Numerical Study On The Influence Of Broken Window Of High-Speed Train On Operation Safety

The northwestern region of my country is always affected by strong wind and sand.Among them,the second double line of Lanxin Railway is one of the most severely affected areas of my country’s railway by wind and sand.When a high-speed train runs in a strong wind and sand area,the window glass on both sides of the carriage may be damaged due to the effect of wind and sand.Damaged windows will seriously affect the safety of train operation and pose a threat to passengers in the carriage.For this reason,it is necessary to study the impact of broken windows on the aerodynamic performance of trains.The research results can provide a theoretical basis for the safe operation of the following trains in the windy environment.This paper takes a domestic CRH5 high-speed EMU as the research object,and establishes a three-dimensional simulation model of train aerodynamic performance analysis.The influence of vehicle speed and wind speed on the aerodynamic characteristics of the train is compared and analyzed.The difference in the flow field and the aerodynamic performance of the train under the crosswind and sandstorm models after the broken windows of the train is analyzed.Based on the related theory of multi-body dynamics,SIMPACK is used to establish the system multi-body dynamics model of the high-speed train,and the aerodynamic load obtained by the high-speed train running under cross wind and sand after the window is broken is applied to the train system dynamics calculation model In this paper,the main safety indicators of high-speed trains in these two environments are studied after the windows are damaged.According to the relevant regulations on the dynamics of high-speed trains,the safety zone of train operation is determined.The research results show that(1)In a crosswind environment,if only the windows on the windward side are damaged,the pressure in the cabin will reach the maximum instantaneously and then return to stability;the position of the damaged windows has a significant impact on the stability of the pressure in the cabin,and the front windows of the cabin will be damaged.The maximum pressure stability reached in the cabin has nothing to do with the damaged area of the window.(2)If the windows on both sides of the carriage are damaged under cross wind,the pressure in the carriage will not become very large due to the pressure relief on the damaged leeward side,and the pressure in the front compartment of the carriage will be the largest;as the vehicle speed and wind speed increase,the pressure in the carriage The stability value of the vehicle will become larger and larger,and the instantaneous change values of the lateral force,lift,overturning moment,and head shaking moment of the carriage will all increase.(3)Compared with the hazards of crosswinds,when the wind speed and the vehicle speed are the same,the damage caused by the broken windows in the wind and sand environment is much greater.With damage to one-side windows,the peak values of wind and sand lateral force and lift at a vehicle speed of 200km/h will increase by 154% and93.5% compared with crosswinds.The instantaneous maximum overturning moment at a vehicle speed of 300km/h is 9.43 k N·m higher than the instantaneous maximum of crosswind;The double-side windows are damaged.The peak value of wind and sand lateral force and lift at a vehicle speed of 200km/h is 164% and 92.7% higher than that under a crosswind.The stability value of the overturning moment at a vehicle speed of 300km/h is 2.9k N·m smaller than that under a crosswind.With the increase of sand diameter or sand volume fraction,if one side window is damaged,the lift force and lateral force become larger,and if the double side window is damaged,the lift force and lateral force change value is smaller than the single side window damage.(4)Damaged windows on one side in sand and cross wind pose a greater threat to the safety of trains.Running in sand and wind is less safe than running in cross wind,and damage on one side is more dangerous than damage on both sides.The following wheel load reduction rate,axle lateral force,and wheel-rail vertical force can be reduced by 24.7%,24%,15.2% at most in the wind and sand environment with damaged double-side windows compared with the damage of single-side windows,and it is required under cross-wind environment with damaged double-side windows.Compared with the one-side window damage,it is reduced by 19.2%,21.3%,and 15.4%.