Probabilistic Method to Determine Widespread Fatigue Damage Average Behavior of Fleet

Widespread Fatigue Damage (WFD) issue is a major threat to the structural integrity of the aging aircrafts, So WFD assessment is a key measurement and necessary task to ensure the continuing airworthiness. A methodology using probabilistic framework to assess WFD was developed. The major feature of this method is that a stochastic process which is introduced to crack initiation and crack growth as well as yield stress and fracture toughness. Stress Intensity Factor (SIF) was incrementally calculated using Finite Element Method (FEM). Numerical studies were performed for panels with five holes using Monte Carlo Simulation (MCS). The WFD Average Behavior, include inspection, monitoring and repair period, was presented, and the convergence of the MCS was also discussed. The effectiveness of this methodology was verified by comparing the experimental data. This approach simulated and evaluated the WFD behavior and got the relative statistic data, which provided a practical engineering method for WFD evaluation.