Use of Composites in Aviation - Research Paper Example

Use of Composites in Aviation Overview of the study The use of composite materials in aircraft has been marked with a dramatic increase since the 1970s. In the past, the aerospace industry relied on materials such as steel, aluminum, and titanium. The increase of competition rise in fuel costs and environmental lobbying form 1970s onwards has infringed pressure on commercial flying to improve performance. To this end, weight reduction has been the main area of focus. The use of composites has proved a key strategy to achieve reduced weights, in addition to reducing production and, maintenance costs.

The use of composites then has increased both in the military, where the objective is to increase payload and flight performance survivability, and in commercial aircraft looking aiming to reduce operation costs. With composites, technology is advancing day by day and competition gaining more ground, it is important to explore the use of composites in the aircraft especially to understand the challenges in the aspect and reflect on its future. This paper looks at how the use of composites has shaped the aviation industry in the past, what improvements being made at present as well as the future of composites in the aerospace industry.

The past use of composites materials The evolution of composites materials in aircraft has been driven by economics, logistics, and expectation of the society (Smith 4). This is facilitated by development in materials, design tools, and processing methods. The primary drive for composite materials in the aerospace industry has been reduction in fuel consumption. The reduction of fuel consumption is both related to the economy where airlines look for a solution driven by increase in fuel prices and maintaining a competitive edge in the market as well as a reduction of pollutant emission.

King, Inderwildi and Carey links the use joining the EU emission trading scheme put pressure on the industry to reduce environmental impact (22). In addition to weight reduction composites have also been sought by aircrafts manufacturers to reduce parasitic drag, reduce corrosion, and increase damage performance (Yancey). The common materials being used for composites include carbon, fiberglass, and boron. The use of composites materials on aircraft was in use as early as in 1957 Boeing 707, which utilized approximately 20m2 polymeric composites mainly tertiary roles, like cabin structures (King, Inderwildi, and Carey 22).

The largest increase in the application of composite has been achieved from the period starting 2005 onwards. Today approximately 50% of all Boeing and Airbus aircraft utilizes composites materials as compared to the 12% composites on Boeing in 2005 (Smith 11). Composites material application ranges from all-composite airplanes such as the Beech Starships to helicopter rotor blades, wing assemblies, seats, propellers, and instrument enclosures (‘Aerospace Composites’ 58.) The use of composites materials has been reported to reduce Airbus aircrafts weights by approximately 20% (‘innovative materials’).

Composite material used further improves airplanes durability, are more reliable and reduces inspection needs during flights (‘Innovative materials’). For these reason airplanes, manufacturers are looking forward to fully leverage the benefits of innovative materials by more application of composites. A380 for instance has only 61% aluminum and uses 20 different alloys and tempers as compared to the earlier A320/330 aircraft that used only 6 composite alloys. The Boeing airplanes manufacturers have taken the lead in utilization of composites materials.

The Boeing 787 for instance makes greater application of composite materials than any other previous airplane. The Boeing's 787 Dreamliner had made it be one of the most fuel-efficient airlines by improving using lightweight composite materials. The application of composites materials in Boeing 787 is illustrated below. Fig. 1. Composite Material Application in Boeing 787 Source: Boeing. Boeing 787: From the Ground up. The 787 Dreamliner despite achieving 20% greater fuel efficiency that its similar size Boeing 767 exposed some weaknesses that composites may bring (Smith 33).

The Dreamliner relied on composite powerful lithium-ion battery to replace some mechanical components with electronics thus cutting down on weight. The lithium battery led to accidents twice leading to the grounding of the airplane on January 2013. The previous Boeing airplane, the 777 also utilized a substantial percentage of composites which constitute fifty percent of its structure as shown below. Fig. 1. Composite Material Application in Boeing 777 Source: Boeing Composite materials technology has further been employed in aircraft turbines components with the aim of achieving higher engine efficiency.

Higher engine efficiency translates into reduced fuel consumption. Yancey explains that initial engines for instance Sir Frank Whittles W1, used stainless steels in their turbine engines, but this was soon replaced by super alloy systems such as nickel-chromium. With time, however, the engines have been becoming hotter and hotter, and ceramic coating has increasingly been employed in coating some of the hot engine parts. From the 1980s polymeric composites, materials in engines started taking ground in applications such as the blades of the engine.

Such composites materials have the benefits of reducing overall mass of the engine and conversely the aircraft. Composite material has also brought so other benefits in addition to weight reduction and efficiency improvements. Boeing reports that the reduced risk of corrosion and fatigue of composites as compared to metal requires reduced scheduled maintenance. For instance, the 777 composite tails is 25 % larger than the previous 767’s aluminum tail, yet it requires 35 % fewer scheduled maintenance labor hours (Boeing 787).

The use of composites materials has also led to improved passenger comfort. The all-composite material floor of the Boeing 787 777 offers less fatigue and bumpiness to passengers in a harsh environment. The need for comfort has heightened competition between airlines and the effect has been more application of composites materials; passengers are willing to invest time and money in search of comfort (‘Innovative Materials’). Current improvements and the future of Composites in Aviation King, Inderwildi, and Carey explain that improvement and development of composite materials for aviation applications guided by three main fronts: the improvements of current material, the development of new materials; and the use of current materials in new and novel structures (25).

New materials include Ceramics Matrix Composites (CMCs). The CMCs are been explored for use in reinforcing ceramic fibres for applications especially in the hot sections of the aircrafts engines. The CMCs would allow turbine inlet temperature as high as 15000c from the current maximum of 12000c which improves fuel efficiency (King, Inderwildi, and Carey 25). Metal Matrix Composites (MMCs) is another new material which that is under test which consists of Aluminum or titanium matrix, nitride or carbide reinforcement.

The MMCs could be applied in loaded surfaces such as turbine fan blades or helicopter rotor blades and floor supports. Just like macro-scale composites, a number of matrix reinforcements possible with CMC and NMC are under investigation. Manufactures are investigation the application of Nano-composites to improve material properties since they utilize huge surface area mass and high length-to-width ratios (Carey 25). These materials are expected to reduce weight of the airplanes further (King, Inderwildi, and Carey 25).

The trend of improving the available incumbent materials is another area currently been undertaken and expected to be carried into the future. This aim of the improvement is to give them superior physical properties as well as to enable their use in other new roles (King, Inderwildi, and Carey 26). Aluminum for instance, is the most common material in aircraft materials, but is less durable and corrodes. The aircraft manufacturers are working on the current aluminum alloys to make a durable and corrosion resistant.

The A380F for instance has three planned alloys use in wing panels, which creates lighter (King, Inderwildi, and Carey 26). Researchers are also focusing on the generation of fourth generation super-alloys with ruthenium aimed at improving micro-structural stability, and increasing high temperature creep strengths (King, Inderwildi, and Carey 26). The use of titanium has in the past been so costly yet it is an efficient composite for aircrafts; researchers are looking in how to reduce the cost involved in its use (King, Inderwildi, and Carey 26).

A major breakthrough in the improvement of the current materials has been a modification of ceramics to enable its application in areas such as shaft bearing, and thermal barrier coating on turbine blades (King, Inderwildi, and Carey 26). Researchers are also doing a lot of research into the application of new composites structure with some fiber metal laminates already in use (King, Inderwildi, and Carey 26). Future new composites structures include the application of lattice and foam and laminate structures.

Lattice is expected to lower weight substantially given that it weighs approximately 15% of a solid plate with similar dimension yet it is equally strong. Efficient use of foam, produced from aluminum alloy, is expected to replace the honeycomb structure, which will lead to higher efficiency and reduced costs (King, Inderwildi, and Carey 27). Application of low density super-alloy foam in noise abatement will replace acoustic liners, and increase engine burn efficiency, again which reduces fuel burn and emissions.

Finally, a number of laminate structures with a variety of the composite constituent are under investigation (King, Inderwildi, and Carey). The laminate structure are aimed at preventing catastrophic failure and improve impact characteristics; fiber metal laminate consisting of layers of composite and aluminum , is already in use and has been associated with high impact strengths and directional strength at lower density. New composites such as aramid, carbon fiber, and glass fiber are also been tested.

Chris, however, warns that the increasing demand for carbon fiber whose global production is limited (only 45000 tonnes produced in 2012, with Boeing and Airbus alone consuming about 23000 tonnes) could lead to higher prices for the composite (23). The use of fuel has been the accounting for the largest operations cost for most airlines, about 40% of all operations (Smith 14). This coupled with the increasing needs to reduce greenhouse gases emissions and provide better comfort to passengers can only be expected to lead to higher application of composites.

Works Cited “Aerospace Composites.” Aerospace Applications. Web. 18 Nov 2013 “Boeing 787: From the Ground up.” Aero. Boeing. Web. 18 Nov, 2013 “Innovative materials.” Airbus. Web. 18 Nov, 2013 King, David, Inderwildi, Oliver, and Carey, Chris. Advanced aerospace materials: past, present and future. Aviation and the Environment. 3.6, 22-27 Smith , Faye. The use of composites in aerospace: Past, present and future challenges. Avalon Consultancy Services Ltd. Web. 18 Nov 2013 Yancey, Robert.

How Composites are strengthening the Aviation Industry. Industry Week. 11 June 2012. Web. 18 Nov 2013