Research On Aerodynamic Load And Load Spectrum Of 400km/h High Speed Train Body

In 2020,the 400 km / h cross-border interconnected high-speed EMU will be put off the production line of long-distance passenger train of China Railway Corporation.As a major innovation achievement of China’s high-speed railway development in the new era,the train is of milestone significance.In the car body design stage,higher speed train means more severe aerodynamic load on the car body.Therefore,the aerodynamic load and aerodynamic load spectrum of high-speed train body at 400 km / h are studied,which provides a reference for the structural design of train body.Taking the 400 km / h EMU as the research object,this paper uses one-dimensional numerical simulation of tunnel pressure wave and rain flow counting method to study the formation mechanism of aerodynamic load spectrum of trains passing through typical tunnels,and then selects the Beijing Shanghai line to statistically analyze the aerodynamic load spectrum of trains passing through all tunnels of the line at different operation times,so as to provide reference for the design of 400 km / h trains,The main contents are as follows:The one-dimensional numerical calculation method of high-speed train tunnel pressure wave is studied,the flow characteristics are described,and the boundary conditions are established.The correctness of the one-dimensional numerical calculation method of tunnel pressure wave is verified by real vehicle test data.In addition,through the research and comparison of rain flow counting methods,the implementation of ASTM e1049-85 rain flow method in the program is completed.Finally,the verification of rain flow method program is completed through the literature legend and the tunnel single car and intersection program.Secondly,the formation mechanism of vehicle aerodynamic load spectrum is studied.By studying the formation mechanism of aerodynamic load peak valley value and pressure wave of single train passing through different tunnel lengths and different positions in the tunnel,and analyzing their aerodynamic load cycle characteristics,the relationship among tunnel pressure wave aerodynamic load peak valley value load cycle count is obtained,That is to say,when the train is running in the tunnel,the pressure load amplitude of the car body is large and the load cycle is half cycle;When the car body is not affected by the pressure wave,the amplitude of aerodynamic load is small,and the load cycle is full cycle.By studying the influence of typical velocity and tunnel length,the characteristics,main composition,distribution law and range of amplitude and frequency of aerodynamic load spectrum are revealed.With the increase of train speed,the amplitude level of the maximum aerodynamic load on the train body increases.When the train speed is 400 km / h,the maximum aerodynamic load amplitude of the train body is 2500 ～ 3000 PA;When the train speed is 450 km / h,the maximum aerodynamic load amplitude of the train body is 3000 ～ 3500 PA.When the tunnel length is 1240 m,the maximum aerodynamic load amplitude of the train body is2500-3000pa;When the tunnel length is 3000 m,5000m and 10000 m,the maximum aerodynamic load amplitude of the train body is 2000-2500 pa.Finally,the Beijing Shanghai high-speed railway line is selected as the research object to study the distribution characteristics of average amplitude aerodynamic load spectrum of 400 km / h train passing through the whole tunnel of the line.The results show that the front and rear cars and the middle cars of the train have the most cycles at the minimum amplitude level of aerodynamic load [0500)PA;The maximum aerodynamic load amplitude of the train decreases gradually from the head car to the tail car.Combined with the train diagram,the characteristics of aerodynamic load amplitude frequency of the up and down car body of the line running for one day are compared.Finally,the relationship between aerodynamic load amplitude frequency of the head and tail car and the middle car running for one day,one year and 30 years is studied,that is,the frequency of the train in the minimum aerodynamic load amplitude level of 0 ～ 500 pa accounts for 51.27% of the total frequency of all aerodynamic load amplitude levels,The frequency ratio of the maximum aerodynamic load amplitude class2000 ～ 2500 pa is 16.31%;The amplitude of aerodynamic load on the train has a significant proportion at the maximum and minimum levels,showing a bipolar distribution.The research of this paper will provide a reference for the research of aerodynamic load spectrum of high-speed train body with speed of 400 km / h in the future.