Research On Bogie Dynamic Performance Of Rapid Speed Wagon Based On Radial Mechanism Error

Improving the efficiency and capacity is a long-term aim and objective of railway freight transport development. As rapid speed wagon bogie is one of the important methods, which could resolve the conflicts between demands and capacity of transport, it has been focused and researched during the railway freight transport developing process. With the rapid development of economy and railway transportation, it shows a tendency of diverse freight transportation and increasing requirements of rapid wagon transport. Therefore, it is imperative to improve the technology of our country’s rapid speed wagon bogie and improve the efficiency and economy of freight transportation. Due to the acceleration of vehicle speed, the force between rail-wheel and the vibration of vehicle system would be more obvious and the vehicle’s stability and safety would meet more challenges. In that case, the correlative factors, which could influence the bogie performance, should be controlled tighter to guarantee the good dynamic performance of rapid speed wagon bogie.After summarized typical rapid speed wagon bogies at home and abroad, this thesis chooses a rapid speed wagon bogie what has a radial mechanism as the research object. Firstly, it analyzed the bogie based on corresponding dynamic theory, followed by the multi-body dynamic methods. Then, based on the consideration of the flexible radial rods, it built the multi-rigid-body dynamic model and the rigid flexible coupling dynamic model respectively by using SIMPACK. After that, it compared the vibration response of these two models. As the radial rod is the key structure of radial mechanism, this thesis focused on its potential errors and the impact on vehicle dynamic performance. The considered errors consist of rod length error and the radial stiffness error of rubber bushing. The considered performance indices include stability, comfort, safety and wear. The analysis results gained from the simulation of dynamics system, taking account of different racial rod errors and railway conditions.The stability and comfort results show that the length error of radial rod has a negative influence on all considered vehicle stability indices and has a certain adverse effects on the horizontal comfort indicators while causing a small range of fluctuations on the vertical comfort indicators. Meanwhile, the radial stiffness error of rubber bushing has a weak influence on all those indices that could be neglected.The curve-passing performance and wear results show that the length error of radial rod not only deteriorated the safety index but also greatly exacerbated the wheel-rail wear. The asymmetric length of racial rods in one bogie leads to the wheelsets’ alignment status and sharp increase of attack angle and lateral displacement through curve-passing while wheelsets always be tilting in straight lines. The influence on curve-passing performance and wheel-rail wear caused by radial stiffness error of rubber bushing is no more significant than those numerical fluctuations caused by the rail excitations. The stiffness increase only leads to the slight increasing trend of wheel set attack angle. Consequently, because of certain environmental factors and time effects, small range of radial stiffness variation of rubber bushing is acceptable.