Strength Analysis And Optimization Design Of EMU Tumbler Axle Box

With the rapid development of China's high-speed railway, people's requirements for the safety and comfortableness of EMU(Electric Multiple Unit) are also constantly improved. The strength problem of railway vehicles has become one of the focuses of people's attention. Bogie is the main component of the EMU, and axle box is an important load bearing and movement joint of bogie. Due to EMU's widely application and faster traveling, axle box has to be faced with more badly working environment, which leads to bear the more complex changing loads and frequent occurrence of fatigue failure. Therefore, people pay more attention to strength performance of axle box.First of all, a type of bogie tumbler axle-box of EMU is chosen as the research object, the research methods and contents of this paper are proposed on the basis of summarizing the research achievements of the axle box at home and abroad.Next, the axle box is simplified under the premise of not affecting the accuracy of the solution. The rigid joint and elastic joint of axle box as the whole model are made by using Solidworks and ABAQUS software, and ANSYS Workbench and ABAQUS software are used to analyze and evaluate the static strength and fatigue strength of axle box. The results of static strength analysis show that the axle box meets the strength requirement under the exceptional load condition. Under the normal service load condition, stress distributions under different working conditions are got; the modified Goodman-Smith fatigue limit diagram is selected to evaluate the fatigue strength of axle box. The results of fatigue strength evaluation show that nodes of selected faces are all in the envelope of Goodman-Smith fatigue limit diagram, axle box meets fatigue strength requirements.Subsequently, the Brown-Miller model is selected to predict the fatigue life of axle box on the basis of the critical plane theory. The results of the whole model of rigid joint and elastic joint are imported severally into the Fe-Safe software, and material fatigue parameters are defined, and the sinusoid load history is prepared, and Morrow formula is selected to correct the mean stress correction, fatigue life of the axle box is predicted after that. Finally, the distribution map of fatigue life and fatigue safety coefficient of axle box is obtained. The result shows that the minimum fatigue life of the two models is more than 12 million times which the EN13749:2005 standard authorized value, the axle box meets design requirements.Finally, in order to obtain the lighter structure of tumbler axle-box of EMU bogie, topological optimization design is made for the axle box with Hypermesh/Optistruct software in the specific case on the basis of the Artificial Materials method; the objective function is minimized structural strain energy to achieve the lightweight design, and strength analysis is also made for the whole finite element model of axle box with the ANSYS Workbench software. The result shows that the new type of axle box structure not only has made the Von-Mises stresses decrease, but also the mass of its has reduced 8.43% compared with the original structure.