Since BMW uses a lot of carbon fiber materials in the i3 and i8 series models, carbon fiber materials have really become an important direction for automobile lightweighting. Especially in recent years, with the advancement of China's carbon fiber research and development capabilities and production technology, the gap between the advanced level of developed countries has continued to narrow, the application level of carbon fiber composite products has also entered a rapid development track, and carbon fiber composite materials have been increasingly It is more and more used in modern public transportation such as automobiles, high-speed rail and light rail.
Carbon fiber brings lightweight cars
Cars use carbon fiber composite parts and components, mainly based on lightweight body. The density of carbon fiber is generally not more than 2g/cm3, 50% weight loss compared with low carbon steel, and 30% weight loss compared with magnesium/aluminum alloy structure; and the designability of carbon fiber used in automobile body is strong, can achieve streamline and curved surface , So as to reduce the types of parts and investment in tooling. Replacing stamping and welding with molding and bonding process can save the investment of production line, mold and fixture;
Carbon fiber has high anti-fatigue strength (up to 70%~80% of the design load), the center of gravity of the car decreases after weight reduction, and the operating stability is higher. The carbon fiber composite material has better vibration absorption effect and has a greater buffer effect on impact. And reduce the generation of impact debris, the impact energy absorption capacity of carbon fiber is 6-7 times that of steel, 3-4 times that of aluminum; Fifth, improve car comfort. Higher vibration damping has a significant effect on the overall noise reduction of the car and improves passenger comfort. The use of carbon fiber interior and exterior materials, in addition to the lightweight of automobiles, also simplifies the manufacturing process of parts, reduces the cost of parts processing, assembly and maintenance, and reduces production costs.
From the original racing cars to high-end commercial vehicles, to the more popular new energy vehicles in recent years, the application of carbon fiber parts has never stopped. For example, the carbon fiber power battery box manufactured according to the requirements of new energy vehicle manufacturers is carbon fiber composite material. Typical application cases on new energy vehicles. According to customer feedback, the volume of this carbon fiber composite power battery box is about 35L, the wall thickness is 2mm, but the weight is only 3kg, which is about the same as the battery box made of traditional steel structure. Weight loss is 65%, and in subsequent impact, vibration and other related tests, all meet the technical requirements.
Carbon fiber has room for development in rail transit
Relevant data shows that by 2025, China's high-speed rail mileage will exceed 38,000 kilometers, and more than 2,500 high-speed rail trains are in service. The energy-saving, environmental protection, comfort and convenience of trains have become the future development direction of high-speed trains. Because of its excellent performance, carbon fiber is more and more concerned and adopted by rail vehicle development companies, and has huge development potential.
Lightweight solutions for high-speed rail are always concerned about two issues: one is that lightweight materials must have sufficient safety, and the other is to minimize the weight while ensuring safety, so as to achieve greater carrying capacity and higher transportation effectiveness.
From high-speed maglev trains with a speed of 400 kilometers per hour and above and double-layer EMUs to high-speed maglev trains with a speed of 600 kilometers per hour, high-speed rail and other rail vehicles have been developing towards high speed, high efficiency, green, and intelligence. Materials play a vital role. Due to the limited space for light weight of vehicle-mounted equipment, the application of carbon fiber composite materials in the mass reduction of rail transit mainly focuses on the body and interior decoration.
The performance of rail transit vehicles in terms of strength, stiffness, fatigue resistance, corrosion resistance and fire resistance is constantly being optimized. The lightweight, impact resistance, load carrying capacity, high weather resistance and high reliability of carbon fiber composite materials The advantages of high availability, long life, and low maintenance have gradually received attention.
Carbon fiber has gradually expanded from the lightweight application of car body parts and car boxes to the application of transportation vehicles and the entire industry. At present, China's urban rail transit is at a high-speed development stage. The energy-saving, environmental protection, comfort and convenience of trains have become the future development direction. The excellent characteristics of carbon fiber composite materials are also increasingly concerned and adopted by many rail vehicle manufacturers. The development space cannot be ignored.