Influence of Random Residual Stress on Fretting Fatigue

Probabilistic risk assessment has increasingly been adopted by certification agencies to address the inherent uncertainties in fatigue crack nucleation and growth processes. Fretting fatigue is a significant damage source for aircraft gas turbine engine components. When present, it can reduce component lives by 40 to 60 percent or more. Surface treatments introduce compressive residual stresses that have the potential to substantially increase component lifetimes. In this paper, an approach is presented for estimating the fretting fatigue risk reduction associated with surface treatment of an actual military engine disk under real-life loading conditions. Residual stresses associated with surface treatment are based on values reported in the literature. A probabilistic model of the fretting process is calibrated based on available failure data and used to quantify the influence of surface treatment on the probability of fracture. [PUBLICATION ABSTRACT]