Composite Materials in Aviation
The development of composite materials is considered to be one of the most important advances in aviation design since aluminum was introduced in the 1920s. Development of various composite materials has had a very positive impact on the performance, shape, reliability, weight, cost and composition of modern aircraft.
Composites are a combination of two or more significantly different inorganic or organic components. Although the components together form a composite material they each maintain their original form and do not blend together. In a composite material, one component will serve as a “matrix”, being the component that holds everything together, with the other component or components serving as reinforcement. An epoxy resin matrix with glass fiber reinforcing is one of the more commonly known composite materials, but continuing research is resulting in the production of various other composite materials which are proving beneficial in aviation design as well as in other industries.
The new Boeing 787 Dreamliner, which is scheduled to enter commercial service in November 2008, has made extensive use of composite materials, resulting in a lighter weight airplane which is expected to have a number of benefits including greater fuel efficiency. This twin-engine, wide-body jet airliner is constructed from 50% composite with aluminum, titanium and steel making up 45% and a variety of components making up the balance of 5%. The composite material most used in the Boeing 787 Dreamliner’s construction is carbon fiber reinforced plastic.
Composite materials in military aircraft have largely replaced conventional materials such as aluminum. Composite materials have greater strength and stiffness, as well as a lower density than aluminum. This enables a smaller, lighter structure to carry the same load. Composite materials have the added advantage of being relatively unaffected by flaws. Fatigue testing of structures made from composite materials has shown that they have a high resistance to cracking and fractures seldom propagate. Composite materials are not subject to corrosion in the way that metallic structures are. However, if a metal is being used as a component of a composite material, corrosion may occur.
With the use of composite materials, an aircraft designer can tailor the strength and stiffness of structures. The composite material can be layered with one layer running in one direction and the next layer at an angle, with a number of different layers being applied, as necessary, to achieve the desired result. This allows designers to use the principles of aerodynamics to the optimum level.
Computer-aided design (CAD) has been an invaluable aid in the development of composite structures and their use in aircraft construction. New staff skills, testing and quality control techniques have had to be developed to ensure that composite structures used in aircraft construction are of the highest quality. This includes quality control using ultrasonic and x-ray examination of composite parts.
With air travel becoming increasingly part of daily life in our global village, we can expect to have more airplanes in our skies than ever before. Through ongoing technological advances, such as the development of composite materials, we can be sure that everything possible is being done to ensure safety and efficiency in the production of aircraft.