In recent years, people's various requirements for car seats with the rapid development of the automobile industry continues to improve, car seats lightweight, multi-functional, environmental comfort and safety are people's basic needs for car seats. Therefore, these aspects have gradually become the main direction of the development of car seats.

Long fiber composite material is composed of resin and long fiber composite material, with a variety of characteristics, such as high strength, low density, short production time and easy to form, suitable for the current development trend of car seats, so in the automotive industry it has gradually become the preferred material for car seats.

Overview of car seats

Car seats are mainly composed of four parts: seat cover, seat pillow, seat foam and seat skeleton. In addition, due to the different needs of the market, some seats also have armrests, waist supports or massage related comfort components. Some seats also have other storage functions such as cup holders and drawers.

At present, consumers are increasingly demanding lightweight, comfort, safety and other aspects of car seat design. However, most of the main materials of conventional seats are metal materials, metal density is heavy, and the development space for improving the lightweight of car seats by optimizing the structure and design alone has been limited.

The long fiber reinforced composite has excellent mechanical properties and can achieve significant lightweight effect. Therefore, it is gradually applied in the automotive field, not only in most simple, non-important parts, but also in some complex shape functional parts, such as the seat skeleton and the front segment module.

The importance of automotive lightweight

The lightweight of the car means that on the basis of the safety performance and strength of the car can be guaranteed, the overall weight of the car is reduced to the maximum extent, so as to enhance the power of the car, and reduce emissions and fuel consumption.

According to relevant tests, the fuel amount of the car has the most direct relationship with the weight of the car itself: for every 1kg of mass reduction of the car, the fuel consumption of 100 kilometers can be reduced by 0.2-0.8L, usually about 4%-5% of the original consumption. Therefore, at this stage, under the background of automobile development gradually favoring environmental protection and energy saving, the lightweight of modern automobile is of great significance in its design and manufacturing process.

The car seat is one of the most important parts in the interior of the car. According to the survey, the weight of the car seat accounts for 1% to 2% of the entire body. Although the car seat occupies a small proportion of the total weight of the body. However, as one of the most important parts of the car, its contribution to the lightweight process of the entire car cannot be underestimated.

Car seat is one of the more complicated parts in the whole car design process. The design process of car seats must be considered from many aspects, such as safety, aesthetic shape, functional diversity and comfort. Only under the premise of meeting the requirements of traditional car seats can the lightweight design of car seats be implemented. While reducing the weight of the car seat, the basic performance of the car seat must be guaranteed, especially the safety of the seat. Under the influence of these requirements, the lightweight design of car seats becomes more challenging and more worthy of research.

Application of long fiber composites in automotive field

Long fiber composite materials have also developed rapidly with the rapid development of industrial economy. At this stage, long fiber composites have become one of the fastest growing industries in the reinforced plastics industry.

The application proportion of long fiber composite materials in the automotive field is large, accounting for about 33% of the total consumption, and will continue to grow with the development of the automotive industry. At present, long fiber composite materials are widely used in automotive interior, functional parts and structural parts. The use of long fiber composite materials to replace the traditional metal materials can reduce the weight of automobiles, and simplify the production process and modular production.

General Motors, one of the largest automobile manufacturers in the world, has applied long glass fiber composite materials to the cargo board of sports vehicles and light trucks. Ford is one of many leaders in the application of composite materials. Its cars use fiber-reinforced sheet plastic as a material for body insulation panels. In 2011, PP-LGF50 material was used in the driving seat of a certain model of car produced by BMW in Germany, which reduced the mass of the car seat by 63% and also increased the service life of the car seat.

The application of long fiber composite material in automobile seat

1) Improve the service life and safety of the seat
The fatigue resistance of long fiber composite material is higher and it has more matrix. Its fatigue fracture does not burst out suddenly, but slowly spreads from the matrix to the collective interface and the fiber.

Therefore, people can detect the damage of long fiber composite materials in advance, and take corresponding remedial measures in time, effectively improving the service life of the seat.

In addition to fatigue resistance, long fiber composite materials also have stable safety, if overloaded parts made of this material, the role of the car seat will not immediately disappear, but first break a small number of fibers. The load is then quickly redistributed and transferred to the undamaged fibers, so that the entire component will not be knocked down by the heavy load in a short time.

2) Reduce the vibration amplitude of the seat
There is a large damping between the interface of the long fiber composite and the matrix, and it has good vibration damping performance. When the same size and shape of long fiber composite material and metal material are tested under the same conditions, the decay time of the former is shorter than that of the latter. Therefore, the car seat using long fiber composite material effectively reduces the vibration frequency and duration of the seat.

3) Reduce seat costs
No chemical reaction is required in the processing of long fiber composite materials: the reinforced fiber is directly extruded in a predetermined direction and arranged on the matrix at the same time to form a layup structure and press it in a high-speed hydraulic press. This method not only saves the cost of buying semi-finished products and reduces the manufacturing cost, but also guarantees the fiber length and optimizes the mechanical properties of the component.

In addition, the matrix is combined with the fiber, and then the mold is heated and cured, it can be made of long fiber composite parts, and the matrix is transformed from a fluid to a solid during the production process, so the car seat made of long fiber composite materials is not easy to crack.

4) Reduce the damage of the seat at high temperature
Long fiber composite materials can achieve high temperature resistance under normal conditions. When the ordinary aluminum alloy is at high temperature, its elastic modulus will be greatly reduced. However, under the same conditions, the elastic modulus and strength of the composite reinforced with long fiber materials can remain unchanged. Because the long fiber composite has a small thermal conductivity, its high temperature resistance is better. The application of long fiber composite materials to car seats can effectively reduce the damage degree of car seats under high temperature conditions.

5) Maintain the stability of various performance of the seat
The characteristics of long fiber composites are high specific stiffness and high specific strength, and their properties have a wide range of variation. According to the different fiber material, fiber content and laying direction, the designed product strength index, flame retardant performance and elastic modulus are also different. When the long fiber composite material is stretched in one direction under a certain layup mode, the material can also be extended perpendicular to the stretching direction, which is completely different from the commonly used materials. In the design process of car seats, materials that are easy to design and can maintain stable performance should be selected. Long fiber composite materials can be flexibly designed in different shapes while maintaining the stability of all aspects of their performance.

Conclusion

As the carrying capacity of the car, the car seat plays a very important role in ensuring the safety of the people in the car when the traffic accident occurs.

Therefore, the development of lightweight, comfort and safety is an inevitable trend in the development of car seats. Long fiber composite material has a variety of excellent performance, improve the quality of car seats while reducing its quality, improve various performance at the same time reduce the cost.

It can be seen that with the rapid development of the automobile industry and the continuous improvement of the technical level in the development of long fiber composite materials, the application prospect of long fiber composite materials in car seats will be increasingly broad.