Carbon fiber composite, also known as carbon composite, is an extremely strong and light fiber-reinforced plastic with carbon fibers. It is also known by other names such as carbon fiber reinforced plastic (CFRP) or carbon fiber reinforced thermoplastic (CFRTP). It is an expensive material to produce, but quite useful in many vital applications where high strength-to-weight ratio and rigidity (stiffness) are necessitated. These critical applications are associated with the major fields such as aerospace, automotive, civil engineering, sports equipment, the superstructure of ships, and an increasing number of consumer and technical applications. However, the problem arises in machining carbon fiber sheets.
Significance of carbon fiber composites
The binging strength and high strength-to-weight ratio are two crucial factors in carbon fiber composites. Carbon fiber reinforced plastics (CFRPs) are composite materials. The composite has two elements: a matrix and a reinforcement.
- The matrix is usually a polymer resin or thermoset resin, such as epoxy to bind the reinforcements together; polyester, vinyl ester, or nylon, are sometimes used as thermoset or thermoplastic polymers as an alternative to thermoset resin (epoxy).
- The reinforcement is carbon fiber for providing strength.
The material properties depend on these two elements. Polyester, vinyl ester, or nylon, are sometimes used as thermoset or thermoplastic polymers as an alternative to thermoset resin (epoxy). (UHMWPE), aluminum, or glass fibers in addition to carbon fibers.
The types of additives introduced to the binding matrix (resin) can affect the carbon fiber reinforced plastic product properties. Silica is the most used additive, but it is sometimes substituted with other materials such as rubber and carbon nanotubes. The material is also referred to as graphite-reinforced polymer (GRP) or graphite fiber-reinforced polymer (GFRP) is less common, as it clatters with glass-(fiber)-reinforced polymer.
Environmental effects on CFRP properties
Polymer-based composites are profoundly affected by environmental factors such as temperature and humidity. Though CFRPs have excellent corrosion-resistance, yet degradation of the mechanical properties of CFRPs is caused by the effect of moisture at wide ranges of temperatures, mostly at the matrix-fiber interface. The carbon fibers themselves are not affected by the humidity; the moisture plasticizes the polymer matrix. The material properties (compressive, interlaminar shear, and impact properties) dominantly influenced by the matrix are thus drastically changed.
Why carbon fiber panels are a better option than steel and aluminum
- Why carbon fiber panels are a better option than steel and aluminum in many vital applications? CFRP has directional strength properties entirely different from isotropic materials like steel and aluminum. The CFRP’s properties rest on the carbon fiber layouts and the carbon fibers’ proportion to the polymer. Reinforcement gives CFRP its strength and rigidity, measured by stress and elastic modulus, respectively. The following mechanism governs the crack hardiness of CFRPs: Debonding between the carbon fiber and polymer matrix,
- Fiber pull-out, and
- Delamination between the CFRP sheets.
A comparative alternative to epoxy-based CRPFs
Epoxy-based CFRPs exhibit practically no plasticity. The CFRPs with epoxy have high strength and elastic modulus, but the engineers face unique challenges of failure detection because of the inelastic fracture mechanics.; the failure occurs terribly. However, the manufacturers have been successful in modifying the existing epoxy material and finding alternative polymer matrix as a measure to toughen CFRPs. PEEK is a promising material, used by the manufacturers, to display an order of magnitude higher toughness with similar elastic modulus and tensile strength. The only problem with PEEK is its high price and difficulty in processing.
CFRP manufacturing and application problems
The following problems are imperative in carbon fiber manufacturing and applications:
- CFRPs are very hard to machine.
- They cause critical casting tool to wear. The tool wear in CFRP machining depends on the fiber orientation and machining condition of the cutting process. However, the tool wear is possibly reduced with the use of various types of coated tools.
- The carbon fibers can cause galvanic corrosion when CRP parts are attached to aluminum.
- The epoxy matrix used for engine fan blades is designed to be impermeable against jet fuel, lubrication, and rainwater; external paint on the composites parts is applied to minimize damage from ultraviolet light.
CRPF is commonly used for critical cyclic-loading applications because of its high initial strength-to-weight ratio, but its design limitation is its lack of a definable fatigue limit. The fatigue failure properties of CFRP are challenging to predict. Therefore, the engineer’s design in considerable strength safety margins to provide suitable component dependability over its service life when using CFRP for these applications.
- Aerospace engineering: Scaled composites are extensively used by the specialist aircraft designing and manufacturing industry throughout the design range. The example of this application is Spaceship One – the first private manned aircraft. It is widely used in micro air vehicles (MAVs) because of its high strength-to-weight ratio.
- Automotive engineering: They are extensively used in high-end automotive racing because low weight is essential for high-performance automobile racing. The unmatched strength-to-weight ratio of the material mitigates the high cost of carbon fiber. Manufacturers developed omnidirectional carbon fiber weaves that apply strength in all directions. The first example of this application is the first carbon fiber monocoque chassis introduced in Formula One by McLaren in the 1981 season.
- Civil engineering: The use of CFRP has a tremendous positive impact on strength. It is an excellent material in structural engineering applications because of its potential benefits in construction. It is highly cost-effective in several field applications: strengthening concrete, masonry, steel, cast iron, and timber structures.
- Microelectrodes made from carbon fiber: These are used either in amperometry or fast-scan cyclic voltammetry to detect biochemical signaling.
- Sports goods: Many contemporary sports products and equipment are made from carbon fiber. For instance, a CFRP bicycle frame has a low weight compared to steel, aluminum, or other metal frames. The use of carbon fiber can also achieve the desired stiffness.
- Other applications: The fire-resistant composites are used in an increasing number of high-end products that require stiffness and low weight. These applications include firearms, drone bodies, laptop shells, lightweight poles, dentistry, and many more.
Though expensive and hard to machine, carbon fiber composites or prepreg composites
provide their excellent value in multiple significant applications.