Stochastic fracture mechanics based fatigue damage assessment for short crack growth

摘要

Fatigue and fracture processes are characterized by randomness due to the uncertaintiesthat are associated with the governing parameters. Typical sources of these uncertainties includevariability in material properties, initial flaw sizes and shapes, geometry, loads, and otherenvironmental factors. Probabilistic fatigue crack growth models that are suitable for the assessmentof long fatigue cracks have been developed and applied by several researchers. The case forshort fatigue crack growth, however, has not received the same level of attention. This paper presentsa robust probabilistic model for short fatigue crack growth, which accounts for the effects ofcrack aspect ratio, stress ratio, as well as crack closure and retardation. Advanced fast probabilisticintegration techniques in conjunction with the response surface methodology are used for theprobability and sensitivity computations. The results obtained from these methods are comparedand successful verified using the direct Monte Carlo simulation scheme, thereby confirming therobustness of the advanced techniques employed. The work reported herein is a valuable contributionof aging structures that are subjected to cumulative damage degradation mechanisms.