Probabilistic safe analysis of the working life of a powder metallurgical turbine disc

The creep and fatigue life testing was carried for the powder metallurgical (PM) alloy FGH95 at 550, 600 and 650 °C. The creep life and the fatigue life at different stress and strain level are obtained from the experiment data. By taking the uncertainty of the mechanical behavior into consideration, the probability density function curves of creep life and fatigue life are provided by statistical method. Then the curve of the creep life-stress is fitted at different temperature for the given confident level, and that of the fatigue life-stress range is fitted as well. The finite element method is employed to calculate the actual stress at the most dangerous point of the PM turbine disc applied by the cyclic working load. The safe life of the powder metallurgy turbine disc with the given confident level is obtained by the above fitted experimental life curves at different temperature.