Analyses of track vertical profile irregularity spectra
Based on the previous studies on fitting functions of power spectrum density(PSD) of track vertical irregularity,the different effects of common and high-speed track spectra on the performance of train,such as running stability,safety and wheel-track dynamic response,have been compared.The results indicate that the running stability of the TKY main line spectrum and the CSTDXY track spectrum is superior to that of the American track spectrum of sixth grade,while the wheel-track dynamic response resulted from TKY main line spectrum lies between those induced by the fifth and sixth grade American track spectra,and the dynamic response induced by the CSTDXY track spectrum is almost identical with that by the sixth grade American track spectrum;the running stability induced by the spectra of 120 km/h and 160 km/h classification,respectively,all lie between those from the sixth and fifth grade American spectra,and the wheel-track forces are almost identical with the sixth grade American spectrum;the running stability of TKY high-speed spectrum and the spectrum of 200 km/h classification is in the middle level compared with German track spectra of high interference and low interference,and the wheel-track force induced by German interference track spectra,which was comparative with that induced by the latter,is smaller than the force induced by the former.Simultaneously,according to the vehicle-track vertical coupling dynamic model,applying trigonometric series method to transfer the functions of PSD into time domain samples as an input of wheel-track excitation,the wheel-track vertical forces were calculated,while the vehicle YZ25T passing by under common irregularity spectra excitation with the velocity of 90 km/h,and under high-speed spectra excitation with the velocity of 200 km/h,respectively,which can well be the validation of wheel-track dynamic effectiveness obtained by the PSD of track vertical irregularity.The results can be used for the selection of wheel-track interaction input,which can further provide certain insights into the study on vibration responses induced by passing trains.