With the development of raw materials and technological progress, the cost of composite materials in rail transit applications is gradually decreasing.
Thanks to the modular design and integral molding technology, the complexity of the structure is greatly reduced, the workload required for production and final assembly is reduced, and the production cost is reduced; due to the fatigue and corrosion resistance of the composite material, maintenance is reduced And repair costs; due to weight reduction, increased operating capacity, reduced energy consumption, and reduced life cycle costs (LCC).
Lightweight, flame-retardant composite compartment floor
The refurbishment of European railway operator Duetsche Bahn's ICE-3 fast train is an example of the ability of composite materials to meet customers' special needs. The installation of air conditioning systems, passenger entertainment systems, and new seats added unnecessary weight to the ICE-3 railcar. In addition, the original plywood floor does not meet the new European fire standards. The company needed a flooring solution that could help it reduce the extra weight and meet fire protection standards-lightweight composite flooring meets exactly these requirements.
German-based composite fabric maker Saertex has supplied the LEO® material system for floors. According to Daniel Stumpp, global marketing director of Saertex Group, LEO is a layered non-curled fabric with higher mechanical properties and lighter weight potential than woven fabrics. The four-component composite system includes a special fire-resistant coating, a glass fiber reinforced material, SAERfoam® (a core material for integrated 3D glass fiber bridges), and LEO vinyl ester resin.
Composites manufacturer SMT, also located in Germany, uses reusable silicon vacuum bags made by British company Alan Harper to make floors in a vacuum infusion process.
The LEO system uses continuous fiber laminates without filler resins and has excellent mechanical properties. In addition, the composite material does not rot, which is a great advantage, especially in areas with snow in winter and very wet floors. Rubber materials for floors, carpets and roofs all meet new fire protection standards.
The OEM of the ICE-3 train did not participate in the ground refurbishment process, but was so impressed with the new laminate floor that it ordered a composite roof section to replace the old metal roof structure on the rail vehicle.
Recycled carbon fiber rail vehicle bogie
The research project of recycled carbon fiber on rail vehicles originated from a vehicle dynamics competition initiated by the British Railway Safety and Standards Committee (RSSB). Because the light carbon fiber rail vehicle bogie frame project led by ELG was the winner, RSSB turned to ELG The company is funding ￡ 1.25 million to design and manufacture prototypes of bogies made of recycled carbon fiber for rail passenger vehicles. A company led by ELG Carbon Fibers has developed a lightweight composite track bogie frame for passenger cars. The track bogie supports the vehicle body, guides the wheelset and maintains its stability. They help improve ride comfort by absorbing track vibrations and minimize the effects of centrifugal forces when the train is bent.
ELG is an expert in recycled carbon fiber products. The company has a comprehensive set of efficient development methods for recovering carbon fiber from manufacturing waste and end parts. Its research team in the project of recycled carbon fiber rail vehicle bogies includes joint institutions including the Huddersfield University Railway Research Centre, Alstom, and the University of Birmingham Sensor and Compliance Materials Research Centre.
One goal of the project is to produce a bogie that is 50% lighter than similar metal bogies. Camille Seurat, product development engineer at ELG, said: "If the bogie is lighter, it will reduce damage to the track, which will reduce maintenance time and costs because the load on the track will be reduced. This will save operators a lot of cost. "Other goals are to reduce lateral wheel-rail forces by 40% and provide lifetime monitoring. The British Nonprofit Railway Safety and Standards Board (RSSB) is funding the project with the goal of producing commercially viable products.
Magma Structures is responsible for the design and manufacture of bogies, and has carried out a large number of manufacturing tests, using press molding, traditional wet molding, impregnation and autoclave-cured prepregs to make many test panels. Since bogies will be produced in limited quantities, the company chose epoxy prepreg cured in an autoclave as the most cost-effective construction method.
The full-size bogie prototype was 8.8 feet long, 6.7 feet wide, and 2.8 feet high. It will be made from a combination of recycled carbon fiber (nonwoven mat provided by ELG) and virgin carbon fiber fabric. Unidirectional fibers will be used for the main strength element and will be placed in the mold using robotics. Selecting an epoxy resin with good mechanical properties will be a newly formulated flame retardant epoxy resin that has passed EN45545-2 certification and can be used in railways.
Unlike steel bogies, which are made of beams welded to two side beams, composite bogies will be manufactured as unique top and bottom sections and then glued together. In order to replace the existing metal bogie, the composite type must be equipped with suspension and brake connection brackets and other accessories in the same location.
"At the moment, we choose to keep the steel parts, but in future projects it may be interesting to replace the steel parts with composite parts, so we can further reduce the final weight," Seurat said.
Preliminary research indicates that the compound bogie should be able to achieve the expected 50% weight reduction. The project team hopes to have a full-size bogie ready for testing by mid-2019. If the prototypes perform as expected, they will produce more bogies for testing rail vehicles produced by rail company Alstom.
China's new generation of composite subway vehicles and light rail vehicles
Last year, at the Berlin International Rail Transit Technology Exhibition in Germany, CRRC Sifang announced the new generation of carbon fiber subway vehicles "CETROVO". The vehicle is developed with a large number of new materials and new technologies, and has traditionally upgraded traditional subway vehicles in terms of energy saving, environmental protection, comfort and intelligence.
Ding Sansan, deputy chief engineer of CRRC Sifang Co., Ltd., introduced that the new generation of subway vehicles has realized the comprehensive application of carbon fiber composite materials in the main load-bearing structures of vehicle bodies, bogies, driver's cabs, etc., and has particularly successfully broken through large-scale carbon fiber Key technologies such as structural design and manufacturing molding have made vehicles "thinner". Compared with the use of traditional metal materials such as steel and aluminum alloy, the body, driver's cab and equipment compartment of the new generation of carbon fiber subway vehicles have reduced weight by more than 30%, bogie weight by 40%, and vehicle weight by 13%.
"Although the manufacturing cost is higher than that of traditional metal materials, carbon fiber composites are more lightweight and have obvious energy saving advantages. They can effectively ensure that trains do not experience fatigue and corrosion during the 30-year service period, reducing maintenance and therefore reducing overall life. Cycle costs. "Ding Sansang said.
According to estimates, the new generation of subway vehicles can save more than 15% of energy; at the same time, it can operate in complex environments such as high temperature and humidity, minus 40 ° C and cold, and 2500 meters high altitude.
Almost at the same time, Wuhan Donghu "Optical Valley Quantum", a composite light rail car developed by CRRC Changchun Rail Bus Co., Ltd., was exhibited to the public for the first time at the Changchun Rail Transit Exhibition.
The car body adopts composite material body technology, which not only brings improvements in light weight, safety, comfort, and service life to the entire vehicle, but also improves the subway composite covering the entire process of design, manufacturing, testing and verification. The material vehicle body technology platform further validates the direction and implementation path of composite materials in the industrial production of rail transit.
The train takes full advantage of the advantages of carbon fiber composite materials, and uses lighter materials to complete the structural design equivalent to metal materials, which makes the whole vehicle lighter than similar stainless steel bodies by about 30%, thereby improving the carrying capacity of the vehicle body and reducing Energy consumption, reducing life cycle costs and reducing line damage are of great significance.
The composite material used in the car body has strong thermal insulation performance, which can be comparable to that of the cold-proof material, ensuring a comfortable temperature inside the car body at all times; the sound insulation and vibration damping performance of the composite car body is also better than that of the metal car body, greatly reducing the train Internal noise and vibration generated during operation effectively improve ride comfort.
It is reported that CRRC Changke's carbon fiber composite light rail vehicle exhibited this time will be finally delivered to Wuhan, and it will be the world's first all-composite railroad train for operation. Its successful development further promotes the large-scale industrial production and application of carbon fiber composite materials in rail transit, and expands the application market of carbon fiber composite materials industry.