Assessment of the High-Frequency Response in Railway Pantograph-Catenary Interaction Based on Numerical Simulation

The numerical model is a well-acknowledged tool to evaluate railway pantograph-catenary interaction performance. The current standard restricts most current simulation tools by a cut-off frequency of 20 Hz. This low-frequency range of interest cannot fully describe the current collection quality of pantograph-catenary. This paper includes simulation with cut-off frequencies up to 200 Hz to investigate the high-frequency behaviour of pantograph-catenary interaction. The reference model of pantograph-catenary in the benchmark is taken as the analysis object. Firstly, the effect of key simulation parameters of the resulting contact force is investigated. A small element length in the finite element model is proposed to prevent the frequency range of interest being contaminated by the numerical error. The contact stiffness has an opposite effect on the contact force in low and high-frequency ranges. Then the source and the amplification factor of high-frequency components of contact force are investigated. The results show that the half and quarter of the dropper/steady arm interval length presents the primary source of high-frequency components of the contact force. The corresponding wavelength can also be found in the high-order modes of the catenary. Finally, a variable time step procedure is also proposed to capture the contact loss occurring at high frequencies accurately. The comparison of the results between the variable and constant time steps indicates that the traditional constant time step may result in errors when calculating the contact loss duration.