An equivalent method considering interaction on fatigue reliability analysis

In many practical engineering projects, the fatigue damage accumulation can degenerate the structural component properties, which may have a significant impact on its reliability. In this paper, a probabilistic approach based on equivalent stress transformation with the interaction effects considered, is proposed to estimate the fatigue reliability under random loading spectrum. Because the traditional cycle-based algorithm costs too much computational time, the equivalent methods are proposed to improve the efficiency without accounting for the historical loading effects. To make the fatigue life prediction more accurate and efficient, the crack closure model is employed to describe loading sequence effects based on the concept of plastic zone. Then the equivalent stress transformation method turns the effective random loading sequence into a constant amplitude loading spectrum. At last the reliability curve can be calculated by using stress-strength interference model. Simulation and experimental data are used to validate this method. Good predictions are observed.