Probabilistic aspects of fatigue crack growth parameters under single overload in 6061-T6 aluminium alloys

In the present investigation, several crack growth tests were performed on compact tension specimen under constant amplitude loading and single overload at an overload ratio of 1.8. The experimental data obtained were used to construct a-N, and da/dN vs ΔK curves and various fatigue crack growth parameters were determined and the variability associated with these parameters are addressed. Normal distribution, Weibull and extreme value distribution etc. were used to study the probabilistic nature of different crack growth parameters and best probabilistic distribution for each parameter are identified on the basis of statistical analysis. The probabilistic models of growth parameters are presented for the reliability assessment of a component under fatigue overload condition. (paper)