ABSTRACT
This chapter gives an example of how probabilistic methods can be used to predict the variability expected in the fatigue test of simple laboratory specimens such as smooth round bars. The variability observed in laboratory experiments is discussed. The physical source of the variability is identified. Fracturemechanics-based models that account for the physical mechanism occurring during fatigue are introduced. Using these models, the governing material parameters likely to have significant uncertainty are identified, and the uncertainty is quantified. A Monte Carlo simulation routine is developed using the mechanistic model and the governing random variables to predict the scatter in the smooth bar response.
For the purpose of this chapter, fatigue is defined as the entire range of damage-accumulation sequences, from crack nucleation of the initially unflawed bar to final fast fracture.
