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| Registros recuperados: 131 | |
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| Baley, C; Perrot, Yves; Busnel, F; Guezenoc, H; Davies, Peter. |
| Flax provides a renewable source of fibres with good mechanical properties, which justifies its use as a reinforcement for polymers. Composite materials made with flax which has only undergone mechanical treatments (stripping followed by combing) results in the presence of bundles of fibres. When a unidirectional flax/polyester ply is loaded in transverse tension the damage mechanisms are complex; cracks develop in the matrix, and at the fibre/matrix interface, but they also appear within the fibres themselves and in the lamellae within the fibre bundles. This emphasises the highly anisotropic nature of these flax fibres, whose average longitudinal Young's modulus is 59 GPa and whose transverse modulus is estimated here to be 8 GPa. (c) 2006 Elsevier B.V.... |
| Tipo: Text |
Palavras-chave: Unidirectional; Transverse tensile; Polyester; Glass; Flax; Composite materials. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-6362.pdf |
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| Maurice, Julien; Creac'Hcadec, Romain; Cognard, Jean-yves; Davies, Peter; Meirinhos, Georges; Mahdi, Stephane. |
| Adhesive bonding is an interesting structural assembling technique for weight saving in modern commercial aircraft, in which the use of composites materials is increasing. In order to meet both optimization and respect of safety conception constraints, the development of accurate numerical strategies is required. Thus, improvement in the experimental characterization and in the design of reliable numerical tools for bonded assemblies is necessary. This paper presents the characterization of the elastic-plastic behaviour of four aeronautical adhesive films, consisting of two epoxy-based resins supported by two types of carrier. The characterization over a wide range of monotonic proportional tensile-shear loads is performed using a modified Arcan test... |
| Tipo: Text |
Palavras-chave: Aeronautical; Mechanical properties of adhesives; Numerical modeling. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00142/25317/26067.pdf |
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| Casari, Pascal; Jacquemin, Frederic; Davies, Peter. |
| This paper presents a method for the characterization of residual stresses in thick filament wound tubes. The three materials considered in the study are wet wound epoxy composite tubes based on E glass, R glass and T700 carbon fibres with three winding angles, [+/- 35], [+/- 55] and [+/- 851 with respect to the longitudinal axis. The aim of the present work is to measure internal stresses, based on strains liberated by cutting composite tubes, and to compare results with predictions from a residual stress model based on the classical equations of solid mechanics. This leads to a simple technique which allows the quick identification of the effects of manufacturing and moisture on the internal multi-axial stress level. |
| Tipo: Text |
Palavras-chave: Moisture; Tube; Composite; Residual stress. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1212.pdf |
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| Le Duigou, A.; Davies, Peter; Baley, C.. |
| Natural fibre reinforced biopolymer composites, or biocomposites, are an alternative to the glass fibre reinforced thermoset composites widely used today in marine applications. Biocomposites offer good mechanical properties and total biodegradability, but if they are to be adopted for marine structures their durability in a seawater environment must be demonstrated. In the present study unreinforced PLLA (Poly(L-Lactic acid)), injected and film stacked flax composites with the same PLLA matrix have been examined. All the samples were aged in natural seawater at different temperatures in order to accelerate hygrothermal ageing. Changes to physico-chemical and mechanical behaviour have been followed by weight measurements, thermal and gel permeation... |
| Tipo: Text |
Palavras-chave: Mechanical properties; Hygrothermal ageing; Biopolymer; Natural fibre; Composites. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6639.pdf |
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| Boisseau, Amelie; Davies, Peter; Thiebaud, F.. |
| The development of ocean energy conversion systems places more severe requirements on materials than similar land-based structures such as wind turbines. Intervention and maintenance at sea are very costly, so for ocean energy supply to become economically viable long term durability must be guaranteed. Cyclic loading is a common feature of most energy conversion devices and composites are widely used, but few data are available concerning the fatigue behaviour in sea water of composite materials. This paper presents the results from an experimental study to fill this gap. The fatigue behavior of composite materials reinforced with different types of glass fibre is characterized in air and in sea water; the influence of testing in sea water rather than air... |
| Tipo: Text |
Palavras-chave: Composite material; Fatigue behaviour; Sea water ageing; Failure mechanism; Tidal turbine. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00134/24554/22685.pdf |
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| Hernandez-moreno, H.; Collombet, F.; Douchin, B.; Choqueuse, Dominique; Davies, Peter; Gonzalez Velazquez, J. L.. |
| This article is the second of a series of three papers concerning monitoring of filament wound cylinders using Bragg gratings. In this second part, the tooling presented in Part I is used to embed gratings and thermocouples in filament wound glass reinforced epoxy composite cylinders during fabrication. Bragg grating strain was obtained from wavelength and temperature response, by a calibration technique described here. Results from tests on five cylinders show the Bragg grating's capability to monitor strain evolution during fabrication, and the capacity to detect several phenomena occurring during cure is established, in addition to quantifying the initial material condition of the cylinder before it enters service. |
| Tipo: Text |
Palavras-chave: Filament winding; Non destructive testing; Residual stress; Smart materials. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7329.pdf |
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| Le Guen-geffroy, Antoine; Davies, Peter; Le Gac, Pierre Yves; Habert, Bertrand. |
| Carbon fiber reinforced composite materials are finding new applications in highly loaded marine structures such as tidal turbine blades and marine propellers. Such applications require long-term damage resistance while being subjected to continuous seawater immersion. However, few data exist on which to base material selection and design. This paper provides a set of results from interlaminar fracture tests on specimens before and after seawater ageing. The focus is on delamination as this is the main failure mechanism for laminated composites under out-of-plane loading. Results show that there are two contributions to changes in fracture toughness during an accelerated wet ageing program: effects due to water and effects due to physical ageing. These are... |
| Tipo: Text |
Palavras-chave: Composite; Delamination; Seawater; Immersion; Ageing. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00652/76410/77458.pdf |
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| Le Gac, Pierre-yves; Roux, Gerard; Davies, Peter; Fayolle, Bruno; Verdu, Jacques. |
| Water sorption has been studied gravimetrically for polychloroprene rubber samples, first at a fixed hygrometric ratio (98% HR) and several temperatures (25, 40, 60 and 80°C) for samples of 1.9 and 3.8 mm thickness (Constant Temperature and Hygrometry, CTH experiments), then at fixed temperature (40°C) and several hygrometric ratios ranging from 0 to 95% HR on samples of 0.1 mm thickness (DVS experiments). CTH experiments reveal an abnormal sorption behavior: after an apparently fickian transient period, the water absorption continues at almost constant rate, no equilibrium is observed after more than 2500 hours, whatever the temperature. DVS experiments reveal a very low Henry’s solubility but the formation of clusters at water activities higher than 40%.... |
| Tipo: Text |
Palavras-chave: Polychloroprene; Water sorption; Clustering. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29903/28350.pdf |
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| Maurin, Romain; Perrot, Yves; Bourmaud, Alain; Davies, Peter; Baley, Christophe. |
| Polyester resins are widely employed for pleasure boat construction. In order to satisfy new environmental legislation on styrene emissions resin suppliers have proposed modified formulations, but these show lower failure strains under tensile loading. This paper examines the influence of wet ageing on mechanical properties of low styrene polyester, together with standard polyester and vinyl ester resins, and their glass reinforced composites. Results are presented from accelerated ageing in natural sea water for nine months, at temperatures of 20, 40 and 60 degrees C. Nano-indentation was used to study local changes in the resin after ageing. The diffusion kinetics of the low styrene emission resins and their composites are similar to those for standard... |
| Tipo: Text |
Palavras-chave: Polymer matrix composites (PMCs); Environmental degradation; Mechanical testing. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00000/11104/7856.pdf |
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| Registros recuperados: 131 | |
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