An exploratory study of retirement for cause of gas turbine engine components

An exploratory study is made of a probabilistic retirement-for-cause (RFC) analysis methodology for gas turbine engine components. The initial fatigue quality is represented by both the statistical distributions of the initial flaw size and the time to crack initiation. Various statistical uncertainties in the entire RFC system, such as nondestructive evaluations, crack growth damage accumulations, etc., have been taken into account. A cost/risk optimization analysis has been formulated to determine the optimal inspection interval and the corresponding life-cycle-cost savings. It is shown that the scheduled inspection maintenance can be used to improve the reliability of gas turbine engine components significantly, and that the application of retirement for cause life management may result in a substantial life-cycle-cost saving. Practical examples are given to demonstrate the application of the proposed methodology.