Study On Stress And Load Spectrum Of Beijing Metro Bogie Frame

As the main transportation tool of urban rail transit,the subway is of great significance for relieving the urban traffic pressure,improving the quality of live of residents,adjusting the layout of urban structure and promoting the economic development of cities.The security problem of its operation is also becoming more and more prominent with the increasing of the operating mileage.Bogie frame fatigue strength is a key factor to ensure the safe operation of the vehicle.Line simulation test for bogie frame is an effective way for the analysis of fatigue strength of the frame.It not only can accurately reflect the actual operation of the line frame,but also greatly reduces the economic cost and time cost test.This paper takes Beijing Metro Bogie Frame as the research object,combine the study of the load spectrum which is important basis for the evaluation of structural reliability,carry out bearing analysis,calibration test,line dynamic stress test,load spectrum compiling work,and proposed the compilation method of concentrated load spectrum,according to the principle of consistency of injury the bench can be effectively used for concentrated load test spectrum of circuit simulation,the main research work is as follows:(1)Classify the load types of Metro Bogie Frame,according to the bogie design standard of EN13749,calculate various loads under simulated operation conditions,determine the dynamic stress measurement points and load identification points of each key parts of the structure.(2)Carry out the frame calibration test,use the electric bridge principle to arrange the force sensor,find the linear relationship between the load and the stress of the key part of the frame,and obtain the load transfer coefficient.The test force frame is made for the actual line test,and the key parts of the frame and bogie are used to identify the load carried in the line test.At the same time,it provides support for the calculation of load spectrum damage and the establishment of damage consistency load spectrum.(3)Test the bogie frame and test all the load of the bogie and the dynamic stress data of the key parts with the change of time.The test data are processed and analyzed,and the measured load spectrum of the frame in the line test is calculated.(4)Study the load spectrum concentration method,determine the fatigue limit,and take the damage of load sensitive points as the basis,and synchronize the load time history of the frame according to the stress time history of the stress measurement points.The load spectrum is obtained by using the rain flow counting method.(5)According to the damage equivalence principle,comparison of stress and time history before and after concentration damage,validate the effectiveness of the concentration method.The key points of fatigue are selected to calibrate the damage consistency of the concentrated load time history and the concentrated load spectrum.MATLAB programming is applied to optimize the concentrated load spectrum damage and the measured stress spectrum damage at the key point of fatigue.The constraint conditions are established,and a reasonable concentration load spectrum calibration coefficient and calibration load spectrum are obtained.It provides refined and effective load data for line simulation test.This research can be used to improve the bogie test evaluation standard,it is significant for improving the reliability of new frame design and existing frame fatigue strength problems.The data would be used to evaluate the service life of key components,enhance the safe running performance of the train,and prevent the occurrence of safety accidents.