RECONSTRUCTED FATIGUE RELIABILITY S-N CURVES OF ZG230-450 CAST STEEL

The commonly fatigue reliability curves with few of given reliability levels can do only reliability design and life prediction with the given reliability levels. For the realization of reliability design, fatigue life prediction and reliability assessment at arbitrary reliability level, reconstruction of the fatigue reliability S-N curves is essential in an entire probability sense. The fatigue limits and the S-N data of railway vehicle ZG230-450 wheel cast steel are first re-constructed by a Monte Carlo simulation with an acceptable error range. The basic reliability curves in the mid-and-short life regime are then estimated by the general maximum likelihood method. The reliability S-N curves of the material covering the mid-and-short life regime and the long life regime are finally established by a so-called probabilistic fatigue limit extrapolating method in an entire probabilistic sense. In addition, the reliability curves in terms of ten thousand km unit suitable for vehicle structures are developed of the material. By the present curves, reliability design, fatigue life prediction, and reliability assessment can be realized at arbitrary reliability level.