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• Vehicle-track coupled dynamics considering track broadband vibrations is modeled. • Time-varying property of wheel-rail coupled vibration modes is firstly clarified. • Field-consistent polygonal wear is reproduced based on the improved fastener model. • Increasing the fastener damping and iron chair mass can suppress wheel polygonal wear. • Track-bed broadband vibrations contribute slightly to the wheel polygonal wear. The wheel polygonal wear on high-speed railway exhibits constant high frequency excitation, which results in strong vibrations/noise and deteriorate railway systems. To get insight into the wheel polygonal wear mechanism, a refined vibration model of ballastless track comprising an improved fastener model and track-bed broadband modal model is proposed, and further its coupled dynamic model with the vehicle is established. The simulation scheme of wheel polygonal wear initiation and a wheel out-of-roundness growth rate index are proposed to measure the growth degree of wheel polygon at each order. The relevance between the wheel polygonal wear and wheel-rail coupled resonances is studied, and the time-varying characteristics of wheel-rail coupled vibration modes in a vehicle-discrete supporting track system are firstly clarified. On this basis, the initiation mechanism of wheel polygonal wear is revealed. The results suggest that the rail 3rd-order bending resonance between bogie wheels contribute significantly to wheel polygonal wear, which is attributed to the time-invariant modal shape of this rail 3rd-order bending vibration as well as the natural frequency consistent with the actual polygonal wear excitation. The effects of the fastener model/parameters and track-bed broadband vibrations on wheel polygonal wear are analyzed. The results show that the improved fastener model eliminates the error between the rail 3rd-bending modal frequency obtained based on the simple model and actual polygonal wear frequency. In addition, increasing the fastener damping and iron chair mass can significantly suppress wheel polygonal wear. Finally, the slight contribution of track-bed broadband vibrations to wheel polygonal wear is confirmed. [ABSTRACT FROM AUTHOR]

In the high-speed railway industry, the pantograph-catenary system is responsible to provide continuous electric energy for the high-speed train. The pantograph-catenary system suffers multiple impacts from the complex work environment. The vehicle-track excitation is one of the normal disturbances to the pantograph-catenary interaction. Previous studies only consider the vertical effect of the vehicle-track vibration on the pantograph-catenary interaction. To address this deficiency, both of the pantograph-catenary and vehicle-track models are constructed in this paper. The validations of both models are verified by the experimental test and the world benchmark, respectively. The pantograph base follows the translations and rotations of the car-body caused by random rail irregularities. In combination with a spatial contact model between the contact wire and the pantograph strip, the spatial vibration of the carbody can be fully considered in the pantograph-catenary interaction. The statistical analysis, stochastic analysis and frequency analysis are performed to make sense of the effect of the random track irregularities on the pantograph-catenary interaction. The deviation of the contact point away from the strip centre caused by the carbody vibration is also analysed. The results show that the reliability of the pantograph-catenary system shows a continuous decrease in the degradation of rail quality. The carbody vibration may cause the de-wirement of the pantograph in extreme conditions. Finally, an application example is given to evaluate the dynamic performance of the pantograph-catenary system running on the China high-speed network with realistic rail irregularities. [ABSTRACT FROM AUTHOR]