Dfr Of Methods, Test In The Maglev Train, Walk The Line Agencies In The Study

The detail fatigue rating (DFR) method, based on probability fatigue, is one of fatigue reliability life design and prediction methods for civil aircraft structure, and has been widespreadly developed both home and abroad. With the DFR technical development and further application, the current test data and existing service information of typical structures can't satisfy the fatigue life analysis and design demands of complicated structure. The research work of this thesis intends to study the DFR theory and test method with its application in the running frame of low-speed magnet driven aerotrain.The statidtical theories of parameter estimation and the goodness-of-fit test of the two-parameter Weibull probabilistic distribution is reviewed, and are coded in this thesis firstly. The thesis introduces the test data processing method and formulation of fatigue reliability life and the relation of fatigue property parameters with DFR data in the whole fatigue life range concerned in engineering, also summarizes the general method and major procedures of DFR to analyze structural fatigue reliability life.The thesis has accomplished 4 basic tests of DFR for 5 kinds of aluminum alloys total of 460 specimens processed in different technological conditions, and deals with the test data. The data processing results show not only the quantatitive effects of the thechonogical conditions on the fatigue lives but also the test data statistical distribution obeying two-parameter Weibull form which coincides with the statistical law provided by Boeing company.The DFR method is applied to the structure detail fatigue life analysis of the running frame of low-speed magnet driven aerotrain for the first time, the work of which further extends the application of this method in different engineering fields, and generalizes the DFR method to the load characters and component configurations of the train.