| High-speed railway is undoubtedly the highlight of the world's railways, with its predominance in high-speed, comfort, safety, transport capacity, low power consumption and so on; High-speed railway achieves remarkable economic and social benefits. China is a country with a big population, passenger transportation of railway has been in a tense for years. It is necessary to develop high-speed railway. As the core tool for high-speed railway, high-speed train represents the level of modernization of rolling stock and expresses the modern technology, such as machinery, electronics, material science and computer-controlled concentrated. In China, there has already been the necessary foundation in building high-speed railway in terms of the economic strength, the industrial scale, the theoretical studies, the test equipment design and the standards of design and manufacture.February 26,2008, the Ministry of Railways and the Ministry of Science and Technology subscribed the "independent innovation of China high-speed train cooperation agreement a joint action plan". The plan wants to develop a new generation of high-speed trains that its speed can exceed 350 kilometers per hour to provide equipment support for the Beijing-Shanghai high-speed railway. Beijing-Shanghai high-speed railway project has been approved by the State Council. It also gives the subject of this dissertation. In this dissertation, we will try to offer a systematic methods and theories of some key design parameters' influence on components'reliability, through the dynamic sensitivity analysis of axles, which are the key components of the Beijing-shanghai high-speed train.Because of the random loading on the axle, in order to do the reliability of fatigue life calculation under a limited life span conditions, it is necessary to explicitly the loading history of the stress changing corresponding with the time at dangerous points under random load. It is possible to measure through the experiment with patch test method, or can be simulated by vehicle dynamics simulation system. In additional, according to the experiment data and combining with the vehicle actual parameters, calculate the load spectrum of wheels. In this paper, we use the third method.In China, in order to simply design, and convenient for manufacturing, maintenance and operating, types of axle shaft have been standardization and seriation. This paper improves the key parts of the axle, based on the axle type RD4A and consulted the content about structural design of the axle from "structural strength of railway rolling stock". Establish axle 3-D solid model, import into FEM software MSC.Patran and make static analysis, get the most dangerous point on the axle----unloading chute. Re-analysis with dynamic load, get the load spectrum of the unloading chute. Use Miner linear damage cumulative principles to estimate axle life, further more, calculating the dynamic reliability of the axle corresponding with the mileage (which is life expectancy).Sensitivity design needs to parameterize the solid model, in this paper, we select several size parameters near the unloading chute and steel material parameters of the axle as variables. Application the software iSIGHT, integrate the model parameterized and the model from MSC.Patran, analysis the changing of the maximum stress on the unloading chute with different parameters, fit a function between selected parameters and maximum stress, finally get the influence of the parameter changing on the reliability of axle life, which is, the reliability of the sensitivity curve.It provides the change of the variable parameters caused the reliable rate of change information, may used to express that between each random variables or parameters crosswise contrast of important degree, supplies the important information for the reliability design. This paper has contrasted the axle journal, size parameter of relief groove circular arc and poisson's ratio of material variables and so on, has listed difference on reliability influence, is advantageous for the reliability design, modification, optimization design and maintenance and so on. |
