High strength and low weight remain the captivating combination that drives the composite materials into new grounds, but other properties are equally important. Composite materials propose good vibrational damping and low coefficient of thermal expansion (CTE) and many others characteristics that can be engineered for specialized applications. Composites are resistant to fatigue and provide design/fabrication flexibility that can significantly decrease the number of parts needed for specific applications — which translates into a finished product that requires less raw material, fewer joints and fasteners and shorter assembly time. Composites also have proven resistance to temperature extremes, corrosion and wear, especially in industrial settings, where these properties do much to reduce product lifecycle costs. These characteristics have propelled composites into wide use. The push for fuel economy in the face of rising oil prices, for example, has made light weighting a priority in almost every mode of mechanical transportation, from bicycles to large commercial aircraft.
Composites have been used in aerospace in applications such as engine blades, brackets, interiors, nacelles, propellers/rotors, wide body wings and single aisle wings. Key aspects such as light weight, high strength, high stiffness and good fatigue resistance are showing a positive impact on the usage of these composites in the aerospace and defense industry. Composites in the aerospace include wide range of industrial, commercial and military applications. Boeing estimates that over the next 20 years, there is a need for 38,050 airplanes. These composites are required to provide high performance for aircraft engines, their components and other related parts. The volumes of fiber reinforced polymer composites often find their sophisticated applications in this industry though their applications in aircraft are relatively a small percentage of the total use.
Composites were first used by the military aircrafts before they were applied to the commercial planes. The initial applications in military aircrafts were in radomes, secondary structures and internal components. The use of glass composites were lower compared to that of metals. Presently, composites are widely used as a result of gradual direct substitution of metal components followed by development of integrated composite deigns. Carbon-fiber reinforced polymer and glass-fiber reinforced are widely used extensively in wings, fuselage sections, tail surfaces and doors. Airbus 320 uses a range of components made from composites including the fin and tail plane which allowed a weight saving of 800kg over its equivalent in aluminum alloy. Composite materials comprise more than 20% of the A380’s airframe.