A Nonlinear Fatigue Damage Prediction Model for Multilevel Loading

This study presents an enhanced cumulative damage model derived from the classical Manson–Halford (M–H) model. Through theoretical analysis, this study examines the advantages of the enhanced model regarding load sequence and interaction effects, validating its practical effectiveness through case studies. The findings reveal that the enhanced model characterizes the cumulative damage process under complex loading conditions more accurately. It also improves computational precision, especially when considering load sequence and interaction effects. Compared to the conventional M–H model and other improved models proposed in the literature, the enhanced model developed in this study demonstrates superior reliability in predicting fatigue life and damage accumulation, thereby providing a more robust theoretical basis for fatigue life assessment in engineering applications. The findings of this study provide novel insights into cumulative damage theory and present significant potential for engineering applications.