Application of the hottest carbon graphite fiber r

2022-08-05
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Application of carbon (graphite) fiber reinforced composites in automobiles

carbon (graphite) fiber has the characteristics of small specific gravity, high strength, high modulus and corrosion resistance. It can be used to manufacture carbon (graphite) fiber reinforced polymer, metal and ceramic matrix composites. It is the most important reinforcement of advanced composites. Carbon fiber reinforced composites are used to manufacture automobile body and engine parts, which can effectively reduce the vehicle weight and improve the vehicle performance. It is one of the important research and development directions of lightweight automotive materials. This paper will briefly describe the performance characteristics of carbon fiber reinforced composites, as well as their prospects and existing problems in the automotive industry

with the rapid development of the automobile industry, reducing fuel consumption and environmental pollution has become a key problem to be solved urgently for the development of the automobile industry and the sustainable development of society. The fuel consumption and CO2 emissions of automobiles are closely related to the weight of automobiles. Relevant studies of the U.S. Department of energy show that the existing automobiles in the United States, if the weight is reduced by 25%, can save 750000 barrels of fuel per day, and the annual CO2 emissions can be reduced by 101 million tons. Therefore, automobile lightweight has become an important direction for the technological development of the automotive industry. In addition to the optimization design and improvement of the structure of various automobile parts, the use of high-performance lightweight materials is an important way to achieve the lightweight of automobiles. For example, aluminum, magnesium, titanium, high-strength steel, engineering plastics and composite materials are used to manufacture automobile body, chassis, engine and other parts, which can effectively reduce the weight of the automobile and improve the efficiency of the engine

carbon fiber reinforced composites have high strength and high modulus, and have been widely used in aerospace and other fields. They are key structural materials for manufacturing important structural parts of satellites, missiles and aircraft. It is also the lightest material suitable for manufacturing the main structure of automobile body and chassis, and has been widely valued by the automobile industry. However, the high price of carbon fiber reinforced composites seriously affects its application in the automotive industry. Therefore, the development of low-cost carbon fiber and high-efficiency carbon fiber reinforced composite production methods and processes has become a key issue in the research of automotive lightweight materials. The United States and Japan have listed it as the research plan of automotive lightweight materials

performance characteristics of carbon fibers and composites

carbon (graphite) fibers are prepared from organic fibers - Polypropylene (Pan) fibers, viscose fibers, asphalt fibers and other filaments through high-temperature solid-state reaction processes such as pre oxidation, carbonization and graphitization. They are composed of graphite microcrystals with preferred orientation, so they have very high strength and elastic modulus (rigidity). Its specific gravity is generally 1.70 ~ 1.80g/cm3, its strength is 1200 ~ 7000mpa, its elastic modulus is 200 ~ 400gpa, and its thermal expansion coefficient is close to zero or even negative (~ 1.5 ×)。 See Table 1 for the properties of various types of carbon fibers

carbon fiber has excellent comprehensive properties such as heat conduction, conductivity, high temperature resistance and corrosion resistance. These excellent comprehensive properties make carbon fiber the most important reinforcing fiber of advanced composites, which can be used to strengthen polymers (thermosetting and thermoplastic polymers) to form high-performance polymer matrix composites; Reinforced aluminum, magnesium, copper and other metals form carbon/aluminum, carbon/magnesium, carbon/copper and other metal matrix composites; High temperature resistant ceramic matrix composites composed of reinforced carbon and ceramics. Carbon fiber composites can be made into various high-performance components that can meet various requirements through the selection of matrix and fiber, and the optimization design of carbon fiber content and distribution, so as to meet the needs of aerospace, electronic information, automobile and other fields. Figure 2 shows the ratio of strength and specific modulus of carbon fiber reinforced composite materials and steel, aluminum, titanium and other commonly used engineering materials when the data and functional requirements are not many and can be met by digital display. It can be seen that the specific strength and specific modulus of carbon fiber reinforced composite materials are several times higher than those of commonly used materials, especially the mechanical properties of carbon fiber reinforced polymer matrix composites are significantly higher than those of commonly used engineering materials

because carbon fiber reinforced polymer matrix composites have sufficient strength and stiffness, they are suitable for manufacturing the lightest materials of main structural parts such as automobile body and chassis. It is expected that the increasingly stringent emission standards for carbon fiber composites put forward higher requirements for automobile manufacturers. The application of carbon fiber composites can reduce the weight of automobile body and chassis by 40 ~ 60%, equivalent to 1/3 ~ 1/6 of the weight of steel structure. The British material systems laboratory has studied the weight reduction effect of carbon fiber composites. The results show that the carbon fiber reinforced polymer body weighs 172kg, while the steel body weighs 368kg, reducing the weight by about 50%. And when the production capacity is less than 20000 vehicles, the cost of producing composite body by RTM process is lower than that of steel body. However, due to the high cost of carbon fiber, the application of carbon fiber reinforced composites in automobiles is limited. They are only used in some F1 racing cars, luxury cars and small batch models, such as the body of BMW's Z-9 and z-22, m3 series roof canopy and body, GM's Ultralite body, Ford's GT40 body, Porsche 911 GT3 load-carrying body, etc

in order to increase the consumption of carbon fiber reinforced composites, the United States, Europe, Japan and other countries have stepped up the research on the low-cost and high-speed production process of carbon fiber precursor (high-grade polypropylene fine filament) and carbon fiber, so as to reduce the price of carbon fiber to about $3/pound. At present, carbon fiber reinforced composites have been used in the production of various parts of racing cars, heavy trucks and hybrid electric vehicles

obstacles and solutions to the wide application of carbon fiber reinforced composites in automobiles

there are some technical obstacles and problems in the application of carbon fiber reinforced composites in automobiles that need to be studied and solved urgently

1. Cost issues. The high price of fibers and matrix materials used in carbon fiber reinforced composites is the biggest obstacle to the wide use of carbon fiber reinforced composites in the automotive industry. Polypropylene fine silk, the precursor of carbon fiber, is expensive. The United States is studying the process of using textile grade polypropylene fine silk as the precursor and can quickly produce cheap carbon fiber, which is expected to reduce the price of carbon fiber to $3/pound

2. Lack of mass production and high production efficiency of carbon fiber composite auto parts

it is necessary to study the process method of auto parts that can grow a variety of shapes and properties. Due to the characteristics of the auto industry, the process cost is required to be low. 1.1 primary components (orifice plate, remote measuring joint, etc.) are blocked or installed incorrectly, and the productivity is required to be high. It is of great significance to study and develop the production process of composite parts with high efficiency and low cost

3. Lack of rapid and mass connection technology for composite materials

4. Recycling of composite automobile parts

there are still some problems to be solved in the recycling of carbon fiber reinforced thermosetting resin matrix composites

5. The design data, test methods, analysis tools and collision models of composite automotive parts are not perfect

carbon fiber composite has sufficient strength and stiffness, which is applicable to all vehicle models and has excellent comprehensive performance. Its application will greatly reduce the dead weight of vehicles by 40 ~ 60%. It is of great significance to vehicle lightweight and has become an important development direction of vehicle lightweight materials. At present, the price of carbon fiber reinforced composites is still relatively expensive, and the process of mass and efficient production of automotive parts still needs to be further developed and improved. These factors make the application of carbon fiber reinforced composites in automobiles limited. The application of carbon fiber reinforced composites in automobiles has been listed as the key content of the development plan of automobile lightweight materials in the world, and significant progress has been made. It is expected that carbon fiber reinforced composites will be widely used in automobiles in 2010

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