Research On Dynamic Stress And Fatigue Of Bogie Frame Under Wheel Polygon And Impact Excitation

The high-speed development of the railway industry put forward higher requirements for the safety and reliability of high-speed trains.During the operation of the train,component failures caused by high-frequency vibrations such as wheel polygons and switch impact always occur,affecting the train running order,and even Endanger driving safety.The bogie frame is the key bearing component of high-speed trains,and its fatigue reliability has an important impact on the safety of train operation.In this paper,by carrying out bench tests under various working conditions,carrying out the dynamic stress response characteristics and fatigue analysis of the high-speed train bogie frame under the wheel polygon excitation and shock excitation.The specific research contents are as follows:(1)Formulate the wheel polygon and impact excitation bench test plan.Determine the wheel polygon excitation test conditions,including the wheel polygon order,amplitude and test speed level.Determine how shock excitation is implemented.Through the modal analysis of the operational frame,the high-order strong response mode and mode shape of the frame are obtained,the weak position of the frame vibration is found,and the arrangement of the measuring points of the frame test frame is guided.And sum up the appropriate time-domain and frequency-domain data processing flow.(2)Carry out wheel polygon excitation test.Based on the equivalent stress of the frame measuring points under working conditions of the 20 th and 37 th order wheel polygon tests,the dynamic stress response analysis of the frame is carried out,and the strong response area of the frame is obtained.Carry out the analysis of the influence of the wheel polygon amplitude,it is found that the stress response increases with the increase of the amplitude.Carry out the impact excitation test,and analyze the response degree of the frame to the impact excitation,and it is found that the spring sleeve area and the brake hanger area are most affected.(3)Analyze the frequency domain response characteristics of the strong response region of the frame under the wheel polygon excitatio.By analyzing the frequency spectrum of the fixed-frequency test signal,the main frequency of the response of the key measurement points under the excitation of each speed level is obtained.Compared with the natural frequency of the measurement point obtained by the time-frequency analysis of the frequency sweep test signal,it is concluded that the main reason for the increase in the response of the measurement point is the occurrence of area resonance.Considering the high-frequency response of key nodes obtained by harmonic response analysis,the frequency-domain response characteristics of each region of the framework are further summarized.(4)Carry out research on the corrected calculation method of vibration fatigue damage in frequency domain.Aiming at the poor accuracy of the current traditional frequency-domain damage calculation methods,a non-Gaussian correction coefficient method suitable for random stationary random vibration signals is obtained.A small damage correction method suitable for shock excitation signal is obtained.The experimental verification results show that the above methods significantly improve the accuracy of the frequency domain damage assessment,and provide experience for the improvement of the frequency domain damage calculation method.83pictures,15 tables,89references.