Dynamic Characteristics Analysis And Fatigue Life Prediction For Traction Motor Frame

Traction motor which is suspended on the bogie is one of the important components of locomotive running gear. With the rapid development of China's railway transport towards higher speed and heavier loading, the service durability of traction motor faces to severer request. During the running of locomotive, traction motor is subjected to not only quasi-static loads such as electromagnetic moment and gear driving torque etc., but random vibration load which is induced by the roughness of the rail. This kind of random load easily leads to fatigue damage of structure. What's more, it is also possible to cause a rather large deformation so that motor would not operate normally. Accordingly, it is necessary to research the vibration law of motor and evaluate its fatigue damage.In this paper, a reliable finite element model which can be used in static and dynamic analysis was firstly established. Then, based on this model, static strength calculation of motor frame was conducted by the Finite Element Method. The result of static calculation showed that the stress level and relative weak position of structure. In order to obtain time history of vibration acceleration and dynamic stress in some key positions on motor frame, a test and measurement was done in real railway line. After further data processing and analyzing, dynamic stress spectrum and auto power spectrum of acceleration were derived. Making use of these test data, on the one hand random vibration analysis was performed, through which structure dynamic characteristic and respond can be achieved. On the other hand, with the dynamic stress spectrum, fatigue damage of traction motor was evaluated based on BS standard which has applied extensively in engineering.Combining the methods of test and finite element simulation, the research of dynamic characteristic and fatigue strength of traction motor frame was conducted. All these work above will give reference to traction motor design. This will help to improve design quality and reduce product cost.