Probabilistic modeling of damage accumulation for fatigue reliability analysis

Combining a nonlinear damage accumulation model, a probabilistic S-N curve and one-to-one probability density functions transformation technique, a general probabilistic methodology for modeling damage accumulation is developed to analyze the fatigue reliability in this paper. The damage accumulation is characterized as a distribution in a general degradation path, which captures a nonlinear damage accumulation phenomenon under multi-level loading conditions, its mean and variability change with time. Experimental data of 45 and LZ50 steels used in the railway vehicle are then used to validate the proposed methodology. The fatigue reliability is analyzed and demonstrated using probabilistic model of cumulative fatigue damage.