400km·h-1高速铁路桥上轨道周期性不平顺与车辆响应特征OA

With the development of high-speed railways towards 400 km·h-1 and higher speed levels,train operation safety and ride comfort impose more stringent requirements on track regularity.Focusing on track regularity of simply-supported bridges with common spans widely used in high-speed railways,a refined track-bridge finite element model is established to reveal the inherent mechanism of periodic track irregularities induced by creep camber of bridge girders.Furthermore,an analysis element for periodic track irregularities on bridges suitable for dynamic simulation is proposed.Based on the established vehicle-track-bridge coupled dynamic model for higher-speed railways,the influence of periodic track irregularities on the carbody response of trains running at 400 km·h-1 is investigated in depth.The results show that an increase in girder creep deformation directly leads to increased rail deformation,with a significant linear correlation between their amplitudes,and the peak rail deformation is always slightly lower than that of girder creep.The proposed calculation element for periodic track irregularities exhibits better consistency with the waveform variation of measured track irregularities.Under the excitation of periodic irregularities,obvious spectral peaks appear at the harmonic frequencies corresponding to a 32 m wavelength in the carbody response spectrum,with the maximum peak occurring at the second harmonic,indicating that the carbody is more sensitive to the excitation of 16 m wavelength,resulting in a double-peak characteristic of the carbody dynamic response within the 32 m wavelength range.The findings provide theoretical support for track condition assessment and track regularity control of 400 km·h-1 high-speed railways.