Fatigue Strength Study Of High Speed EMU Wheelset

The higher speed the vehicle has, the more deteriorative service environment its components face, the higher requirement for its security and reliability has to be posed. The wheelset that transfers wheel-rail force directly plays a very important role in the train system. Therefore, it is very important to conduct the theory and test study of fatigue strength for wheelset and other key components in a comprehensive manner.Based on the theory and test overview of the research literature about the fatigue strength of wheelset and accelerated fatigue tests, this thesis provides detailed introduction about strength design standards on the wheel and axle at home and abroad.In this thesis, fatigue strength assessment for powered axles of CRH2,CRH3 and CRH5 is conducted by applying the standards of Japan and Europe respectively and comparative analysis of results is made. By means of the finite element method, the assessment of the contact pressure of interference fit and the static strength of wheelset is conducted. The whole locomotive non-linear dynamic model of CRH3 is established using the SIMPACK software according to the actual structural Parameters, load time history of journal and position of wheel-rail contact by taking Beijing-Tianjin track spectrum as excitation. In addition, the S-N curves of material is edited and the fatigue life of wheelset is predicted combining the load histories and the stress result by chooseing the appropriate fatigue life prediction method using the NSOFT software, straight plate wheel and S plate wheel of high speed EMU as well as the features between axles used by Europe and Japan are analyzed and compared based on the result of fatiegue life, the influence of the magnitude of interference and wheelflats on fatigue life is also analyzed. Finally the threshold value of load amplitude that influences fatigue life of wheelset is calculated based on the principle of equivalent damage and damage distribution agreement.In the thesis, the preliminary design of the wheelset fatigue test rig is put forward, and the test method and test functions of this test bench is put forward based on summarization of fatigue test method of wheelset at home and abroad.