Analysis On Vibration Characteristics Of High-speed Train Under Track Irregularity Excitation

With the rapid increase of train speed and bearing weight, the interaction between wheel and rail has also greatly enhanced. And the result is that the vibration of vehicle-track coupling system becomes more and more significant. The track irregularity is the main factor for vibration of vehicle-track coupling system. To ensure the safety and riding comfort of the vehicle, it is of great significance to study the vibration response of vehicle-track coupling system under the effect of track irregularity. This thesis based on the theory of vehicle-track coupling system, with the high-speed railway ballastless track irregularity spectrum industry standard(TB/T 3352-2014) as the benchmark, analyzes the dynamic response of high-speed vehicle-track coupling system aiming at the speed above 300km/h. The main research contents are as follows:(1) The ballastless track irregularity power spectrum is transformed into time domain by means of discrete Fourier transform method. And the time domain track irregularity is the excitation of following vehicle-track vertical and lateral coupling models.(2) The vehicle-track vertical coupling geometric model is established. According to the D'Alembert principle, the vertical dynamic equations of the system are derived. The responses of time domain and frequency domain are analyzed under the vertical track irregularity excitation. Time domain analysis result indicates that the vertical vibration acceleration and pitch vibration displacement of vehicle body will increase with the increase of vehicle speed. Frequency domain analysis result shows that the primary frequency of vertical track irregularity excitation should be far away from the frequency of 0.5~0.9Hz to avoid the vertical resonance of the vehicle body.(3) The vehicle-track lateral coupling geometric model is established. According to the D'Alembert principle, the lateral dynamic equations of the system are derived. The time domain and frequency responses of the track are analyzed under the directional and horizontal irregularities. Time domain analysis result shows that the lateral vibration acceleration of the vehicle as the speed increases showed a trend of increasing. Frequency domain analysis result shows that in order to avoid the lateral resonance of the vehicle body, the primary frequency of lateral track irregularity excitation should be far away from the frequency of 0.5~1.3Hz.(4) This dissertation selects vertical and lateral vibration acceleration as the measure and identifies the sensitive wavelength range of vertical and lateral track irregularity of 300km/h, 350km/h and 400km/h by entering different cutoff wavelength of track irregularity data. The result shows that sensitive wavelength and the range of adverse wavelength also increase with the increase of the running speed. Finally, Sperling index is used for evaluating the vertical and lateral ride quality of the high-speed vehicle under different running speed. When the speed increases, the ride quality will be reduced.