On-board measurement of aerodynamic loads for high-speed trains negotiating transitions in windbreak walls

The safety risk of a high-speed train due to the fluctuation of aerodynamic loads cannot be neglected, especially for transitions in the windbreak walls. In this study, the dynamic response of a high-speed train under cross winds is exploited to identify the aerodynamic loads. Firstly, the full-scale testing of a high-speed passenger train under cross winds is introduced to make insight into the wind-induced safety issues. Significant carbody lateral, roll and yaw motions can be observed in the secondary suspension and wheel-rail interface. Secondly, a new measurement approach of the aerodynamic loads is proposed based on the inertia and suspension loads. The comparison of identified aerodynamic loads shows good coincidence in the time history with that from the field testing. Then, a simplified aerodynamic load function with the damped sinusoid characteristic is applied to the vehicle dynamic simulations. The calculated derailment coefficient and wheel unloading ratio show good coincidence with that of the tested results. The parametric studies show that the overturning and derailment risks are of great relevance to the amplitude and frequency coefficients in the aerodynamic load waveform. Both the overturning and wheel climbing derailment risks are necessary to be evaluated for railway vehicles under transient aerodynamic loads.