Abstract: The running safety of high-speed trains under crosswinds is studied based on theories of the aerodynamics and multi-body system dynamics. The connection between the distant meteorological wind speeds and the wind speeds at the monitoring point of the high-speed trains which is 4 m high above the track surface and 3.8 m far away from the center of the windward track is studied. The effects of slip angles and bridge heights on the aerodynamic load characteristics are analyzed. The aerodynamic loads are dealt with as the external loads on the train to analyze the running safety of high-speed trains on bridges and the running security domain of high-speed trains on the bridge are given. The results show that, the wind speeds at the monitoring point are proportional to the meteorological wind speeds, and the proportional factor increases with the increase of the bridge height. For a bridge whose height is no less than 10 m, when the vehicle speed is fixed and the wind speeds at the monitoring point are the same, the bridge height has little effect on the aerodynamic force coefficients, aerodynamic moment coefficients or the operational safety indicators of high-speed trains. If the height of the bridge is less than 10 m, the aerodynamic force coefficients, aerodynamic moment coefficients and the operational safety indicators can not be determined only by the wind speeds at the monitoring point, thus the effect of the bridge height can not be ignored. When the wind speeds at the monitoring point are taken as a reference, the high-speed trains running on a low bridge are more dangerous than those on a high bridge. Thus, the running security domain of high-speed trains running on bridges with different heights along the rail line should be established according to the safe operation on the low bridge.

Key words: Running security domain, Aerodynamic force coefficient, Bridge, High-speed trains, Monitoring point, Multi-body system dynamics