posted on 2018-11-20, 16:20authored byDylan J. Agius, Chris Wallbrink, Weiping Hu, Mladenko Kajtaz, Chun H. Wang, Kyriakos I. Kourousis
Strain-life methodologies are commonly employed for fatigue estimation in military aircraft structures. These methodologies rely on models describing the elastoplastic response of the material under cycling. Despite the numerous advanced plasticity models proposed and utilised in various engineering problems over the past decades, the Masing model remains a popular choice in fatigue analysis software, mainly due to its simplicity. However, in the case of military aircraft load spectra including scattered overloads the Masing model fails to represent adequately transient cyclic phenomena, such as mean stress relaxation and strain ratcheting. In this study, four well-known constitutive plasticity models have been selected as potential substitutes for the Masing model within a defence organisation in-house developed fatigue analysis software. These models assessed were the well-known Multicomponent Armstrong Frederick Model (MAF) and three of its derivatives: MAF with threshold (MAFT), Ohno-Wang (OW) and MAF with Multiplier (MAFM). The models were calibrated with the use of existing experimental data, obtained from aircraft aluminium alloy tests. Optimisation of the parameters was performed through a genetic algorithm-based commercial software. The models were incorporated in the fatigue analysis software and their performance was evaluated statistically and compared against each other and with the Masing model for a series of different flight load spectra for a military aircraft. The results show that all four models have achieved a drastic improvement in fatigue analysis, with the MAFT model giving a slightly better performance. Crown Copyright (C) 2017 Published by Elsevier Masson SAS. All rights reserved.
History
Publication
Aerospace Science and Technology;71, pp. 25-29
Publisher
Elsevier
Note
peer-reviewed
Other Funding information
Australian Department of Defence
Rights
This is the author’s version of a work that was accepted for publication in Aerospace Science and Technology . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Aerospace Science and Technology, 2017, 71, pp. 25-29, https://doi.org/10.1016/j.ast.2017.09.004