Weakest-Link Approach for Fatigue Limit of 30CrNiMo8 Steels (Preprint).

摘要

The transfer of fatigue data from laboratory specimens to field components under multiaxial fatigue is a difficult task. This is particularly the case in the transfer of data from specimens with well-defined shapes to components in the field with arbitrary shapes. A number of effects are to be considered in the transfer of data from a laboratory specimen to a field component. These effects include: pure size effect, pure gradient effect or notch size effect, and load type effect. The research question for this study was: Can an effective weakest-link approach for the fatigue limit of 30CrNiMo8 steels be developed. The specific aims constructed to address the research question were: (1) to develop an algorithm for the weakest-link approach to capture the pure size effect; (2) to perform verification studies on the algorithm for the weakest-link approach; and (3) to investigate volume effect and other effects on predictions of the probabilities of failure. The theory of the weakest-link formulation combined with the Dang Van fatigue failure criteria was used to develop an algorithm for the calculated probability of failure.