Nowadays, composite materials are used in different industries due to its benefits it provides in comparison to metals. Mainly, these benefits are because of the lightweight and high strength mechanical properties it has for structural applications. However, in recent years, composite materials have enlarged it use to not structural applications and more centred in the day-to-day life because of their thermal characteristics. Below there is a list of applications of composite materials.
AEROSPACE
The main applications of composote materials is in the aerospace sector. The principal reason for using fiber-reinforced polymers in aircraft and helicopter applications is weight saving, which can lead to significant fuel saving and increase in payload. Composite materials have been introduced in the aerospace industry in the 70s. The firsts components developed with these materials were the wing, fuselage and empennage components. From this point it has extend its use to nowadays.
In 1987, the A310, developed by Airbus, was the first commercial aircraft manufacturer to make extensive use of composites in their A310 aircraft. Using composite materials reduced about the 10% of the aircraft’s weight. Later, in 2006, Airbus introduced the A380, which 25% of its weight was made of composite materials.
SPACE
Weight reduction is the primary reason for using fiber-reinforced composites in many space vehicles. Carbon fibre are used because its low density and very low coefficient of thermal expansion (CTE). The low CTE is important because for dimensional stability of the structure in the space environment where the temperatures at day and night can vary from -100ºC to 100ºC. However, as explain in the advantages and disadvantages of composite materials posts, they are affected by environmental factors such as moisture that leads to degradation of the matrix composite structure
Pressure Vessels
Composite pressure vessels are made by filament winding carbon, S-glass, or Kevlar 49 fiber reinforced epoxy around an inner liner, which can be either an aluminum alloy tube or a blow molded high density polyethylene tube. The primary purpose of the liner is to prevent any diffusion or leakage of gas through the composite outer layers. Although the aluminum liner is heavier than the polyethylene liner, it is preferred in very high-pressure applications such as the oxygen tanks used in chemical laboratories or air-breathing tanks carried by firefighters on their backs during a firefighting operation
AUTOMOTIVE
Not all applications of composite materials are used in top end applications. The advantages they provide include weight reduction, vibration damping, and design flexibility, all of which contribute to better performance. such as higher speed, more power, and less fatigue or physical exhaustion.
Fiber-reinforced composites have become the material of choice in motor sports where lightweight structure is used for gaining competitive advantage of higher speed and cost is not a major material selection decision factor.
All major body, chassis, interior, and suspension components in today’s Formula 1 race cars use carbon fiber-reinforced epoxy. One major application of carbon fiber-reinforced epoxy in Formula 1 cars is the survival cell, which protects the driver in the event of a crash. The nose cone located in front of the survival cell is also made of carbon fiber-reinforced epoxy.
Exterior body components, such as the hood or door panels, require high stiffness and damage tolerance (dent resistance) as well as a ‘‘Class A’’ surface finish for appearance. The composite material used for these components is E-glass fiber-reinforced sheet molding compound (SMC) composites, in which discontinuous glass fibers (typically 25 mm in length) are randomly dispersed in a polyester or a vinyl ester resin.
Unileaf E-glass fiber-reinforced epoxy springs have been used to replace multileaf steel springs with as much as 80% weight reduction. Other structural chassis components, such as drive shafts and road wheels, have been successfully tested in laboratories and proving grounds. They offer opportunities for substantial weight savings, but so far they have not proven to be cost-effective over their steel counterparts.
SPORTS
Polymer matrix composites containing glass, carbon, and Kevlar fibers arc finding an increasing number of applications in the sporting goods industry. The advantages they provide include weight reduction, vibration damping, and design flexibility, all of which contribute to better performance. such as higher speed, more power, and less fatigue or physical exhaustion. The following exmples are sports equipment that used composite materials:
- Tennis and squash rackets
- Fishing poles
- Skis
- Poles used in jumping
- Sails
- Surf boards,
- Roller skates
- Bows and arrows
- Javelins
- Protection helmets
- Bicycle frames
- Golf clubs
- Oars
Tennis rackets
The head of most modern tennis rackets is made of carbon fiber reinforced epoxy or a combination of carbon, glass. and Kevlar 49 fiber reinforced epoxy in the outer layers and a core of either a polyurethane foam or a short carbon or glass fiber reinforced injection molded nylon. These tennis rackets are lighter in weight and stiffer than either wood or aluminum tennis rackets.
Golf clubs
Carbon fiber golf clubs are 20-40% lighter than stee l shafts. They usually contain several layers of 0″ carbon fibers along the length and a thin layer of 90º glass fiber/epoxy overwrap. Carbon fibers provide high flexural stiffness as well as strength, while the 90″ overwrap prevents longitudinal splitting in the carbon fiber layers.
Bike frames
frame with approximately 50% weight saving over alloy steel, weight is the frame material commonly used in bicycles. Besides weight savings, the carbon fiber frames provide better fatigue resistance, no corrosion problem, and an improved ride quality.
The carbon fiber tubes are commonly made with 0 and ±45° fiber orientations using either a hand lay up technique. braiding. or pultrusion . The carbon fiber layers are sometimes wrapped over a thin aluminum alloy tube to ensure against severe abrasion or cut. Glass fiber layers are used between the inner aluminum tube and the carbon fiber layers to prevent galvanic corrosion of the aluminum tube. Kevlar fiber layers are added on the outside to improve abrasion and impact resistance of the tube. Cast aluminum lugs are used to join the carbon fiber tubes at their ends and form the triangular frame structure. Epoxi adhesives are used for joining.
Fishing rods
The first composite fishing rod was made of glass fiber reinforced epoxy. In recent years, carbon fiber reinforced epoxy has become more popular in fishing rods because it is a stiffer material and therefore gives a smaller tip deflection than the glass fiber rods. It also dampens the vibrations more rapidly, reducing the waves in the fly line.
MARINE APPLICATIONS
The use of fibre reinforced composites in the marine industry started with recreational boats in the 1950s. Glass fibre- reinforcement polyesters are used for marine applications such as boats, yacht, fishing boats… The main application of glass fibre in marine applications are the hulls and decks. Today nearly 90% of the pleasure boats are constructed of either glass fiber reinforced polyesters or vinyl esters. Contact molding is used in making the majority of these boats. Even though this process is labor-intensive, the equipment cost is low and therefore affordable by many of the small companies who build these boats.
However, for more demandant applications, carbon fiber is used. Carbon fiber reinforced epoxy is used in racing boats where weight reduction is extremely important. For example, in America’s Cup racing boats, the complete hull, deck, mast, keel, boom. and many internal structures are constructed using either solid laminates of carbon fiber/epoxy or sandwich laminates of carbon fiber/epoxy skins and honeycomb and foam cores. Carbon fibers are sometimes hybridized with other lighter weight fibers such as high modulus polyethylene fibers to improve the impact resistance and reduce the boat’s weight.
The masts arc up to 32 m tall and encounter loads of 200 kN while deflecting close to 1.5 m at the tip. The International America’s Cup Class (IACC) rules limit the fiber and resin types that can be used in these boats. For example, the hulls can use high strength carbon fibres with a modulus of 230-245 GPa, while the masts, booms, and spinnaker poles can use fibres with a maximum modulus of 310 GPa. Higher modulus fibres are banned.
Here are some example of composite materials used for marine applications:
- Hovercrafts
- Rescue crafts
- Patrol boats
- Trawlers
- Landing gears
- Anti-mine ships
- Racing boats
- Pleasure boats
- Canoes
INFRASTRUCTURE
Another applications of composite materials are in civil infrastructure. Fiber-reinforced polymers have a great potential for replacing reinforced concrete and steel in bridges, buildings, and other civil infrastructures. The principal reason for selecting these composites is their corrosion resistance, which leads to longer life and lower maintenance and repair costs. Reinforced concrete bridges tend to deteriorate after several years of use because of corrosion of steel-reinforcing bars (rebars) used in their construction. The corrosion problem is exacerbated because of deicing salt spread on the bridge road surface in winter months in many parts of the world. The following are examples of composite materials used for insfrastructure:
- Swimming pools
- Facade panels
- Profiles
- Partitions, doors, furniture, bathrooms
- Housing cells
- Chimneys
- Concrete molds
- Various covers (domes, windows, etc.)
The photo shows the Real Madrid’s stadium whose roof was made of composite materials to reduce weight.
