Anhui Plato Coated Fabrics Co.,LTD

Information dynamics

Carbon fiber composite materials have wide application prospects in sports equipment field

Word:[Big][Middle][Small] QR Code 2018/4/20     Viewed:    

Carbon fiber is of great significance to the new material field. However, many people do not understand carbon fiber material. In simple terms, it is a high-carbon inorganic polymer fiber material. "The quality is lighter than that of metallic aluminum, but its strength is higher than that of steel." It has four product forms: fiber, cloth, prepreg and chopped fiber. Fabric refers to a fabric made of carbon fiber; prepreg is a uniform arrangement of carbon fibers in one direction, and the carbon fiber or cloth is impregnated with resin to convert it into a sheet; chopped fibers refer to short fibers. According to different proportions, these products will be applied together with the resin to form a carbon fiber reinforced composite (CFRP). At present, new materials used to manufacture sports equipment are mainly composite materials, and carbon fiber composite materials are among the best. In a sense, modern athletics is a sport that challenges the limits of human fitness. The slightest improvement in the world record of any project often requires and depends on technology. The use of new materials to enhance the performance of competition equipment, and thus improve the performance of the case is common.
Advantages of carbon fiber composites for sports equipment
1, Light weight
Sports equipment such as poles, golf clubs, tennis racquets, bicycles, skis, kayaks, etc., rely on humans to make them move. People want their quality to be as light as possible; even if they rely on power other than manpower to make them sporty. The equipment, such as racing cars, sailing boats, motor boats, etc., are also lighter in quality under the same conditions. The carbon fiber composite material has unparalleled advantages in this respect, its density is 1.76 to 1.80 g/cm3, the composite material density is 1.50 to 1.60 g/cm3, and the steel is about 7.87 g/cm3, aluminum 2.7 g/cm3, titanium 4.5 g/cm3. Obviously, carbon fiber composites are much lighter than metal materials.
2, High specific strength and high specific modulus
The specific strength (strength per unit mass) and specific modulus (modulus per unit mass) of carbon fiber composite materials are 4 and 3 times that of Chinese fir, 3.4 and 4.4 times that of Chinese zelon, and 7 to 7 times that of steel. 1 2 times and 3-5 times. The outstanding specific strength and specific modulus make it can be used to manufacture various products that are light, strong and rigid, and are particularly suitable for making sports equipment.
3, High fatigue strength
The structure of carbon fiber is stable. After it is made into a composite material through millions of cycles of stress fatigue tests, its strength retention rate can still reach 60%, while steel is 40% and aluminum is 30%. The high fatigue resistance makes the sports equipment longer life.
4, Small thermal expansion coefficient
The coefficient of thermal expansion of carbon fiber is almost negative at room temperature. When the temperature is 200 to 400°C, the coefficient of thermal expansion thereof is zero. When the temperature is lower than 1 000°C, the coefficient of linear expansion thereof is 1.5×10K.
5, Good damage and safety performance
In the carbon fiber composite material, due to the action of the matrix, the strains of the fibers are substantially the same when pulled in the fiber direction. As a result of the stress of the fractured fiber due to the transfer of the matrix, most of the remaining fibers still function except for the fact that the fracture does not play a role. The breakage of individual fibers does not cause chain reaction and catastrophic rapid destruction, and thus breakage safety performance is very good.
6, Good damping performance
The polymer matrix of carbon fiber composite material has viscoelasticity. There are frictional forces in the matrix and in the interfaces where there are micro-cracking and de-bonding. In the vibration process, viscoelasticity and frictional force make part of the kinetic energy converted into heat energy. Therefore, its damping is greater than that of steel and aluminum alloy, and damping can be increased if specific measures are taken.
7, Design freedom
The development of composite molding technology has greatly increased the freedom of design. A significant feature of fiber composites is anisotropy. By changing the direction and manner of fiber layup, local reinforcement or enhancement of stress conditions in a certain direction can be based on the player's age, gender, skill level, physical strength, etc. Different situations are designed to maximize the use of sports equipment, which is generally difficult to achieve for isotropic metal materials.
Carbon fiber product form and main molding technology for sports equipment
The carbon fiber composite material can be integrally molded through a reasonable design, which can save many combined frames and assembly frames and reduce production costs. With the development of technology, there are many methods for molding sports equipment, including winding molding, compression molding, RTM molding, and pultrusion molding.
1, Winding molding technology
In a special winding machine, the prepreg is evenly and regularly wrapped around a rotating mandrel, and finally the mandrel is cured and removed to obtain the product. The winding method is applicable to the manufacture of simple rotating bodies such as cylinders, spheres, and some positive curvature or barrel-shaped products, as well as non-rotary parts. The distinctive feature is that the fibers can be arranged in accordance with certain laws according to the force conditions of the products, so as to give full play to the strength of the fibers, obtain light and high-strength products, and achieve continuous and mechanized production in the process, and the production cycle is short. The production efficiency is high and the labor intensity is low. The disadvantage is that the mandrel needs to be removed after the product is cured, and it is not suitable for the manufacture of products with concave curved surfaces. Golf clubs and fishing rods can be made in this way.
2, Molding technology
The compression molding process is a method of curing a composite article by heating and pressure within a closed mold cavity. Molding mold consists of two parts: female and male molds. Reinforcing materials are usually chopped fiber mats, continuous fiber mats and fabrics. The press molding method has high production efficiency, accurate product dimensions and smooth surface, and is particularly suitable for manufacturing high-volume products with relatively high precision and repeatability requirements. The products with complex structure can be formed at one time without auxiliary processing (such as car, milling, planing, grinding, drilling, etc.) that will damage the performance of the products. The appearance and size of the products are reproducible. The disadvantages are: the design and manufacture of molds are complex, the initial investment is high, and they are easily limited by equipment.
3, RTM molding technology
RTM (Resin Transfer Molding, abbreviated RTM) is a commonly used molding technique for composite materials. The technique is to lay the fibers or preforms into closed mold cavities, inject the resin liquid into the mold cavity with pressure, saturate the fibers or preforms, and then cure and demold the molded products. The advantages of RTM technology are that it can manufacture high-quality, high-precision, low-porosity, high-fiber-content complex composite components, and can obtain a smooth double surface without gel coat resin; the product has short production time and high production efficiency from design to production. RTM molds and products can be designed using CAD, easy mold manufacturing, a wide range of material selection; RTM molding components and pipe parts easy to achieve local reinforcement or to manufacture locally thickened components, composite materials with a core material can be molded once; RTM molding Less volatility in the process helps protect workers and the production environment. At present, RTM technology is generally used to mass produce body parts of bicycles and rowing boats.
4, Pultrusion technology
For continuous production of fiber composite profiles. Pultrusion refers to a method in which a fiber bundle or a strip fabric is pulled by an external force and is subjected to dipping, extrusion molding, heat curing, and fixed length cutting to produce a linear product having a specific cross-sectional shape and an unlimited length. . It passes the impregnated continuous fiber through a molding die with a certain cross-sectional shape, solidifies in the mold cavity or gels in the mold cavity, and the mold is heated and solidified, so that an infinitely long profile can be continuously pulled out under the pulling force of the traction mechanism. Products. The pultrusion process is simple and the efficiency is high. When the pultrusion method is used to prepare the products, the reinforcing fibers are arranged in parallel along the axial direction and can effectively utilize its strength; the isotropic products can be prepared by using fiber mat reinforcement materials; the use of braided belts can improve the products Transverse intensity. Pultrusion products are characterized by high strength, light weight, easy decoration, and good surface quality. These properties are ideal for many types of sports facilities and related applications such as fishing poles, bows, poles, ski poles, and more.
Application Example of Carbon Fiber Composite Materials in Sports Equipment
The higher the specific strength of carbon fiber composites, the lower the self-weight of the components; the higher the specific modulus, the greater the stiffness of the components. Therefore, taking full advantage of the characteristics of carbon fiber composites can improve the performance of many sports.
1, Pole vault
The pole vault has been formally absorbed as a competition item in the first Olympic Games. The poles were made of hickory wood, and they were heavy, inflexible, and had poor energy storage characteristics. As a result, the kinetic energy of players was mostly wasted, so they jumped out. The best result is only 3.3 m. Afterwards, bamboo rafts replaced wooden poles, where the light and light qualities are conducive to running. Elasticity is conducive to the transformation of energy. In the 1960s, athletes began to use nylon vaults, and soon nylon vaults were replaced by glass fiber tantalum. The constant reform of the pole vault material has caused the world record to be repeatedly brushed. Nowadays, pole vault has developed into the fourth generation. Glass fiber and nylon have been replaced by carbon fiber composite materials with better performance. The material of different parts can be designed according to the difference in the force of the poles, so that the overall performance is optimal. The latest carbon fiber stays can ensure that the poles are both flexible and strong without breaking or kinking. It can convert the kinetic energy of the athlete's quick run into the elastic deformation energy of the poles. When the poles are bent to the maximum curvature, This part of the elastic deformation can be released again, turning into the athlete's potential energy, helping the athlete to leap up and fly over the crossbar.
2. Golf clubs
In the 1930s, steel rods were the standard golf clubs in the United States. In 1972, the United States first used carbon fiber composite materials to make clubs. By 1998, the number of carbon fiber golf clubs exceeded that of steel rods. The golf club is composed of a handle, a shaft, and a club head. The golf club made of carbon fiber composite material can reduce the weight by about 10% to 40%. According to the principle of conservation of momentum, when the total weight of the golf club is certain, the head-heavy bar is light and it is easy to increase the swing speed, so that the ball can obtain a greater initial speed. In addition, the carbon fiber composite material has high damping characteristics, which can prolong the hitting time and the ball can be hit farther.
3, Tennis rackets
The development trend of tennis rackets is large-scale and lightweight. At present, most high- and mid-range tennis rackets in the world are made of carbon fiber composite materials. Large tennis racquets need to be made of carbon fiber composite materials that are lightweight, strong and have a large specific modulus. They can withstand stronger network cable pull than wooden frames to ensure that they do not deform when hit. The carbon fiber composite material with good vibration damping has given tennis players greater comfort while giving tennis a greater initial speed.
4, Bow and arrow
In the archery project, improving the performance of archery equipment is an important way to improve the performance of archery, and the main method to improve the performance of its equipment is to improve the specific elasticity of the bow and arrow. The best bow in the world today is a series of carbon fiber composite products. The bow (bow piece) made of carbon fiber composite material can withstand the bending stress of 50 kg/Hun2, giving the arrow the maximum initial speed and the longest range. With bow archery and a relaxation, the fatigue resistance of carbon fiber composite materials is unmatched by FRP and metal materials, so the life of the manufactured bow arms is longer.
5, Bicycle
With the rapid development of modern society, bicycles are not only transportation and transportation tools, but also have many functions such as fitness, tourism, and competition. High-end bicycle frame, fork parts, wheels, crankshaft and seat support are all made of carbon fiber composite materials, which not only makes the bicycle more beautiful, but also gives the car a good rigidity and shock absorption. The weight of the car body further decreased, and ride comfort was better.
The rapid development of modern science and technology has had an unprecedented impact on sports. Today's world of sports competition is essentially a competition of science and technology, and advanced and novel materials are one of the important conditions for improving the level of sports science and technology. Nowadays, in many sporting events, the physical and mental arousal of people has almost reached the limit. The victory and defeat are often only between the slightest. It is difficult to win with only strong muscles and a good competitive state. The more we rely on the wisdom of scientists, the more equipment we fight. People expect the athletes to challenge the limits through the upgrade of sports equipment. It can be said that the modern Olympic Games are no longer purer than the athletes in any country who run faster, jump higher, and lift more heavily, after the competition between athletes and athletes. It is a comprehensive competition between national and national science and technology development and people's hearts. The various records of the Olympic Games are not only a manifestation of human breakthrough in the physiological limits, but also a concentrated demonstration of technological innovation in sports.

Go Back