Effect of Track Irregularity Amplitude on Dynamic Performance of Vehicle System under High-speed Operation

By means of the vehicle-track coupled dynamics theory and the corresponding simulation software,the effect of track irregularity amplitude on the dynamic performances of high-speed vehicle system is investigated. The limit amplitudes of track irregularities under high-speed operation are discussed. The analysis results show that the dynamic responses of vehicle system increase gradually with the increase of track irregularity amplitude. The higher the running speed,the greater the vehicle dynamic response increasing with the increase of track irregularity amplitude. It is found that the controlling index of vehicle dynamic performances under different irregularity excitations is different, and the corresponding amplitude ( half peak) intervals of track irregularity are also different when the controlling index of vehicle dynamic performances reaches its limit value at the speed of 250km/h to 400km/h. The dynamic controlling index of vehicle dynamic performances excited by track vertical profile irregularity in the long wavelength rang is the carbody vertical vibration acceleration. The controlling indexes of vehicle dynamic performances excited by track alignment irregularity and track cross-level irregularity in the long wavelength rang are the derailment coefficient and the carbody lateral vibration acceleration. When the running speed is from 250km/h to 400km/h, the limit amplitude of track vertical profile irregularity in the long wavelength rang is large, it is about 10mm. The limit amplitudes of track alignment irregularity and track cross-level irregularity in the long wavelength rang are about 3.0 similar to 4.0mm and 3.0 similar to 6.0mm ( rounded values). The analysis results also show that track gauge irregularity in the long wavelength range has little effect on the dynamic performance of high-speed vehicle system,the effect of its amplitude is not obvious.