A hybrid distribution characteristics of equivalent structural stress method for fatigue evaluation of welded structures

In the fields of engineering design and fatigue life prediction, handling limited sample data has consistently posed a challenge. A hybrid distribution characteristics of equivalent structural stress (HDC-ESS) method is presented for the design of fatigue life prediction models with small sample sizes. The method integrates the equivalent structural stress (ESS) method with the maximum likelihood estimation (MLE) method based on the idea of sample augmentation, and adds closed-loop reliability verification to ensure its robustness and correctness. By employing three distinct approaches, an analysis and comparison were conducted on the failure data of small specimen obtained from high-frequency fatigue tests of welded joints. The outcomes reveal that the HDCESS method, in comparison to the conventional direct method and the MLE-integrated equivalent structural stress approach, exhibited an enhancement of goodness of fit by 0.1866 and 0.1988, respectively. Furthermore, it exhibited remarkable performance in enhancing stability and optimizing sample quantity.