0000000000212900
AUTHOR
Stéphane Fontaine
Mise En Œuvre D'un Stratifié Bio-Sourcé. Influence Des Paramètres Procédé Sur Les Propriétés Du Composite À Base De Lin
International audience
Comportement Viscoélastique De Matériaux Composites À Renfort Lin Et Matrice Époxyde
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…
Investigation of Impact Induced Damage on Composite Plates by Analysing the Radiated Aerial Acoustic Signal
International audience
Vieillissement environnemental accéléré et propriétés mécaniques des fibres issues du chanvre
International audience; Ce travail a pour objectif de caractériser l’influence d’un vieillissement environnemental accéléré sur les propriétés mécaniques de fibres extra-xylémiennes issues du chanvre. Le protocole de vieillissement accéléré proposé dans cette étude consiste en des cycles de 24h comprenant une phase d’immersion de 12h dans une eau distillée à 70°C et une phase de séchage de 12h dans une étuve contrôlée à 50°C. Les résultats montrent une perte de masse significative et une diminution des propriétés de rigidité et de résistance en traction de l’ordre de 50% après 30 cycles de vieillissement.
Effect of moisture uptake on flax-reinforced composite laminates: influence on dynamic and quasi-static properties
International audience; This study proposes to investigate the effect of moisture uptake on a wide spectrum of mechanical behaviours of unidirectional flax fibre-reinforced epoxy laminates. It includes tensile monotonic and fatigue testing. Results show that UD flax-epoxy composites, whenexposed to hygrothermal conditioning at 70°C and 85% RH, exhibit a diffusion kinetic which follows a one dimensional Fickian behaviour. The mass uptake at equilibrium is approximately 3.3 % and the diffusion coefficient 6.5 10-6 m2.s-1. Water vapour sorption is shown to induce a significant change in the shape of the tensile stress-strain curve. Contrary to all expectations, water saturation does not degrad…
MULTI AXIAL TESTING OF ADHESIVELY BONDEDJOINTS OF FIBER REINFORCED THERMOPLASTIC POLYMERS
International audience; In order to predict the mechanical behaviorof adhesively bonded joints, it is necessary to develop robust numerical models.This robustness is only reached if an extensive experimental database with tensile, shear and complex combined peel and shear loads can beestablished. The purpose of this study is to present a multi axialdevice for testing adhesively bonded joints, using KS2-type specimens traditionally utilized for spot-weld characterization. The tests were conducted on a glass fiber reinforced thermoplastic polymer(PA6-6) composite adhesively bonded with a flexible polyurethane adhesive. This adhesive/substrate combination allowsshort process times and good per…
Microstructure et vieillissement hygrothermique de composites renforcés de fibres de lin unidirectionnelles
The current production of structural composite materials relies mainly on non-renewable fossil resources. Many regulations encourage the industry to move towards eco-friendly solutions. Within that general background, vegetal fibers appear to be an interesting alternative to synthetic fibers due to their good mechanical properties and their low density. However, using these fibers for structural composites is still limited because of their hydrophilic behavior which impacts processing, in-service properties and durability. The aim of this work is to study the effect of hygrothermal ageing, based on a sorption-desorption sequence, on the mechanical properties of flax fibers reinforced epoxy …
Design and development of 100 % bio-based high-grade hemp/epoxy composites
International audience; In order to develop 100% bio-based high-grade epoxy composites, in this study, bio-based epoxy thermosets and hemp slivers are processed and characterized by different technologies. Epoxy resins are synthesized from the diglycidylether of Eugenol, extracted from cloves. They are cured with bio-based acid anhydrides. The physicochemical properties of the resulting epoxy resins are characterized using thermogravimetric analyses (TGA), differential scanning calorimetry (DSC), and nanoindentation. The mechanical properties of hemp fibres extracted from the slivers are also determined using tensile tests. After their processing and characterization, these bio-based consti…
Fabrication De Matériaux Composites À Fibres De Lin En Vue D’une Application De Mobilier Urbain Ultraléger Et Mobile
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…
Influence du chargement thermohydrique sur le comportement mécanique statique, cyclique et dynamique des composites renforcés de fibres de lin
International audience; Ce travail porte sur la caractérisation de l’influence d’un chargement thermohydrique sur le comportement en traction quasi-statique, en fatigue et vibratoire d’un matériau composite lin/époxy unidirectionnel. Les résultats montrent que lorsque ces composites sont exposés à ces conditions hygrothermiques (70°C et 85% d’humidité relative), ils absorbent de l’eau suivant une loi de Fick 1D. L’absorption d’eau induit un changement de l’allure de la réponse en traction, diminue le module élastique d’environ 20% et augmente le coefficient d’amortissement d’approximativement 50%. La résistance sous chargement monotone n’est pas significativement affectée par l’absorption d…
IDENTIFICATION OF THE VISCOELASTIC CONSTITUTIVE EQUATIONS OF FLAX FIBREREINFORCED LAMINATESBY VIBRATION ANALYSIS
International audience; Experimental and numericalapproaches to identify the viscoelastic properties of flax fibrereinforced epoxy composite laminatesare proposed in this study. The method used consisted theidentification of the evolutions of both loss factor and stiffness through the use of the frequency responses. Several free-free symmetrically guided beams were excited on the dynamic range of 10 to 4000 Hz with a swept sine excitation focused around their first’s modes. A fractional derivative Zener model was used to predict the behaviourof on-axis ply complex moduli. The modified ply constitutive law was then implemented in Classical Lamination Theory (CLT) calculation routine. The pro…
Bio-composites for structural urban outdoor applications - A study of the impact of fiber content on the durability of flax fiber-reinforced epoxy composites
International audience
Design and synthesis of biobased epoxy thermosets from biorenewable resources
International audience; Biobased diepoxy synthons derived from isoeugenol, eugenol or resorcinol (DGE-isoEu, DGE-Eu and DGER, respectively) have been used as epoxy monomers in replacement of the diglycidyl ether of bisphenol A (DGEBA). Their curing with six different biobased anhydride hardeners leads to fully biobased epoxy thermosets. These materials exhibit interesting thermal and mechanical properties comparable to those obtained with conventional petrosourced DGEBA-based epoxy resins cured in similar conditions. In particular, a high Tg in the range of 90–130 °C and instantaneous moduli higher than 4.3 GPa have been recorded. These good performances are very encouraging, making these n…
Viscoelastic Testing of a Flax Fiber-Epoxy Resin Composite Laminate
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Effects of Stacking Sequence on the Mode -I Delamination of Carbon/Epoxy Laminates
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Characterization of the dynamic behaviour of flax fibre reinforced composites using vibration measurements
International audience; Experimental and numerical methods to identify the linear viscoelastic properties of flax fibre reinforced epoxy (FFRE) composite are presented in this study. The method relies on the evolution of storage modulus and loss factor as observed through the frequency response. Free-free symmetrically guided beams were excited on the dynamic range of 10 Hz to 4 kHz with a swept sine excitation focused around their first modes. A fractional derivative Zener model has been identified to predict the complex moduli. A modified ply constitutive law has been then implemented in a classical laminates theory calculation (CLT) routine.
Toward Sustainable PLA-Based Multilayer Complexes with Improved Barrier Properties
Poly(lactic acid) or PLA is currently considered as one of the most promising substitutes of conventional plastics, with low environmental impact, especially for food packaging applications. Nevertheless, some drawbacks, such as high permeability to oxygen, are still limiting its industrial applications. The objective of this study was to highly increase the oxygen barrier performance of PLA without compromising its sustainable nature and following the principles of circular economy perspective. Coproducts coming from mill industries, such as wheat gluten proteins (WG), were used to produce PLA-WG-PLA multilayer complexes with improved barrier performance. Different technologies of industri…
Study of the Time Dependent Properties of Flax Fiber Reinforced Composites
International audience
Etude Sur Le Comportement Visco-Élastoplastique Des Composites À Base De Renfort De Fibre De Lin
International audience
Basic Modeling of the Visco Elastic Behavior of Flax Fiber Composites
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…
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…
Méthode D'essais Multiaxiaux Hors Plan Pour Des Assemblages Composites Thermoplastiques (Pa 6-6) Collés Avec Un Adhésif Hyper-Élastique
International audience; La prédiction du comportement de joints collés rend nécessaire le développement de modèles numériques robustes. Cela nécessite l’obtention d’une base de données expérimentale pour des chargements monotones multiaxiaux (traction, cisaillement et combinés). Dans cette étude, un moyen de chargement multiaxial pour la caractérisation mécanique de joints collés, utilisant des éprouvettes KS2 habituellement employées pour la caractérisation des assemblages soudés, est proposé. L’assemblage étudié est composé de substrats en matériau composite à renfort tissé en fibres de verre à résine thermoplastique polyamide 6-6 et d’un adhésif polyuréthane mono-composant à comportement…
Effects of cyclic moisture-induced ageing on a bio-based laminated composite
International audience
Towards Fully Bio-Based Thermosets: From Prepolymers Synthesis to Composite Applications
International audience
Pla/Protein Complex Films: Multilayer Process and Properties. Matbim 2017
International audience
Étude d'un procédé de traitement innovant des fibres de chanvre sous condition de fluide supercritique et propriétés induites
International audience
An original method to compute epipoles using variable homography: application to measure emergent fibers on textile fabrics
International audience; Fabric's smoothness is a key factor to determine the quality of finished textile products and has great influence on the functionality of industrial textiles and high-end textile products. With popularization of the 'zero defect' industrial concept, identifying and measuring defective material in the early stage of production is of great interest for the industry. In the current market, many systems are able to achieve automatic monitoring and control of fabric, paper, and nonwoven material during the entire production process, however online measurement of hairiness is still an open topic and highly desirable for industrial applications1. In this paper we propose a …
A New Method to Measure 3D Textile Defects by Using Dual-lens Camera
International audience; Industrial textile fabric with functionalization always has a high standard requirement. Take polytetrafluoroethylene (PTFE) conveyor belt as an example, the base fabrics must be of first-rate quality, with no weaving faults or broken fibers on coated surface [1]. In a previous work, we have proposed an original method to measure the height of the fiber based on variable homography. This measurement is based on a single camera acquiring two successive frames. This scheme is working well, but measurement depends on conveyor speed used for scrolling fabric. In this paper, we propose an improvement by using a new acquisition device based on two mini-lenses assembled as …
Prediction of Dissipative Properties of Flax Fibers Reinforced Laminates by Vibration Analysis
This study proposes an experimental-numeric method to identify the viscoelastic properties of flax fibres reinforced composite laminate (flax/epoxide). The used method consists in identifying the evolutions of both loss factor and stiffness when vibrational frequency changes. In this way, several free-free symmetrically guided beams are excited on a dynamic range of 10 to 4000 Hz with sweep sine excitation focused around the 4-first’s modes. Fractional derivative Zener model is used to identify the on-axis ply complex moduli and describe the laminate dissipative linear behavior with the classical laminate theory. Results obtained on a quasi-isotropic laminate show that this model adequately…
Vieillissement accéléré et propriétés mécaniques des fibres issues du chanvre
International audience; L’objectif de ce colloque est de regrouper les personnes du monde académique et de l’industrie intéressées par le comportement en fatigue et la durabilité des composites biosourcés et de leurs constituants. Ce colloque permettra de faire un état des lieux sur les connaissances actuelles, de partager les dernières avancées effectuées dans le domaine et d’échanger sur les principaux verrous à lever pour accéder à une utilisation pérenne des composites biosourcés dans les applications structurales.
Determination of dynamic properties of flax fibres reinforced laminate using vibration measurements
International audience; Experimental and numerical methods to identify the linear viscoelastic properties of flax fibre reinforced polymer (FFRP) composite are presented in this study. The method relies on the evolution of storage modulus and loss factor as observed through the frequency response. Free-free symmetrically guided beams were excited in the dynamic range of 10 Hz to 4 kHz with a swept sine excitation focused around their first modes. A fractional derivative Zener model has been identified to predict the complex moduli. A modified ply constitutive law has been then implemented in a classical laminates theory calculation (CLT) routine. Overall, the Zener model fitted the experime…
Crystal structure of the diglycidyl ether of eugenol
The diepoxy monomer (DGE-Eu) was synthesized from eugenol by a three-step reaction. It consists of a 1,2,4-trisubstituted benzene ring substituted by diglycidyl ether, a methoxy group and a methyloxirane group. The three-membered oxirane rings are inclined to the benzene ring by 61.0 (3) and 27.9 (3)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, forming layers parallel to the ab plane.
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…
Etude du comportement en fatigue d’un composite lin-époxy soumis à un vieillissement hydro-thermique.
International audience