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Christoforo, John Carmen. "Wood-based material use in the United States pallet and container industry." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-11102009-020207/.
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Müller, Christoph, Sven Eichhorn, Detlef Krug, and Andreas Weber. "Holzwerkstoffe in technischen Anwendungen – Anforderungen aus Sicht des Maschinenbaus." Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-95423.
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Im Vortrag werden die Holzwerkstoffe charakterisiert und anderen Konstruktionswerkstoffen und technischen Verbundmaterialien gegenüber gestellt. Anhand eines Ausführungsbeispiels wird deren technologische und wirtschaftliche Leistungsfähigkeit analysiert. Darauf aufbauend werden notwendige Maßnahmen zur Verbesserung der Werkstoffe sowie zu deren Etablierung in der Technik dargestellt. Aus dem Vergleich der jeweiligen Eigenschaftsprofile werden zukünftige Nutzungsmöglichkeiten der Holzwerkstoffe in der Technik abgeleitet. Ein Ausblick zeigt den möglichen Entwicklungsspielraum für Holzwerkstoffe in technischen AnwendungenThe properties of wood materials are compared to several engineering materials, like metal alloys, polymers and fiber reinforced plastics. The technologic and economic efficiency of plywood is illustrated by the implementation of a wooden beam. Accordingly necessary measures for the improvement of wood materials and their recognition in mechanical engineering are shown. A perspective of further fields of applications for wood materials in a technical context is given
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Eichhorn, Sven, Ronny Eckardt, and Christoph Müller. "Einblick in die Geschichte der Holzwerkstoffe im Maschinen- und Anlagenbau und aktuelle Möglichkeiten der angemessenen technischen Nutzung." Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-61031.
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Der Einsatz von Holz- und speziell Holzfurnierlagenverbundwerkstoffen (WVC) konzentrierte sich in den vergangen Jahrzehnten nahezu ausschließlich auf den Möbelbau und den Bausektor. Eine Verwendung von Holzwerkstoffen im Sinne einer angemessenen technischen Nutzung der vorhandenen Eigenschaften im Maschinen- und Anlagenbau wird hingegen aktuell kaum praktiziert. Der Vortrag zeigt anhand der Darstellung und Analyse des Standes der Technik Einsatzmöglichkeiten des Werkstoffes im Maschinen- und Anlagenbau auf und charakterisiert dabei die Bereiche, in denen noch verstärkt gearbeitet werden muss, um diese Einsatzmöglichkeiten angemessen nutzen zu können. Weiterhin werden grundlegend relevante Werkstoffeigenschaften für das angestrebte Einsatzgebiet charakterisiert und erste Einblicke in Bauformen aus WVC gegeben, mit denen ein praktischer Einsatz im Allgemeinen Maschinenbau und damit in der Fördertechnik technisch sinnvoll istFor the last decades the usage of plywood materials (Wood Veneer Composites) was mainly focused on furniture and civil engineering. At the moment there is no adequate technical use of wood based materials in mechanical engineering in respect to its particular properties. Following the state of the art several fields of application in mechanical engineering are presented as well as subjects were identified which need further investigation. Relevant material properties for the aspired technical application are characterized. Furthermore an insight in realized designs of WVC structures is given
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Tran, Thi Ngoc Huyen. "Study of compression behavior of wood-based fiberboard : caractérisation à partir de techniques d'imagerie non destructives." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14666/document.
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La thèse a pour but de caractériser les propriétés mécaniques de matériaux à base de fibres de bois en relation avec les propriétés intrinsèques des fibres et leur arrangement spatial complexe. Ce type de matériau, dont les caractéristiques dépendent de sa configuration, est hétérogène à différentes échelles : à l’échelle microscopique de la fibre, à l’échelle mésoscopique du réseau des fibres et à l’échelle macroscopique du matériau. Pour observer ces hétérogénéités, différents moyens expérimentaux de caractérisation sont utilisés, notamment la microtomographie aux rayons X et la corrélation d’images volumiques. Ces deux techniques permettent à la fois de visualiser et numériser la position spatiale des différentes fibres du matériau à l’échelle microscopique dans le volume, et d’obtenir le champ tridimensionnel de déformation à cœur. Comme résultats, le matériau étudié montre un comportement non-linéaire avec une déformation résiduelle et un effet d’hystérésis en charge/décharge, qui suit le modèle de Van-Wyk. A l’échelle microscopique, le champ de déformation 3D apparait fortement hétérogène et est intimement lié aux porosités localesThis thesis aims at characterizing the mechanical properties of wood-based fibrous material in relation with the intrinsic properties of the fiber as well as the complex architecture of random fibrous assembly. This material, whose characteristics strongly depend on its configuration, is heterogeneous at different scales: microscopic scale of individual fibers, mesoscopic scale of fiber assembly and macroscopic scale of sample. In order to observe these heterogeneities, different experimental characterization methods are employed, especially X-ray microtomography and Digital Volume Correlation. These both techniques allow us to visualize and digitize the spatial position of different phases of material at microscopic scale as well as the full 3D strain field inside the material. The obtained results are following: the material shows a non-linear mechanical behavior with hysteresis and residual deformation during cyclic compression tests, which respects Van Wyk's model. At microscopic scale, the 3D strain field is strongly heterogeneous and deeply related to local porosities
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Phan, Ngoc Anh. "Simulation of time-dependent crack propagation in a quasi-brittle material under relative humidity variations based on cohesive zone approach : application to wood." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0008/document.
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Cette thèse est consacrée à la simulation du comportement à la rupture de bois sous des chargements à long terme et sous des conditions d'Humidité Relatives (HR) de l'air variables. Il est connu que le bois est un matériau fortement hygroscopique, ses propriétés mécaniques et de rupture sont en effet très dépendantes de sa teneur en eau. En outre, la stabilité d'une fissure existante dans un élément structural peut être fortement influencée parles variations, en particulier brusques, d'humidité relative qui peut conduire à la rupture inattendue de l'élément.L'approche thermodynamique proposée intègre l'effet de mécanosorption dans l'expression analytique de la déformation, en découplant les déformations mécaniques et celles dues au comportement mécanosorptif du matériau. En outre, la rupture quasi-fragile du matériau boisest traduite par un modèle de zone cohésive dont les paramètres de cohésion sont fonctions de la teneur en eau afin de simuler l’effet de l'humidité sur les propriétés de rupture. Sur cette base, une formulation incrémentale permet l'intégration de l'effet des variations soudaines d’humidité relative (autrement dit, le choc hydrique) sur la zone d’élaboration(zone cohésive) en introduisant un champ de contraintes supplémentaires le long de cette zone. Fonction de la variation de HR, ce champ de contraintes supplémentaires dépend de l'état de contrainte et de l'ouverture de la fissure le long de la zone cohésive, mais également de l'humidité en pointe de fissure (matériau non endommagé). Dans l'analyse par éléments finis, un opérateur tangent algorithmique est utilisé pour résoudre le problème non linéaire en combinant le modèle de mécanosorption et le modèle de zone cohésive et en intégrant l'effet du choc hydrique.La simulation du comportement d'une éprouvette entaillée soumise à un chargement constant et à des variations cycliques de HR montre un fort couplage entre le comportement mécanosorptif et l'effet du choc hydrique HR sur la zone d’élaboration. Ce couplage entraîne une augmentation de la propagation des fissures et conduit à une fissuration plus précoce par rapport à celle obtenue à partir du modèle de mécanosorption seul ou à partir du modèle de zone cohésive en intégrant l'effet des variations soudaines de HR. En outre, le couplage entre le modèle mécanosorptif et le modèle de zone cohésive en intégrant l'effet du chochydrique montre l'intérêt d'une telle approche numérique pour décrire le comportement complexe des éléments de charpente en bois soumis à des conditions climatiques variables,comportement qui ne peut être prédit par une simple superposition des deux modélisationsThis thesis is dedicated to the simulation of the fracture behavior of wood under long-termloading and variable relative humidity conditions. Indeed, wood is well-known to be a highlyhygroscopic material in so far as its mechanical and fracture properties are very dependenton moisture. Moreover, the stability of an existent crack in a structural element can bestrongly affected by the sudden variations of relative humidity (RH) and can lead tounexpected failure of the element.The thermodynamic approach proposed in this thesis includes the mechano-sorptive effect inthe analytical expression of the deformation, by operating a decoupling of the strain in amechanical part and a mechano-sorptive part in material. Moreover, the quasi-brittle fractureof wood is here simulated from a cohesive zone model whose cohesive parameters arefunctions of the moisture in order to mimic the moisture-dependent character of the fractureproperties. On this basis, an increment formulation allows the integration of the effect ofsudden RH variations on the fracture process zone (cohesive zone) by introducing anadditional stress field along this zone. As a function of the RH variation, this additional stressfield depends on not only the stress state and the crack opening along the cohesive zone butalso the material moisture ahead of the zone (undamaged material). In the finite elementanalysis, an algorithmic tangent operator is used to solve the non-linear problem combiningmechano-sorptive model and cohesive zone model including the effect of sudden RHvariations.The simulation of a notched structural element submitted to a constant load and cyclic RHvariations exhibits a strong coupling between the mechano-sorptive behavior and the effectof the RH variations on the fracture process zone (FPZ). This coupling results in an increaseof the crack propagation kinetic and leads to a precocious failure compared to those obtainedfrom the mechano-sorptive model or from the effect of sudden RH variations on the FPZ.Moreover, the coupling between the mechano-sorptive model and the effect of sudden RHvariations on the FPZ which cannot be predicted by a simple superposition of both effects,showing the interest of such a numerical approach in order to describe the complex behaviorof wood structural elements submitted to variable climatic conditions
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Eckardt, Ronny, and Sven Eichhorn. "Neue Bauweisen in der Intralogistik durch Holzverbundwerkstoffe - Verbindungselemente für dynamische Belastungen." Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-61936.
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In der technischen Logistik bieten Bauweisen aus Holzverbundwerkstoffen, speziell aus schichtförmigen aufgebauten Halbzeugen (WVC – Wood-Veneer- Composites), eine Alternative zu Konstruktionen aus Metallwerkstoffen, vor allem aufgrund ihrer guten spezifischen mechanischen Eigenschaften sowie ihrer günstigen Korrosionseigenschaften. Benötigte Verbindungsmittel entstammen dabei dem Bau- oder Möbelsektor und sind vorrangig statischen Belastungen angepasst.
Der Vortrag gibt einen kurzen Einblick in Bauweisen mit WVC und stellt dabei Forschungsergebnisse zu statischen und dynamischen Untersuchungen an prinzipiell geeigneten Verbindungselementen in den Vordergrund. Dabei wird vor allem auf holztypische Problemstellungen im Zusammenhang mit dynamischen Belastungen eingegangen. An Funktionsmustern werden mögliche Anwendungen in der Fördertechnik, speziell für den Stückguttransport, dargestellt.
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Eckardt, Ronny, and Sven Eichhorn. "Konstruktion und Erprobung modularer Maschinengestelle aus Holzfurnierlagenverbundwerkstoff (WVC)." Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-61046.
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Durch die Entwicklung der vorgestellten modularen Bauweise ist es möglich, Maschinengestelle aus Holzfurnierlagenverbundwerkstoff (WVC) einfach herzustellen und technisch sinnvoll einzusetzen. Die modulare Bauweise kann sowohl für statische als auch dynamische Beanspruchungen im Allge-meinen Maschinenbau angewendet werden. In einem Baukastensystem werden Maschinenteile aus WVC durch geeignete Verbindungsmittel lösbar zusammengesetzt. Damit ist es möglich, eine hohe Flexibilität in der späteren Nutzung mit einer hohen Variantenvielfalt des Aufbaus durch entsprechend verschiedene Bauteile zu kombinieren. Im Vortrag werden die verschiedenen Belastungen des Holzverbundes im Maschinenaufbau charakte-risiert und auf Probleme bei der Konstruktion eingegangen. Abschließend werden Ergebnisse zu Dau-eruntersuchungen der Verbindungstechnik und des gesamten Maschinenaufbaus vorgestellt und diskutiertThe development of the presented modular construction allows to manufacture wood veneer compos-ite (WVC) machine racks easily in a technical reasonable way. The modular construction can be used for both static and dynamic loading conditions in mechanical engineering. In the modular construction system the WVC machine components are connected detachable with adequate fasteners. This leads to high flexibility during the construction and assembly process of machine components. In the current presentation the different loading conditions of WVC profiles are characterized and the problems during construction described. Finally the results of the long term testing of the connection technique are presented and the complete machine system is discussed
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Eichhorn, Sven, Ronny Eckardt, and Christoph Müller. "Schwingungs- und geräuschdämpfende Leichtbauelemente im Maschinenbau auf Basis von Konstruktionswerkstoffen aus Holz." Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-201000990.
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Im Forschungsprojekt wurde eine Bauweise für ein modular aufgebautes und flexibel einsetzbares Gestellsystem entwickelt, welches durch integrativen Leichtbau den vorteilhaften Einsatz von Holzfurnierlagenverbund-werkstoffen (WVC) für Verarbeitungs- und Fördermaschinen ermöglicht. Die ingenieurtechnisch relevanten Eigen-schaften des Holzbasiswerkstoffs (u.a. strukturelle Dämpfungseigenschaft) wurden ermittelt und darauf aufbauend ein Profil als Strukturelement des Gestellsystems entwickelt. Hier lag besonderes Augenmerk auf der Gestaltung des Profilquerschnitts. Es wurden verschiedene Querschnittsgeometrien vergleichend untersucht, wobei sich ein ge-schlossenes Kastenprofil als günstig erwies. Ausgehend vom entwickelten Profil wurde die für ein modulares Sys-tem notwendige Verbindungstechnik konzipiert. Folgend wurde schrittweise die modulare Bauweise in Strukturein-heiten umgesetzt sowie parallel Untersuchungen zu Steifigkeit und Festigkeit der Profile fortgeführt. Während der Erprobung von Struktureinheiten unter praxisnahen Bedingungen wurden gewisse konstruktive Verbesserungspo-tentiale deutlich. Diese Änderungen sowie die gewonnenen Erkenntnisse aus der Material- und Strukturprüfung kamen im Prototyp zur Umsetzung. Schallpegelprofile verschiedener fördertechnischer Anlagen und des entwickel-ten Prototypen wurden abschließend aufgenommen und verglichenAim of the present study was to develop a modular designed and widely employable rack system. Positive properties of wood based materials (WVC) in lightweight structures were identified and integrated for the application in fabri-cation and conveyer technologies. For this purpose relevant properties of wood materials had been investigated (e.g. damping properties). The results of these analyses were the basis for the development of a beam profile, the basic structural design element for the future rack system. The most effort was put into finding the optimal beam cross section. Several different cross sections had been compared, a square sectional beam profile showed the best per-formance. Based on the square sectional beam profile proper connection methods for the modular rack were devel-oped. Structural units were subsequently realized step by step, while the investigation of stiffness and strength of the profiles was continued. The testing of the structural units under simulated field conditions revealed some minor constructional improvement capabilities. The constructional improvements and the knowledge from the material and profile testing were put into practice in the prototype. Finally sound measurements were carried out to compare several conveyors made of different materials (including the prototype) in respect to the emitted sound level
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Fitzgerald, Lydia A. "EFFECT OF BEDDING TYPE AND SOIL INCORPORATION ON NITROGEN MINERALIZATION RATE OF BROILER LITTER AMENDED SOILS." UKnowledge, 2019. https://uknowledge.uky.edu/pss_etds/123.
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Broiler litter (BL) is a high value manure available to Kentucky crop producers to utilize as a fertilizer. The rate of BL application, timing of application, and method of application are all important factors to take into account when utilizing BL. A laboratory incubation was conducted to observe nitrogen (N) mineralization rates of BL amended soils over time under different conditions. Different application methods, application rates, watering frequencies, and bedding materials were used to determine their influence on N mineralization. Broiler litter applied on the soil surface, at lower rates, at lower watering frequency resulted in lower mineralization rates than BL that was incorporated, at higher rates and higher watering frequency. The rice hull bedding BL treatments had a significantly higher initial amount of NH4+-N than the wood-based bedding materials. The increased NH4+-N content produced a lower pH due to higher rates of nitrification. The difference in NH4+-N resulted in the rice hull BL treatments containing more inorganic N throughout the incubation. The wood-based BL contained significantly more carbon (C), zinc (Zn), and potassium (K). The results collected will help improve current nutrient recommendations and provide information that will help utilize BL more efficiently and economically.
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Eichhorn, Sven, Ronny Eckardt, and Christoph Müller. "Integrative Bauweisen mit Holzfurnierlagenverbundwerkstoff (WVC) für den Maschinen- und Anlagenbau." Universitätsbibliothek Chemnitz, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-79120.
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Aufbauend auf historischen Anwendungen von Holzwerkstoffen in der Technik werden Vor- und Nachteile aus der Sicht des Maschinenbaus dargestellt sowie eine aktuelle Eignung dahingehend diskutiert. Besondere Aufmerksamkeit erfährt der integrative Leichtbau mit Holzfurnierlagenverbundwerkstoffen (Wood Veneer Composite, WVC). Durch deren modifizierbares Eigenschaftsprofil, in Verbindung mit einer an den Anwendungsfall angepassten Bauweise, ist eine zusätzliche Funktionsintegration möglich. Das Potenzial der Holzwerkstoffe wird an verschiedenen Konstruktionsbeispielen erläutert. Ergänzend werden Biege-Ersatz Emodul und Bauteilverformung eines Strukturelementes sowie Ergebnisse aus Ermüdungsversuchen der Verbindungstechnik dargestellt. Abschließend werden Probleme beider Umsetzung verschiedener Prototypen beschrieben und deren Lösung aufgezeigtBased on several historical applications of Wood Veneer Composites (WVC) the advantages and disadvantages of wood materials in today`s mechanical and plant engineering are discussed. Integrated WVC lightweight structures are especially taken into account. The highly modifiable mechanical properties of WVC’s allow application-adapted integration of further technical functions. The capabilities of integrated lightweight structures based on wood materials are demonstrated on several technical applications. Furthermore results of flexural tests, precisely the retrieved substitutet bending modulus and the maximal deflection as well as results of fatigue testing of the connecting components are given. Finally problems occurring during realization of WVC lightweight prototypes and their potential solutions are shown
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Eichhorn, Sven, Andreas Weber, Katrin Feig, Christoph Müller, and Detlef Krug. "Entwicklung von Qualitätshalbzeugen aus Spezialholzwerkstoffen für Anwendungen im Maschinenbau und in der Fördertechnik." Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-188704.
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Es wurde ein plattenförmiges Qualitätshalbzeug aus Spezialholzwerkstoffen für den konstruktiven Einsatz im Maschinebau, mit dem Schwerpunkt Fördertechnik entwickelt. Mit diesem Halbzeug sind ökologisch vorteilhafte Konstruktionen möglich. Entwicklungsschwerpunkte waren: einstellbare, hohe absolute und spezifische mechanische Eigenschaften mit kleinen Streuungen. Die Entwicklung wurde durch verschiedene Werkstoffprüfungen von Labor- und Industriewerkstoffen begleitet und deren Ergebnisse mittels speziell erarbeitetet Bewertungskriterien evaluiert. Weiterhin wurde das Werkstoffverhalten von diversen Holzwerkstoffen unter dynamischer Belastung klassifiziertA panel-shaped high quality semi-finished product made of special wood-based materials for structural applications in mechanical engineering, with a focus on materials handling technology, was developed. With said semi-finished product ecologically advantageous constructions are possible. Development priorities were: adjustable, high absolute and specific mechanical properties with little variation. The development was accompanied by various materials tests of laboratory and industrially manufactured materials, and their results were evaluated by specially developed evaluation criteria. Furthermore, the material behaviour of various woodbased materials under dynamic loading was classified
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Müller, Christoph. "Untersuchung von Holzwerkstoffen unter Schlagbelastung zur Beurteilung der Werkstoffeignung für den Maschinenbau." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-184057.
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In der vorliegenden Arbeit werden Holzwerkstoffe im statischen Biegeversuch und im Schlagbiegeversuch vergleichend geprüft. Ausgewählte Holzwerkstoffe werden thermisch geschädigt, zudem wird eine relevante Kerbgeometrie geprüft. Ziel der Untersuchungen ist die Eignung verschiedenartiger Werkstoffe für den Einsatz in sicherheitsrelevanten Anwendungen mit Schlagbelastungen zu prüfen. Hierzu werden zunächst die Grundlagen der instrumentierten Schlagprüfung und der Holzwerkstoffe erarbeitet. Der Stand der Technik wird dargelegt und bereits durchgeführte Studien werden analysiert. Darauf aufbauend wird eine eigene Prüfeinrichtung zur zeitlich hoch aufgelösten Kraft-Beschleunigungs-Messung beim Schlagversuch entwickelt. Diese wird anhand verschiedener Methoden auf ihre Eignung und die Messwerte auf Plausibilität geprüft. Darüber hinaus wird ein statistisches Verfahren zur Überprüfung auf ausreichende Stichprobengröße entwickelt und auf die durchgeführten Messungen angewendet. Anhand der unter statischer und schlagartiger Biegebeanspruchung ermittelten charakteristischen Größen, wird ein Klassenmodell zum Werkstoffvergleich und zur Werkstoffauswahl vorgeschlagen. Dieses umfasst integral die mechanische Leistungsfähigkeit der geprüften Holzwerkstoffe und ist für weitere Holzwerkstoffe anwendbar. Abschließend wird, aufbauend auf den gewonnenen Erkenntnissen, ein Konzept für die Bauteilprüfung unter Schlagbelastung für weiterführende Untersuchungen vorgeschlagenIn the present work wood-based materials are compared under static bending load and impact bending load. Several thermal stress conditions are applied to selected materials, furthermore one relevant notch geometry is tested. The objective of these tests is to investigate the suitability of distinct wood materials for security relevant applications with the occurrence of impact loads. For this purpose the basics of instrumented impact testing and wood-based materials are acquired. The state of the technology and a comprehensive analysis of original studies are subsequently presented. On this basis an own impact pendulum was developed to allow force-acceleration measurement with high sample rates. The apparatus is validated by several methods and the achieved signals are tested for plausibility. A general approach of testing for adequate sample size is implemented and applied to the tested samples. Based on the characteristic values of the static bending and impact bending tests a classification model for material selection and comparison is proposed. The classification model is an integral approach for mechanical performance assessment of wood-based materials. In conclusion a method for impact testing of components (in future studies) is introduced
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Wolkenhauer, Arndt. "Plasma treatment of wood and wood-based materials by dielectric barrier discharge at atmospheric pressure /." Göttingen : Sierke, 2009. http://d-nb.info/993076556/04.
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Ong, Benjamin. "THE RACKING PERFORMANCE OF PAPERBOARD AND WOOD BASED SHEATHING MATERIALS." Miami University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1152192631.
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Cook, Steven M. "Fastener withdrawal resistance of wood-based composite panel products." Morgantown, W. Va. : [West Virginia University Libraries], 2001. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=1987.
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Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains x, 127 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 89-92).
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Forbes, Craig L. "An Analysis of hardwood lumber and other wood-based materials use in the wood furniture industry /." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-12232009-020419/.
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Bouchikhi, Aurélie. "Contribution à la formulation d’un béton végétal structurel à base cimentaire incorporant des co-produits / déchets de bois." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2019. http://www.theses.fr/2019MTLD0009.
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Le bâtiment est un secteur particulièrement émissif en gaz à effet de serre. Pour tenter de réduire l’impact des matériaux sur l’environnement, de nombreuses recherches visent à étudier différentes alternatives pour limiter l’épuisement des ressources, la consommation d’énergie et le rejet de composés polluants. Dans ce contexte, les bétons biosourcés se positionnent comme une alternative sérieuse au béton traditionnel, avec une empreinte carbone plus faible.Cette thèse industrielle, portée par l’entreprise ALKERN, leader en France et en Belgique de produits préfabriqués en béton, a pour objectif de contribuer à la formulation d’un béton végétal incorporant des co-produits / déchets de bois structurel à impact environnemental plus faible que le Naturbloc®, un bloc actuellement sur le marché. Ce dernier produit est constitué de granulats de bois minéralisé puis introduit dans une matrice cimentaire.Ce travail s’articule en trois volets. Les bois témoin (non traité) et de référence (minéralisé) ont d’abord été caractérisés. Dans un second temps, des traitements alternatifs à la minéralisation du bois ont été testés et caractérisés, notamment au regard de leur reprise en eau et leur aptitude à relarguer ou contenir les extractibles présents dans les végétaux. Leur compatibilité avec une matrice cimentaire a également été évaluée. Il a ainsi pu être mis en évidence que la nature du substrat influence les résultats et l’interaction des granulats avec la pâte cimentaire.Enfin, le bois traité a été introduit dans la matrice cimentaire témoin et dans une matrice alternative à plus faible impact environnemental. Cette dernière a été obtenue soit par un changement de liant, soit par une adjuvantation spécifique du béton. L’ensemble des résultats montrent qu’il existe un lien direct entre les propriétés physico-chimiques des granulats et les performances mécaniques obtenues pour le bétonThe construction industry produces a high amount of greenhouse gases. In order to reduce the impact of materials on the environment, a lot of researches are focused on the study of different alternatives to limit the exhaustion of resources, the energy consumption and the rejection of polluting compounds. In this context, bio-based concrete seem to be a serious alternative to traditional concrete, with a lower carbon footprint.The aim of this industrial thesis, supported by the company ALKERN, leader in France and in Belgium for precast concrete products, is to contribute to the formulation of structural green concrete incorporating co-products / wood waste with an environmental impact lower than the Naturbloc®, a block already available on the market. This last product is made of wood aggregates mineralized and then introduced in a cementitious matrix.This work is divided into three parts. Firstly, the control wood (untreated) and reference wood (mineralized) were characterized. Then, alternative treatments to replace cement coating of wood were tested and characterized, especially in terms of water uptake and ability to leach or hold the extractives present in vegetables back. Their compatibility with a cementitious matrix was also evaluated. The study highlights the fact that the nature of the substrate has an influence on the results and on the interaction between aggregates and cementitious paste.Finally, treated wood was introduced into a cementitious matrix and in an alternative matrix with a lower environmental impact. The latter was obtained either by change of the binder or by use of additives in bio-based concrete. All the results show the existence of a direct link between physico-chemical properties of aggregates and mechanical performances of concrete
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Neagu, Razvan Cristian. "Hygroelastic behaviour of wood-fibre based materials on the composite, fibre and ultrastructural level." Doctoral thesis, KTH, Hållfasthetslära (Avd.), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4098.
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Wood fibres can be used as reinforcement in plastics for load carrying purposes. Some advantages compared with conventional man-made fibres are that wood fibres come from a renewable resource, have high specific stiffness and strength, are generally less hazardous to health, biodegradable, and can be manufactured at low cost and high volumes. A clear disadvantage with cellulose-based materials for structural use is their dimensional instability in humid environments. The hygroelastic properties are of high importance in materials development of improved wood-fibre composites. This work deals with the stiffness and hygroexpansion of wood fibres for composite materials. The long-term aim is to design engineered wood fibre composites based on better basic knowledge of wood fibres. Mechanistic models have been used to link the fibrous microstructure with macroscopic composite engineering properties. The properties have been characterized experimentally for various wood-fibre composites and their fibre-mat preforms, by means of curvature measurements at various levels of relative humidity, as well as tensile and compressive tests. From these test results and microstructural characterization, the longitudinal Young’s modulus and transverse coefficient of hygroexpansion of wood fibres were identified by inverse modelling. Some effects of various pulp processes and fibre modifications on the elastic properties of the fibre were observed, illustrating how the mixed experimental-modelling approaches can be used in more efficient materials screening and selection. An improved micromechanical analysis for wood-fibre composites has been presented. The model is more appropriate to combine with laminate analogy, to link fibre properties on the microscale to the macroscopic composite properties and vice versa. It also offers the possibility to include the effects of ultrastructure since it can account for an arbitrary number of phases. An approach to model ultrastructure-fibre property relations has been demonstrated. It includes analytical modelling of multilayered cylindrical fibres as well as finite element modelling of fibres with irregular geometry characterized with microscopy. Both approaches are useful and could be combined with experiments to reveal insights that can pave way for a firmer link between the wood fibre ultrastructure and wood fibre properties.QC 20100914
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Neagu, Răzvan Cristian. "Hygroelastic behaviour of wood-fibre based materials on the composite, fibre and ultrastructural level /." Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4098.
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Subyakto. "Improvement of fire retardance of wood based materials using chemical coating and carbon overlaying." Kyoto University, 2002. http://hdl.handle.net/2433/149531.
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Sehaqui, Houssine. "Nanofiber networks, aerogels and biocomposites based on nanofibrillated cellulose from wood." Doctoral thesis, KTH, Fiber- och polymerteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32079.
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Nanofibrillated cellulose (NFC) from wood is an interesting material constituent of high strength and high aspect ratio, which easily forms networks through interfibril secondary bonding including hydrogen bonds. This has been exploited in preparation of new materials, which extend the range of properties for existing cellulosic materials. The objective is to explore processing-structure and structure-property relationships in NFC materials. Dense networks of NFC, referred to as “nanopaper” having a random-in-the-plane orientation of the fibrils have been successfully prepared by a papermaking-like process involving vacuum filtration and water evaporation using laboratory papermaking equipment. Large, flat and transparent nanopaper sheets have thus been prepared in a relatively short time. Using the same preparation route, NFC was used to reinforce pulped wood fibers in dense network structures. NFC networks formed in the pore space of the wood fiber network give an interesting hierarchical structure of reduced porosity. These NFC/wood fiber biocomposites have greater strength, greater stiffness and greater strain-to-failure than reference networks of wood fibers only. In particular, the work to fracture (area under the stress-strain curve) is doubled with an NFC content of only 2%. The papermaking preparation route was extended to prepare nanocomposites of high NFC content with a cellulose derivative matrix (hydroxyethyl cellulose, HEC) strongly associated to the NFC. Little HEC was lost during filtration. The NFC/HEC composites have high work to fracture, higher than that of any reported cellulose composite. This is related to NFC network characteristics, and HEC properties and its nanoscale distribution and association with NFC. Higher porosity NFC nanopaper networks of high specific surface area were prepared by new routes including supercritical drying, tert-butanol freeze-drying and CO2 evaporation. Light-weight porous nanopaper materials resulted with mechanical properties similar to thermoplastics but with a much lower density and a specific surface area of up to 480 m2/g. Freeze-drying of hydrocolloidal NFC dispersions was used to prepare ultra-high porosity foam structures. The NFC foams have a cellular foam structure of mixed open/closed cells and “nanopaper” cell wall. Control of density and mechanical properties was possible by variation of NFC concentration in the dispersion. A cellulose I foam of the highest porosity ever reported (99.5%) was prepared. The NFC foams have high ductility and toughness and may be of interest for applications involving mechanical energy absorption. Freeze-drying of NFC suspended in tert-butanol gave highly porous NFC network aerogels with a large surface area. The mechanical behavior was significantly different from NFC foams of similar density due to differences in deformation mechanisms for NFC nanofiber networks.QC 20110406
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Plinke, Burkhard. "Größenanalyse an nicht separierten Holzpartikeln mit regionenbildenden Algorithmen am Beispiel von OSB-Strands." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-98518.
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Bei strukturorientierten, aus relativ großen Holzpartikeln aufgebauten Holzwerkstoffen wie z.B. OSB (oriented strand board) addieren sich die gerichteten Festigkeiten der einzelnen Lagen je nach Orientierung der Partikel und der Verteilung ihrer Größenparameter. Wünschenswert wäre eine Messung der Partikelgeometrie und Orientierung möglichst im Prozess, z.B. am Formstrang vor der Presse direkt durch den „Blick auf das Vlies“. Bisher sind regelmäßige on-line-Messungen der Spangeometrie aber nicht möglich, und Einzelspanmessungen werden nicht vorgenommen, weil sie zu aufwändig wären. Um die Partikelkonturen zunächst hinreichend für die Vermessung zu restaurieren und dann zu vermessen, muss ein mehrstufiges Verfahren angewendet werden, das eine Szene mit Strands und mehr oder weniger deutlichen Kanten zunächst als „Grauwertgebirge“ auffasst. Zur Segmentierung reicht ein Watershed-Algorithmus nicht aus. Auch ein zweistufiger Kantendetektor nach Canny liefert allein noch kein ausreichendes Ergebnis, weil sich keine geschlossenen Objektkonturen ergeben. Hinreichend dagegen ist ein komplexes Verfahren auf der Grundlage der Höhenschichtzerlegung und nachfolgenden Synthese: Nach einer Transformation der Grauwerte des Bildes in eine reduzierte, gleichverteilte Anzahl von Höhenschichten werden zwischen diesen die lokalen morphologischen Gradienten berechnet und herangezogen für die Rekonstruktion der ursprünglichen Spankonturen. Diese werden aus den Höhenschichten aufaddiert, wobei allerdings nur Teilflächen innerhalb eines für die gesuchten Spangrößen plausiblen Größenintervalls einbezogen werden, um Störungen zu unterdrücken. Das Ergebnis der Rekonstruktion wird zusätzlich verknüpft mit den bereits durch einen Canny-Operator im Originalbild detektierten deutlichen Kanten und morphologisch bereinigt. Diese erweiterte Höhenschichtanalyse ergibt ausreichend segmentierte Bilder, in denen die Objektgrenzen weitgehend den Spankonturen entsprechen. Bei der nachfolgenden Vermessung der Objekte werden Standard-Algorithmen eingesetzt, wobei sich die Approximation von Spankonturen durch momentengleiche Ellipsen als sinnvoll erwies. Verbliebene Fehldetektionen können bei der Vermessung unterdrückt werden durch Formfaktoren und zusätzliche Größenintervalle. Zur Darstellung und Charakterisierung der Größenverteilungen für die Länge und die Breite wurden die nach der Objektfläche gewichtete, linear skalierte Verteilungsdichte (q2-Verteilung), die Verteilungssumme und verschiedene Quantile verwendet. Zur Umsetzung und Demonstration des Zusammenwirkens der verschiedenen Algorithmen wurde auf der Basis von MATLAB das Demonstrationsprogramm „SizeBulk“ entwickelt, das Bildfolgen verarbeiten kann und mit dem die verschiedenen Varianten der Bildaufbereitung und Parametrierung durchgespielt werden können. Das Ergebnis des Detektionsverfahrens enthält allerdings nur die vollständigen Konturen der ganz oben liegenden Objekte; Objekte unterhalb der Außenlage sind teilweise verdeckt und können daher nur unvollständig vermessen werden. Zum Test wurden daher synthetische Bilder mit vereinzelten und überlagerten Objekten bekannter Größenverteilung erzeugt und dem Detektions- und Messverfahren unterworfen. Dabei zeigte sich, dass die Größenstatistiken durch den Überlagerungseffekt und auch die Spanorientierung zwar beeinflusst werden, dass aber zumindest die Modalwerte der wichtigsten Größenparameter Länge und Breite meist erkennbar bleiben. Als Versuchsmaterial dienten außer den synthetischen Bildern verschiedene Sortimente von OSB-Strands aus Industrie- und Laborproduktion. Sie wurden sowohl manuell vereinzelt als auch zu einem Vlies arrangiert vermessen. Auch bei realen Strands zeigten sich gleiche Einflüsse der Überlagerung auf die Größenverteilungen wie in der Simulation. Es gilt aber auch hier, dass die Charakteristika verschiedener Spankontingente bei gleichen Aufnahmebedingungen und Auswerteparametern gut messbar sind bzw. dass Änderungen in der gemessenen Größenverteilung eindeutig den geometrischen Eigenschaften der Späne zugeordnet werden können. Die Eignung der Verarbeitungsfolge zur Charakterisierung von Spangrößenverteilungen bestätigte sich auch an Bildern, die ausschließlich am Vlies auf einem Formstrang aufgenommen wurden. Zusätzlich wurde nachgewiesen, dass mit der erweiterten Höhenschichtanalyse auch Bilder von Spanplattenoberflächen ausgewertet werden könnten und daraus auf die Größenverteilung der eingesetzten Deckschichtspäne geschlossen werden kann. Das vorgestellte Verfahren ist daher eine gute und neuartige Möglichkeit, prozessnah an Teilflächen von OSB-Vliesen anhand von Grauwertbildern die Größenverteilungen der Strands zu charakterisieren und eignet sich grundsätzlich für den industriellen Einsatz. Geeignete Verfahren waren zumindest für Holzpartikel bisher nicht bekannt. Diese Möglichkeit, Trends in der Spangrößenverteilung automatisch zu erkennen, eröffnet daher neue Perspektiven für die ProzessüberwachungThe strength of wood-based materials made of several layers of big and oriented particles like OSB (oriented strand board) is a superposition of the strengths of the layers according to the orientation of the particles and depending from their size distribution. It would be desirable to measure particle geometry and orientation close to the production process, e.g. with a “view onto the mat”. Currently, continuous on-line measurements of the particle geometry are not possible, while measurements of separated particles would be too costly and time-consuming. Before measuring particle shapes they have to be reconstructed in a multi-stage procedure which considers an image scene with strands as “gray value mountains”. Segmentation using a watershed algorithm is not sufficient. Also a two-step edge detector according to Canny does not yield closed object shapes. A multi-step procedure based on threshold decomposition and recombination however is successful: The gray values in the image are transformed into a reduced and uniformly distributed set of threshold levels. The local morphological gradients between these levels are used to re-build the original particle shapes by adding the threshold levels. Only shapes with a plausible size corresponding to real particle shapes are included in order to suppress noise. The result of the reconstruction from threshold levels is then matched with the result of the strong edges in the original image, which had been detected using a Canny operator, and is finally cleaned with morphological operators. This extended threshold analysis produces sufficiently segmented images with object shapes corresponding extensively to the particle shapes. Standard algorithms are used to measure geometric features of the objects. An approximation of particle shapes with ellipses of equal moments of inertia is useful. Remaining incorrectly detected objects are removed by form factors and size intervals. Size distributions for the parameters length and width are presented and characterized as density distribution histograms, weighted by the object area and linearly scaled (q2 distribution), as well as the cumulated distribution and different quantiles. A demonstration software “SizeBulk” based on MATLAB has been developed to demonstrate the computation and the interaction of algorithms. Image sequences can be processed and different variations of image preprocessing and parametrization can be tested. However, the detection procedure yields complete shapes only for those particles in the top layer. Objects in lower layers are partially hidden and cannot be measured completely. Artificial images with separated and with overlaid objects with a known size distribution were generated to study this effect. It was shown that size distributions are influenced by this covering effect and also by the strand orientation, but that at least the modes of the most important size parameters length and width remain in evidence. Artificial images and several samples with OSB strands from industrial and laboratory production were used for testing. They were measured as single strands as well as arrangements similar to an OSB mat. For real strands, the same covering effects to the size distributions revealed as in the simulation. Under stable image acquisition conditions and using similar processing parameters the characteristics of these samples can well be measured, and changes in the size distributions are definitely due to the geometric properties of the strands. The suitability of the processing procedure for the characterization of strand size distributions could also be confirmed for images acquired from OSB mats in a production line. Moreover, it could be shown that the extended threshold analysis is also suitable to evaluate images of particle board surfaces and to draw conclusions about the size distribution of the top layer particles. Therefore, the method presented here is a novel possibility to measure size distributions of OSB strands through the evaluation of partial gray value images of the mat surface. In principle, this method is suitable to be transferred to an industrial application. So far, methods that address the problem of detecting trends of the strand size distribution were not known, and this work shows new perspectives for process monitoring
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Shalbafan, Ali Verfasser], and Arno [Akademischer Betreuer] [Frühwald. "Investigation of Foam Materials to be Used in Lightweight Wood Based Composites / Ali Shalbafan. Betreuer: Arno Frühwald." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1036729729/34.
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Shalbafan, Ali [Verfasser], and Arno [Akademischer Betreuer] Frühwald. "Investigation of Foam Materials to be Used in Lightweight Wood Based Composites / Ali Shalbafan. Betreuer: Arno Frühwald." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1036729729/34.
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Kalantarzadeh, Mina. "Development of a heat treatment to enhance the antimicrobial properties of wood based mulches and animal bedding materials." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616950.
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Heat treatment is the most commonly practiced technology to add value to products derived from wood materials. Traditionally, heat treatment enhances the resistance of wood materials to weathering and decay fungi, but despite its wide use in sectors such as construction, wood preservation and food packaging, there has been little attempt to appl~ heat treatme'nt in other areas to manage food-borne and plant diseases. A preliminary study indicated that preheating increased the inhibitory. effect of pine wood shavings against the imp0l1ant foodborne pathogen of broilers, Salmonella Enteritidis (SE). Thus the first objective of this study was to optimise a heating regime to evaluate the effect of the enhanced inhibitory activity on SE in direct contact and also reducing ammonia emission of a constructed litter using heated wood. Heating to 120°C for 72 hours was the most effective treatment. In addition, heated pine wood had antimicrobial activity against other known microorganisms in poultry bedding including Staphylococcus aureus, Escherichia coli and Saccharomyces cerevisiae as well as SE. Hardwood shavings of ash, beech, red oak also showed antimicrobial activity against SE as did similarly treated softwood species such as pine and cypress. In vitro assays of dominant chemicals derived from fractionation of the extract demonstrated that bio-active fractions containing vanillin and dehydroabietic acid exhibited antimicrobial activity, but weak or no activity after purification. Overall, the in vitro assays suggested that a synergistic interaction occurred between vanillin and dehydroabietic acid decreasing the minimum inhibitor levels of vanillin. A second objective of the study was to investigate the potential of heat-treated woodchips of Japanese larch and rhododendron to control Phytophthora ramorum (PR) an invasive pathogen of larch in VK forests. Results demonstrated that heattreated pine, larch and rhododendron woodchips inhibited the recovery of zoospores of PR compared with air-dried woodchips. This inhibition was maintained even if the larch woodchips were diluted with soil. The in vitro assays revealed that their methanol crude extracts had an inhibitory effect on PR zoospores and also reduced germination of chlamydospores compared with extracts from air-dried wood. Chemical analysis of crude extracts of all three showed some of the induced compounds were present in all the extracts but differed in concentration. Coniferaldehyde was the most active compound against all three propagules. The dominant resin acids, DHAA and abietic acid (AB) decreased the minimum inhibitory level of the tested phenolic compounds against PR but had no effect when tested alone. Results of a field trial using heat-treated and air-dried woodchips were consistent with the bioassay results of crude extracts and indicated that heat treated materials have potential to reduce the survival of PR under natural conditions. Finally, based on xvi overall results of bioassays in both parts of this study a mechanism of action for the synergism between aromatic compounds such as vanillin and coniferaldehyde and resin acids dehydroabietic and abietic acid was hypothesized.
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Shu, Jiang. "An Experiment Management Component for the WBCSim Problem Solving Environment." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/36448.
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This thesis describes a computing environment WBCSim and its experiment management component. WBCSim is a web-based simulation system used to increase the productivity of wood scientists conducting research on wood-based composite and material manufacturing processes. This experiment management component integrates a web-based graphical front end, server scripts, and a database management system to allow scientists to easily save, retrieve, and perform customized operations on experimental data. A detailed description of the system architecture and the experiment management component is presented, along with a typical scenario of usage.Master of Science
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Garth, John Stuart. "Experimental Investigation of Lateral Cyclic Behavior of Wood-Based Screen-Grid Insulated Concrete Form Walls." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1857.
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Insulated concrete forms (ICFs) are green building components that are primarily used for residential wall construction. Unlike most polystyrene based ICF variants, the Faswall ICFs used in these experiments were significantly denser because they were made from recycled wood particles and cement. The current design approach for structures constructed with this type of wall form only allows the designer to consider the contribution of the reinforced concrete cores. Previous research has shown that this approach may be conservative. This project experimentally evaluated the lateral structural response of these types of grid ICF walls under increasing amplitude of in-plane cyclic loading. Two different height-to-length (aspect) ratios (approximately 2:1 and 1:1) were investigated, as was the effect of simultaneous gravity load. Furthermore, the reinforced concrete grid was exposed for each aspect ratio in order to examine the contribution of the ICF blocks to the lateral response. Analyses of hysteretic behaviors and failure modes indicated conservatism in the current design approach for estimating lateral strength and ignoring the beneficial contribution of the ICF blocks to overall performance. The presence of the wall forms increased the lateral shear capacity of the walls by an average of 42% (compared to the walls with forms removed), while also increasing the deformation capacity by an average of 102%. Furthermore, by considering an additional gravity load of 10 kips-per-lineal-foot (klf), the shear resistance of the walls increased by 32% (versus walls only subjected to self-weight), on average, and the deformation capacity of the walls increased by an average of 19%. Comparisons of the experimental results to several design equations led to the recommendation of a design equation that was previously accepted for another type of ICF system.
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Checchia, De Ambrosio Giovanni. "Synthetic Redundancy - An adaptive, hi-res timber frame tectonics based on a digital materials strategy." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14359/.
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Con questa tesi di ricerca si indagano le potenzialità di processi mereologici digitali applicati all’ architettura, generando sistemi complessi differenziati.L’obiettivo è quello di creare un sistema tettonico articolato, formato da elementi discreti e caratterizzati da una determinata morfologia e finite potenzialità di sviluppo e aggregazione. Si vuole indagare come un tale organismo può essere soggetto a logiche di auto-organizzazione e differenziazione sulla base di feedback esterni, coerentemente con vincoli di tipo costruttivo e materiale.Partendo da singole componenti orientate, dotate di limitate ma specifiche possibilità di movimento, il sistema ha capacità di organizzarsi e ordinarsi secondo logiche esclusivamente basate su interazioni locali e regole di allineamento, coesione e continuità strutturale, correlate agli altri elementi presenti nel network.
Il sistema, ispirato e guidato da un algoritmo che simula processi morfogenetici in diversi fenomeni biologici (Reaction-Diffusion Algorithm), è dotato di alta ridondanza e gerarchizzazione strutturale e ha la capacità di differenziarsi generando macro elementi, che, caratterizzati da prevalente sviluppo volumetrico o di superficie, permettono l’integrazione di elementi costruttivi standard in una possibile declinazione architettonica.
L’assemblaggio che ne risulta, complesso ed eterogeneo, costituito da elementi lamellari in legno, è capace di performance spaziali e strutturali, dispiegando le sue qualità nella capacità di auto-organizzarsi. Le strutture di cui è composto e i pattern che emergono sono frutto di regole locali, essendo stato deliberatamente scelto un approccio di tipo bottom-up per l’organizzazione del sistema.
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Quitadamo, Alessia. "Influence of wood flour and cellulose on the properties and the stability of formulations based on polyolefins and bio-based polymers." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI015.
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L'objectif de cette recherche est le développement de matériaux à haute valeur ajoutée, avec une grande quantité de charges bio-dérivées, aboutissant à un produit plus écologique. La stratégie poursuivie est basée à la fois sur l'introduction de fibres naturelles et sur l'utilisation de mélanges de polymères à base d'huile et bio-dérivés comme matrices, réduisant la quantité non biodégradable dans le matériau. Le projet de thèse est basé sur le développement de mélanges HDPE / PLA remplis de charges naturelles, telles que la farine de bois et les fibres de papier recyclées. Le polyéthylène haute densité a été choisi car il est l'un des polymères recyclés les plus représentatifs du marché. L'acide poly (lactique) a été sélectionné car il s'agit d'un polymère biodégradable important sur le marché. La méthodologie développée ici peut être étendue à d'autres polymères biodégradables, tels que l'isolat de protéine de soja (SPI). La farine de bois est un déchet diffus qui peut être utilisé pour la production de composites bois-plastique. Les fibres de papier recyclées sont issues de déchets de papier industriels, qui ne peuvent pas être soumis aux procédés de recyclage traditionnels. Des additifs ont été introduits pour faire face au problème d'hydrophilie différente entre les polymères à base d'huile / bio-dérivés avec des charges naturelles. La composition et les processus de production optimaux sont des défis, non seulement pour l'utilisation de ces matériaux, mais aussi pour leur élimination. La fin de vie de ces échantillons peut être évaluée par une biodégradabilité et une compostabilité contrôlées, en corrélant la structure du matériau avec la capacité de se biodégrader. La production d'un matériau à impact environnemental réduit avec des propriétés cohérentes avec leurs applications est un premier avantage environnemental. L'obtention d'une biodégradabilité contrôlée, en fonction des applications, valoriserait nos matériaux. Plusieurs caractérisations ont été réalisées afin d'analyser l'effet de différents compatibilisants et traitements tels que: tests de traction, microscopie électronique à balayage, calorimétrie différentielle à balayage, analyses thermogravimétriques, spectroscopie infrarouge, chromatographie d'exclusion de taille et tests de compostageThe objective of this research is the development of high-added value materials, with high amount of bio-derived fillers, resulting in a more eco-friendly product. The pursued strategy is based on both the introduction of natural fibres and the use of oil-based and bio-derived polymer blends as matrices, reducing the non-biodegradable amount in the material. The thesis project is based on the development of HDPE/PLA blends filled with natural fillers, such as wood flour and recycled paper fibres. High-density polyethylene has been chosen because it is one of the most representative recycled polymers on the market. Poly(lactic) acid has been selected as it is an important bio-degradable polymer on the market. The methodology developed here can be extended to other bio-degradable polymers, such as Soy Protein Isolate (SPI). Wood flour is a diffuse waste material, that can be used for production of Wood Plastic Composites. Recycled paper fibres are derived from industrial paper waste, which cannot be subjected to traditional recycling processes. Additives have been introduced in order to face the problem of different hydrophilicity between oil-based/bio-derived polymers with natural fillers. The optimal composition and production processes are challenges, not only for the use of these materials, but also for their disposal. The end-of-life of these samples can be evaluated through controlled bio-degradability and compostability, correlating material structure with the ability to biodegrade. The production of a material at reduced environmental impact with properties consistent with their applications is a first environmental advantage. Obtaining a controlled biodegradability, as a function of the applications, would give enhanced value to our materials. Several characterizations have been performed in order to analyse the effect of different compatibilizers and treatments such as: tensile tests, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analyses, infrared spectroscopy, size exclusion chromatography and composting tests
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Bouchut, Arthur. "Nouveau procédé pour la fonctionnalisation de surface des panneaux à base de bois." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI004.
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Développement d’une nouvelle méthode de fonctionnalisation qui aura pour but de pérenniser l’emploi des panneaux à base de bois et l’aspect de leur finition, en favorisant la stabilité de la couche supérieure exposée aux diverses conditions d’utilisation. En effet, les systèmes actuels, qui traitent très peu les panneaux en profondeur, sont très sensibles aux variations de température et d’humidité. Les éléments constitutifs des panneaux, hydrophiles, varient dimensionnellement, ce qui entraine l’apparition de fissures, de ruptures d’adhésion, et donc, d’obsolescence de la protection/finition avec le temps. Ceci est principalement le cas dans les conditions d’utilisation humides, telles que les salles de bains et les cuisines. Les panneaux perdent alors leur résistance mécanique qui justifiait leur emploi et se dégrade également visuellement. Objectif : Mise au point d’un revêtement pour panneaux de bois en utilisant une approche originale qui consiste à utiliser de façon concomitante deux stratégies de modifications de surfaces : adsorption non-covalente et greffage covalent. Il s’agira de déposer une pré-couche, interagissant de façon non-covalente avec les constituants du panneau de bois, puis de greffer sur cette pré-couche, de manière covalente, un revêtement fonctionnel. Cette pré-couche aura donc le rôle de promoteur d’adhésion puisqu’elle interagira avec le panneau de bois et réagira avec le revêtement. De plus, le recyclage des panneaux de bois sera facilité puisque le revêtement ne sera lié au panneau que par des interactions susceptibles d’être rompues sous certaines conditions (haute température)Development of a wood panel coating by using two strategies of surfaces modification: Non-covalent adsorption and covalent grafting. A pre-layer, interacting in a non-covalent manner with the wood panel, then a functional coating covalently grafted on this pre-layer. This pre-layer will therefore promote the adhesion of the coating with the wood panel. In addition, the recycling of wood will be facilitated since the coating will only be linked to the panel by non-covalent interaction and may be broken under certain conditions (high temperature)
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Vrána, Tomás. "Impact of moisture on long term performance of insulating products based on stone wool." Licentiate thesis, KTH, Civil and Architectural Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4490.
Full textAbstract:
Demands for energy have been increasing in the whole world. According to higher consumption, the price of energy rises yearly too. This evokes usage of insulating products in a wider range. By adding insulation, we lower the amount of energy needed to heat our homes, resulting in fewer associated greenhouse gas emissions and a lower monthly heating bill. Savings depend on insulation thicknesses and on conditions, in which the insulant is kept. Mineral insulation based on stone wool is also a member of building insulants that defends buildings and constructions against temperature changes of the ambient. However, even when we use modern technologies and building techniques to reduce high energy losses, we can never provide unimpeachable protection of stone wool from damage. During a construction process on a building site or at fast climate changes, it often happens that stone wool is exposed to rain precipitaions or other climate effets. This brings water to the insulating structure. Besides the loss of insulating qualities, the stone wool is left permanently wet. Even the fibres of stone wool are inorganic, they still can be attacked by degradation processes due to organic agents fixing fibres together. Analysis of damaged flat-roof constructions using stone wool and verification of material properties is a starting point of this licentiate thesis.
The attached paper section can be divided into two parts:
In-situ practice that notes troubles with insulating materials based on stone wool with inbuilt moisture on a building site
Laboratory measurement that observe material properties of stone wool under varying conditions
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Shu, Jiang. "Experiment Management for the Problem Solving Environment WBCSim." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/28713.
Full textAbstract:
A problem solving environment (PSE) is a computational system that provides
a complete and convenient set of high level tools for solving problems
from a specific domain. This thesis takes an in-depth look at the experiment
management aspect of PSEs, which can be divided into three levels: 1) data
management, 2) change management, and 3) execution management. At the data
management level, anything related to an experiment (computer simulation)
should be stored and documented. A database management system can be used
to store the simulation runs for a PSE. Then various high level interfaces
can be provided to allow users to save, retrieve, search, and compare these
simulation runs. At the change management level, a scientist should only
focus on how to solve a problem in the experiment domain. Aside from
running experiments, a scientist may only consider how to define a new
model, how to modify an existing model, and how to interpret an experiment
result. By using XML to describe a simulation model and unify various
implementation layers, changing an existing model in a PSE can be intuitive
and fast. At the execution management level, how an experiment is executed
is the main concern. By providing a computational steering capability, a
scientist can pause, examine, and compare the intermediate results from a
simulation. Contrasted with the traditional way of running a lengthy
simulation to see the result at the end, computational steering can leverage
the user's expert knowledge on the fly (during the simulation run) and
provide new insights and new product design opportunities. This thesis
illustrates these concepts and implementation by using WBCSim as an example.
WBCSim is a PSE that increases the productivity of wood scientists conducting
research on wood-based composite materials and manufacturing processes.
It integrates Fortran 90 simulation codes with a Web based graphical front
end, an optimization tool, and various visualization tools. The WBCSim
project was begun in 1997 with support from United States Department of
Agriculture, Department of Energy, and Virginia Tech. It has since been
used by students in several wood science classes, by graduate students and
faculty, and by researchers at several forest products companies. WBCSim
also serves as a test bed for the design, construction, and evaluation of
useful, production quality PSEs.Ph. D.
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Deshpande, Shubhangi. "Data Driven Surrogate Based Optimization in the Problem Solving Environment WBCSim." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/35901.
Full textAbstract:
Large scale, multidisciplinary, engineering designs are always difficult due to the complexity and dimensionality of these problems. Direct coupling between the analysis codes and the optimization routines can be prohibitively time consuming. One way of tackling this problem is by constructing computationally cheap(er) approximations of the expensive simulations, that mimic the behavior of the simulation model as closely as possible. This paper presents a data driven, surrogate based optimization algorithm that uses a trust region based sequential approximate optimization (SAO) framework and a statistical sampling approach based on design of experiment (DOE) arrays. The algorithm is implemented using techniques from the two packages SURFPACK and SHEPPACK that provide a collection of approximation algorithms to build the surrogates and three different DOE techniques: full factorial (FF), Latin hypercube sampling (LHS), and central composite design (CCD) are used to train the surrogates. The biggest concern in using the proposed methodology is the generation of the required database. This thesis proposes a data driven approach where an expensive simulation run is required if and only if a nearby data point does not exist in the cumulatively growing database. Over time the database matures and is enriched as more and more optimizations are performed. Results show that the response surface approximations constructed using design of experiments can be effectively managed by a SAO framework based on a trust region strategy. An interesting result is the significant reduction in the number of simulations for the subsequent runs of the optimization algorithm with a cumulatively growing simulation database.Master of Science
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Morales, Elen Aparecida Martines. "Técnicas de propagação de ondas na estimativa de propriedades mecânicas de painéis OSB." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-28022007-105842/.
Full textAbstract:
Um dos painéis derivados de madeira que tem se destacado é o OSB (Oriented Strand Board). Cada vez mais se evidencia a necessidade de novas tecnologias relacionadas à avaliação das propriedades mecânicas desse tipo de derivado de madeira, atualmente realizada através de ensaios destrutivos, efetuados horas ou dias após a respectiva produção. A utilização de métodos não-destrutivos tem se mostrado eficiente na caracterização mecânica e na avaliação da qualidade da madeira, e promissora em relação aos derivados de madeira. O objetivo geral deste trabalho foi investigar a eficiência de técnicas não-destrutivas de ensaio, de ultra-som e de stress wave, na estimativa de parâmetros físicos e mecânicos de painéis OSB fabricados no país. Foram considerados dois grupos, com 10 painéis de espessuras nominais de 15mm cada, que possuíam valores de resistência e de módulos de elasticidade na flexão estática, na direção longitudinal, distintos entre si. Primeiramente foram conduzidos os ensaios não-destrutivos, de ultra-som e de stress wave, nos painéis OSB e, em seguida, os ensaios destrutivos para a caracterização físico-mecânica e subseqüentes comparações. Os painéis estudados apresentaram valores de velocidades e constantes dinâmicas diferenciados na espessura e nas direções longitudinal e transversal. Os coeficientes de correlação obtidos entre os valores de velocidades e de constantes dinâmicas e os das propriedades físico-mecânicas, dos dois grupos de painéis, na espessura e direção transversal, não atingiram 0,70 e, na direção longitudinal superaram 0,90. Mostrou-se que é equivalente a estimativa de parâmetros mecânicos na flexão estática, ou até mesmo o estudo de painéis OSB, com a utilização dos métodos não-destrutivos de ultra-som e de stress wave. Com os resultados obtidos são gerados importantes subsídios para possibilitar a avaliação da produção de painéis OSB, viabilizando eventuais correções e ajustes até no decorrer do próprio processo produtivo.Wood based materials production has grown in the national market, as it is the current international trend. Such products have been an interesting alternative to the sawn wood. Among them, OSB (Oriented Strand Board) has been of an outstanding importance. Its potential of production in the national context is expressive when supplying civil construction, furniture industry, and others. However, this fact also makes clear the need of innovative technologies for mechanical properties evaluation of this wood based material, since until the present day it has been conducted with destructive tests which are only made hours or days after production. Nondestructive methods utilization has been proven to be efficient for mechanical characterization and quality evaluation of sawn wood, and quite promising for wood based materials. The main goal of this research has been to investigate the efficiency of nondestructive testing (ultrasound and stress wave) when estimating physical and mechanical parameters of OSB panels made in Brazil. Two groups of ten 15mm thick panels have been used, having each one of them strength and modulus of elasticity in static bending values distinct from each other in longitudinal direction. First the two types of nondestructive testing have been conducted on all OSB panels and then destructive tests have also been conducted for physical-mechanical characterization and following comparisons. Values of velocities and dynamic constants both in thickness and longitudinal and transversal directions have been different in the two groups of studied panels. Correlation coefficients between values of velocity and dynamic constants and values of physical-mechanical properties of the two groups of panels have not reached 0,70 in thickness and transversal direction, but they have exceeded 0,90 in longitudinal direction. It has been shown that ultrasound is analogous to stress wave either when estimating static bending mechanical parameters or studying OSB panels by nondestructive testing. Such results generate some important subsidies to the evaluation of OSB production, making feasible eventual corrections and adjustments even in the course of its process.
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Busser, Thomas. "Etude des transferts hygrothermiques dans les matériaux à base de bois et leurs contributions à l'ambiance intérieure des bâtiments." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAA010/document.
Full textAbstract:
L’objectif général de la thèse est de progresser dans la compréhension du comportement multi-physique des bâtiments en bois et d’améliorer l’évaluation de leur performance énergétique associée au confort hygrothermique. Les professionnels du secteur, ainsi que des études scientifiques, montrent des écarts entre les calculs et les mesures de performance (consommations, confort) de ces bâtiments. Les raisons de ces écarts ne sont pas encore bien élucidées : l’impact de l’humidité et de la chaleur latente dans ces constructions sont souvent mis en avant comme explication probable, bien que cela reste encore du domaine de la recherche. Les travaux les plus récents montrent que les fondements se situent probablement au niveau du comportement hygrothermique des matériaux à la base de bois en régime instationnaire. Ce travail de thèse se focalisera principalement sur deux échelles d’études : échelle matériau et échelle bâtiment. L’un des axes de travail de la thèse portera sur la caractérisation expérimentale des propriétés hygroscopiques de matériaux à base de bois et sur leur modélisation. Le second axe de travail portera sur l’intégration à l’échelle bâtiment de ces matériaux : en modélisation, intégrer l’impact des propriétés spécifiques de ces matériaux dans les assemblages constituants les parois, puis dans les bilans complexes à l’échelle du bâtiment. Une étude expérimentale portera sur une pièce de vie avec une forte présence de bois dans l’enveloppe du bâtiment pour caractériser le confort hygrothermique, et quantifier l’apport de l’inertie hygrique de l’enveloppe sur la performance de l’ambiance en termes de confort. Le cas échéant, des mesures seront également réalisées à l’échelle « paroi » d’une part, sur des constructions réelles d’autre partThe general aim of the thesis is to advance the understanding of multi-physical behavior of wooden buildings and improving the assessment of their energy performance with comfort hygrothermal. Sector professionals and scientific studies show the differences between the calculations and performance measures (consumption, comfort) of these buildings. The reasons for these differences are not yet well understood: the impact of moisture and latent heat in these constructions are often put forward as a likely explanation, although this is still research. The most recent studies show that the foundations are likely to fall at the hygrothermal behavior of materials at the base of wooden unsteady. This work will focus primarily on two studies scales: scale and scale building material. One of the lines of work of the thesis will focus on the experimental characterization of hygroscopic properties of wood-based materials and their modeling. The second strand of work will focus on building wide integration of these materials in modeling, integrating the impact of specific properties of these materials in the walls constituent assemblies and in complex balance sheets at the building scale . An experimental study will focus on a living room with a large presence of wood in the building envelope to characterize the hygrothermal comfort, and quantify the contribution of Hygric inertia of the envelope on performance in terms of the atmosphere comfort. If necessary, measures will also be drawn to scale "wall" on one hand, on real structures on the other
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Chennouf, Nawal. "Phénomènes de transfert de chaleur et de masse dans les composites de bois de palmier dattier : comportement sous sollicitations dynamiques." Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC0012.
Full textAbstract:
Promouvoir le béton à base de bois de palmier dattier (DPC) dans la construction neuve et dans la rénovation des bâtiments existants nécessite en premier lieu une caractérisation complète de son comportement hygrothermique à multi échelle (matériau, paroi et bâtiment). Dans ce travail de thèse, le comportement hygrothermique du béton de bois palmier dattier a été étudié expérimentalement à l'échelle matériau, puis à l'échelle mur. Dans une première partie, les isothermes d’adsorption-désorption ainsi que l’effet d’hystérésis du DPC ont été caractérisés dans des conditions statiques. Les résultats recueillis ont révélé une capacité hydrique élevée de ce matériau par rapport à d’autres matériaux de construction. Par ailleurs, la valeur du tampon hydrique et l'effet de la température sur les cycles successifs d'adsorption / désorption ont également été évalués dans des conditions dynamiques. Il a été constaté que le processus de sorption est fortement affecté par la variation de la température. Les résultats obtenus ont permis de classer le DPC comme un matériau hygroscopique possédant une excellente capacité de régulation d’humidité. Dans la deuxième partie de la thèse, le comportement hygrothermique d’un mur en DPC a été étudié expérimentalement à l’aide d’une chambre climatique. Plusieurs scénarios de variations de température et d'humidité relative ont été appliqués sur une seule face du mur. Les variations de la température et d'humidité à différentes profondeurs de la paroi ont été mesurées à l'aide de capteurs. Plusieurs phénomènes thermo-hydriques ont été mis en évidence tels que l'effet du couplage de transfert de chaleur et d'humidité relatif aux phénomènes d'évaporation-condensation et d’adsorption-désorption. En outre, une inertie thermique et hydrique importante a été observée à travers le mur de DPC, ce qui permet de limiter la surchauffe et de réduire la condensation interstitielle pour des constructions durablesPromoting the date palm concrete in new constructions and renovating buildings requires a full hygrothermal characterization at several scales (material, wall and building). In this thesis, the hygrothermal behavior of date palm concrete was experimentally investigated, firstly at material scale then at wall scale. In the first part, the adsorption-desorption isotherms and the hysteresis effect of DPC were characterized under static conditions.The results revealed a high hygric capacity for this material compared with other classical building materials. The moisture buffer value and the effect of temperature on successive adsorption/desorption cycles were also assessed under dynamic conditions. It was found that the sorption process is highly affected by the temperature. Furthermore, this bio-based mortar was classified as hygroscopic and breathable material with excellent moisture buffer capacity. In the second part of the thesis, we have experimentally investigated the hygrothermal behavior at wall scale. The investigation was performed using a climatic chamber where the variation of temperature and relative humidity were applied on one side of the wall. These both parameters were measured at different depths of the biobased wall using sensors. Several thermo-hygric phenomena were highlighted such as the high coupling effect between the heat and moisture transfer due to the evaporation-condensation and adsorption-desorption phenomena. Besides, significant thermal and hygric inertia was observed through the DPC wall which allows mitigating overheating and reducing interstitial condensation for sustainable constructions
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Liao, Qi Feng, and 廖琪鋒. "The conditioning effect on the relative humidity of wood based material." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/53596044573199093498.
Full text
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劉益宏. "A study on ignitability of wood-based material by thermal radiation." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/74039623735101465386.
Full textAbstract:
碩士中華大學
營建管理研究所
91
This research used Taguchi method to discuss the ignitability research of wood-based material under different variables. Such as the material, the thickness, the amount of coating, and the formulation of coating Taguchi method used the orthogonal array of L9(34) for experiments constituted. The test method of this research was similar to that of ASTM E1623. By analyzing the result of Taguchi method for the influence ranking of wood-based materials which are subjected to thermal radiation, the most important factor is the formulation of coating, which possesses 48.72%. According to the results of Taguchi method for the optimal combination factors, it is aimed at the amount of coating for the corresponding research. By regression analysis, the best amount of coating for wood-based materials is 391g/m2. Using Taguchi method and base of the factors and levels to set up the orthogonal array, it can simplify the variables of experiment. Then the experiment numbers are less than these of full factorial experiments, and the experiments have better reproducibility.
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Tien-YuChen and 陳天宇. "An Innovative Approach to Selling Wood Material to Makerspaces：A practice-based research of Woodmall." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/wba42j.
Full textAbstract:
碩士國立成功大學
創意產業設計研究所
105
Since 1991, the central theme of Taiwan’s timber policy reforms has been the conservative for forest resources. Taiwan has become a country underline on both afforestation and substantial reduction of deforest. On the other hand, the foreign imports are multiple sources and adequate supplying. Therefore, the demand for local market matter-of-course tends to the imported wood material rather than the insufficient domestic supply. It becomes a chance for Woodmall, the only wood material supplier that selling foreign countries material on-line in Taiwan. Woodmall is a start-up since 2016 that try to seek out a better change for the industry and solve the wood material demand problem. This study aims to focus on Woodmall starting strategies and explore their innovative approach to selling to makerspaces. For Woodmall first phase of strengthen-up strategies, the research team plans to establish the downstream market, especially the new trend of makerspaces. Not only do they attach makerspaces to develop and increase the brand awareness, but also manipulate several tests to develop the innovative approach. On the other hand, makerspace is a new type of co-working and design area that mainly blooms in Taiwan since 2015. Woodmall tends to dig in the makerspace market while the market is still a blue ocean. As the strategy is pretty different from the previous that a startup company tends to match a blue ocean, “how can Woodmall make an innovative approach as a sale character?” is worth to be observed. Go on with the structure, the researcher reaches an outcome for both Woodmall and the industry, as several makerspace communities. Woodmall and makerspaces are making mutual benefit since the innovative approach is developed. Woodmall, as an upstream supplier, offers wood materials to downstream consumers, while makerspaces are the blue ocean market with a great demand that can create a new flow chart model. For such interaction, makerspaces can further transform into a co-creation community and even establish an industrial innovation system. As a whole, it is the so-called innovative approach brought about by Woodmall is benefit to the industry and valuable.
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Santos, Pedro Gil Girão dos. "Hybrid performance-based wood panels for a smart construction." Doctoral thesis, 2020. http://hdl.handle.net/10316/93165.
Full textAbstract:
Tese no âmbito do Doutoramento em Engenharia Civil, apresentada à Faculdade de Ciências Tecnologia da Universidade de CoimbraA madeira lamelada-cruzada (cross-laminated timber, CLT), tendência moderna em termos de construção em madeira, demonstra elevado potencial para sistemas maciços de construção de madeira. O conceito dos painéis CLT (camadas ortogonais) reduz significativamente a anisotropia dos painéis, garante maior estabilidade física e permite ligações mais fáceis e eficientes entre os elementos e destes com outros componentes da construção, tornando esses painéis uma solução versátil para suportar cargas fora/ e no plano dos mesmos. Este sistema possui vantagens significativas em relação à construção das tradicionais estruturas leves de madeira, abrindo um campo completamente novo para o uso da madeira na construção. Por outro lado, como se trata de um sistema maciço de madeira, é necessário um volume significativo de matéria-prima para produzir os painéis, aspeto que é apontado como uma das principais barreiras para a implementação do CLT de uma forma mais abrangente, porventura devido aos custos associados. Neste contexto, o objetivo da presente tese consistiu no desenvolvimento de uma solução de painel alternativa, ou pelo menos complementar, baseada em CLT, mas utilizando menos quantidade de madeira, combinando desempenho mecânico com melhor isolamento térmico e peso reduzido. A solução desenvolvida, denominada madeira isolada cruzada (cross-insulated timber, CIT), consiste em substituir a camada interna de um painel CLT de cinco camadas por uma à base de material de isolamento (espuma rígida de poliuretano), tendo, por isso, algumas semelhanças com o conceito de painel de madeira estrutural isolado (SIP). Os principais aspetos focados nesta tese, tendo em vista o desenvolvimento do painel incluem: (i) a definição da estrutura do painel e dos possíveis materiais para a sua constituição; (ii) a caracterização dos materiais selecionados para o desenvolvimento do painel, incluindo as camadas adesivas; (iii) a caracterização mecânica dos painéis; (iv) a otimização funcional e económica dos painéis; (v) a avaliação do impacte ambiental dos painéis; (vi) a caracterização acústica dos painéis; e (vii) o desenvolvimento de sistemas de conexão para os painéis. No primeiro aspeto, foi definida uma estrutura composta por um núcleo em espuma rígida de poliuretano entre dois pares de camadas cruzadas em madeira de Pinho bravo. Em alternativa, para as faces exteriores dos painéis, foi também considerada a Acácia Austrália. No segundo aspeto, os resultados de caracterização dos materiais permitiram verificar o comportamento complexo da espuma de poliuretano, tendo-se observado um comportamento não-linear e rotura dúctil em compressão e um comportamento linear e rotura frágil em tração. Da adesão entre materiais, concluiu-se que as adoção de pressões de aperto mais elevadas conduzem a uma melhor adesão dos mesmos e, dos ensaios de envelhecimento, concluiu-se que ao invés de uma redução da resistência, particularmente no poliuretano, houve um aumento da mesma devido à pós-reticulação do material. No terceiro aspeto, foi possível verificar que o modo de rotura dominante nos ensaios de flexão foi o corte do núcleo. Os modelos analíticos identificados na revisão do estado-da-arte descreveram bem o comportamento inicial observado (linear) e, para descrever a fase não-linear observada, os modelos numéricos desenvolvidos demonstraram um bom nível de precisão. No quarto aspeto, concluiu-se que a exigência de um desempenho térmico mínimo (envolvente exterior do edifício) torna a solução de painel desenvolvido na tese mais competitiva face aos painéis CLT. No quinto aspeto, através de uma análise de ciclo-de-vida, concluiu-se que a produção de poliuretano e a assemblagem do painel constituem os processos de produção com maior impacte ambiental; dos cenários de fim-de-vida considerados, a opção de incineração com recuperação de energia revelou ser a que implica menores impactes. Da comparação com sistemas de CLT, concluiu-se que o painel desenvolvido implica, de uma forma geral, maiores impactes. No sexto aspeto, verificou-se, o menor isolamento dos painéis de CIT face aos de CLT de igual espessura, devido à menor massa. Os modelos analíticos identificados no estado-da-arte para painéis sanduiche não se revelaram adequados para avaliação do isolamento a sons aéreos dos painéis, pelo que o modelo de Sharp para elementos isotrópicos e homogéneos com uma adaptação revelou uma melhor descrição dos mesmos; para descrição do isolamento a sons de percussão, a lei do invariante revelou-se eficaz. No sétimo aspeto foram desenvolvidas várias ligações, sendo que uma delas foi testada experimentalmente, e cuja resistência se enquadrou dentro do previsto pelos modelos analíticos identificados no estado-da-arte. Globalmente, o estudo realizado nesta tese mostrou que os painéis desenvolvidos têm potencial para complementar os atuais sistemas em CLT, nomeadamente no que diz respeito ao aos elementos da envolvente exterior.
Cross-Laminated Timber (CLT), a modern trend in timber construction, shows high potential for massive timber construction systems. Compared to traditional systems, the CLT panels’ layout (crosswise layers) significantly reduces the anisotropy of the panels, guarantees higher physical stability and allows for easier and more efficient connections between elements and other building components, making these panels a versatile solution to bear both out-of-plane and in-plane loads. This system has also significant advantages with respect to traditional wood light-frame construction, opening a completely new field for the use of timber in construction. On the other hand, as this is a massive wood system, a significant volume of wood raw material is required to produce the panels and this is pointed out as one of the main barriers for CLT implementation, perhaps due to the associated costs. In this context, the objective of the present thesis consisted of the development of an alternative, or at least complementary, CLT based panel solution but using less amount of wood, combining mechanical performance with improved thermal insulation and reduced weight. Such solution, named cross insulated timber (CIT), consists of replacing the inner layer of a five-layer CLT panel by an alternative one made of insulation material (polyurethane rigid foam), and thus having some similarities with the structural insulated timber panel (SIP) concept. The main aspects that are focused on this thesis for the panel development, include: (i) the definition of the panel layout and potential materials for its constitution; (ii) the characterization of the selected materials for the panel development, including the adhesive layers; (iii) the mechanical characterization of the panels; (iv) the functional and economic optimization of the panels; (v) the evaluation of the environmental impact of the panels; (vi) the acoustic characterization of the panels; (vii) the development of connection systems for the panels. In the first aspect, a structure consisting of a polyurethane core between two pairs of Maritime pine crossed layers was defined. As an alternative to this, for the exterior faces of the panels, Acacia Australia was considered. In the second aspect, the results of material characterization tests allowed to verify the complex behaviour of the polyurethane foam, which presents non-linear behaviour and ductile failure in compression, and linear behaviour and brittle failure in tension. From the adhesion between materials, it was concluded that the adoption of higher bonding pressures leads to better adhesion of the same ones and, from the ageing tests, it was concluded that instead of a reduction in strength, particularly in polyurethane, there was a strength increase due to additional cross-linking due to post-curing. In the third aspect, it was possible to verify that the dominant failure mode in the bending tests was core shearing. The analytical models identified in the state-of-the-art review described well the observed initial behaviour (linear) and, to describe the observed nonlinear phase, the numerical models developed demonstrated a good level of precision. In the fourth aspect, it was concluded that the requirement of a minimum thermal performance (in the case of the exterior envelope of the building) makes the panel solution more competitive against CLT panels. In the fifth aspect, through a life-cycle analysis, it was concluded that the production of polyurethane and the assembly of the panel constitute the production processes with the greatest environmental impact; among the considered end-of-life scenarios, the option of incineration with energy recovery proved to be the one with the least impacts. From the comparison with CLT systems, it was concluded that the developed panel presented, in general, greater impacts. In the sixth aspect, less insulation of the CIT panels compared to the CLT panels of equal thickness was registered, due to the lower mass. The analytical models identified in the state-of-the-art for sandwich panels did not prove to be suitable for assessing the airborne sound insulation of the panels, so the Sharp model for isotropic and homogeneous elements with an adaptation provided more accurate predictions; for describing the insulation to impact sounds, the invariant law proved to be effective. In the seventh aspect, several connections were developed, one of which was experimentally tested, and whose resistance fit within the predictions provided by the analytical models identified in the state-of-the-art. Overall, the study conducted in this thesis showed that the developed panels have the potential to complement the current CLT systems, namely concerning the elements of the external envelope.
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Lin, Xiang. "Direct coupling of imaging to morphology-based numerical modeling as a tool for mechanics analysis of wood plastic composites." Thesis, 2011. http://hdl.handle.net/1957/26472.
Full textAbstract:
Polymeric composites reinforced with bio-materials have advantages over composites with synthetic reinforcements. Bio-based composites use low-cost and renewable reinforcements, have nonabrasive properties for machining, have improved damping characteristics, and have potential for energy recycling. However, the limited use of bio-based composites is because their mechanical properties are typically much lower than those of synthetic composites.
The objective of this study was to combine state-of-the-art imaging tools with emerging numerical modeling methods for an integrated, multi-level characterization of bio-based reinforcements and their composites. Digital photography (2D) will allow collection of full-field digital images of the surface of sample composites, which will be used for characterization of the morphological structure of fillers (copper wire or wood particle) and of model composites. Mechanical experiments (tension load) on isolated fillers and on model composites will allow imaging of the deformed material. By correlating relative positions of thousands of surface features between consecutive images, digital image correlation (DIC) algorithms can be used to map surface deformation fields and calculate surface strain fields.
Digital imaging methods can only record deformations and strains. The interpretation of those strains in terms of material properties, such as position-dependent modulus of a heterogeneous composite material, requires simultaneous modeling. The modeling must
use morphology-based methods that can handle anisotropy, heterogeneity, and the complex structure of bio-based composites such as wood plastic composites. This research used the material point method (MPM) as a modeling tool. MPM is a particle-based, meshless method for solving problems in computational mechanics. The crucial advantage of MPM over other methods is the relative ease of translating pixels from digital images into material points in the analysis. Thus digital images (2D) used in our experiments were used as direct input to the MPM software, so that the actual morphologies, rather than idealized geometries, were modeled. This procedure removes typical uncertainties connected with idealization of the internal features of modeled materials. It also removes variability of specimen to specimen due to morphology variations.
Full-field imaging techniques and computer modeling methods for analysis of complex materials have developed independently. This research Coupled imaging and modeling and used inverse problem methodology for studying bio-particulate composites. The potential of coupling experiments with morphology-based modeling is a relatively new area. This work studied the morphology and mechanical properties of copper wire (for validation experiments) and wood particles used for reinforcement in polymer composites. The goal was to determine the in situ mechanical and interfacial properties of copper wire and then wood particles. By comparison of DIC results to MPM, the conclusion is MPM simulation works well by simulating 3D composite structure and using Matlab software to do qualitative and quantitative comparisons. Copper validation tests showed that copper wire is too stiff compared to polymer such that the inclusion modulus had low effect on the surface strains (DIC experimental results). Wood particle worked better because modulus of wood is much lower than copper. By qualitative comparison of the wood particle specimens, we could deduce that the in situ properties of wood particles are lower than bulk wood. Quantitative analysis concentrated on small area and got more exact results. In a 90 degree particle quantitative study, MPM simulations were shown to be capable of tracking the structure of wood particle plastic, which involved failure. The entire approach, however, is not very robust. We can get some results for mechanical properties, but it does not seem possible to extract all anisotropic properties from a few DIC tests, as some researcher have suggested.Graduation date: 2012
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ZHUANG, CHUN-HE, and 莊純合. "Acoustical properties of wood & wood based materials." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/97734847773181943321.
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Shiu, Miaurong, and 許妙戎. "Property of wood-based materials tested by ultrasonic." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/22581936077968287667.
Full textAbstract:
碩士國立中興大學
森林學系
89
The purpose of this study was to apply the nondestructive ultrasonic wave to test the ultrasonic velocity of wood and wood based materials, and to use destructive universal testing machine to test their strength. The finding of this study were summarized as follows： Ultrasonic velocity is increased with the density of the increased particleboard. The coefficients of determination (R2) of the regression analysis between density and longitudinal wave and between density and surface wave were 0.93 and 0.92, respectively. However, the density and ultrasonic velocity of solid wood showed that they had no relations because of the structure of solid wood. Fiber angle of wood affected the transport velocity of ultrasonic. Also, the velocity is decreased with fiber being angle increased. Producing flow direction of merchant particleboard and fiberboard had a little impact on ultrasonic velocity. That was to say, the directionality of panels wasn’t obvious. Surface layer direction of plywood had also a little impact on ultrasonic velocity. The velocity of longitudinal wave is decreased with the increased specimen length, but the relationships among them were not obvious. When the length of specimen was longer than 15cm, velocity of surface wave is increased with the increased specimen length, and the relationships among them were not obvious, either. The relationships between thickness and ultrasonic velocity of particleboard and fiberboard were not obvious, but the ultrasonic velocity of plywood is decreased with the increased thickness. The ultrasonic was applied to test the mechanical property of wood based panels. The relationship between MOE and the velocity of longitudinal wave or surface wave was statistically significant, and R2 values of them are 0.86 and 0.85, respectively. The relationships between MOR and their velocities were also statistically significant, and their R2 values were 0.84 and 0.83, respectively. IB specimen was tested with longitudinal wave which frequency was 40 and 100 KHz, and R2 values of them are 0.74 and 0.75, respectively. Based the result of this study, it showed that the ultrasonic was not suitable to test the artificial defect with hole, if the wavelength was larger than the size of artificial defected hole. As the results mentioned above, results applied to test in wood based panels of longitudinal wave and surface wave were similar. These results showed the longitudinal wave and surface wave could cooperate with each other.
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Chang, Chia-Fang, and 張嘉芳. "Ultrasonic Velocity and Properties of Wood-based Materials." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/89441327874644164121.
Full textAbstract:
碩士國立屏東科技大學
木材工業系
92
The purpose of this study was to investigate the ultrasonic wave velocities in wood and particleboard by the nondestructive testing method with ultrasonic. Five probes with different ultrasonic frequencies (40kHz, 100kHz, 250kHz, 500kHz and 1MHz) were used to evaluate the effects of frequencies on the wave velocities of solid wood, commercial particleboard, and laboratory made particleboard, respectively. In order to understand the influence of defects on the wave velocities of particleboard, different types of drilled holes and grooves were made in commercial particleboard. Particleboards manufactured with different resin contents and density levels were used to establish the relationships between strength properties and ultrasonic wave velocities. Results showed that insignificant effects of ultrasonic frequencies on the longitudinal or transverse ultrasonic wave velocities were found. It is suggested that low ultrasonic frequency was more feasible for commercial particleboard. The ultrasonic wave velocity of the commercial particleboard parallel to long axis was 5-10% higher, in comparison to that of perpendicular direction to long axis. Either 40kHz or 100kHz probes was used during the evaluation, ultrasonic wave velocities were not obviously affected by quantities and dimensions of holes on the tested panels. Depth and quantities of single-side grooves didn’t alter ultrasonic wave velocities in commercial particleboard significantly. But velocities decreased with increasing quantities of grooves on both sides of panels, especially for the grooving depth of 2/3 panel thickness. The ultrasonic wave velocities in the particleboard made from laboratory increased with increasing resin content (6- 10%) and density (0.5- 1.0 g/cm3). Both the bending strength and internal bonding strength have similar trend as ultrasonic wave velocities.
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GUO, BO-WEN, and 郭博文. "Studies on the thermal conductivities of wood-based materials." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/37307082419251971245.
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Huang, Wun-Jheng, and 黃文正. "Producing Composite Particleboard from Peanut Husk and Wood-based Materials." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/58708860393592657382.
Full textAbstract:
碩士國立嘉義大學
林產科學系研究所
95
The purpose of this study was to strengthen the particleboard made from agricultural residues such as peanut husk by using different wood-based materials. The board size, target density and types are 450mm × 450mm × 10mm, 0.65g/cm3, 15 respectively. The binder to be used is phenolic formaldehyde resin (PF). The resin content of PF is lower (i.e.6％) than commonly used in UF (i.e.10％) . Pressing temperature, pressure and time are 190℃, 2.74MPa, 8min respectively. As the low bending strength of particleboard made from peanut husk, we used different kinds of wood-based materials such as radiata pine particle, red lauan veneer, bamboo veneer etc. to increase the mechanical properties. Free formaldehyde release of the boards ranged from 0.71 to 1.41mg/L (meets F3 of CNS 2215-2006). Board density, moisture content and thickness swelling were 0.60~0.63g/cm3, 3.35~4.71％, 12.74~42.30％ respectively. In mechanical properties, board internal bond strength, screw holding strength, bending strength, modulus of elasticity andwet bending strength were 0.075~0.64 MPa,198.51~526.42 N,3.05~34.08MPa,277.91~3212.61MPa,and1.33~21.45MPa respectively.
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SHIE, JIA-CHI, and 謝佳琪. "Surface nanocoating treatment of wood-based materials forimprovement of water-proof performance." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/53789366987017967506.
Full textAbstract:
碩士中華大學
營建管理研究所
94
The present work investigates the enhancement of water-repellency on rough surface using nanoscale roughness inherent in metal-oxide nanoparticles together with a hydrophobic fluoromethylic copolymer coating via the Taguchi and analysis of variance（ANOVA）methodologies. Based on the concepts of nanocoating processing, five operating factor including the concentration of binder, solid ratio of ZnO, wetting time, and numbers of spraying layers, are chosen. Through the surface roughness is generally influenced by solid ratio, more nanoparticles can randomly stack to build up a rougher surface, causing more partially sitting on an air film, capable of promoting the super-hydrophobic behavior. The reconfirmation test using the optimal parameter setting demonstrates that the super-hydrophobic surface can be achieved, and its contact angle is as high as 168 .
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Lee, Wei-Ju, and 李威儒. "Wood-based Materials Tested by Nondestructive Testing Methods in the Production Line." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/40187936202510530344.
Full textAbstract:
碩士國立中興大學
森林學系
87
A b s t r a c t The purpose of this study was focusing on the testing of plywood and particleboard in the production line and how to classify the different grades of plywood and particleboard. Because of noise problem and limit the use of testing machine, only using stress wave timer (SWT) and ultrasonic materials tester (UMT) to inspect the board in the production line, and then using SWT, UMT, TTAS, VFT to determine the properties of different materials these were brought back from plywood and particleboard mills to the laboratory, finally using destructive testing machine (universal testing machine) to obtain the value of static modulus of elasticity (MOE) ,and compare the correlation between dynamic modulus of elasticity (MOEd) and MOE. The important results are summarized as the followings: 1.In the manufacturing process of particleboard, the results showed that stress wave velocity after trimming was the fastest, stress wave velocity after hot press was secondary, then stress wave velocity after sanding was the slowest, but it showed no significant difference for statistic analysis. Secondly, although workers apply sight-measuring to be as the basis, it still has some degree of accuracy for different grades (grade A and grade B) of particleboard. Grade A and grade B particleboard of 18mm thickness showed that the strength of grade A was higher than that of grade B tested by both NDT and DT. 2.In the manufactured process of plywood, the results showed that stress wave velocity after clod press was the slowest, then stress wave velocity after hot press was the next, and stress wave velocity after trimming was the fastest, also the results of different grades of plywood (grades A , B and C of 15mm thickness)showed that there was no correlation between factory classification and the strength obtained from the NDT. 3.When using SWT and UMT to test full size of wood-based materials（plywood and particleboard）, it does not affect stress wave and ultrasonic velocity too much for smaller defects on the side or smaller flaws on the surface of board.
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Hsieh, Ming-Huan, and 謝明桓. "Co-gasification of Wood-based Materials and Microalage in a Fluidized Bed." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/82841842958913965568.
Full textAbstract:
碩士國立中興大學
森林學系所
100
Gasification can be defined as the conversion of feedstocks (e.g., biomass, waste, coal, etc.) to combustible gas (H2, CO, CH4 and CnHm) by partial oxidation at the elevated temperature. In this study, the Spirulina platensis torredied pellet and Eucalyptus globulus torrefied pellet were co-gasified in a 30 kWth bubbling fluidized bed gasifier to investigate the effect of gasification temperature, equivalence ratio, mixed ratios and steam injection on syngas compositions, the lower heating value, and tar content, etc. Before feeding into the gasifier, the higher heating value of microalgae and Eucalyptus globulus pellets can be increased after torrefaction treatment. With a lower O/C ratio, torrefied biomass can favor gasification. After gasification, the CO, CH4, H2, tar content and lower heating value of syngas decrease with increasing the equivalence ratio, but CO2 shows the contrary tendency. In addition, CO content of syngas increased firstly then decreased with increasing the mixed ratio of the microalgae torrified pellet, but CO2 show the contrary tendency. It can also be seen, adding more microalgae pellet during co-gasification can cause sintering phenomenon. This is because that expansion of the microalgae torrified pellet after heating caused agglomeration of the bed materials and defluidization. Moreover, steam injection can increase H2 content of syngas and reduce CH4 content, but tar content increased. An optimal operating condition can be found that the gasification temperature is 800℃, ER is 0.3, and mixed ratio of the microalgae is 30%.
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Chen, Chao-Yi, and 陳朝羿. "Co-gasification of Wood-based Materials and Sludge in a Fluidized Bed." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/24026703621967742384.
Full textAbstract:
碩士國立中興大學
森林學系所
99
In this study, wood pellets of Cryptomeria japonica and sludge pellets from Taichung Futien Water Resources Recycling Center were co-gasified in a 30 kWth bubbling fluidized bed gasification system with a diameter of 7.6 cm in the bed region, 19.8 cm in the freeboard region, and a total high of 1.9 m. The results show that when wood pellets or sludge pellets were gasified, respectively, the CO2 concentration increased with increasing the equivalence ratio (ER) but other syngas products showed the contrary results. The yields of H2 and CO increased with increasing the gasification temperature. An optimal operating condition can be found that gasification temperature is 800oC and ER is 0.3 for gasification of wood pellets . While wood pellets and sludge pellets were co-gasified, the yields of H2 and CO2 increased with increasing the sludge mixed ratio, but the heating value of the syngas decreased. In addition, the ash contained in the sludge decrease the tar content during gasification was not significat. Adding dolomite substituted for the bed material also can diminish the tar content. Injecting steam would cause defluidization by agglomeration of the bed material when the sludge was gasified. This is due to that the sludge contains a large amount of ash. However, co-gasification with wood pellets can decrease the effect of agglomeration by the ash from the sludge pellets.