Effect Of Wind Barrier On Operation Safety Of High-Speed Trains

In recent years,as the span of large-span bridges continuously increases,the bridge span direction may be more than ten meters or even dozens of meters wide.When the railway bridge is located in a strong side wind environment,the huge bridge tower blocking effect will make the train change the wind force of the body of the wind load will affect the vehicle dynamic response,thus affecting the train safety and passenger comfort,which requires the dynamic characteristics of the train passing through the bridge tower area under the side wind environment.In present thesis,a CRH3 EMU is taken as the research object.Based on the actual vehicle parameters,a three-dimensional aerodynamic model of wind-vehicle-bridge is established.The aerodynamic parameters of the high-speed train passing through the bridge tower area are studied,and the aerodynamic characteristics of the train with or without the bridge tower,at different speeds,wind speeds and wind deflection angles are analyzed.The distribution law of airflow field in the bridge tower area and its influence on the aerodynamic performance of the train are obtained.The variation of aerodynamic force and torque of the train under cross wind and sudden wind is compared,and the internal law of aerodynamic characteristic load and external wind speed and speed is obtained.The vehicle dynamics model of the train passing through the bridge tower under wind load is established,and the driving safety is analyzed.The research results show that:(1)at the wind speed of 13.8m/s,as the vehicle speed increases,the aerodynamic force and torque of the train increase significantly.Train speed increases by 250km/h for every 50km/h,head head moment by about 28%,side rolling moment by 12% and nod moment by 58%.For the tail car,the head torque increased by 17%and the side roll torque increased by 19%.(2)At wind speed of Class 6-8 with wind rating,The lateral force of the head crane increases by 30%,Increase lift increased by 25%,Head-shaking moment is increased by about 18%,Side rolling torque is increased by about75%;The lateral force of the tailcar increases by 15% with the wind grade,Increase lift increased by 30%,The head torque increases by 20%,Side rolling torque increases by 8%;(3)Wind speed 13.8.m/s and vehicle speed 250km/h,Within the 0-10 range,Wind partial angle has little effect on the train lateral force and lift,The lateral force of the train varies most over the wind bias angle of 20-30,The pneumatic lift received by the train varies most in the range10-20.(4)The peak aerodynamic wind of the train increases with the train speed,and the aerodynamic drag and lift continue to increase with the speed,including the head car has the largest force,the middle number and the smallest tail car.Among the three moments of the train,the first car is the largest,the tail car is the second,the smallest car.(5)The meeting car has a great impact on the train when driving at high speed.Keep other parameters unchanged,at the vehicle speed of 200km/h,the train lift increases by about 25%;the transverse force decreases by 17%;the shaking moment drops by about 25%,45%,and the nodding moment drops by 1.25% of 300km/h;the lateral force increases by about 7%;the shaking moment is the same;the nodding moment increases by about 50%.The higher the vehicle speed,the greater the impact on the pneumatic performance of the train.(6)When the wind speed is13.8m/s,with bridge tower and without bridge tower,the vehicle speed shall be less than or equal to 200km/h;According to the safety factor function analysis,under the base frequency wind speed of 13.8m/s,the maximum safe speed of the train is 218km/h when driving in the constant wind environment,and the maximum safe speed is 240km/h when the train travels in the random wind environment.