Effect of aerodynamic loads on the vibration behavior of a high-speed train bogie bottom fairing

Although existing drag reduction techniques have been optimized for high-speed trains operating below 400 km/h, these methods are insufficient for newer high-speed models with increased aerodynamic loading, structural stress, and energy efficiency for next-generation high-speed trains. The bogie bottom fairing offers a promising solution to this limitation by reducing aerodynamic drag and improving the flow dynamics in the bogie region. However, as train operating speeds of not less than 400 km/h, aerodynamic drag accounts for 90% of the total drag force on the train, the impact of aerodynamic forces on fairings cannot be ignored. It is essential to understand the dynamic response of the fairing to ensure operational safety and component stability. In this study, we developed a vehicle system dynamics model incorporating the bogie bottom fairing based on its structural features and installation configuration. Under the condition that the train runs at 380 km/h, we used measured aerodynamic loads as input excitations and validated the model against the observed vibration data. The simulation results showed that the vertical vibration amplitude error remained below 4%, and the main frequency error was less than 0.8%, confirming the model’s reliability. We then analyzed the vibration behavior under three typical scenarios: single-train open-track operation, open-track train meeting, and single-train tunnel passage. While the dominant vibration frequencies remained consistent across scenarios at the same measurement points, the amplitudes varied significantly. The central base plate region experienced the highest vibration amplitude during the train meetings, with a peak 18.5% higher than the minimum value observed. Tunnel passage conditions also strongly influenced the vibrations in the support region of the base plate. A comparative analysis of the system with and without aerodynamic loads confirmed the substantial impact of these forces, emphasizing the need to account for aerodynamic effects when designing and evaluating high-speed train components under critical operating conditions.