January 24, 2019 Source: Watching the topic

The Spring Festival is getting closer and closer. This kind of devil time, high-speed rail and trains are always attracting attention. In recent years, the high-speed rail has been slowed down due to its speed and stability, which has eased the pressure of the Spring Festival.

Such a convenient and fast way of transportation is booming, and the fiber application behind it is also indispensable!

Speaking of fiber applications in high-speed rail, carbon fiber is a well-deserved "star material" in "China Speed." In fact, our rail vehicles are also experiencing a leap from the “iron age”, the “aluminum age” to the “carbon age”. According to relevant data, by 2025, China's high-speed rail will exceed 38,000 kilometers, and the number of active high-speed trains exceeds 2,500.

The energy-saving, environmental protection, comfort and convenience of trains have become the future development direction of high-speed trains. Carbon fiber is increasingly concerned and adopted by rail vehicle development companies due to its excellent performance, and its development potential is huge!

Fiber properties

1, carbon fiber GQ4522

(high strength)

Carbon fiber GQ4522 has many advantages such as high axial strength and modulus, high specific performance, low density and small thermal expansion coefficient. Its composite material is widely used as structure because of its characteristics of light weight, high strength, high temperature resistance, corrosion resistance and excellent thermodynamic properties. Materials: 1. Aviation aircraft structural parts, wind blades, carbon core cables, sports equipment and other civilian fields; 2. High-end equipment, building reinforcement, new energy vehicles, carbon-carbon composite materials and other industrial fields.

2, carbon fiber QZ5526

(High strength Chinese model)

The carbon fiber QZ5526 has a 20% higher tensile strength than the carbon fiber GQ4522 and a 28% increase in modulus. It is a product upgrade from high-strength standard carbon fiber to high-strength medium carbon fiber. As a composite material, it has the characteristics of light weight, high strength and high modulus of elasticity. It can reduce weight by 30% compared with traditional aluminum alloy structure, and contributes greatly to the improvement of weapon equipment performance. It is widely used in the manufacture of aircraft bodies, engines and missile casings.

Today, carbon fiber composites are more advantageous than traditional lightweight materials: low density, high strength and high modulus. Therefore, it is often used as a lightweight and environmentally friendly material for rail transit – the current application is mainly focused on the high-speed rail body and interior decoration.

▲Comparative analysis of performance of carbon fiber composite materials and other lightweight materials Source: "Application Research of High-speed EMU Carbon Fiber Composite Materials"

▲ Metro vehicle weight distribution ratio

Source: "Application of Carbon Fiber Reinforced Composites in Rail Vehicles"

Specifically, its application has gradually evolved from the load-bearing structural parts such as the car interior and interior equipment to the load-bearing members such as the car body and the frame; from the apron, the shroud and other components to the top cover and the driver's cab, The development of large-scale structures such as vehicle bodies and the importance of taking on roles are also obvious to all. Next, let's take a closer look!

▲ Patent distribution of carbon fiber composite materials in rail transit

Source: "Application of Carbon Fiber Composites in Rail Vehicles from the Perspective of Patent Analysis"

Vehicle interior decoration application

A flame retardant carbon fiber reinforced material is laminated on the car trim panel, toilet, toilet room, seat, water tank, front cover of the car, and roof panels on both ends of the double-decker bus. In addition to flame retardant properties, it also enhances the hygienic performance and corrosion resistance of toilets, toilets, seats and water tanks.

Equipment cabin application

The curved beam of the main load-bearing structural part of the equipment compartment adopts the carbon fiber reinforced composite prepreg cross-laying design, and is manufactured by the bag press forming process, and the obtained sample has high yield and controllable manufacturing cost. The other main load-bearing structural member beam is formed by vacuum-introduced carbon fiber composite molding and curved aramid honeycomb sandwich structure to improve its performance.

Body shell application

The function of the car body is to install the foundation and the load-bearing skeleton. The modern EMU car body adopts the overall bearing steel structure or light metal structure to meet the strength and rigidity requirements under the lightest self-weight.

The carbon honeycomb sandwich composite member aluminum honeycomb sandwich structure is easier to achieve weight reduction. Compared with the conventional aluminum alloy body, the total mass of the composite vehicle body shell is reduced by 40%, and the static strength, fatigue strength and fire safety of the vehicle body are improved. And all performance indicators can meet the design requirements.

Head cover application

Carbon fiber reinforced composite paving design, foam core in the middle, carbon fiber composite material is still used in the upper and lower joints. The head cover made of carbon fiber composite material has outstanding impact resistance and mechanical properties. It can withstand 660km/h high-speed impact of 1kg aluminum bullet and static load of 350kN. The flame retardant performance reaches DIN5510 standard S4.

Bogie application

The bogie is a particularly important high-strength component on the high-speed rail that supports the body, steering and braking and ensures that the locomotive is operating safely and smoothly on the track.

As the main carrier related to the safety of the entire vehicle, the performance of the bogie must meet the requirements of safety, running comfort, wear resistance, and easy maintenance. The overall bogie made of carbon fiber composite material can be reduced by 30% compared with the ordinary steel frame.

Brake pad application

Brake pads made of carbon fiber can accept more brake friction and thermal shock, low brake noise, good wear resistance, lower wear rate than steel fiber brake pads, strong corrosion resistance and prolong the life of brake pads.

This shows that the importance of carbon fiber composites for high-speed rail! At the same time, we also believe that the application of carbon fiber in high-speed rail will become more and more mature through technical cooperation and project research and development. Not only the Spring Festival, but also bring more surprises and convenience to our future life.