| The Mechanical properties of railway vehicle converter cabinet affect the reliability of electronic systems and safety of train operation directly. With the advancement of train speed, fatigue failure of vehicle converter cabinets becomes more and more serious. In order to keep reliability of the cabinet, it needs us to study the structure strength and fatigue property urgently. Owing to the failure of obtaining practical fatigue load spectrum of structure, obtaining stress distribution by the finite element method, making an experimental fatigue life predication on the structure with experimental standard load spectrum and carrying out prototype fatigue test is an effective way to keep durability of the structure in the designing stage.The thesis summarizes present status of the strength and fatigue analysis of domestic converter cabinet, and a method of fatigue strength analysis based on experimental standard for the cabinet is brought forward. Finite element model of converter cabinet was built with analysis software ANSYS. Then static strength analysis, model analysis and impact strength analysis on the cabinet were carried out according to correlative standards. Based on the stress distribution of converter cabinet under unit load, the nominal stress approach of finite element and experimental standard load spectrum, fatigue simulation of the converter cabinet was finished with MSC. Fatigue. Thus, we got 98% total fatigue life distributions of converter cabinet under sine and random vibration load. Through analyzing random vibration, we obtained the response power spectrum of converter cabinet and also used power spectrum density method to analyze vibration fatigue life of the converter cabinet. Based on these analyses, we made an improvement on the structure and fatigue strength analysis of the improved converter cabinet was carried out again. It shows that strength and fatigue durability of new structure are improved. At last, the thesis makes a comparison between the calculation results and the test results so as to verify the rationality of the calculation results.Study method in the thesis not only has certain reference value on fatigue strength evaluation of railway vehicle parts, but also is of great significance of improving its passing rate and safe driving. |
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