INFLUENCE ANALYSIS ON TRACK VIBRATION DUE TO COUPLED IRREGULARITY EXCITATION OF METRO WHEEL-TRACK

The input wheel-track dynamic excitation directly affects the calculation results of vehicle-track coupled models. Nowadays, in the research of metro-train induced environmental vibrations, only the track irregularity excitation was considered but the effect of wheel roughness was ignored. To establish a metro wheel-track coupled excitation and to comprehensively analyze the influences of track irregularity, the out-of-round wheels of a metro train were measured, and the track irregularities and rail roughness in a metro running tunnel were also measured. Based on the vehicle-track coupled analytical model in the frequency domain, the track dynamic responses were calculated, and the influences on the results of different wheel-track simulations were compared. Furthermore, the rail vibrations were measured in the same metro running tunnel, which were used to validate the calculation accuracy by different simulations. The research results indicate that: the vibration responses will be underestimated in typical frequency band domination by wheel irregularities using the US irregularities power spectrum density (PSD) and Sato irregularities PSD, and accordingly, it is difficult to obtain the accurate vibration responses between 8 Hz and 200 Hz. The wheel-rail coupled irregularity PSD obtained by energy superposition can reflect the complete wheel-rail excitation information, which can be used to obtain the accurate simulation results between 8 Hz and 200 Hz.