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Etude du délaminage en mode II de composites unidirectionnels soumis à des sollicitations rapides : approche globale et approche locale

Abstract : One of the major benefits of laminate composites reinforced with long fibers is the ability to orient the fibers of each ply to optimize its mechanical properties such as strength and stiffness, relative to loads imposed. Despite excellent properties in the plane, laminates present a problem for materials made by laminating: the inter-laminar fracture. This failure mechanism is characterized by a delamination or debonding between the plies of the laminate. It is commonly called the "delamination". In addition, little information exists in the literature concerning the mode II delamination pure. Moreover, it is even less prolific in terms solicitations fast. The objective of this thesis is to study this mode of delamination when this type of composite material is subjected to high speed loading. The test mode II delamination (CLS Cracked-Lap-Shear) was applied to two standard types of unidirectional composite materials using a guiding system ensuring a quasi-pure mode II. The test campaigns were carried out using a tensile machine at high speed. A Photron high speed camera type was used to shoot up crack propagation speeds of about 1000m/s. The application of the technique of field measurement by image correlation was used to measure local displacement fields near the crack tip. Two different methods of measurement are studied and applied to tests to monitor the crack propagation: the contrast method and a method combining measurement by image correlation and finite element method. In addition, two approaches: the first called "local" and the second called "global" has been applied to determine changes in the rate of energy release according to the speed of propagation of the crack. With the results obtained by these two approaches, we showed that the theoretical law proposed by Yang is able to adequately represent the evolution of the energy release rate depending on the speed of propagation of the crack during mode II delamination. The evolution law of Yang has been validated.
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Contributor : Anh Tuan Tran <>
Submitted on : Friday, July 15, 2011 - 1:28:38 PM
Last modification on : Friday, July 17, 2020 - 2:54:12 PM
Long-term archiving on: : Sunday, October 16, 2011 - 2:21:08 AM

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  • HAL Id : pastel-00608858, version 1

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Anh Tuan Tran. Etude du délaminage en mode II de composites unidirectionnels soumis à des sollicitations rapides : approche globale et approche locale. Mécanique des matériaux [physics.class-ph]. Arts et Métiers ParisTech, 2011. Français. ⟨NNT : 2011ENAM0021⟩. ⟨pastel-00608858⟩

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