What are the Benefits of Carbon Fiber Reinforcement in Vehicles?
By Space Coast Daily // September 18, 2020
Over the years, manufacturers have spent millions of dollars in research to make vehicles lighter and safer. Most modern F1 cars contain little to no steel or aluminum in their body panels or chassis. Instead, the reinforcement is carbon fiber, the same material used in aerospace and marine applications.
Although it’s more expensive to use than conventional materials, manufacturers are starting to use it more frequently in consumer vehicles. However, due to the cost involved, it’ll undoubtedly increase the price of new cars.
So, how will the consumer benefit from paying more for carbon fiber reinforcement?
What Is Carbon Fiber?
Carbon fiber, aka graphite fiber, is a polymer (a lightweight and solid material). It’s lighter, twice as stiff, and five-times more robust than steel. This makes it ideal for the manufacturing of various parts.
It’s material that’s strengthened by thin crystalline strands of carbon that get twisted like yarn. It’s woven together to form cloth. This can be laid over a mold and coated with plastic or resin if a permanent shape is needed. Some of its properties are:
■ High tensile strength
■ High in stiffness
■ Low strength to weight ratio
■ High chemical resistance
■ Low thermal expansion
■ Can withstand excessive heat
The Advantages of Carbon Fiber Reinforcement (CFR)
Due to its superior properties, CFR has caught the attention of consumer vehicle manufacturers. Replacing steel and aluminum components with carbon fiber parts offers a weight reduction of up to 60%. In turn, this increases fuel efficiency with as much as 30% and reduces CO2 emission by about 20%.
Carbon fiber has an Anisotropic condition, which is the ability of a material to have different properties based on the direction of measurement. Thus CFR can be tailored to suit specific needs according to the path of the highest stress.
Furthermore, the thickness can be locally adjusted to fit high or low tension areas. This isn’t easy to achieve with stamped sheet metal. Thus, CFR parts on average weigh:
■ 40% lighter than aluminum
■ 50 to 60% less than fiberglass
■ 75% lighter than steel
The number of individual parts needed to produce a car body can be reduced by 30% by introducing high-volume CFR vehicles. This can be achieved by integrating specific smaller pieces, such as fasteners and supports, with structural and body components.
The crashworthiness of a vehicle’s structure depends on the amount of energy it can absorb from an impact before it becomes fatal for the passenger. This factor is increased by failure modes and mechanisms, such as crumple zones, that provide a gradual deterioration in the load profile during a crash.
This factor is enhanced by the strength and stiffness of CFR, thus increasing the vehicle’s safety. Tests done by BMW show that the energy absorption of a carbon fiber car body was 1.5 times better than that of steel.
Toughness and Durability
The durability of CFR in extreme conditions has been proven through its use on helicopters and jet fighters. This material has also passed rough road durability, hail testing, crash simulators, and variable extreme temperature tests.
Furthermore, CFR can be tailored to withstand specific strain through its potential to shape wall thickness, layer structure, and fiber orientation. It also doesn’t rust, which makes vehicles more durable, especially in coastal regions.
Improved Aesthetic Appeal
Its design potential allows for long, sweeping curves that provide a high-tech look, which improves road hold ability and aerodynamics. Graphite fiber can be shaped to take virtually any form. Testing has also shown that even in hot and humid climates, painted CFR surfaces maintain their quality.
Disadvantages of Carbon Fibre Reinforcement
The cost to produce graphite fiber vehicles is estimated to be 18 times more expensive than steel. Certain manufacturers have started using specific CFR components. However, due to its cost, its application in the production car sector is still minimal.
Production Technology Issues
Many production technology issues have yet to be overcome. Some procedures involve manual labor, which is expensive and time-consuming. Carbon fiber also has a limited shelf-life, which contributes to the difficulty of ensuring that the thickness of sheet molding compound batches is within the acceptable limit.
Japan and Europe place significant emphasis on recycling end-of-life(ELV) vehicles. The target is set on recovering 95% in weight of the materials used to produce a specific vehicle. However, various types of resin are used in the production of graphite fiber components. This increases the dismantling costs and decreases the recovery value of the car.
The resin isn’t commonly recycled and typically ends up on a landfill site. Since carbon thermosets aren’t biodegradable and pose several health and safety risks, this option holds little appeal.
The Future of Vehicle Manufacturing
Although some factors hold back the wide-spread use of carbon fiber reinforcement in the automotive industry, the benefits are undoubted. Using this technology will produce lighter yet safer cars, while potentially saving the consumer a lot of money and simultaneously reducing their carbon footprint.