By Zhang Lipeng in Beijing | CRRC | Updated: 15/01/2018
At the beginning of New Year, CRRC Changchun Railway Vehicles Co., Ltd. achieved significant breakthrough in the rail transit sector and developed the first metro carbody made of full-carbon fiber composites in the world with the wholly-owned intellectual property right. The successful R&D of full composite material carbody not only reduces the weight of carbody, energy consumption and emission, but also improves its safety, comfort and longevity, etc. More importantly, it explores the direction and implementation approach for the application of the carbon fiber composite materials in railway equipment scale-up industrialized production.
It is reported that the carbody has the thin-walled cylindrical integral load-carrying structure with the carbody length of 19,000mm, width of 2,800mm and the carbody ceiling-to-rail height of 3,478mm. It boasts state-of-art performance and highlighted features as follows:
Highly lightweight carbody: The full-composite metro carbody manufactured by CRRC Changchun gives full play to the advantages of carbon fiber composite materials. This facilitates lighter materials to be structurally same to the metal materials; so that the total weight can be reduced by about 35% compared with the metal metro carbody. It is meaningful in terms of higher carrying capacity, lower energy consumption, less lifecycle cost and less damage to rail lines, etc.
Breakthrough of several technological bottlenecks: The full-composite material metro carbody is featured with breakthrough of many issues like design analysis technology of overall load-carrying carbody composites, carbody connection technology, low cost of composite materials, stereotype fabrication technology of large-dimension components and static strength testing of composite material carbody. Through more than 10 material performance tests, modular design verification and testing of more than 6,000 elements, typical parts, components, full-size testing parts, etc., as well as repetitive optimization validation, the company finally overcomes the difficulty in application of composite materials to loading structure of rail vehicles. The resulting carbody has excellent performance and satisfies the service requirements under extreme severe conditions and scenarios.
High-degree safety and long lifespan: CRRC Changchun has carried out plenty of verification of all performance indicators of carbody and testified its advantage in fatigue strength by simulation analysis so that the carbody is safer and more reliable. Its vibration resistance is 18% higher than similar metal carbodys that more effectively prevent the resonance between the carbody body and bogie. As the composite materials applied demonstrate favorable corrosion-, acid- and alkali-resistance, the carbody may be in service in the environment of metal oxidation and corrosion for a long time with no need of special anti-corrosion treatment. Its lifecycle is longer than stainless steel.
Great riding comfort: The composite materials have strong heat insulation; and its thermal conductivity is close to that of cold-proof materials. As a result, the full-composite carbody is parallel to the metal carbody laid with cold-proof materials regarding the heat insulation. Additionally, the composite materials also have better noise insulation than metal that significantly reduce vibration and noise and improve the riding comfort.
High dimensional precision and good appearance quality: The composite materials can be flexibly designed and integrally molded; so that the full-composite carbody may to the greatest extent realize the integration of components and parts, and be molded as a whole. The modules of carbody are mechanically connected that removes the size and position deviation caused by welding deformation of conventional metal carbody, and thus improves both dimensional precision and appearance quality.
Laying the foundation for a complete rail industry standard system in China: The novel materials especially carbon fiber materials are rarely applied in the rail transit industry, let alone the related industry standard. In light with the successful application experience and standard of carbon fiber in the international aviation sector, the metro carbody R&D initiates the material standard, design code, technique guidance, quality inspection criteria, testing judgment and maintenance strategy, etc. of carbon fiber application in rail transit, thus laying the foundation for a complete rail industry standard system in China.