Study On Vibration Fatigue Of Bogie Traction Motor Structure

After several major speed-increasing processes of railway vehicles in China,the running speed of freight cars and passenger cars has been greatly improved.As the speed of rail vehicles increases,the fatigue life of locomotive components and welds seriously affects the stability and safety of trains during operation.Stress analysis and random vibration fatigue analysis of components on locomotive bogies appear in the anti-fatigue design stage of locomotives especially important.The traction motor of the locomotive is fixed on the bogie of the locomotive by bolt connection.It is necessary to conduct a more detailed study on the random vibration fatigue life of the base metal and the welds of key parts of each component of the locomotive according to the actual situation.This paper takes the traction motor structure of a bogie as the research object,and uses the finite element simulation method to study the strength of the traction motor and the fatigue life of the structure.And through the comparison of three fatigue research methods,the accuracy of the results is verified and the advancement of the frequency-domain structural stress method is also proved.The main content of the paper is as follows:(1)The bogie traction motor model is established based on the finite element method,the hexahedral solid grid is used to discretize the motor model,and the Lanczos method is used to calculate the first ten order modes of the traction motor.(2)Based on the TB / T2436-93 standard,five load conditions are set,the static strength analysis of the traction motor is performed to determine whether the structural strength meets the safety requirements.Based on the IEC 61373-2010 standard,the modal method is used to calculate the stress value of the traction motor in vertical,horizontal,and vertical impact conditions,and compared with the allowable stress of the material,to determine whether the components of different materials meet the safety design requirements.(3)Random vibration analysis of the traction motor structure based on the IEC61373-2010 standard.Random vibration fatigue life prediction is performed based on the nominal stress method,and the fatigue life of welds and base materials is calculated.Introduce a new method of fatigue analysis-frequency domain structural stress method.By defining the key welds of the structure,the excitation load of random vibration is equivalent to the structural stress,and the equivalent structural stress in the frequency domain is obtained by the superposition method,and then the fatigue life of the key weld of the traction motor is predicted by the main S-N curve.(4)Introduce the three-interval fatigue life prediction method to predict the fatigue life of the weld of the motor structure again.The comparison of the three fatigue life prediction methods verifies the rationality of the results and illustrates the characteristics of the threemethods.(5)Improve the fatigue life of dangerous welds by optimizing the structure of dangerous welds.