Fretting corrosion takes place on the wheelset surface of the Shinkansen vehicle axle, where the wheel is press-fitted, and sometimes the pits enlarge to cracks. Probabilistic fracture mechanics was applied to an integrity assessment of the Shinkansen vehicle axle and a series of calculations were performed in order to assess the influence of various factors on these failure probabilities. However, the propagation rate of fretting fatihue crack had some uncertainity because the data used were not in the situation of pressed-fitted condition and from tests using small specimens made of axle steel. Therefore, in the present study, bayesian analysis was performed to estimate appropriate value for the uncertain propagation rate of cracks that could be initiated at the wheelseat of Shinkansen vehicle axle by the results of fatigue test using full-scale model. Using the obtained crack propagation rate, recalculations of failure probabilities of the Shinkansen vehicle axle in operation were performed. The results are summarized as follows: 1. Modifications were made to regard the artificial flaws that were created in the wheelseat as ideal cracks. First, the size of compressive yielded region was added to that of artificial flaw and the whole size should be regarded as an initial crack size. Then, the correct fatigue lives were obtained by subtracting the corresponding crack initiation lives from the failed cycles that were obtained from the tests by using axles that had artificial flaws 2. The resulting probabilities of failure were almost the same as those that were not modified though slightly lower. The difference in crack propagation rate of such a degree was thought to exert only a minor influence of the failure probabilities. Although the difference was not so significant, more reliable results of the failure probability were obtained 3. No axles broke from the crack existing on the counter-gear side wheelseat both in the fatigue tests using a full-scale model and in numericai calculations which simulated the tests. Therefore, the favorable influence of the residual compressive stress on the failure of the axle was indirectly confirmed.


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    Titel :

    Bayesian analysis for the accurate fatigue crack propagation rate using full-scale shinkansen vehicle axle models


    Beteiligte:
    Akama, M. (Autor:in)


    Erscheinungsdatum :

    2003


    Format / Umfang :

    9 Seiten, 6 Bilder, 3 Tabellen, 6 Quellen


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Datenträger


    Sprache :

    Englisch