Why do sports cars like to use carbon fiber as materials ?
Carbon fiber (CF) is a new type of fiber with high strength and high modulus with carbon content of more than 95%. It is a kind of microcrystalline graphite material which is made of organic fibers such as flake graphite microcrystalline and other organic fibers stacked along the axial direction of the fiber, and is obtained by carbonization and graphitization. Carbon fiber is "flexible and internal rigid", which is lighter than aluminum, but its strength is higher than that of steel, and has the characteristics of corrosion resistance and high modulus. It is important data in national defense, military industry and civil. It not only has the inherent characteristic of carbon data, but also has the soft processability of textile fiber, and is a new generation of reinforced fiber.
Carbon fiber has many excellent functions, such as high axial strength and modulus, low density, high specific function, no creep, high temperature resistance and good fatigue resistance in non oxidation environment. The specific heat and conductivity are between non-metal and metal, and the thermal expansion coefficient is small and has anisotropy, corrosion resistance is good, and X-ray transmission is good. Excellent conductive and heat conduction function, good electromagnetic shielding, etc. Compared with traditional glass fiber, the young's modulus is more than three times that of carbon fiber; compared with Kevlar fiber, Young's modulus is about twice as much as that of the fiber, and it is insoluble and non swelling in organic solvent, acid and alkali, and has excellent corrosion resistance.
After carbon fiber is applied to the car, the most obvious advantage to the car manufacturing is the lightweight of the car, and the most direct impact is the progress of energy saving, acceleration and braking function. Generally speaking, the vehicle weight is reduced by 10%, the fuel consumption is reduced by 6% - 8%, the emission is reduced by 5-6%, the acceleration of 0-100km/h is improved by 8-10%, and the braking interval is shortened by 2-7m. The vehicle body lightweight can make the center of gravity of the vehicle move down, improve the stability of the car operation, and the operation of the vehicle will be more safe and stable. The carbon fiber composite data has excellent energy absorption rate, and the energy absorption ability of collision is six to seven times of steel and three to four times of aluminum, which further ensures the safety of the car.
The carbon fiber composite data has higher vibration damping. It takes 9 seconds for light alloy to stop vibration, and the carbon fiber composite data can be stopped in 2 seconds. Therefore, carbon fiber is applied to the car. The progress and dedication of NVH (noise, vibration and acoustic vibration roughness) of the whole vehicle are also great, which will greatly enhance the comfort of the car. The fatigue strength of steel and aluminum is 30-50% of tensile strength, while the carbon fiber composite data can reach 70-80%, so the fatigue reliability of the data using carbon fiber composite data on the car has made great progress.
If the specific strength is calculated, the carbon fiber composite data is much more than carbon steel, and can exceed some special alloy steel, so it has higher specific strength. Using carbon fiber data, while reducing the body quality, it can also make the power demand smaller, so that smaller driving engines and suspension devices are selected. After reducing kinetic energy and reducing impact risk, this spiral type result will further reduce the body quality. Therefore, the lightweight effect of carbon fiber material parts is obvious when replacing the original steel parts.
The planning of carbon fiber composite data is very strong, and it can be used in product planning sensitively according to different requirements. According to the stress condition of product structure, the products with different thickness and anisotropy can be made by adjusting the structure and placement of fiber. The sandwich structure can be used to improve the rigidity of all parts to reach the best lightweight planning scheme. The carbon fiber can be arranged according to the stress direction, which can give full play to the different strength of composite data, so as to save data and reduce the components. Because of its isotropy, the metal data will be in excess of the strength in the other direction after meeting the technical requirements of the maximum stress direction.
The application of car body and chassis, because of the
Carbon Fiber Reinforced polymer matrix composite materials, has enough strength and rigidity, it is the lightest information for the manufacture of main structural parts such as car body and chassis. It is predicted that the application of carbon fiber composite data can reduce the mass of car body and chassis by 40% ~ 60%, which is equivalent to 1 / 3-1 / 6 of the steel structure quality. The common car body and some modified body are all for this purpose, and the visual effect is excellent and cool.
The application of brake pads, carbon fiber is also used on the brake pads due to its environmental protection and wear-resistant characteristics, but the products containing carbon fiber composite materials are all expensive, so this brake pad is mainly used in the advanced cars. Carbon fiber brake discs are widely used in racing cars, such as F1 racing. It can reduce the speed of the car from 300 km/h to 50 km/h within 50m interval. At this time, the temperature of the brake disc will rise to above 900 ℃, and the brake disc will turn red due to absorbing a large amount of heat. The carbon fiber brake disc can withstand the high temperature of 2500 ℃ and has excellent braking stability.
