A Dynamic Analysis of High Speed Trains Passing Based on the Pneumatic Response of the Air Springs

As the dynamic characters of the air spring are influenced greatly by its internal pressure,in order to analyze more deeply the running safety of high speed trains passing,the pneumatic response of the air spring under the flowfield around the trains is taken into consideration. A pneumatic fluid mechanics model of the air spring and a vehicle dynamics model of a certain type of EMU are connected together and the pressure time history of the trains passing flowfield is taken as the external excitation for the air spring and the carbody to analyze the dynamics characters of EMU in the cases of different speeds. The results show that,the higher the passing speed,the greater the fluctuation of the air spring internal pressure; the vertical comfort is better than the horizontal comfort during passing; the wheel / rail vertical force and the rate of wheel load reduction are influenced less by the passing flowfield,which still have large safety margins during passing; in the case of 450km /h,the fluctuation of the air spring internal pressure can reach 30. 78%. What's more,the axle lateral force and the derailment coefficient are beyond the safe limit by the moment when the front nose of the train passes the observation point,which will affect the running safety.