Research On Stiffness Of The Rail Fastening System Of Linear Motor Metro Vehicle

Linear Induction motor (LIM) track transportation plays an important role in the urban public transport. But it also inevitably brings negative effects to the urban environment, which with the noise and the vibration influence is particularly prominent. The rail fastening becomes one of the main ways to solve the noise and vibration of the LIM metro vehicle effectively. Rail fastener is one of the most important connectors, which used to connect rails and sleepers or other foundation under rail. Fastener stiffness is an important factor that affects the overall stiffness of the track. In this paper, the dynamic model of linear motor metro vehicle is selected, elastic rail model is established. Determine the range of the overall stiffness of the track, and the impact of the fastener stiffness on the overall stiffness, by studying the theoretical value of the overall stiffness of the track and the calculation method of the theoretical value of the fastener stiffness. Study the impact of lateral and vertical stiffness of the fastening system of vehicle track system on four parts (carbody. bogie, wheelset and sleeper) vibration energy and system dynamics indexes, by dynamic time domain simulation analysis. To find the reasonable lateral and vertical stiffness of the fastening system, based on vibration energy theory and dynamic index theory. The main research contents of this paper are as follows:Under the change of lateral and vertical stiffness of fastening system, research the effect on the vibration energy of four parts in the LIM metro vehicle in different speeds. In order to avoid the peak value and the maximum value of vibration energy of any part, as well as possible to make the four part of the minimum vibration energy. The results show that the reasonable lateral stiffness of the fastening system should be taken as large as possible in the allowable range, and the reasonable vertical stiffness of the fastening system is 30MN/m.The sensitivity of the index of the lateral stiffness under different fastening system is studied. The results show that among the dynamic indexes of the system, the sensitivity of the lateral vibration displacement of sleeper is the highest, and also, the sensitivity of the lateral vibration acceleration of wheelset and frame and sleeper, and wheel/rail lateral force are also relatively high. Therefore, these sensitive indexes can be judged in the determination of the lateral stiffness value of the LIM track-rail coupling model. We can find out the proposed lateral stiffness value is about 50MN/m. For the vertical stiffness of the fastener system, the results show that the sensitivity of the verticle vibration displacement of sleeper, the verticle vibration acceleration of wheelset and frame and sleeper, and the wheel/rail verticle force are relatively high. Therefore, these sensitive indexes can be judged in the determination of the verticle stiffness value of the LIM track-rail coupling model. We can find out the proposed verticle stiffness value is about 40MN/m.Combined with the proposed stiffness value of the fastening system given by the vibration energy analysis method and the dynamic index optimization method, we can come to conclusion that the reasonable range of lateral stiffness of the fastening system is between 50MN/m to 60MN/m:and the reasonable range of verticle stiffness of the fastening system is between 30MN/m to 40MN/m. Further calculations and field tests are needed to verify the accuracy of the more accurate values. And this conclusion is widely applicable to the running speed range of the linear motor metro vehicle.