The state function based on fatigue accumulation model has a great
influence on accuracy of fatigue reliability analysis of components. A
nonlinear fatigue accumulation model considering the interaction of
loads is proposed in this paper. By introducing the square ratio of
front and back loads as the new load interaction factor into the
conventional toughness exhaustion model, thus it is improved to reflect
the load sequence and interaction effect simultaneously. Moreover, the
fatigue state function based on proposed model is constructed, which is
analyzed by the probability density evolution method. The time-varying
fatigue reliability curve is obtained by analyzing the generalized
density evolution equation. The proposed model are verified using four
experimental data, and results shows that the predication residual life
fraction such obtained is more accurate. And accuracy and efficiency of
the proposed time-varying fatigue reliability analysis method is
validated using multi-level loading experimental data.