Carbon Fiber

Carbon Fiber | Carbon-Fiber-Reinforced Polymer

Carbon Fiber is a polymer and is sometimes also known as graphite fiber. It is made of a highly lightweight material that is also very robust. Compared to steel, carbon fiber is five times stronger and twice as rigid. Carbon fiber is the ideal production material for many goods, even though it is lighter than steel and stronger, stiffer, and more elastic than steel. These are only a few of the factors that influence why engineers and designers select carbon fiber for manufacturing.

High stiffness, high tensile strength, good strength to weight ratio, high chemical resistance, high temperature tolerance, and minimal thermal expansion are only a few benefits of carbon fibers. Due to these qualities, carbon fiber is widely used in the military, motorsports, aerospace, and other competitive sports. However, they are relatively pricey when compared to fibers that are similar, like glass, basalt, or plastic.

Carbon Fiber Properties

On top of being strong, carbon fiber:

Is high in stiffness
Is high in tensile strength
It has a low weight to strength ratio
Is high in chemical resistance
Is temperature tolerant to excessive heat
Has low thermal expansion

As a result, carbon fiber is widely used in a variety of sectors, including the aerospace, automotive, military, and recreational industries.

Three to ten times stiffer than glass fibers, carbon fibers are exceptionally robust and stiff. For structural aircraft applications including floor beams, stabilizers, flight controls, and the main fuselage and wing structure, carbon fiber is used. Its high strength and resistance to corrosion are advantages.

Due to disadvantages like lesser conductivity than aluminium, parts of aircraft that are vulnerable to lightning strikes must have a lightning protection mesh or coating. The high price of carbon fiber is another drawback. Gray or black in hue, carbon fiber is offered as prepreg and dry fabric. When utilized with metallic structures and fasteners, carbon fibers have a high potential for galvanic corrosion.

Although the phrases are sometimes used interchangeably, one of the first distinctions to be noted among fibers is the difference between carbon and graphite fibers. The hexagonal (graphene) layer networks found in carbon serve as the foundation for carbon and graphite fibers. Graphene is classified as graphite if the layers or planes are arranged in three dimensions. Typically, this request requires prolonged time and temperature processing, which raises the cost of graphite fibers. Weak bonds exist between the planes. Only two-dimensional organization within the layers is typically evident when disorder is present. The term "carbon" refers to this substance.

History of Carbon Fiber

By baking bamboo or cotton threads at high temperatures to produce an all-carbon fiber filament, Thomas Edison invented carbon fiber in 1879. By 1958, high-performance carbon fibers had being produced just west of Cleveland, Ohio. These fibers were ineffective, had a 20% carbon content, and had inferior strength and stiffness characteristics.

The strong potential of carbon fiber was first realized in 1963 when a new production method was created at a British research facility.

How is Carbon Fiber Made

A method that is partially chemical and partially mechanical creates carbon fiber. Long fiber strands are first drawn, then heated to a very high temperature without allowing the fibers to come into touch with oxygen to prevent burning. When this happens, the fibers become carbonized, which is when the fiber's atoms aggressively vibrate and expel the majority of the non-carbon atoms. There are now very few non-carbon atoms left, leaving a fibre made of long, closely interlocked strands of carbon atoms.

Spinning, stabilizing, carbonizing, treating the surface, and sizing are common processes used to create carbon fibers from polyacrylonitrile.

The carbon atoms are linked together in crystals that are roughly parallel to the fiber's long axis to create carbon fiber because this crystal alignment gives the fiber a high strength to volume ratio (in other words, it is very strong for its size). The tow, which may be used on its own or woven into a fabric, is made up of thousands of carbon fibers.

Carbon fiber sheet

To create a composite, carbon fibers are typically mixed with other materials. For instance, it can be baked after being infiltrated with a plastic resin to create carbon-fiber reinforced polymer, also known as carbon fiber, which has a very high strength-to-weight ratio and is incredibly hard but slightly brittle. In order to create reinforced carbon-carbon composites, which have a very high heat tolerance, carbon fibers are additionally composited with other materials, such as graphite.

CFRP (Carbon-fiber-reinforced polymer)

Carbon fiber-reinforced plastics are exceptionally strong and light fiber-reinforced polymers that incorporate carbon fibers. They are also known as carbon fiber, carbon composite, or just carbon. They are also known as carbon fiber-reinforced plastics, carbon fiber-reinforced polymers (CFRP, CRP, CFRTP), and carbon fiber-reinforced polymers (Commonwealth English). CFRPs can be costly to create, but they are frequently employed in areas where a high strength-to-weight ratio and stiffness (rigidity) are necessary, including sports equipment, aerospace, automotive, civil engineering, and a growing range of consumer and technical applications.

Aviation Uses

With wing spars and fuselage parts made of 52% CFRP, the Airbus A350 XWB surpasses the Boeing 787 Dreamliner as the aeroplane with the highest weight ratio for CFRP, which is 50%. One of the earliest commercial aircraft with composite wing spars was this one. The Airbus A380 was among the first commercial aircraft to include a central wing-box made of CFRP; it is also the first to have wings with a cross-section that is smoothly curved rather than divided into portions span-wise. Aerodynamic efficiency is maximized by this cross-section’s flowing, continuous design. Additionally, CFRP is used to construct the trailing edge, the empennage, the rear bulkhead, and the unpressurized fuselage. Due to issues with the production of these parts, order delivery dates have been pushed back significantly. While metallic structures have been studied and utilized on airframes for years, and the procedures are very well understood, many aircraft that use CFRP have encountered delivery date delays because of the relatively new techniques used to create CFRP components. Due to the peculiar multi-material and anisotropic properties of CFRP, the monitoring of structural ageing is a persistent issue for which new techniques are continually being researched.

A Hyfil carbon-fiber fan assembly was in use on the BOAC-operated Vickers VC10 Rolls-Royce Conways in 1968.

Scaled Composites, a producer and designer of specialized aircraft, extensively utilized CFRP in all of their designs, including the first private crewed spaceship Spaceship One. Micro air vehicles (MAVs) frequently use CFRP due to its excellent strength to weight ratio.

Other thermoset or thermoplastic polymers, such as polyester, vinyl ester, or nylon, are occasionally employed as the binding polymer. The binding polymer is frequently a thermoset resin, such as epoxy. The type of additives used to the binding matrix can change the final CFRP product's characteristics (resin). Silica is the most used addition, however others like rubber and carbon nanotubes can also be employed.

Graphite-reinforced polymer or graphite fiber-reinforced polymer are other names for carbon fiber (GFRP is less prevalent because it competes with glass-(fiber)-reinforced polymer).

CFRP Properties

Composite materials include CFRP. The composite in this instance is made up of a matrix and a reinforcement. Carbon fibre is used as reinforcement in CFRP, which gives it its strength. Typically, a polymer resin, such epoxy, serves as the matrix to bind the reinforcements together. Due to the fact that CFRP is made up of two separate parts, these two elements determine the material's qualities.

Stress and elastic modulus are used to quantify the stiffness and strength of CFRP, respectively. CFRP possesses directional strength qualities, in contrast to isotropic materials like steel and aluminium. The carbon fiber arrangements and their proportion to the polymer have an impact on the characteristics of CFRP. Carbon fiber reinforced plastics can also be governed by the two separate equations that govern the net elastic modulus of composite materials using the characteristics of the carbon fibers and the polymer matrix.

Conclusion

Composites made of carbon fibre reinforced polymer (CFRP) have the highest stiffness and strength of any type, but they are significantly more expensive than composites made of glass fibre reinforced polymer (GFRP). The best performance is provided by continuous fibres in a matrix made of polyester or epoxy. Composite materials made of carbon fibre reinforced polymer (CFRP) are being used more often in a variety of fields. They are robust and lightweight, used in sailboats, motorised bicycles, and especially modern vehicles where high strength-to-weight ratios are necessary. Additionally, they are utilised in laptops, tripods, golf clubs, fishing rods, racquet frames, and stringed instrument bodies.