Lightweight Design Of Medium-Low Speed Maglev Train Carbody

With the rapid development of urbanization,the form of urban railway transportation has a diversified tendency.The medium-low speed maglev train is a new form of urban rail transportation which has advantages of safety,low vibration noise and maintenance cost,smaller turning radius,good grade ability and strong terrain adaptability,etc.Besides,it has a good capacity to adapt to various geographical and cultural in different cities.Thus,the medium-low speed maglev train will gradually become more and more popular for future urban rail transportation.A carbody structure corresponds to a new type medium-low speed maglev system which contains three levitation frames for reaching the operation speed of 160km/h was designed.The structure and operating principle of the new maglev train were introduced,and their effects on carbody design were analyzed.Several main load working contion were discussed and calculated according to the characteristics of maglev train.A carbody design scheme was formed based on the principle of lightweight design and the method of modular design.Finally,a carbody finite element model was built and analyzed.The research results are as follows:1)The main functional systems of the medium-low speed maglev train consist of levitation and steering system,traction system and brake system.The load distribution and transmission are different from that of the conventional wheel-rail vehicles because the motive power is distributed in every vehicle and the traction doesn't rely on the adhesive force anymore.Besides,for the three-levitation-frame maglev train,the carbody length,support position and support point number are different from those of the conventional carbodies due to the changes of levitation frame structure and number.All the features of the new maglev train require a lightweight-design carbody.2)The main load of maglev train carbody contains vertical load,longitudinal load and lateral load.As a result of the structure and function characteristics,the carbody load of maglev train have a great difference from that of the conventional train.After detailed analysis of the load characteristics of the three-levitation-frame maglev train,five load working conditions were determined,that is,empty condition,overcrowding static load condition,overcrowding curve-passing condition as well as two rescue conditions.3)The carbody structure was designed by using existent carbody materials on the basis of conventional carbodies.The carbody was divided into six modules.The car body structure was built with large size aluminum alloy frames and sandwich panel modules.The modular design is benefit for rapid design and design changes,and can be used in different sizes of car bodies.The modularization of sandwich panels and aluminum alloy sections will make it convenient to machining and installing,and accelerate the process of design and production.4)The carbody finite element model was built according to the carbody structure,and the strength analysis and local structure optimization were carried out.A carbody which meets the requirements of all working conditions was formed.In the structure,foam material mainly bears the shear force.The maximal stress of foam material for the simulation results is less than 0.2MPa while the maximal stress it can bear is 0.7MPa.What's more,the foam material has a good ability of sound insulation and vibration attenuation.With this kind of material Carbodies will provide a good riding comfort for passengers.In summary,the sandwich panel is an excellent material for carbody lightweight design.