Sixteen major application areas for carbon fiber

Carbon fiber is the most important inorganic high-performance fiber, which is determined by factors such as its material nature, industrial technology complexity, application importance and market size. Its first market application is carbon fiber reinforcement commercially available in 1972. Resin fishing rod. Since then, carbon fiber applications have rapidly evolved to include high-end development represented by aerospace main structural materials. The most important application form of carbon fiber is as a reinforcement of resin material, and the carbon fiber reinforced resin (CFRP) formed has excellent comprehensive performance in missiles, space platforms and launch vehicles, aircraft, advanced ships, rail vehicles, electric Automobiles, trucks, wind turbine blades, fuel cells, power cables, pressure vessels, uranium enrichment ultracentrifuges, special tubes, public infrastructure, medical and industrial equipment, sports and leisure products, and fashion living appliances, etc. There are practical and potential applications. The application of carbon fiber in the above fields and its recent technological advances are reviewed below.

1CFRP as a key material for missiles, space platforms and launch vehicles

Carbon fiber is the material basis of the modern aerospace industry and is irreplaceable. CFRP is widely used in aerospace fields such as missile weapons, space platforms and launch vehicles. In terms of missile weapon applications, CFRP is mainly used to manufacture primary and secondary bearing structural components such as project fairings, composite supports, instrument cabins, bait chambers and launchers (Fig. 1); CFRP ensures structural deformation in space platform applications. Small, good carrying capacity, radiation resistance, aging resistance and good space environment tolerance, mainly used to manufacture structural components such as load-bearing cylinders, honeycomb panels, substrates, camera tubes and parabolic antennas for satellites and space stations (Fig. 2); In the application of launch vehicles, CFRP is mainly used to manufacture components such as the shaft fairing, instrument compartment, casing, interstage section, engine throat and nozzle (Fig. 3). At present, CFRP has become more and more mature in spacecraft applications, and it is an indispensable key material for spacecraft lightweighting, miniaturization and high performance.

2CFRP as the structural material of the aircraft

In large advanced aircraft, CFRP is widely used as the main bearing structural material. And in the recent development of new airships, CFRP is also used as a structural material.

The oil crisis of the mid-1970s was the direct cause of the application of carbon fiber to aircraft manufacturing. To alleviate the energy crisis, the then US government launched the "Aircraft Energy Efficiency Program." Modern aircraft fuselage is made of metal and composite materials such as steel, aluminum and titanium. To save fuel and improve operational efficiency, reducing the quality of the fuselage has always been one of the core challenges in aircraft design and manufacturing technology. The mature application of CFRP in the manufacture of aircraft fuselage provides the most effective way to reduce the quality of aircraft fuselage. For example, a Boeing 767 aircraft made of metal (40% CFRP) has a fuselage mass of 60 t, and when the CFRP dose is increased to 50%, the fuselage quality of the new Boeing 767 aircraft drops to 48 t. This alone greatly improved the energy and environmental benefits of the aircraft.

The Boeing 777X aircraft under development (Fig. 4) and the newly launched Boeing 787 aircraft have used up to 50% of the fuselage composite material [5]. The Boeing 777X is a large twin-engine aircraft under development by Boeing based on the Boeing 777. The first aircraft is scheduled to be put into operation in 2020. The main wing of the Boeing 777X is made of CFRP and has a wingspan of about 72m (235 feet). It is one of the longest wingspans in the current passenger aircraft. The longer the wingspan, the greater the lift, so the Boeing 777X's single-seat fuel consumption and operating costs are very competitive. In addition, the CFRP wing is not only high-strength, flexible, but also foldable at the end, so most airports can meet the needs of their wide-wing display. The main bearing structures of the main wing and fuselage of the Boeing 787 are manufactured using TORAYCA® brand carbon fiber prepreg from Toray Industries, Inc. In November 2005, Toray and the US Boeing Company signed a 10-year agreement to supply carbon fiber prepregs for the Boeing 787 Dreamliner. On November 9, 2015, Toray announced a comprehensive agreement with Boeing to supply approximately $11 billion worth of carbon fiber prepregs for Boeing's 787 and 777X aircraft. Boeing plans to increase the monthly production of the 787 aircraft from 10 in 2015 to 12 in 2016 and 14 in 2020. At the same time, the ratio of large modules will also increase, which will greatly promote the demand for CFRP. . Toray Composites (America), Inc., located in Tacoma, Washington, USA, to ensure material supply for 12 Boeing 787 aircraft per month. In January, the company expanded its production; at the same time, Japan Toray decided to invest about US$470 million to build raw silk, carbon fiber and prepreg in its acquired Spartanburg County, South Carolina plant. The integrated production line with an annual production capacity of 2,000 tons is the first time Toray has built an integrated carbon fiber production line in the United States for the development of Boeing 777X aircraft and the demand for 14 Boeing 787 aircraft.

On August 17, 2016, the UK's newly developed "Airlander 10" large airship completed its maiden voyage (Figure 5). The airship is a lighter-than-air spacecraft designed to perform reconnaissance, surveillance, communications, transportation of cargo and relief supplies, and passenger traffic. The airship uses the Vectran fabric produced by Kuraray Co., Ltd. as the skin, and the skin is filled with pressurized helium. The shape and structure of the material is CFRP, which minimizes the quality of the airship. In the unattended situation, the airship can float for up to 5 days in the air at one time.

3 CFRP as an advanced ship hull structure

CFRP is very obvious for improving the structure, energy consumption and maneuverability of ships.

Sweden has a traditional advantage in boat manufacturing technology. Its sandwich composite technology is world-class, and CFRP technology was used to develop military ships earlier. The Swedish Navy Visalth Visby, launched in June 2000, is the world's first naval vessel using CFRP in the hull structure (Figure 6). The ship has a length of 73.0 m, a width of 10.4 m, a draft of 2.4 m and a displacement of 600 t. The hull adopts a CFRP sandwich structure with high strength, high hardness, low quality, impact resistance, low radar and magnetic field signals, and excellent electromagnetic wave absorption. performance.

Due to cost reasons, although the use of CFRP in ships is still a long time, it has actually been used to manufacture key components for civil new concept boats and military ships. In 2010, Kockums of Germany built a new concept solar adventure ship, TuANor PlanetSolar, for Swedish explorers with almost all CFRP. The ship is 31.0 m long and 15.0 m wide and is powered by solar energy. On September 27, 2010, Swedish explorer Raphael Domjan drove the ship out to sea and began a global expedition (Fig. 7).

CFRP has also been used in the manufacture of ship propeller blades, integrated masts and superficial surface ship superstructures.

Low noise and quiet operation are a core technology in the field of military ships and a key indicator of the performance of ships (especially submarines). Because the propeller is running at high speed, it will produce vacant air bubbles on the blade, causing the blade to be ablated, accompanied by strong vibration and noise. CFRP blades are not only lighter and thinner, they also improve cavitation performance, reduce vibration and underwater characteristics, and reduce fuel consumption. Figure 8(a) shows the propeller used by the Israeli Deadliest submarine; Figure 8(b) shows the CFRP large freighter propeller developed by Nakashima Propeller Co., Ltd., which was in May 2014. Installed on the Taiko Maru chemical tanker. Figure 9 shows the CFRP thruster system produced by Rolls-Royce plc for Benetti yachts.

In addition, stealth is also an important indicator for evaluating the advanced level of military ships. To improve stealth performance, it is necessary to reduce the radar reflection cross section of the ship's hull and reduce its optical characteristics. In the past, a number of whip-like and strip-shaped antenna masts were erected on the ship's superstructure, which greatly hindered the ship's stealth capability in the detection equipment. In 1995, the US military began researching an integrated mast system that designed various antennas into a planar or spherical array and integrated into an integrated mast system made of a composite material that reflects electric waves. It is weatherproof and salt spray resistant. Infringement. What's more, the entire superstructure of the US military's next-generation warships is made of composite materials. On October 15, 2016, the US Navy held the ceremony for the first Zumwalt-classdestroyer. The ship is the next generation of the US Navy's main battleship, which integrates the most advanced naval ship technology, such as hull modeling, electric driving force, command and control, intelligence communication, stealth protection, detection and navigation, and firepower configuration. Transcendence. It is particularly noteworthy that the ship's superstructure and embedded antenna system was designed and manufactured by Raytheon, USA, using Integrated Composite Deckhouse and Assembly (IDHA) for light weight and high strength. It has good rust resistance, good wave permeability, excellent stealth performance, and the probability of being found is less than 10% (Figure 10).

4 CFRP as the body structure of rail transit vehicles

Lightweight is a key technology to reduce energy consumption in train operations. Metal-made rail trains, although high in strength, have high quality and high energy consumption. Taking the C20FICAS stainless steel subway train as an example, its energy consumption per kilometer is about 3.6×107 J (ie 10 kWh), and the operation of 150,000 km consumes about 540 000 GJ of energy; if the quality can be reduced by 30%, it can save energy by 27,000×30. %=8,100 GJ73.

CFRP is the focus of the new-generation high-speed rail train body selection. It not only makes the rail train body lightweight, but also improves high-speed running performance, reduces energy consumption, reduces environmental pollution, and enhances safety [11]. At present, the application trend of CFRP in the field of rail vehicles: from non-loaded structural parts such as car interior and interior equipment to vehicle body, frame and other bearing members; from the apron, shroud and other components to the top cover, the driver's cab The development of large-scale structures such as vehicle bodies; mainly based on mixed structures of metal and composite materials, and the amount of CFRP is greatly increased.

Figure 11 shows the mass ratio of each part of the intermediate train of a subway train, in which the body quality accounts for about 36%, the vehicle equipment accounts for about 29%, and the interior decoration accounts for about 16% [10]73. Since the in-vehicle equipment has almost no weight-reducing space, the body and interior decoration have become the focus of weight reduction. In 2000, the French National Railways Corporation (SNCF) developed a double-layer TGV trailer using carbon fiber composite materials; the Korean Railway Research Institute (KRRI) developed a TTX tilting train with a running speed of 180 km/h. The car body is made of stainless steel reinforced skeleton, the side wall body and the top cover are made of aluminum honeycomb core, and the skin is made of CFRP sandwich structure. The total mass of the car body shell is 40% lower than that of the aluminum alloy structure, and the car body strength and fatigue Strength, fire safety, dynamic characteristics and other performance are good, and put into commercial operation in 2010.

In 2011, the Korea Railway Research Institute (KRRI) developed the CFRP subway steering frame with a mass of 635 kg, which is about 30% less than the quality of the steel frame. The roof of the CFRP high-speed train jointly developed by the Japan Railway General Technology Research Institute (JRTI) and the East Japan Railway Company reduced 300-500 kg per car. In September 2014, the CFRP frame side beam developed by Kawasaki of Japan was about 40% smaller than the metal beam.

5CFRP as the body structure of electric vehicles

Research by the British Materials Systems Laboratory on materials lightweighting and lowering production costs shows that for every 10% reduction in vehicle quality, fuel consumption can be reduced by 6%. Among the existing materials, CFRP has the best light weight effect; in addition, the rapid development of automotive design and composite technology. These have made CFRP application in the automotive industry far faster than people expected.

The launch of the BMW BMWi model has led this trend. In 2008, BMW held a conference in Munich with the aim of revolutionizing urban transportation technology. It established a “Project i” think tank. The only task was to “forget everything that was done before and rethink. all". In 2009, the think tank formed a new concept of energy saving - "BMW Vision Efficient Dynamics", which laid the ideological foundation for BMW's follow-up research. It required special design of the body and drive system to achieve New energy efficiency, and the previous idea is to integrate existing energy-saving technologies into existing templates. In 2011, BMW established the “Born Electric Technology” and created the BMWi brand, which allows people to use all-electric energy in their daily driving journey. In the same year, the first all-electric BMWi3 concept car realized the technical demonstration. . In 2012, the BMWi8 concept car with high energy efficiency and superior performance of sports car was launched. It uses lightweight materials such as CFRP, aluminum and titanium to achieve breakthrough weight loss. In the same year, the new BMW i3 electric drive system (eDrive Propulsion) System) was launched to achieve zero emissions. In 2013, the BMW i3 was mass-produced. In 2014, the BMW i8 was mass-produced. In 2016, BMW launched the BMW i Vision Future Interaction concept car at the Consumer Electronics Show in Las Vegas (Figure 13). At the same time, it launched the new BMWi3 (94Ah) model. 1 245kg, a cruising range of up to 200 km on a single charge, and an acceleration time of 7.3 s per 100 km, with unique flexibility.

Among them, the BMW i3 adopts the "LifeDrive" modular body structure design, which consists of two parts: the occupant (Life) module and the chassis drive (Drive) module. The occupant module is also called the life module (Fig. 14). It constitutes the passenger space for the occupants. The life module made of CFRP is light in weight, very safe, and has a spacious and convenient ride. The chassis drive module, also known as the eDrive drive system, is constructed of aluminum alloy and integrates a motor (maximum power 125 kW, maximum torque 250 N·m), power components such as batteries and fuel engines.

Through cooperation with SGL Automotive Carbon Fibers, SGL Automotive has been developing its own carbon fiber for more than 10 years. The manufacturing process of the life module of the BMWi3 type car: the carbon fiber is woven into a fabric and then immersed in a special resin to make a prepreg; the prepreg is heat-set into a rigid body part; the specially developed technology is used to complete the body parts. Automatically bonded to complete body parts (Figure 15). The resulting CFRP body has a very high compressive strength, can withstand faster acceleration, and the vehicle's agility and road feel are very good.

6CFRP as the body structure of the new concept cargo truck

World retail giant Walmart has 11,500 stores in 63 regions in 28 countries. It has a fleet of nearly 6,000 trucks in the United States that will deliver its products to thousands of stores throughout the United States. In order to maintain sustainable viability and efficiency, the team has always been aiming at “less mileage and more transportation”, relying on improving driver driving technology, adopting advanced traction trailers, improving process and system planning, etc. to achieve 2007-2015. During the year, the fleet traveled over 4.8 million km, the number of containers shipped exceeded 800 million, and the transportation efficiency increased by 84.2% compared with 2005.

Among them, the performance of the traction trailer is of great importance to achieve the goal of “doing more and less running”, so Wal-Mart invested heavily in the new concept truck research project of “The Walmart Advanced Vehicle Experience”. The new concept trucks have been developed with integrated aerodynamics, microturbine hybrid drive systems, electrification, advanced control systems, and cutting-edge technologies such as CFRP bodies. The main technical innovations: advanced aerodynamic design, elegant overall design, aerodynamic performance increased by 20% compared with the current Model 386 truck; micro-turbine hybrid electric drive system is clean, efficient, fuel-efficient; driver seat design in the center of the cab, with 180° field of view; electronic dashboard provides customized range and performance data; sliding doors and folding steps for added safety and security; and a spacious cab with retractable bedroom with rollaway bed. The entire body of the towing trailer is made of CFRP. The top and side walls are made of 16.2 m (53 ft) long single plates. The excellent mechanical properties ensure the structural strength of the car body. Adhesive with advanced adhesives maximizes The number of rivets is reduced; the convex nose shape design can effectively improve the aerodynamic performance under the premise of fully ensuring the cargo capacity; the low profile LED lighting is more energy-saving and durable.

At present, the program has completed 84% of the task, but there are still many innovative technologies to be further developed. It is foreseeable that Wal-Mart's new concept trucks have a significant impact on the advancement of truck technology and the expansion of carbon fiber applications.

7 CFRP as a reinforcing structure for wind turbine blades

Wind energy is the most cost-effective renewable energy source, and wind power generation has achieved rapid development in the past 10 years. As of May 2016, global wind power installed capacity has reached nearly 427 billion MW (Table 1). It is predicted that by 2020, the installed capacity of new wind power will increase at an annual rate of 25%; by 2020, wind power will account for 11.81% of the world's total power generation.

In order to improve the wind energy conversion efficiency of wind turbines, it is the key to increase the capacity of a single unit and reduce the mass per kilowatt. In the early 1990s, wind turbines had a single unit capacity of only 500 kW, and today, offshore wind turbines with a single unit capacity of 10 MW have been commercialized. Wind turbine blades are the key components for effective wind energy capture in wind turbines. The length of the blades increases with the increase in the capacity of the wind turbine. According to the top rotation theory, in order to obtain greater power generation capacity, wind turbines need to install larger blades. In 1990, the impeller diameter (Rotor Diameter) was 25 m; in 2010, the impeller diameter reached 120 m. In 2011, Kaj Lindvig predicted that the impeller diameter of offshore wind turbines would reach 135 m in 2015 and 160 m in 2020. But this prediction was quickly broken, and the 10 MW offshore wind turbine that American Superconductor Corp. has put into market in 2016 has an impeller diameter of 190 m. However, due to the length of the blade, there is controversy over whether the industry needs to develop wind turbines with a capacity of 10 MW or more, but the mainstream view is that it needs to be developed. The chief technology officer of Siemens Wind Power believes that the scientific law of the relationship between area and volume will eventually limit the growth of the impeller diameter, but it has not yet reached the limit, and it is technically feasible to manufacture 10 MW wind turbines; In terms of operational efficiency, reducing the operating cost per megawatt hour requires increasing the capacity of the wind turbine (Figure 17).

The increase in the diameter of the impeller imposes a lighter and higher requirement on the quality and tensile strength of the blade. CFRP is a key material in the manufacture of large blades that compensate for the lack of performance of fiberglass composites (GFRP). However, for a long time, due to cost factors, CFRP has only been used in blade manufacturing for key parts such as spars, roots, tips and skins. In recent years, as the price of carbon fiber has stabilized and decreased, and the length of the blade has been further lengthened, the application of CFRP has increased and the dosage has been greatly improved. In 2014, Sinoma Technology Wind Power Blade Co., Ltd. successfully developed the longest 6 MW wind turbine blade in China. The blade has a total length of 77.7 m and a mass of 28 t. The main beam is made of 5 t domestic CFRP. If the GFRP design is used, the blade quality will be approximately 36 t (Figure 18).

8 carbon fiber paper as electrode gas diffusion material for fuel cell

A fuel cell is a device that directly converts chemical energy into electrical energy without burning. Fuel cells operate under isothermal conditions, which use electrochemical reactions to directly convert chemical energy stored in fuels and oxidants into electrical energy. It is a high-profile clean energy technology with very high conversion efficiency (except 10% energy). In the form of waste heat, the remaining 90% is converted into available heat and electricity and is environmentally friendly; in contrast, when using fossil fuels such as coal, natural gas and petroleum to generate electricity, 60% of the energy is waste heat. Form waste, and 7% of the power is wasted in the transmission and distribution process, and only about 33% of the energy can actually be used on the powered device (Figure 19).

Among various fuel cells, the proton exchange membrane fuel cell (PEMFC) is an ideal power source for automobiles because of its high power density, high energy conversion rate, and low temperature startability, and its small size and portability. The proton exchange membrane fuel cell consists of three main parts: the cathode, the electrolyte and the anode. The working principle is as follows:

(1) The cathode ionizes liquid hydrogen molecules. When liquid hydrogen flows into the cathode, the catalyst layer on the cathode ionizes the liquid hydrogen molecules into protons (hydrogen ions) and electrons.

(2) Hydrogen ions pass through the electrolyte. The electrolyte located in the central region allows protons to pass through to the anode.

(3) The electrons pass through an external circuit. Since electrons cannot pass through the electrolyte, they can only pass through an external circuit, thus forming a current.

(4) The anode ionizes the liquid oxygen. When liquid oxygen passes through the anode, the catalyst layer on the anode ionizes the liquid oxygen molecules into oxygen ions and electrons, and combines with the hydrogen ions to form pure water and heat; the anode receives electrons generated by ionization. A plurality of proton exchange membrane fuel cells can be connected to form a fuel cell stack, which can increase the output of electric energy.

United Technologies is a global leader in military and civilian fuel cell technology. UTC Power was originally a business unit of United Technologies, and its products are widely used in spacecraft, submarines, construction, bus and home vehicles. In the early 1990s, UTC Power had built a large fixed fuel cell power station and put it into commercial operation. For more than 10 years, UTC Power has been working on the development of fuel cell technology for bus and home vehicles. In December 2005, the fuel cell developed by UTC Power was put into use on a hybrid bus, and commercial operation was carried out by SunLine Transit in Thousand Palms (CA), California, USA. .

Since 2008, due to breakthroughs in technical bottlenecks such as cost and longevity, the commercial application of fuel cells has made substantial progress. The FCveloCity® fuel cell developed by Ballard Power Systems Inc. is the seventh generation of expandable modular fuel cell developed for bus and light rail. It can be used to form 30~200. kW power supply. The 85 kW class FCveloCity® fuel cell, which was launched in June 2015, is mainly used for electric buses.

As a high-performance composite material, carbon fiber paper is an indispensable porous diffusion material for the gas diffusion layer in the fuel cell proton exchange membrane electrode (Fig. 23). The gas diffusion layer (GDL) constitutes the channel through which the gas diffuses from the flow cell to the catalyst layer. It is the heart of the fuel cell and is a very important supporting material in the membrane electrode assembly (MEA). Its main function is as a connecting membrane electrode group and a graphite plate. Bridge. The gas diffusion layer can help the by-product generated outside the catalyst layer, water flow away as soon as possible, avoiding overflow caused by accumulated water; it can also help maintain a certain moisture on the surface of the membrane to ensure the conductivity of the membrane; during the operation of the fuel cell, help The heat conduction was maintained; in addition, sufficient mechanical strength was provided to maintain the structural stability of the membrane electrode assembly as the water absorption was expanded (Table 2).

In proton exchange membrane fuel cells and direct methanol fuel cells, the combined effect of using both carbon fiber paper and carbon fiber cloth as a gas diffusion layer is better. Each fuel cell electric vehicle consumes about 100 m2 of carbon fiber paper (ie 8 kg).

At the Global Rail Equipment Fair held on September 23-26, 2016, Alstom of France released its newly developed world's first liquid hydrogen fuel cell electric train. The car is part of the Alstom Coradia iLint series of regional trains, according to 2014 with the German Landers of Lower Saxony, North Rhine-Westphalia, Baden A new generation of zero-emission fuel cell powered trains developed by the public transport department of Baden-Württemberg and the Public Transportation Authorities of Hesse. The newly released liquid hydrogen fuel cell electric trains are all developed with mature technology. The roof is equipped with hydrogen fuel cells. The bottom of the passenger compartment is equipped with lithium batteries, converters and electric motors. It will open up a larger application market space for fuel cells and promote Further development of carbon fiber paper technology (Figure 24).

9 CFRP as the core material of power cable

Electrical energy is a necessary energy source for production and life. There is a serious line loss problem in the process of transferring electrical energy from a power plant to a power station. Line loss refers to the electrical energy loss caused by power transmission links such as transmission, substation, and distribution.

Increasing the current transmitted in the overhead line can cause the cable to heat up. If the cable material has poor heat resistance at this time, the bearing capacity of the cable will decrease, and sag will occur. The sag is an important source of line loss and a major factor limiting the transmission capacity of overhead lines.

The reinforced steel core in the steel core aluminum wire is sag when heated, and the sag will cause the cable to sag seriously when it exceeds 70 °C, and it is more likely to contact the adjacent object to cause a short circuit, and even fall to the ground to endanger the life of the personnel. A short circuit caused by a sag causes an instantaneous overload of adjacent overhead lines and transformers, causing catastrophic failure. Although the self-supporting aluminum stranded wire can allow a short, high operating temperature (150 ° C), it can not avoid the occurrence of sag.

Composite core material aluminum wire (ACCC) replaces metal core material with composite core material, which opens up a more effective technical way to solve the problem of overhead line sag. In 2002, based on the patented technology of ACCC, CTC Global, a global leader in power supply and distribution equipment technology, launched product research and development in order to put it into use. The development goal at that time was to develop CFRP core materials to carry aluminum conductors without any changes to the existing overhead line carrying towers and without increasing the current conductor quality or diameter to reduce thermal sag, increase tower distance, and load. Larger current, reduced line loss, improved reliability of the power supply network, etc. In 2005, the company launched the commercial ACCC wire product for the first time. The strength of the CFRP core aluminum wire developed and produced is twice that of the same quality steel core aluminum wire, and the current capacity transmitted is twice that of other core aluminum wires. The damage is reduced by 25%~40% compared with other core aluminum conductors, and its high capacity, high efficiency and low sag performance far exceeds other material core aluminum conductors.

For cross-section comparison of aluminum conductors of the same diameter, the diameter of the steel core is significantly larger than the diameter of the CFRP core, which allows the CFRP core aluminum conductor to accommodate 28% more aluminum conductors, thereby increasing the current passing capability.

10CFRP as a winding reinforcement for pressure vessels

High-pressure vessels are mainly used for the storage of gaseous or liquid fuels required for aerospace vehicles, ships, vehicles and other vehicles, as well as for the storage of gas by firefighters and divers using positive-pressure air breathing apparatus. In order to store as much gas as possible in a limited space, it is necessary to pressurize the gas. Therefore, it is necessary to increase the pressure bearing capacity of the container and enhance the container to ensure safety.

In the 1940s, the United States began research on the use of composite materials for reinforcing high-pressure vessels in weapons systems. In 1946, the United States developed a filament wound pressure vessel; in the 1960s, filament winding technology was used on the solid rocket motor casings of Polaris and Saturn to achieve a lightweight and high structure. In 1975, the United States began to develop lightweight composite high-pressure gas cylinders, using S-glass fiber / epoxy, para-aramid / epoxy winding technology to manufacture composite materials to enhance pressure vessels.

Later, scientists have developed a variety of advanced composite materials enhanced by glass fiber, silicon carbide fiber, alumina fiber, boron fiber, carbon fiber, aramid fiber and PBO fiber (Table 3). Among them, para-aramid has been used extensively for the winding reinforcement of various aerospace pressure vessels, and then gradually replaced by carbon fiber [30] 37, [31] 47. In the 1970s, filament wound metal lining light pressure Containers are used extensively in power systems for spacecraft and weapons; in the 1980s, carbon fiber reinforced seamless aluminum alloy lined composite pressure vessels emerged, which made pressure vessels less expensive to manufacture, lighter in weight, and more reliable. . The composite reinforced pressure vessel has a fatigue failure mode that leaks before rupture, improving safety. Therefore, fully wound composite high pressure vessels have been widely used in spacecraft such as satellites, launch vehicles and missiles. A titanium alloy spherical helium cylinder used by the Appolo moon landing spacecraft has a volume of 92L, a burst pressure of ≥47MPa, and a mass of 26.8kg. The standard aerospace steel-lined composite helium cylinder has a mass of 20.4kg and is lined with aluminum. The mass of the composite helium cylinder is 11.4kg, and the mass of the unlined composite cylinder is only 6.8kg (compared to the mass of the titanium alloy spherical helium cylinder by 75%).

High performance fibers (Table 3) are the main reinforcements for fully wound fiber reinforced composite pressure vessels. By designing and controlling the content, tension and winding trajectory of high-performance fibers, the performance of high-performance fibers can be fully utilized to ensure uniform and stable performance of composite pressure vessels, and the difference in burst pressure is small. Nearly 70% of the material cost of a high-pressure helium-type hydrogen cylinder (full metal winding) is a reinforcing fiber, and the remaining 30% is a liner and other materials.

In the 1930s, Italy took the lead in using natural gas as a fuel for cars. Steel gas cylinders are used in early car gas, and its heavy weight problem has always limited the expansion of steel cylinders. In the early 1980s, a composite gas cylinder with a glass fiber ring reinforced aluminum (or steel) liner was born. Due to the poor axial strength of the hoop-reinforced composite gas cylinder, the metal liner is still thick. In order to solve this problem, a full-wound fiber-reinforced composite gas cylinder which is enhanced in the circumferential direction and the axial direction has been developed at the same time, and the thickness of the metal liner is greatly reduced, and the quality is remarkably reduced. In the 1990s, composite gas cylinders with plastic as the liner appeared. In the field of new energy vehicles, the application of high-pressure gas cylinders is mainly high-pressure hydrogen storage bottles for fuel cell power vehicles, and the pressure has reached 70 MPa.

11 CFRP as a high-speed rotor material for uranium enrichment ultra-high speed centrifuges

The uranium 235 content of uranium dioxide in civil nuclear reactor fuel assemblies is 4.0% to 5.0%, and the uranium 235 content in nuclear fuels required for nuclear bombs is at least 90.0%.

The main component of natural uranium ore is uranium 238, of which uranium 235 accounts for only 0.7%. In industry, uranium enrichment is often carried out by gas diffusion method. Although this method has large investment and high energy consumption, it is the only feasible method at present. The uranium hexafluoride gaseous compounds of uranium 235 and uranium 238 differ by less than one percent in mass. At pressure separation, less than one percent of the mass difference causes the uranium uranium uranium uranium gaseous compound to pass through the porous membrane at a slightly faster rate. The uranium 235 content increases slightly for each pass of the porous membrane, but the increment is very small. Therefore, in order to obtain pure uranium 235, uranium hexafluoride gas is required to pass through the porous membrane thousands of times. Industrial processing is the concentrating of uranium 235 by allowing uranium hexafluoride gas to repeatedly pass through cascaded centrifuges.

Uranium concentrated gas centrifuge technology is the key to nuclear fuel production and an important indicator of nuclear technology. The uranium enriched gas centrifuge has the characteristics of high vacuum, high speed, strong corrosion, high Mach number, long life and non-maintenance. Its development involves mechanical, electrical, mechanical, materials science, aerodynamics, fluid mechanics, computer applications, etc. The theory and technology of the discipline is very difficult [32]. The speed of the rotor in the centrifuge is directly related to the gas separation efficiency. The higher the rotor speed, the higher the gas separation efficiency. Therefore, ensuring the rotor speed above 60000r/min is the most basic performance requirement for uranium enriched gas centrifuges. This high speed puts very demanding requirements on the material of the rotor. The metal rotor can't reach such a high speed at all, because it can't cross the resonant frequency, the metal rotor will break when it reaches the resonant frequency; the CFRP rotor does not have this problem, it can withstand more High speed. Therefore, as early as the 1980s, CFRP was used to manufacture high-speed rotors for uranium enriched gas centrifuges. With the advancement of CFRP technology, the rotor made of CFRP can withstand higher speeds and the uranium enrichment efficiency is greatly improved.

In view of the important role of CFRP high-speed rotors in uranium enrichment production, Western countries have been using CFRP high-speed rotors for non-nuclear embargoed gas centrifuges. On November 9, 1992, the United States "Nuclear Fuel" magazine reported that Karen Heinz Schaap, a former employee of the European uranium enrichment company (Urenco), a subsidiary of Maschinenfabrik Augsburg-Nurnberg AG, co-operated with his wife. A company called Ro-Shc. The couple sold at least 20 CFRP centrifuge rotors to Iraq through Ro-Shc. On November 2, 1992, the federal prosecutor of Augsburg issued an arrest warrant to Kar1 Heinz Schaap. This matter further confirms the importance of CFRP in uranium enriched gas centrifuge technology.

12 CFRP as a reinforcing material for special tubes

Unlike the pressure vessel's long-term continuous withstand pressure, special tubes such as barrels, barrels, and hydraulic actuators need to withstand high voltage and release high voltage for a long time. These special-purpose pressure-bearing tubes, reinforced by carbon fiber winding or prepreg, are effective in reducing their own quality, improving heat dissipation, improving accuracy, and extending life.

PROOF Research, a technology-based company headquartered in Montana, USA, has developed a CFRP-enhanced barrel.其将先进复合材料技术与热-机械设计原理相融合，并采用了航空专用碳纤维和航天高温树脂，研制出新一代运动用和军用枪馆。与钢质枪管相比，CFRP增强枪管自身质量最高可减小64%，射击精度可达比赛级要求。此外，该公司研制的CFRP增强枪管在设计与制造工艺上适应了碳纤维的纵向(即沿枪管长度方向)热扩散率特性，能更有效地通过枪管壁散热，极大地提高热扩散效率，且枪管能快速冷却，并可在持续开火状态下更长时间地保持射击精确度，是被美国军队唯一验证过的CFRP增强枪管。

CFRP技术在枪管上的成功应用很快推广到对各式炮管的增强。同时，利用CFRP增强的特种液压作动筒也已面市。

13 CFRP作为公共基础设施建设用的关键材料

桥梁是重要的交通基础设施。在建设跨江河、跨海峡的大型交通通道中，需修建很多大跨度的桥梁。悬索桥是超大跨度桥梁的最终解决方案。

但跨径增大会使得悬索桥钢质主缆的强度利用率、经济性和抗风稳定性急剧降低。目前，在大跨度悬索桥中，高强钢丝主缆自身质量占上部结构恒载的比例已达30%以上，主缆应力中活载所占比例减小。如，跨度1991 m的日本明石海峡大桥，钢质主缆应力中活载所占比例仅约为8%。

此外，跨径增大还会降低桥梁的气动稳定性。有研究表明，从气动稳定性角度考虑，2000m的跨径是加劲梁断面和缆索系统悬索桥的跨径极限。而改善结构抗风性能需解决好提高结构整体刚度、控制结构振动特性和改善断面气动特性等3个问题。大跨度悬索桥的结构刚度取决于主缆的力学性能。CFRP的力学特性使得其成为了大跨度悬索桥主缆的优选材料。利用悬索桥非线性有限元专用软件BNLAS，研究主跨3500m的CFRP主缆悬索桥模型的静力学和动力学性能最优结构体系，得出：CFRP主缆自身质量应力百分比大幅降低，活载应力百分比提高到13%(钢主缆为7%)，结构的竖弯、横弯及扭转基频大幅提高；CFRP主缆安全系数的增加将提高结构的竖向和扭转刚度；增大CFRP主缆的弹性模量可大幅减小活载竖向挠度，提高竖弯和扭转基频。

总之，CFRP主缆可明显提升大跨径悬索桥的整体性能。

此外，建筑与民用工程领域是最早将碳纤维用于结构增强的。通过在桥梁等建筑物上铺覆碳纤维织物，可提高水泥结构体的耐用性，以及水泥结构建筑物的抗震性能。

未来，CFRP很可能成为名副其实的建筑材料。世界各国都在加快技术开发，使CFRP能直接用作建筑结构材料。如，利用CFRP的导电性制作建筑用电磁防护材料；在CFRP中嵌入传感器制作智能建筑材料，利用传感器传送的数据实时掌握建筑物结构可能受到的损害。

14 CFRP在医疗器械和工业设备领域的应用

在医疗器械领域，利用其X射线全透射性，其被用于制造X光检查仪用移动平台；利用CFRP优异的机械性能，其被用于制造骨科用和器官移植用等医疗器械，以及制造假肢、矫形器等康复产品。

由短切碳纤维与质量分数占10%~60%的尼龙或聚碳酸酯模塑成型的CFRP部件，质量轻、厚度薄、抗静电、抗电磁，在电子信息产品如笔记本电脑、液晶投影仪、照相机、光学镜头和大型液晶显示板等中应用广泛。加之CFRP具有优异的抗撕裂性能，还可用于制造轴承、辊轴、管材等产品，其强度与钢质产品相同，但质量可大幅降低。

15 CFRP在体育休闲用品领域的应用

体育休闲用品是CFRP最早进入市场化的应用领域。随着性价比的提高，这一领域已形成了对CFRP的稳定需求。滑雪板、滑雪手杖、冰球杆、网球拍和自行车等，是CFRP在体育休闲用品中的典型应用(图33)。

16碳纤维作为时尚元素材料

碳纤维本身具有的黑亮色泽，以及其机织物和缠绕物构成的纹理、走向和质感，为时尚设计师们提供了丰富的想象空间和造型元素。目前，使用碳纤维制成的服装饰品有鞋、帽、腰带、首饰、钱包(夹)、眼镜架等，旅行用品有行李箱等，居家用具有桌、椅、浴缸等(图34)。所有这些制品都展示出了碳纤维高冷、坚韧、骄傲和优雅的时尚特质。它们既是日用品，又是艺术品，给人们的生活增添了极致奢华的技术和艺术享受。

17结语

综上可见，碳纤维在众多领域有着广泛的应用。应用市场的不断细分还将推动碳纤维技术的差别化发展，将有更多、更好的碳纤维制品被制造出，以促进社会绿色发展、满足人们多样化的生活需求。