| The body of the high-speed EMU bears a variety of loads in operation,including longitudinal,torsional and pneumatic.With the increase of speed,the stochastic disturbance frequency domain caused by line unevenness is widened,the vibration of vehicle body is intensified,and the reliability of vehicle body structure can not be ignored.Therefore,this paper relies on the sub-task of "Research on fatigue reliability of car body,equipment cabin and bogie" of the scientific research project "Key Technologies of High Speed Passenger Transport Equipment with Speed of 400 km per hour and above" subject 5 "Research on High Safety Travel,Structure,Fire Prevention and Electromagnetic Compatibility Technology".The measured data of CR400AF carbody in 250 km/h-390 km/h range of running speed straight curve are selected to fit the Weibull distribution,and then the relationship between body load and speed is obtained.Finally,the load spectrum of 400 km/h EMU carbody is obtained,which provides a basis for the design and evaluation of 400 km/h EMU carbody.(1)Carbody load identification is completed,and the load spectrum of 350 km/h EMU car body is obtained by combining the measured data of the line.The load and strain transfer coefficient and the load stress transfer coefficient of the frame are obtained through the calibration test and finite element analysis.Then the line tests are carried out on the Zheng Xu passenger dedicated line at different speeds,and the load time history of the carbody under different speeds is obtained.(2)The load characteristics of the carbody under typical working conditions are analyzed,and the load types with obvious law of speed and straight curve working conditions are obtained.Through data processing.Combined with speed and gyroscope signal,load characteristics of main load and local load under straight speed and curvilinear working conditions are analyzed.The load types that are sensitive to straight curve and speed are obtained,which lays the foundation for the establishment of 400 km/h EMU carbody load spectrum.(3)Through mathematical statistics and non-linear fitting,the load spectrum of 400 km/h EMU carbody under straight curve condition is compiled.Taking the load with obvious law of velocity and straight curve as the research object,study their characteristics of loading spectrum under different speeds of line and curve respectively.Then use Weibull distribution to fit to them,and the Weibull fitting parameters of these loads are obtained.Fitting the parameters and velocities of Weibull fitting with quadratic polynomial,we get the function relation between speed and Weibull fitting parameters,and get the Weibull distribution parameter of 400 km/h EMU carbody load spectrum.The same with quadratic polynomial to determine the 400 km/h EMU carbody of the load spectrum of the maximum value,divided into 16 equal parts,after determining the load spectrum of the total frequency,By using the inverse solution of Weibull distribution function,the frequency of each load amplitude corresponding to each level is obtained,and the load spectrum of the 400 km/h EMU carbody is obtained. |
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