Bizeul, Matthieu. Study of the fatigue crack growth in thin composite skins made of woven plies. PhD, Institut Supérieur de l'Aéronautique et de l'Espace, 2009, 256 p.
(Document in French)
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Helicopter blades are made of composite sandwich materials mainly loaded in fatigue. Normally, they have relatively thin skins. A through-the-thickness crack could appear in these coatings. The aim of this study is to characterize the through-the-thickness crack propagation in fatigue in thin woven glass fabric laminates. A specific fatigue test is developed so that these structures parts can undergo real stress conditions. A wide experimental campaign is undertaken which allows stating crack growth rates in several laminates. The propagation path is linked through microscopic investigations to specific damages of woven plies. Crack initiation duration influence on experimental results is also underlined. The finite element modelling is based on the architecture of the fabric and on the fatigue behaviours of the matrix and the fibre. The fatigue damage matrix is introduced with user spring elements that link the two fibres directions of the fabric. The glass fibre fatigue behaviour is based on S-N curves. Numerical results are compared to measured crack growth rates levels and observed damages in the crack tip.
|Item Type:||PhD Thesis|
|Institution:||Université de Toulouse > Institut Supérieur de l'Aéronautique et de l'Espace - ISAE|
Département de Mécanique des Structures et Matériaux - DMSM (Toulouse, France) - Matériaux composites
|Deposited By:||matthieu bizeul|
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