Verification of Fatigue Path Probability Integration (FPPI) for Fatigue Risk Management with Multiple Maintenance Options

Abstract

A fatigue path probability integration (FPPI) algorithm was developed for fatigue risk management using nondestructive inspection (NDI) or in situ NDI for multiple maintenance scenarios. FPPI is an efficient probabilistic method which is a probabilistic framework using a baseline crack growth histories repeatedly for multiple maintenance plans under various uncertainties such as variability in material properties, initial flaw size, random processes of the fight loading, inspection reliability and inspection dependency for complex repair scenarios for high computational accuracy and efficiency. In this study, Monte Carlo simulations (MCS) with several billions of flight simulation were conducted to verify and demonstrate the FPPI algorithm for flight life plans with multiple maintenance options and variable inspection intervals under various flight conditions subject to various uncertainties. The study also demonstrated that FPPI is several orders of magnitude more efficient than traditional MCS for equivalent accuracy