French Naval Operations in Spitsbergen During Louis XIV's Reign

In 1895 the Secretary of the Geographical Section of the Committee for Historical Works, Dr. Ernest-Theodore Hamy, published a detailed description of a highly unusual naval chart, undated but probably drawn around A.D. 1630. This valuable document, the property of a British collector, showed "without question, Spitsbergen, the name places being partly in French while, in the middle of the chart, is a coat of arms showing the fleur-de-lys in the style of Louis XIII. The map is entitled La France Artique (sic)!" ... To try to establish the exact date or provenance of this chart is beyond the scope of this paper. ... The essential importance of this chart is its spectacular proof of a continuous French presence in the waters and along the coasts of Spitsbergen, throughout the greater part of the seventeenth century

An experimental assessment of the saturated transverse permeability of Non Crimp New Concept (NC2) multiaxial fabrics.

Over the past few years some manufacturing processes involving resin impregnation in dry preforms prior to cure, and more specifically resin infusion across the fabric thickness (the so-called Resin Infusion Processes) have been developed. In these increasingly used processes, the transverse permeability of the fabric controls both manufacturing cycles and dimensions, and consequently the mechanical properties of the final composites. A big effort has been realized to obtain reliable experimental techniques for measuring the transverse permeability. Since the distinction between saturated and effective permeabilities is still being discussed, and the flow-front is hardly defined in such small dimensions (of the order of 1 mm), our measurements on some so-called Non-Crimped New Concept (NC2) are carried out for saturated flow, i.e., the fiber network is completely impregnated right from the onset of the experiment. In our case [1], these measures rely on the measurements of the pressure drop induced by the flow of a controlled fluid across the fabric, easily converted into transverse permeability through Darcy's law. One of the main results of these measurements is that the low NC2 transverse permeability depends on the face of the fabric receiving the fluid. This original behavior may, in turn, be translated into manufacturing guidelines to achieve optimal processing configuration. An attempt to relate this differential to the stitching hole surface is proposed which appears to explain some minor phenomena. On the contrary, the 3D shape of the stitching hole reconstruction from polishings could yield some appropriate explanation

Influence of the stitching density on the transverse permeability of Non-Crimped New Concept (NC2) multiaxial reinforcements : measurements and predictions

International audienceNew manufacturing processes arise for polymer-based composites which involve resin infusion through dry pre-forms. Modelling approaches of these processes require to assess new physical characteristics of the materials. In this paper, the transverse permeability of new multiaxial stitched materials, referred to as NC2, is investigated. First, in the framework of Darcy's flows, this permeability is assessed for various biaxial NC2 using a specific device. Through this approach it is shown that the transverse permeability depends strongly on the stitching density. Then, the results from a simplified FE study carried out at the blanket scale are shown to correlate quite well the experimental measurements and evidences established in the first part

Méthode de grille : contribution à la conception d'une structure en matériaux composites en milieu industriel

L'objectif de ce papier est de contribuer à la diffusion des techniques de champ dans l'industrie mécanique. Les méthodes optiques de mesure de champs conduisent en effet à une connaissance quantitative des champs cinématiques à la surface des pièces et peuvent se révéler d'une aide efficace dans la phase de conception de structures en milieu industriel. Le papier souligne la richesse de cette approche à travers la conception d'une structure originale, du type poutre en Té, en matériaux composites pour l'aéronautique. La première partie introduit la problématique des liaisons de préformes en vue de la réalisation de pièces structurales en composites. La seconde partie présente l'essai permettant d'exercer une traction sur l'assemblage en Té et de caractériser son comportement. Le principe d'un essai instrumenté par grille a été retenu pour disposer d'informations suffisantes et tester la faisabilité de la mise en œuvre de cette technique en milieu industriel. La troisième partie souligne la méthodologie expérimentale utilisée et l'apport de la méthode de champ tant en ce qui concerne la connaissance de l'essai que le comportement de la structure

Problématique de la mesure de perméabilité transverse de pré-formes fibreuses

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Modélisation et approche expérimentale des variations dimensionnelles de circuits imprimés.

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Characterization of transient through-thickness permeabilities of Non Crimp New Concept (NC2) multiaxial fabrics

International audienceIn order to support the development of the recent composite manufacturing processes involving resin infusion across dry preforms prior to cure, a big effort has been realized to obtain reliable experimental techniques for measuring the through-thickness permeability. Some of our previous works focused on the through-thickness permeability measured in saturated regime for some so-called Non Crimped New Concept (NC2) multiaxial fabrics [Drapier S, Pagot A, Vautrin A, Henrat P. Influence of the stitching density on the transverse permeability of non-crimped new concept (NC2) multiaxial reinforcements: measurements and predictions. Compos Sci Technol 2002;62(15):1979-1991; Elbouazzaoui O, Drapier S, Henrat P. An experimental assessment of the saturated transverse permeability in Non Crimp New Concept (NC2) multiaxial fabrics. To appear in J Compos Mater]. But since in the real processes, both saturated and transient permeabilities are encountered, experimental assessments of these two permeabilities has to be achieved. If in saturated regime the through-thickness permeability is relatively easy to assess, in transient regime, however, the flow front is hardly defined in such small dimensions (order of 1 mm). Relying on optical fibre sensors to detect the flow front, transient through-thickness permeabilities are assessed here for various fibre volume fractions. using a Darcy's law to deduce the permeability from the fluid pressure and velocity. These measurements exhibit a satisfying reproducibility and appear to be consistent with the saturated permeabilities, in the sense that here again the permeability measured depends on the face receiving the fluid [Elbouazzaoui O, Drapier S, Henrat P. An experimental assessment of the saturated transverse permeability in Non Crimp New Concept (NC2) multiaxial fabrics. To appear in J Compos Mater]. Moreover, the transient permeabilities appear to be around a factor 10 larger than the saturated permeabilities. Since the differentiation between saturated and transient permeabilities is an open problem, these experimental results can be used for some process simulations as well as a basis for some theoretical developments of the permeability prediction in both regimes

Contribution to composite T beam design in industrial environment by using the grid technique

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Assessment and prediction of the influence of the stitching density on the transverse permeability of NC2 multiaxial reinforcement.

International audienc