A comparison of marquetry and sculpting techniques in industrial furniture manufacture in 1900 and 2000

A l'aube du XXe siècle, Louis Majorelle et Émile Gallé réussirent à allier Art et Industrie. En marge des pièces exceptionnelles et uniques, ils produisaient des objets d'ameublement de série, comportant eux aussi des éléments décoratifs marquetés et sculptés, inspirés de la Nature, caractéristiques des créations de cette époque. Aujourd'hui, les techniques de marqueterie et de sculpture ont bénéficié des grands progrès technologiques du XXe siècle mais restent peu utilisées par les industriels de l'ameublement. En comparant les pratiques de 1900 et de 2000, nous avons voulu montrer que les productions industrielles actuelles pourraient s'enrichir de ces techniques décoratives

Optimisation de la durée de vie d'un outil de coupe pour l'industrie du bois (analyse et compréhension des modes d'usure)

Quelle que soit la nature d'une production, l'usure d'un outil a des conséquences importantes sur elle. L'usure est un phénomène commun à toutes les industries, et la maîtrise de ce phénomène constitue toujours une avancée pour les industriels qui font l'effort de le comprendre. Ce travail porte sur l'analyse et la compréhension du phénomène complexe de l'usure des outils lors de la coupe de matériau bois ou dérivé du bois. Nous avons étudié l'impact de la corrosion et de l'abrasion sur l'usure d'une arête de coupe dans la seconde transformation du bois. Compte tenu des spécificités liées au matériau bois et à sa coupe, l'étude de la corrosion s'est fait par l'intermédiaire d'un test d'électrochimie alors que l'étude du phénomène abrasif a nécessité la création d'un banc d'essais spécifique : TEEMO. En complément de ces études nous avons procédé à une pré-analyse des températures générées durant un usinage. Les résultats obtenus au travers de ce projet valident la théorie de départ, à savoir que la corrosion interagit avec l'abrasion pour générer l'usure globale d'une arête de coupe. Aux vues de ces travaux, la composition chimique d'un matériau de coupe est un facteur aussi important dans la lutte contre l'usure que les propriétés mécaniques du matériau.For each kind of production, the tool's wear can make important consequences on her. Wear is a common subject through the industry, and this phenomenon mastering always makes an advancement for entreprises who are interested in. This work deals with the wear phenomenon decomposition between different processable studies in order to permit a study and a global comprehension of this complex phenomenon. That's why we decided to separate the general cutting hedge general wear in wood industry second transformation between two parts : corrosion and abrasion. According to the wood material and his cutting specificities, the corrosion study was made by an electrochemistry test adaptation whereas the abrasion one needed the creation of a specific testing stand : TEEMO. To complete this study, we carried out experiments on generated temperature during the machining process. Through all this project, the results validates the departure theories i.e. corrosion and abrasion have interaction to generate the cutting hedge global wear. With the sights of this work, the chemical composition of the cutting material is a factor as important as the material mechanic properties against the wear.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Améliorations des performances d'outils de coupe pour la première transformation du bois

La société SIAT-BRAUN, premier de sciage résineux de France, présente une problématique industrielle liée à ses outils de coupe. Les scies débitant le bois doivent être les plus fines possibles afin de préserver la matière d'oeuvre, mais aussi très robustes pour supporter les conditions de coupe qui ne cessent de se durcir. La maîtrise de la matière première ainsi que des paramètres de réglage des machines sont des conditions sine-qua-none du bon travail des outils. Ainsi, nous arrivons à des situations limites où les règles actuelles ne répondent pas correctement aux exigences recherchées. Le mémoire comporte une étude technico-économique de la scierie et de son évolution, ainsi que du matériau bois employé. L'explication du fonctionnement de la ligne de sciage de l'entreprise, une des plus modernes, d'Europe, achève cette présentation.L'analyse des connaissances actuelles englobe les différents paramètres et calculs relatifs à l'usinage du bois, ainsi que les divers éléments composant une scie circulaire et ses géométries associées. Les interactions entre tous ces éléments sont aussi présentées. Le métier d'affûteur, personne en charge de la maintenance des outils et garante de leur bon fonctionnement, est présenté ainsi que des améliorations mises en place au niveau de la méthode ainsi que des machines de l'atelier.Pendant cette thèse, de nombreuses améliorations ont été réalisées sur les différents outils de coupe, afin de répondre aux exigences de la production en gardant une fiabilité la plus importante possible. La dernière partie proposera les améliorations restant à valider sur l'adéquation entre les matériaux et la géométrie angulaire des scies circulairesSIAT-BRAUN is the largest industrial sawmill in France and faces typical industrial challenges with its sawing technologies.Wood saws must be as thin as possible, in order to maximize yield and save raw material and robust enough to endure tougher and tougher sawing conditions. Good raw material control and optimized machine parameterization are critical to ensure good results. The current theoretical background, does not always match these requirements and we are therefore always testing its limits.An economical and technical analysis of the sawmill and its evolution makes up the first part of this thesis. We will be detailing the key operations of one of the most modern sawmill in Europe.Current knowledge analysis must include the various parameters and calculations necessary to machine wood, as well as the different blade components and their geometric specifications. We will discuss the interactions between these elements. The job of the filer (the person in charge of tool maintenance) will also be discussed, as well as several improvements implemented in the workshop.Many improvements have been suggested and implemented while working on this thesis, in order to react to production needs while preserving reliability. In the last section of this thesis we will discuss several improvements that remain to be validated on how to best match appropriate cutting materials and blade geometryNANCY1-Bib. numérique (543959902) / SudocSudocFranceF

Analyse et conception d'un outil de coupe pour la valorisation des sous produits d'élagage des haies (démarche intégrée d'innovation et de prototypage)

La problématique de l entreprise NOREMAT, fabricant de matériels pour l entretien des accotements routiers, est de sans cesse proposer à ses clients une NOuvelle REntabilité du MATériel. En ce qui concerne la coupe des haies, celle-ci a souhaité, à travers une recherche scientifique, la découverte d un nouveau concept de coupe, plus économique et plus écologique. Après une succession d étapes préliminaires : étude des haies françaises, des possibilités de valorisation des déchets, proposition d une conception choisie, étude des phénomènes de coupe, un prototype à vue le jour. Ce nouvel outil remplit trois fonctions principales : il coupe la haie de façon économique et sécuritaire, il broie les déchets obtenu et les transforme en plaquettes pour le chauffage et il récupère ces plaquettes pour leur utilisation future. Grâce à l étude de la formation des plaquettes et à la maîtrise des conditions de coupe pendant l usinage des branches, l outil est capable de couper bien mieux que ces prédécesseurs, tout cela en consommant moins d énergie, en valorisant les déchets produits et en préservant son environnement direct. D un point de vue scientifique, ces recherches ont permis une meilleure compréhension de la formation du copeau dans le cas particulier de la coupe d éléments flexibles.NOREMAT is specialized in the manufacturing of equipments for the maintenance of road verges. Its issue is to continuously propose profitable equipments to its customers. The company also wishes to design, thanks to scientific research, a new trimming concept offering more cost-efficient and ecological solutions. After a series of preliminary steps (analysis of French hedges, waste valorization options, design suggestion, analysis of trimming phenomena), a prototype was designed. This new tool fulfills three major functions: it cuts hedges economically and safely, it crushes the wastes into heating chips and collects them. Based upon the study of chips formation and the control of cutting parameters during the branches processing, this new tool offers a better trimming in comparison with the existing devices, while requiring less energy, adding value to waste products and protecting its surrounding area. Regarding scientific contribution, these researches have lead to a better understanding of the chip s building up in the specific case of flexible elements trimming.NANCY1-Bib. numérique (543959902) / SudocSudocFranceF

A dynamic measurement of a disc chipper cutting forces

International audienceNowadays wood chips produced from raw material of inferior quality are mainly used to feed domestic and industrial boilers. For this use, a good chip size distribution and low manufacturing energy consumption are required. Cutting forces are still inaccurately measured during the wood chipping process, which implies the use of oversized chippers' motors. A test bench for chipping wood under reasonably realistic conditions of industrial production is improved by adding an indirect force measurement system with high bandwidth of 3 KHz. The dynamic experimentations give the data needed to compute the curve presenting the vertical component of the cutting force, which is composed of three sections; the first one presents the values of the impact force; the second one is relatively straight and it refers to shear stress in wood; the third section corresponds to the period between two crosscuts

Experimental investigation on full-scale glued oak solid timber beams for structural bearing capacity

International audienceThis paper presents an experimental investigation on full-scale glued solid timer beams made of oak timber, for structural purposes. Similar experimental work was previously presented by the authors using beech timber (Tran et al., 2012). Here, the results from the previous work were served for comparison purpose between the performances of the two hardwood species (oak and beech). The obtained results showed that the glued solid timber beams made of oak timber perform relatively more much better than their counterparts made of beech timber, which was explained by the weakness in the finger-joint due to a poor adhesion within the beech timber

Experimental and numerical analyses of the structural response of adhesively reconstituted beech timber beams

International audienceThe aim of this work was to study the behaviour of adhesively reconstituted beams made of local beech timber. Experimental and numerical results are presented. Contributions of numerical modelling for the analysis of adhesively bonded assemblies for beech timber components are the main focus of the present paper. Numerical simulations are based on the Cohesive Zone Model (CZM) of Abaqus software to allow for accurate description of the progressive damage of the bond-lines up to final failure. The effects of several parameters were investigated ones the finite element model has been verified against experiments. The numerical results have showed that the modelling approach was convenient to study the behaviour of such beam systems with limited destructive tests, which are likely to be very expensive and time consuming. The parametrical study undertaken demonstrated a significant enhancement of the load-carrying capacity of beams by optimising the finger-jointing geometry

Finite element analysis of flexural strengthening of timber beams with Carbon Fibre-Reinforced Polymers

International audienceThis study focuses on the flexural behaviour of timber beams externally reinforced using Carbon Fibre-Reinforced Plastics (CFRP). A non-linear finite element analysis was proposed, and was validated with respect to experimental tests carried out on seven beams. All the beams had the same square cross-section geometry and were loaded under four-point bending, but had different numbers of CFRP layers. The Abaqus software was used, and different material models were evaluated with respect to their ability to describe the behaviour of the solid timber beams. Elasto-plastic behaviour with damage effect was assumed for the timber material, linear elastic isotropic model was used for the CFRP, and a cohesive model was used to represent the interaction between two adherent surfaces (CFRP and timber). These two surfaces were paired and, taking into account the presence of an adhesive layer, one of them was defined as the master surface whilst the other was the slave surface. Predicted and measured load-mid-span deflection responses and failure modes were compared. The increases of flexural strength for the two different reinforcement schemes with 2 and 3 layers of CFRP composite sheets were 41.82% and 60.24%, respectively, with respect to the unreinforced timber beams. The maximal difference between calculated and experimental ultimate load-bearing capacity for reinforced solid timber beams with 2-layers of CFRP was around 1.2%

Advanced studies in wood at the service of industrial development

L'enseignement supérieur du bois en France est essentiellement délivré par quatre grandes écoles : l'ENGREF (École nationale du Génie rural, des Eaux et des Forêts) à Nancy pour la Formation des Ingénieurs forestiers (FIF) plus orientée sur les aspects forestiers, l'ENSTIB (École nationale supérieure des Technologies et Industries du Bois) à Épinal, l'ENSAM (École nationale supérieure d'Arts et Métiers) dans son unité de Cluny, et l'ESB (École supérieure du Bois) à Nantes. Chacune de ces écoles est présentée avec ses origines et ses spécificités

Growing winter wheat cultivars under different management intensities in France: A multicriteria assessment based on economic, energetic and environmental indicators

International audienceSince the 1970s, winter wheat management in France has focused on growing high-yielding cultivars with the intensive use of external inputs. However, over the last 10 years, breeding priorities have changed in favour of the development of cultivars with multiple resistance to fungal diseases and lodging. Low-input strategies have also been developed, to reduce costs and to meet environmental targets. In this study, we assessed the economic, energetic and environmental performances of three cultivars (C) grown under four management intensities. Two of these cultivars (Isengrain and Tremie) are both high-yielding and disease-susceptible, whereas the third (Oratorio) is multiresistant to diseases and lodging but has a lower potential yield. The four crop management systems (CM) were designed with a decrease in input level (seeds, N fertilizer, fungicides, growth regulator) from CM1 to CM4. We set up a multi-year ant multi-site network to test the C-CM pairs in a wide range of environments. The evaluation of C-CM pairs was based on a set of indicators dealing with economics (profitability, input and machinery costs per tonne), environment (pesticide use, N recovery), and energy (energy use efficiency, energy costs). As regards profitability and costs per tonne, we assessed the vulnerability of the C-CM pairs to several grain and oil price scenarios. The demonstration of synergy between the two types of innovation (multiresistant cultivars, low-input management) is a major result: each makes the other more profitable, increasing its chances of adoption in the field. The ecology-based technology package, involving the use of lower-yielding multiresistant cultivars under lower external input levels, was more profitable when grain prices were low (less than (sic)123-157 per tonne (for low and high oil prices, respectively)). By contrast, the intensive technology package, consisting of high-yielding cultivars and high levels of external inputs (N, fungicides and growth regulators), was more profitable when grain prices exceeded (sic)123-157 per tonne (for low and high oil prices, respectively). However, it was less optimal in terms of fossil energy use and potential on environmental impact. In a context of fluctuating grain and oil prices and a need to preserve resources (e.g. fossil energy, water quality), our results demonstrate the potential benefits of using low-input crop management systems. with cultivars displaying multiple resistance to diseases and lodging (Oratorio-CM3). The loss of productivity (1 t ha(-1) less than for Isengrain-CM2) due to the lower yield potential of the multiresistant cultivar and the lower levels of inputs must be seen as a necessary evil if we are to decrease the overuse of resources. There is a need to adapt current procedures for cultivar evaluation, to promote the breeding of multiresistant cultivars for low-input systems. New cultivars should be evaluated under a range of conditions, from high- to low-input systems. (C) 2011 Elsevier B.V. All rights reserved