Track Irregularity Prediction and Effect on the Dynamic Response of the 600 km/h Maglev System

The absence of 600 km/h operational high-speed Maglev lines leads to a unavailability of empirical track irregularity data at this speed, challenging accurate assessment of the system's dynamic response. This study presents a framework for track irregularity estimation suitable for 600 km/h applications, integrating measured data at 430 km/h and dynamic simulation outputs from a vehicle-magnetic force-track coupling model. By implementing filters and wavelet signal decomposition, the effective wavelength of track irregularity spectrum is extended to 1 m-200 m, optimizing its suitability for dynamic calculation at high-speed operation. Additionally, the autoregressive (AR) spectral estimation is employed to preserve characteristic frequencies of high-speed Maglev systems while enhancing the resolution of the irregularity spectrum. Finally, the obtained track irregularity spectrum is numerically inverted and applied into the dynamic coupling model for 500 sets of dynamic simulation analysis. The results show that the dynamic response of the 600 km/h Maglev system under the irregularity proposed in this study is greater than that under the irregularity proposed in existing research and 430 km/h measured irregularity. The track irregularity obtained in this study is more accurate and appropriate for evaluating the dynamic characteristics of 600 km/h Maglev systems. The stochastic results show there is a probability of 0.04% that the stability index of the car body surpasses the threshold of 2.5, while the minimum levitation gap of individual points exceeding the permissible range of $\pm$4 mm.