| The thesis researches on the structure, modeling method, body static strength and Fatigue life meeting the problem of CRH2 EMU. The finite element model of the body needs is established. Through querying books and documents, I got the calculation standard of domestic and foreign body strength. And I got the analysis which can use in the CRH2 type EMU strength standard by comparison. Then, I analyze the strength of body by finite element method, estimating the fatigue life of vehicle by ANSYS WorkBench.Firstly, we need to know the Finite element software, and then according to the existing vehicle model make a simple geometric model of body. There are two commonly used body modeling method: the neutral surface method and the section equivalent method. A lot of trial and research show that the section equivalent method can greatly simplify the body modeling than the neutral plane method, and the finite element mesh quality is better than the neutral plane method. Therefore, simplifying the complex hollow aluminum alloy body by using the section equivalent method, making the simplified model, and the geometric model is provided the more simple calculation and finite element analysis for subsequent.Secondly, getting the European vehicle body design standard EN 12663, Japan Railway vehicle body design principles of JIS E 7106 and TB/T 1335 in China " Interim Provisions for200km/h and higher speed railway vehicle strength design and test evaluation " through the inquiry of books and documents. Comparing the difference among three standards on vertical load, axial load, stack load, determined using the EN 12663 standard as the basis of the strength of the EMU aluminum alloy body design calculation and verification. Analyze the strength and stiffness of the EMU body structure by using the Structural static module of the finite element software ANSYS Workbench. The result is that in a variety of load conditions,the maximum equivalent stress of the structure is less than the material allowable stress, static strength to meet the design requirements. the stiffness require the under frame structure deformation is less than the allowable value. In the fatigue load conditions, According to the ORE report that convert Multi axial stress into uniaxial stress, drawing the Goodman fatigue limit diagram material modified, the fatigue strength of each selected position of body that meets the design requirements. Then, starting from the basic theory of modal analysis and transient dynamics, getting the vibration patterns of each modal and modal function in the most prone to deformation of body through the analysis of 11 free modes that extracted by body, to obtain the first order bending natural frequency, and then getting the first order vertical bending natural frequency is higher than the specified value requirements that is compared with the specified value.Finally, estimating and researching the fatigue life of vehicle that based on understanding the basic meaning of the fatigue life. According to the ORE report, we candraw the modified Goodman fatigue limit diagram of the selected parts of the body, which meets the fatigue strength design requirements. By combining the S-N curve of material, in the finite element software ANSYS WorkBench, Analysis of body structure fatigue life, the results show that the body meets the requirements of fatigue life. |
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