Mise En Œuvre D'un Stratifié Bio-Sourcé. Influence Des Paramètres Procédé Sur Les Propriétés Du Composite À Base De Lin

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Effect of residual stresses on torque behaviors of composite laminate

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Numerical modelling of low velocity multi-impact test on different stacking sequences

The use of composite materials in the industrial field has been growing significantly for many years. This increase is explained by the fact that the industry, especially aeronautics which was pioneering in this field, is interested in the lightening of structures in order to be able to take up the new environmental challenges. Whether in the aeronautical field or in the land transport sector, structural elements may undergo multi-impactsor impact. Even at low velocitypose a threat to the integrity of the material and the structure itself. The objective of this work is to propose a numerical model to determine the damage within a composite structure subjected to low energy multi-impact. The…

Propriétés acoustiques de matériaux poreux saturés d'air incluant une porosité partiellement ouverte

International audience; Nous étudions les propriétés d'un matériau à microgéométrie complexe incluant une porosité partiellement ouverte ou de culs-de-sacs. Ce type de matériau peut être obtenu par dissolution de grains de sel (NaCl) noyés dans une matrice de métal solidifié. Cette matrice est obtenue après invasion sous pression négative et à haute température des grains de sels par le métal sous forme liquide, puis refroidissement jusqu'à solidification du métal. La comparaison des résultats expérimentaux et théoriques sur le coefficient d'absorption acoustique d'une couche de ce métal poreux montre que le modèle de Biot-Johnson-Allard ne fournit pas des résultats aussi satisfaisants que …

Effect of Multi-Impact on Qiqh Carbon/Epoxy Composite LaminateEffect of Multi-Impact on Qiqh Carbon/Epoxy Composite Laminate

This work is motivated by increasingly used of composite structures under severe loading conditions. During their use, these materials are often subjected to impact as for example, in the aeronautical field the fall of hailstone on structure composites. In fact, the low energy traditional impact tests don’t allow to see the evolution of the damage and don’t permit also to compare the best tolerance to impact between different stratifications. The multi-impact tests made it possible to find a solution to this problem. In this work, multi-impact tests are performed on three carbon/epoxy stratifications. The final goal is to predict the durability of the composite structures during impact load…

Determination of the residual stresses in composite laminate using the compliance method

Residual stresses play an important role on the mechanical behavior of composite laminate. The development of new methods to determine the residual stresses gradient within the laminates is necessary. This article presents the adaptation of the compliance method in the case of composite laminates carbon/epoxy [02/902]s. The incremental drilling of a constant width groove allows for each increment to measure the strains (using strain gages) and displacements (using an optical device) of particularly points of the structure surface. These experimental data are compared with results given by a finite elements simulation. This comparison allows to raise the residual stresses in the composite la…

Dependence between aging treatments and residual stresses on composite laminate

International audience; The objective of this paper is to study the influence of residual stresses due to fabrication conditions on the thermomechanical behavior of carbon/epoxy laminate structures (cross ply). These studied laminates have undergone various cycles of thermal aging. The addition of a post-cure cycle after the end of the initial cycle makes it possible to reduce the residual stresses level. The incremental hole-drilling method is used to measure the residual strain in the laminates. These measured strains and the numerical calibration coefficients obtained by the finite element method allow to calculating the residual stress distribution in composite depth. The obtained resul…

Optimisation de la méthode du trou incrémental pour la mesure des contraintes résiduelles dans les matériaux composites stratifiés

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Élaboration et étude du comportement en compression d’un nouveau matériau composite : Métal Poreux Polymère Composite (MPPC)

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Studies of residual stresses in composite laminates by the finite element method

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Impact Test and Mixture Approach to the Study of the Acoustic Properties of Rigid Frame Porous Materials with Functionally Graded Macroscopic Physical Parameters

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Approche des contraintes résiduelles dans les composites stratifiés par la méthode de la compliance

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Importance des contraintes résiduelles sur le comportement mécanique d'un composite stratifié

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High sound pressure model for cellular metallic foam with semi open cells

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Experimental characterization of composite laminates under low-velocity multi-impact loading

The use of composite materials undergoes a significant growth in many industries including aeronautic, railway, and automotive. Laminated composites are often subjected to severe loading conditions...

Étude du comportement aux multi-impacts des structures composites

Aging effect on residual stresses field in composite laminate

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Impacts Des Paramètres De Mise En Œuvre Puis D’un Vieillissement Hygrothermique Sur Les Propriétés Mécaniques Et Physico-Chimiques D’un Stratifié Unidirectionnel Lin – Époxy

International audience; L’effet de massification automobile qui accompagne les besoins croissants de mobilité terrestre et l’offre de nouvelles infrastructures routières qui soutient de nouvelles demandes rendent les modèles de mobilité actuels de plus en plus difficilement acceptables. En effet, les personnes souffrent de l’inconfort des villes engorgées (nuisances), de l’insécurité lors de transports du fait de défaillances techniques ou humaines, de la très grande difficulté d’optimiser ses itinéraires en fonction des horaires ou circonstances exceptionnelles (accident par exemple). Par ailleurs, la mobilité se heurte toujours aux contraintes liées aux rigidités des infrastructures compo…

Nouvelle approche dans l'analyse des contraintes résiduelles par l'interférométrie de Speckle

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Determination of residual stresses in the case of composite laminate

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Effects of cyclic moisture-induced ageing on a bio-based laminated composite

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Multi-impact damage of laminated composite materials studied with a compressed air cannon

Etude acoustique des mousses métalliques bicouches avec interface à gradient de propriétés

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Residual strain and stress analysis by speckle interferometry combined with the drill of a groove

A new method for residual stresses determination combining Electronic Speckle Pattern Interferometry (ESPI) with the machining of a groove. The internal stress field is perturbed as the depth of the groove is increased incrementally [1]. The structure finds a new equilibrium state generating displacements which are measured using ESPI. This method was tested on an aluminium alloy plate treated locally by ultrasonic shot-peening. The investigation of the images obtained with the phase shifting technique and fringe patterns makes it possible to analyze, simultaneously, the stress profile along two directions: along the depth of the structure, and along the groove direction.

Tolérance À L'impact Et Au Vieillissement Hygrothermique De Composites Carbone/Époxy Et Lin/Époxy

International audience; L’effet de massification automobile qui accompagne les besoins croissants de mobilité terrestre et l’offre de nouvelles infrastructures routières qui soutient de nouvelles demandes rendent les modèles de mobilité actuels de plus en plus difficilement acceptables. En effet, les personnes souffrent de l’inconfort des villes engorgées (nuisances), de l’insécurité lors de transports du fait de défaillances techniques ou humaines, de la très grande difficulté d’optimiser ses itinéraires en fonction des horaires ou circonstances exceptionnelles (accident par exemple). Par ailleurs, la mobilité se heurte toujours aux contraintes liées aux rigidités des infrastructures compo…

The Influence of Ageing on the Impact Damage of Carbon Epoxy Composites

Abstract This study looks into the influence of ageing on the carbon epoxy composite when impact is applied. Three different stacking sequences were investigated, one sequence with the classic lay-up, whereas the other two have quasi-isotropic and quasi-homogeneous behaviour. The specimens were aged up to 2100 h (3 months) in a climatic chamber with a temperature of 70 °C and relative humidity of 85%. The mass was measured regularly during the hygrothermal ageing treatment. The mass was always measured directly after exiting the climatic chamber and it was noted that for each stacking sequence, the same regular increase in mass is observed until stabilisation. The specimens were then impact…

Influence des paramètres expérimentaux sur la détermination des contraintes résiduelles par la méthode du trou incrémental

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Application de la méthode de la flèche à la détermination des contraintes résiduelles dans les composites stratifiés

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Nouvelle méthode de mesure des contraintes résiduelles dans les matériaux composites stratifiés

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Influence Des Conditions De Fabrication Sur Les Propriétés Mécaniques Et Physico-Chimiques D'un Composite Lin/Époxy Unidirectionnel

This study focused on the development of a manufacturing process of laminated composites made from DGEBA epoxy matrix and flax fibers. The aim is to produce a material with good and low dispersed mechanical properties. Thermocompression is the chosen manufacturing method because it enables the production of composite with high fiber content. We used separated matrix and reinforcement, and not a prepreg, to fully control each component of our composites. Several curing cycle parameters have been tested in order to optimize mechanical properties and processing time. A multi-scale analyze has been carried on the produced composites in order to quantify the range of properties’ modifications. T…

Influence of the residual stress on the mechanical behaviour of composite laminates during monotonous tensile and torque loading

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Importance des contraintes résiduelles sur le comportement mécanique d’un composite stratifié

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