Theoretical Analysis Of Wheel/Rail Rolling Noise For High-Speed Trains

In modern society, with the development in economy and the improvement on peoples standard of living, the more comfortable and more efficient transportation means is required. Furthermore, In order to increase the railway's competitive capability, the train speed has been increased drastically in resent years. However, the noise pollution problem becomes more and more serious. The purpose of this dissertation is to control noise of high-speed trains. Study on theoretical analysis of wheel/rail rolling noise has been thoroughly investigated in this dissertation. In this paper the following problems are researched.First, the wheel/rail coupled vibrations excited by the small-scale roughness of the running surfaces of the wheel and rail have been studied by using the spectrum analysis method, considered the area of contact between the wheel and rail. The formulas of the space-averaged spectra of vibration level of the wheel and rail have been presented.Second, the rail is regarded as the girder of infinite length on the flexible foundation, and the wheel is regarded as elastic loop. Thus, expressions for the impedances of the wheel and rail have been presented.Finally, based on the wheel/rail coupled vibration studied, no considered the effects of the ground on the sound reflection, the prediction expressions for the sound pressure level spectrum of the wheel/rail rolling-noise have been given by means of the application of the structural sound radiation theory. Moreover make use of the test results in authorized reference and the measured data in our country, showed the prediction expression is correct, and it is shown that below the 2000HZ the rail is the primary source in the total wheel/rail noise, above the 2500HZ the wheel is the primary source.The theoretical analysis of wheel/rail rolling lays a foundation for the thorough investigation on the control problem of wheel/rail rolling-noise.