Advanced damage tolerance and risk analysis methodologies and tools for aircraft structures containing multiple-site and multiple-element fatigue damages

Abstract

This article presents the results obtained from the development of advanced damage tolerance analysis (DTA) and risk analysis methodologies and tools for aircraft structures, including build-up structures containing multiple-site fatigue damage (MSD) and multiple-element damage, to support the Canadian Forces aircraft structural life cycle management. The DTA methods developed include new closed-form solutions and generic finite element (FE) based tools to calculate the stress intensity factors and the b-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 structures with MSD and multiple-element damage 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 National Research Council Canada's risk analysis code probabilistic damage tolerance analysis 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.