High Speed Train Running Safety Under Cross Winds

With the rapid development of high-speed railways and the steadily increasing of the train speed, the dynamics problems caused by interaction between train and air need to be solved urgently. Especially since the Lanxin high-speed line was put into use and the construction of some coastal high-speed line is in accelerated process,the running safety of high-speed train caused by cross wind is becoming increasingly prominent.The running safety of high-speed train is not only related to vehicle system dynamics,but also needs the comprehensive studies on aerodynamics and fluid-solid coupling dynamics,which increases the difficulty of the studies on such problems.This paper has built a high-speed vehicle model with considering the random wind load.Then the vehicle running posture and running safety in crosswind environment have been analyzed by simulation,and the wind resistant measures have been proposed.Firstly, the head car of high-speed train was selected as the study object, because the aerodynamic performance of the head car normally is worse than other cars. The vehicle dynamics model was built based on the parameters of the head car by using the dynmic simulation software Simpack.In this paper the randomly fluctuating wind was selected as the wind load and the Simu spectrum was used which is more similar to the natural wind. Then the spectrum was used to reproduce the wind speed time-domain samples by taking advantage of the auto regressive AR model of linear filtering method. Synthetic wind speed was obtained by wind speed and vehicle speed.And then the aerodynamic forces and moments acted on car body were calculated according to the aerodynamic theory.After building the wind load model, the car body and wheelset posture and running safety of vehicle changed with the wind speed, wind direction and vehicle speed were explored. At the same time, detailed analysis on the relative motion between car body and wheelset was conducted in the time domain. The safety indexes contain the coefficient of derailment, rate of wheel load reduction, lateral force of wheel axle, wheel/rail vertical force and overturning coefficient. The running safety domain under different wind speed was calculated as well.In order to propose wind-resistance methods, this paper firstly studied the effect of suspension parameters on running safety. The results indicated that the suspension parameters in the given range have little effect on the running safety. Thus, the methods of semi-active lateral damper and active anti-roll torsion bar were proposed. Then simulation was undertaken to analyze the effect of the two methods by combining Simpack software and Matlab/simulink control module.