrationUS Transportation CollectionFiber-reinforced metal laminates (FML) are hybrid composites consisting of alternating thin layers of metal sheets and fiber-reinforced resin prepreg. The most commonly used metal for FML is aluminum, and the fibers can be Kevar or glass. The FML with glass fiber (tradename GLARE) has been selected for applications in aircraft structures such as the crown panels and leading edges for A380 as shown in Figure 1. These laminates possess excellent properties of both metal and fibrous composite materials. This combination results in a new family of hybrid laminates with an ability to impede and arrest crack growth caused by cyclic loading, with excellent impact and damage tolerance characteristics and a low density. Also, the corrosion resistance is excellent because the prepreg layers are able to act as moisture barriers between the various inner aluminum layers, whereas the metal layers protect the fiber/epoxy layers from picking up moisture. As a result, GLARE laminates offer the aircraft structural designer a damage-tolerant, light-weight, cost-effective solution for many applications. GLARE laminates seem poised for a much larger future in the primary structure of pressurized transport fuselages.The research and development activities to date have covered a variety of important aspects pertaining to mechanical properties of GLARE. However, there are still limited and insufficient information available about mechanical behavior of GLARE in published literature, especially for the cross-ply configuration of GLARE (GLARE 3, GLARE-4 and GLARE-5), and some areas still remains to be further verified by more detailed testing. Also, the damage tolerance and durability certification methodology of a GLARE laminate in comparison with a certification of aluminum structures needs to be established. The objectives of the proposed work are to investigate the damage tolerance and durability of bi-directionally reinforced GLARE laminates. Such information will be used to support the airworthiness certification of GLARE structures.[Abstract taken from Research Project Summaries, JAMS 4th Annual Technical Review Meeting, page 32. Available at http://depts.washington.edu/amtas/events/jams_08/presentations.html]90