Advanced damage tolerance and risk assessment methodology and tool for aircraft structures containing MSD/MED

This paper presents results from NRC's development of advanced damage tolerance analysis (DTA) and risk assessment methods and tools for aircraft structures, including build-up structures containing multi-site fatigue damage (MSD) and multi-element damage (MED), to support the Canadian Forces (CF) aircraft structural life cycle management. The DTA methods developed include new closedform solutions and generic finite element (FE) based tools to calculate the stress intensity factor (SIF) and the f-solutions for build-up structural configurations. To facilitate the risk assessment, an in-house crack growth analysis program, CanGROW, was developed to simultaneously grow multiple cracks. Guidelines were established to calculate the residual strength of MSD/MED structures using global and/or local FE models, considering load redistribution among adjacent components. For the MSD risk analysis, an efficient Monte Carlo simulation technique was developed to determine the crack size distributions at different inspection intervals, which were then used in NRC's risk analysis code ProDTA to calculate the single flight hour probability of failure. Case studies on critical locations of the CC-130 centre wing structure are presented to demonstrate the capability of the developed methods and tools.Peer reviewed: YesNRC publication: Ye