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Stratégies de calcul pour l'optimisation multiobjectif des structures composites

Abstract : This thesis deals with the search for innovative composite solutions for mass reduction of aeronautical structures. Composite materials offer new degrees of freedom for structural design and optimisation. The aim of this study is to propose a methodology for robust optimisation of the stacking sequence of composite sub-components. The proposed strategy consists of three interlinked elements : the optimisation algorithm, the calculation strategy and the method to account for design uncertainties. A multiobjective optimisation algorithm is developed, that yields a set of optimal trade-offs between conflicting objectives. It is an evolutionary algorithm, whose efficiency is greatly increased compared to generic algorithms, through the introduction of multiscale mechanical models specific to layered composite materials. The algorithm is particularly suited to take into account the industrial guidelines for stacking-sequence design. To reduce calculation costs, different strategies are implemented, that imply detailed simulations and model approximation. A robust optimisation method is proposed, to account for uncertainties, lack of knowledge or potential errors. The first application deals with the buckling and post-buckling behaviour of stiffened panels. The second application deals with strength optimisation of bolted joints in composite structures, whose calculation is still problematic. A model is developed for the prediction of bearing failure, based on a progressive approach of the laminate failure and the onset of delamination, with excellent results compared to experimental data. This model is applied to the maximisation of the strength of an elementary joint with one fastener. It is also integrated in a multilevel approach for the calculation of complex junctions involving hundreds of fasteners.
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https://tel.archives-ouvertes.fr/tel-00514120
Contributor : François-Xavier Irisarri <>
Submitted on : Wednesday, September 1, 2010 - 11:56:10 AM
Last modification on : Friday, October 23, 2020 - 4:52:14 PM
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François-Xavier Irisarri. Stratégies de calcul pour l'optimisation multiobjectif des structures composites. Mécanique [physics.med-ph]. Université Paul Sabatier - Toulouse III, 2009. Français. ⟨tel-00514120⟩

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