Life-time analysis and design of powder metallurgy turbine disk

Based on boundary uncertainty theory, the service life of a powder metallurgy processed (PM) turbine disk has been analyzed. First, the general formulations are presented. The effects of the boundary uncertainty variables on PM disk life response are formulated mathematically by Taylor expansion based on the boundary uncertainty descriptions. In order to present the lifetime results (output), to a specified uncertainty a critical relative maximum deviation has been presented for the required bounds of the (input) variables. Using experimental data for the PW alloy FGH95, the boundary life of an FGH95 turbine disk has been derived. The two key bounded variables among all possible ones are chosen as an example, and the accepted jointed bounds for the two variables have been calculated to satisfy a specified fatigue life of more than 4000 cycle number. The example shows the advantage of the boundary uncertainty than the classic probability method and can be applied to a simple sample.