| Widely studied the fatigue strength evaluation methods of mechanical structure, lots of researches on fatigue strength evaluation methods of electric locomotive car-body structure have been done in this thesis. The main objective of this research is to find out the fatigue strength evaluation methods suitable for locomotive car-body structure based on the comparison of different fatigue strength evaluation methods.The FE model of locomotive car-body structure has been constructured according to the actual structure, and the static strength and modal analysis have been done. The multi-body system dynamic model of locomotive system has been constructured according to the structural parameters, and the load time history on the key bearing positions of locomotive car-body structure is achieved through calculation, and the necessary conditions is provided for the fatigue strength evaluation of locomotive car-body structure.Based on the infinite life fatigue evaluation, the key bearing parts of locomotive car-body structure are evaluated by using the Goodman fatigue cure method, the resistance structure fatigue reserve coefficient calculation method and multi-axis fatigue safety factor method. The difference and scope of the three methods are achieved by comparing the evaluation results. It shows that the resistance structure fatigue reserve coefficient calculation method can be used as a new research method for the fatigue strength evaluation of locomotive car-body structure.A stepped shaft model has been built and the quasi-static method, transient method and frequency-domain method are used to calculate its fatigue life, in order to clarify the scope of this three methods, and provide theoretical basis for locomotive car-body structure fatigue life prediction. The fatigue life of the key bearing parts on locomotive car-body structure is calculated by using the quasi-static method, and the simulation results are compared with the locomotive dynamic stress test results, and it shows that it is feasible to use quasi-static method for fatigue life prediction of locomotive car-body structure.The results show that the resistance structure fatigue reserve coefficient calculation method and quasi-static method can be used to evaluate the fatigue strength of locomotive car-body structure better, and provide the effective methods for anti-fatigue design of locomotive car-body structure. |
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