Response analysis of high-speed rail system accounting for abrupt change of foundation stiffness

A relatively recently developed method known as the moving element method (MEM) is further extended to deal with moving loads that travel along inhomogeneous visco-elastic foundation. The proposed computational scheme is applied to investigate the dynamic response of high-speed rail system for the situation where there is an abrupt change of foundation stiffness. The influence of different factors, including the degree of change of foundation stiffness, traveling velocity of the train and the severity of track irregularity, on the response of the train as well as the track is examined and discussed. The phenomenon of ‘jumping wheel’, which occurs when there is a momentary loss of contact between the wheel and track, is accounted for in the proposed model. Results are presented to illustrate the effect of ‘jumping wheel’ on the dynamic response of the train-track system.

For a given ratio of amplitude to wavelength track irregularity, the dynamic amplification factor (DAF) in wheel-rail contact force is observed to increase to a peak value before decreasing as the wavelength increases, for all cases of foundation stiffness ratios n. Figure optionsDownload as PowerPoint slideHighlights
► Moving element method adopted to analyze high-speed rail involving rail transition.
► Vertical track irregularity modeled in terms of sinusoidal function.
► Hertz contact theory adopted to allow for loss of contact between wheel and rail.
► Track transition may trigger loss of contact between wheel and rail.
► Effect of track transition is large with small track irregularity wavelength.