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Application of glass fiber reinforced composite materials in automobiles

Non-metallic materials used in automobiles include plastics, rubber, adhesive sealants, friction materials, fabrics, glass and other materials, involving petrochemical, light industry, textile, building materials and other related industrial sectors, so non-metallic materials are used in automobiles. How it reflects a country's comprehensive economic and technological strength, but also contains a large number of technology development and application capabilities of related industries.
Currently, glass fiber reinforced composite materials used in automobiles include: glass fiber reinforced thermoplastic material (QFRTP), glass fiber felt reinforced thermoplastic material (GMT), sheet molding compound (SMC), resin transfer molding material (RTM), and hand lay-up. FRP products.
At present, the glass fiber reinforced plastics used in automobiles mainly include: glass fiber reinforced PP, glass fiber reinforced PA66 or PA6, and a small amount of PBT and PPO materials.
Reinforced PP is mainly used to make engine cooling fan blades, timing belt upper and lower covers, etc., but some products have defects such as poor appearance quality and warpage, so non-functional parts are gradually filled with PP by inorganic fillers such as talc powder. Alternative.
Reinforced PA materials have been used in passenger cars and commercial vehicles, and are generally used to make small functional parts such as lock body covers, safety wedges, insert nuts, accelerator pedals, shift upper and lower guards. - Protective cover, opening handle, etc. If the material quality selected by the parts manufacturer is unstable, the production process is improperly used or the material is not well dried, the weak part of the product will be broken.
The plastic intake manifold is a new technology developed in recent years. Compared with the aluminum alloy cast intake manifold, it has the advantages of light weight, smooth inner surface, shock absorption and heat insulation, etc., so it is widely used in foreign automobiles. The materials used in it are all glass fiber reinforced PA66 or PA6, mainly using the fuse core method or vibration friction welding method. At present, the relevant units in China have carried out research in this aspect and achieved phase results.
With the demand for lightweight and environmental protection, the foreign automotive industry is increasingly inclined to use GMT materials to meet the needs of structural components, mainly because GMT materials have good toughness, short molding cycle, high production efficiency and low processing cost. It is regarded as one of the materials of the 21st century, and is mainly used to produce multi-functional brackets for passenger cars, instrument panel brackets, seat frames, engine guards, battery brackets, etc., FAW-Volkswagen currently The AudiA6 and the A4 have been produced using GMT materials, but none have been localized.
In order to improve the quality of the whole vehicle to catch up with the international advanced level and achieve the purpose of weight reduction, shock absorption and noise reduction, the relevant domestic units have carried out research on GMT material production and product molding process during the period of the Eighth and the Ninth Five-Year Plan, and have mass production. The capacity of GMT materials, the production line with an annual output of 3,000 tons of GMT materials has been built in Jiangyin, Jiangsu. The domestic automobile production plant also uses GMT materials for some models, and has begun trial production in batches.
Sheet Molding Compound (SMC) is an important glass fiber reinforced thermosetting plastic. It has been widely used in automobiles due to its excellent performance, mass production and A-grade surface. At present, foreign SMC materials have made new progress in the application of automotive products. Now, the application of SMC in automobiles is large, which accounts for 70% of the SMC. The fastest growth is the structural parts and the transmission parts. In the next five years, the use of SMC in automobiles will continue to increase by 22% to 71%, while in other industries it will increase by 13% to 35%.
Foreign application status and development trend
(1) High content of glass fiber reinforced sheet molding compound is increasingly used in automotive structural components. In Ford's 1995 two models (Ex-plorer and Ranger) last showed it on structural parts. The application, due to its many functions, is widely considered to have advantages in structural design, and is therefore popularized in automotive instrument panels, steering gears, radiator systems, and electronic device systems.
The upper and lower brackets molded by Budd Company of the United States use unsaturated polyester composite materials containing 40% glass fiber. The two-piece front-end structure type car meets the needs of users. The front end is low cab forward and the upper bracket is fixed at the front end. The canopy and front body structure, while the lower bracket cooperates with the cooling system. The two brackets are coupled to each other and to the hood and the body structure and the front end are stabilized.
(2) Application of low-density SMC material The low-density SMC has a specific gravity of 1.3. In practical applications and tests, it shows that the weight of the standard SMC is 30%, and the standard SMC has a specific gravity of 1.9. The use of this low density SMC can reduce weight by approximately 45% compared to similar parts made of steel.
Low-density SMC is used in the interior panels and new roof interiors of all of the General Motors' Corvette 99 models. In addition, there are door, hood, trunk lid and so on.
The US DodgeVipex also uses this low-density SMC in the hood, and the Automotive 99 has 1/2 of this material to make the hood. The low-density SMC hood reduces weight by up to 35% over steel.
(3) Other applications SMC's application in automobiles is used to produce other parts in addition to the above-mentioned new applications, such as: cab door, inflatable roof, bumper frame, cargo door, sun visor, A And D column, body panel, roof drain pipe, side rails on the carport, truck wagons, etc. The large amount is used for the outer panel of the body.
Domestic application overview With the introduction of domestic passenger car production technology, it is first used in passenger cars, mainly used for spare tire storage and bumper frame, etc. It is also currently used in commercial vehicles, such as the lifter cover and expansion. Water tank, line speed clamp, large/small partition, air intake cover assembly, etc. Demand for the domestic SMC material industry
1. Research on low-density SMC materials, in order to better achieve the goal of vehicle weight reduction, foreign countries have begun to use low-density SMC to make automotive parts. According to foreign data reports, compared with ordinary SMC and low-density SMC, the density is reduced from 1.9. By 1.31, the tensile strength increased from 56 to 80 MPa, the flexural strength increased from 151 to 186 MPa, the flexural modulus increased from 8.8 to 10.1 GPa, and the unnotched impact increased from 925 to 940 J/m. From the above data, it is seen that the mechanical properties are generally improved, and foreign countries have actually used to produce door frames, rear cover decorations, engine covers and other products.
2. Reuse of SMC. In the concept of people, thermoset composite materials are not recyclable, and today's environmental protection has been put on the agenda, which has to consider the prospects of SMC use. According to the data, both painted and bonded SMC can be recycled, and parts made from recycled SMC do not affect its performance. Some car manufacturers use recycled SMC to make various parts, reducing the weight of each part by 10%. The hood made of the new SMC material weighs 9kg, while the hood made of 25% recycled material is 8kg. In the near future, bumpers made from recycled SMC will be used in heavy commercial vehicles, while hoods, movable roof linings, side panels, grill panels and exterior panels can also be used with recycled SMC. Production. The recycling of SMC is a relatively new job for our domestic materials industry, and this is an important requirement.
3. Other needs.a. The promotion and application of SMC color parts can save the spraying process of SMC parts (including the front and back processing steps); b. The realization of the A-level surface of SMC parts; and the research on the low-pressure forming technology of c.SMC parts.The RTM method presses the resin into a closed mold placed in a glass fiber and cures it at room temperature or heat. Compared with the SMC method, the RTM method has simple production equipment, low mold cost, and excellent product properties, but is only suitable for small and medium batch production. It is reported that the auto parts produced by RTM molding methods have been extended to the whole body cover. Domestic RTM molding technology is still in the development stage for the manufacture of automotive parts. The mechanical properties, curing time and finished parts of raw materials are required to reach the production level of similar foreign products. At present, the automotive parts developed by the domestic RTM molding method include a windshield, a rear tailgate, a shroud, a ceiling, a bumper, and a Fukang rear lift door.However, how to make the RTM process be applied to the car faster and better, the material requirements for the product structure, the level of material performance, the evaluation criteria, the realization of the A-level surface, etc. are the concerns of our automotive industry and also the RTM. Pre-conditions that can really be promoted in automotive parts.

Why use glass fiber reinforced plastic (FRP)From an automaker's point of view, FRP is an attractive alternative to other materials, such as SMC/BMC:●Save weight●Component integration●Freedom of design●The investment is much less● Make the integrated antenna system a reality●Compatible with E-coat (electronic coating) (online color customization)●Stable size (low linear thermal expansion coefficient, equivalent to steel)● Maintain high mechanical properties even under high temperature conditions