Дисертації з теми "Mousses de polyuréthanes – Matériaux – Fatigue"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-17 дисертацій для дослідження на тему "Mousses de polyuréthanes – Matériaux – Fatigue".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Le, Bail Jean-Baptiste. "Modélisation du comportement mécanique sous chargement d’une butée d’amortisseur en mousse de polyuréthane : vers une démarche de dimensionnement en fatigue." Electronic Thesis or Diss., Brest, École nationale supérieure de techniques avancées Bretagne, 2022. http://www.theses.fr/2022ENTA0003.
Повний текст джерелаPolyurethane foam jounce bumpers are widely used in the automotive industry. Their main function is to absorb vertical shocks to the wheels and contribute to the integrity of the vehicle suspension. The mechanical response of this type of parts implies to take into account different mechanisms, from the buckling of the walls of the part to the self-contact through the geometrical non-linearities. The current characterization of these polyurethane foam jounce bumpers in fatigue is currently limited to the customer’s specifications and to the tests predefined by him. The objective of this thesis is to carry out a complete experimental characterization of the mechanical behavior in order to identify an Hyperfoam type behavior law. This characterization is also based on imaging techniques, SEM and tomographic, in order to characterize the link between the microstructure and the mechanical behavior of the jounce bumper. This study should allow to define a global approach for the fatigue design of polyurethane foam jounce bumper
Santiago-Medina, Francisco José. "Tanins condensés pour mousses rigides et nouvelles réactions de réticulations des matériaux polyphénoliques." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0248/document.
Повний текст джерелаAn alternative to industrial phenol or resorcinol industrial products may be tannins or lignin. Both are natural polyphenols, the tannin is extracted from different parts of plants, while lignin is usually obtained as a secondary product in the pulp and paper mill. These two products are the main basis on which I have worked during the development of this thesis. In a first part, a study of characterization and differentiation between different tannins with the same origin and that present a different behavior when used in the same application under the same conditions has been done. Highlighting the GPC as a fundamental technique for the differentiation between sulphited quebracho tannins. On the other hand, the interactions between different substances with tannin and with lignin have been studied. As the study of the reaction between diamines (such as hexamethylenediamine) with tannin and lignin to obtain a polycondensed resins. Also, in this section have been obtained polyurethanes with at least 70% of natural substances in their preparation without using any isocyanate in the process. In addition, aldehydes derived from lignin, such as vanillin, have been used next to pine tannin for the manufacture of adhesives in the preparation of particleboards, obtaining satisfactory results according to European standards and from completely natural substances. Finally, within an industrial project the initial steps have been carried out for the development of a rigid tannin foam applicable by projection for the thermal insulation of buildings. Where a new mechanical foaming system has been developed for tannin foams based in fire-fighting foams or in the foams of the tunneling operations, this new system of foaming avoids the problems of shrinkage during the formation of the foam
Deschanel, Stéphanie. "Dynamique des précurseurs de la rupture des matériaux hétérogènes : application aux mousses polymères vitreuses." Lyon, INSA, 2005. http://theses.insa-lyon.fr/publication/2005ISAL0093/these.pdf.
Повний текст джерелаIn order to predict failure time of materials, a new approach has been considered : fracture can be viewed as a critical phenomenon. For some materials fracture can be seen as a clustering of microcrackes. We focus on heterogeneous materials (vitreous polymer foams) whose fracture can be described as a phase transition. Our main experimental tool is the monitoring of the acoustic emission signatures of the microfractures, which occur during mechanical tests. We highlighted diffuse microcrack nucleation and progressive localization into a dominating crack with a good fit of the energy by a power law. The exponet of this power law does not seem to depend neither on the material density, the loading mode, nor the behavior law. The time intervals between two damaging evants seem to be power law distributed only if the stress remains nearly constant for the most part of the test. A critical region where the cumulative energy could be described by a power law appears only for creep tests
Talal, Cheikhalard. "Synthèse de polyuréthane macroazoamorceurs (PUMAI) et leur utilisation pour préparer des copolymères à blocs polyuréthane-b-polyvinyle : applications dans le domaine des adhésifs et matériaux composites." Lyon, INSA, 1997. http://www.theses.fr/1997ISALO111.
Повний текст джерелаIn this work, the synthesis of polyurethane macroazo initiators (PUMAI) based on 2,2' azobis (2-cyanopropanol) (ACP) was investigated for the synthesis of thermoplastic and thermoset block copolymers. The study of the structure and reactivity (radical initiation ability and condensation with Isocyanates) of ACP showed that this molecule is very useful for the elaboration of PUMAI. Before block copolymers elaboration, we have studied the two stages of PUMAI synthesis. This synthesis was possible in solution with stannous catalyst at low temperature. From PUMAI, poly(urethane-b-styrene) and poly(urethane-b-methyl methacrylate) were elaborated, fractwnated and characterized in both structural and mechanical point of view. PUMAIs were also used for cross linking of unsaturated polyesters/styrene resins. They are able to Imitate radical polymerization and to reduce shrinkage (in order to be used instead of some. Low shrink or low profile additives as polyvinyl acetate and some polyurethanes). They are linked by covalent bond to the poly( ester/styrene) ma tri x after cross linking with or without fillers (glass fibers). Ali analyses realized on block copolymers and composites "poly(ester/styrene/urethane)/glass fibers" have shown that the block efficiency of PUMAIs is about 50% and proved their interest m the block copolymers synthesis
Caty, Olivier. "Fatigue des empilements de sphères creuses métalliques." Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0084/these.pdf.
Повний текст джерелаMetal hollow spheres can be piled up and soldered together to form a cellular material. The initial hollow spheres exhibiting a mono-disperse size and thickness, the resulting material is rather homogeneous. This kind of material allows a remarkable flexibility in terms of microstructural design. The thickness and diameter of the spheres, the nature of the metal used (nickel, steel. . . ) can be varied. This allows to tailor the microstructure in order to reach the target properties imposed by the design on the material. Before being able to tailor these properties and invent the material meeting a specific design (material by design), it is necessary to know the relation between the varying parameters and the resulting properties. This study aims at determining and modelling the effects of the microstructure of hollow spheres metals on their fatigue properties. Fatigue properties of a rather large range of metal hollow sphere structures were determined by mean of conventional fatigue tests. All the data were collected to build S-N curves. The constitutive material, the density, the thicknesses of the walls, the diameters and the fatigue loading mode were varied to determine the effect of each parameter. Tomographies of samples tested ex-situ reveal the different kinds of fatigue damage mechanisms and their influence on the macroscopic behavior. The three-dimensional X-ray tomographic images could also be used for meshing and to calculate the behaviour of the structure. This step has been done with a shell finite element model obtained from tomographic images. The model is enriched by a direct thickness measurement on the tomographic images. The values measured are affected to the shell elements. The model permits to determine the stress and strain field inside the microstructure. The fatigue behaviour has been modelled by post processing the proportion of yield elements and the size of yield areas. These models permit to determine the fatigue limit of numerically built hollow sphere structures and investigate parameters never experimentally studied
Lambour, Stéphanie. "Chimie des isocyanates et des cyanates pour l'amélioration de la tenue thermique de revêtements souples." Lyon, INSA, 2000. http://www.theses.fr/2000ISAL0085.
Повний текст джерелаIn the present work, we have developed formulations based on cyanate ester monomers, reinforced with reactive filler and with high thermal stability according to the established ageing test. These materials [macrodiol/cyanate ester/filler] are obtained by calandaring followed by thermal treatment at higher temperature. They revealed a stable thermo-mechanical wear. Actually, stress and strain at break vary until 30%. Initial values of σrupt. And ɛrupt. Are higher than silicone ones and these polymers are easily transformed, more than fluoro-elastomers; both are the main competing products for the future application. This work allowed us to give details on these complex networks with interconnected structure of micro-domains. Triazines repartition is homogeneous enough to give continuous properties like a very wide glass transition. These properties are in relation to the chosen stoechiometric ratio, the polymerization temperature or the type of introduced macrodiol. Finally, thermo-mechanical wear of these filled networks are quite different of the commercial polyurethanes or polyurethane-ureas (ex: ADI® IV-95) or the formulated ones in the laboratory (ex: C36*/H12MDI/3-DCM). Chemical cure of these polymers does not stabilize material properties during the ageing test. For ali these synthesized polymers, physico-chemical analyses on the aged samples let us think of degradation by a depolymerization path as many results in the literature. As a conclusion, the cyanate ester network can be modified by a thermal treatment at high temperature but soluble fraction holds constant and does not affect their thermo-mechanical wear
Youssef, Souhail. "Etude par tomographie X et modélisation par éléments finis du comportement mécanique des mousses solides." Lyon, INSA, 2004. http://theses.insa-lyon.fr/publication/2004ISAL0079/these.pdf.
Повний текст джерелаThe mechanical properties of cellular materials are related to their micro-structure. In fact, macroscopic stresses are the consequence of stresses in the cell wall and struts and of stresses in the cell walls and struts and of the cell failure mechanisms. In the present work we perform tomography during in situ compression tests on different type of foams to inspect the 3D-microstructure and deformation mechanisms. We also present a method to transform large data images of actual microstructures into a tetrahedral mesh, which will be used to model the mechanical behaviour by the finite element method. We finally confront computation results and in situ observations to validate the model. X-ray Computed Micro Tomography (XRCMT) has been widely used recently as a non-destructive technique that gives picture of the interior of cellular solids. This allows studying architectural parameters and, when coupled with in situ loading tests, deformation mechanisms of foams. Local deformation mechanisms of closed cell foam have been studied during compression experimentally by X-Ray tomography and numerically by FEM. The presence of elastic buckling and plastic yielding of foam walls was observed. The combination of effective e modelling tools gives attractive opportunities to build sufficiently large data model to represent the foam structure. Once the modelling technique was validated, we use it to study the effect of various bulk material properties for a same microstructure of the foam on the mechanical behaviour. The mechanical response of these foams was also studied numerically under various uniaxial loads configuration and multiaxial loading
Denay, Anne-Gaëlle. "Mécanismes et tenue mécanique long-terme de mousses polyuréthanes pures et renforcées aux températures cryogéniques." Phd thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2012. http://tel.archives-ouvertes.fr/tel-00740110.
Повний текст джерелаMorvan, Myriame. "Caractérisation des odeurs de matériaux de l'habitacle automobile par "nez électronique", analyse sensorielle et analyse physico-chimique." Toulouse, INPT, 2001. http://www.theses.fr/2001INPT026G.
Повний текст джерелаChen, Xinyi. "Polyuréthanes à base de tannins et de glucides sans isocyanate (NIPU) pour adhésifs, mousses et finitions." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0286.
Повний текст джерелаThis research was focus on bioresources, including tannin, lignin, soybean protein, humins, to prepare bio-based wood adhesives and foams. There are four main parts, including two kinds of wood adhesives preparation by using bio-resources, i.e., bio-sourced NIPU wood adhesives and bio-based (tannin, SPI, and lignin) wood adhesives without toxic formaldehyde; two kinds of tannin-foam products, i.e., typical tannin-furanic foam and non-isocyanate polyurethane foams. (1) Commercial humins, soybean protein isolation (SPI), and mimosa tannin have been utilized to prepare wood adhesives, based on the formulation of non-isocyanate polyurethanes (NIPU). The basic properties of the adhesives were determined. Techniques such as MALDI-ToF and FTIR were used to detect the products obtained and for analyzing the reaction mechanisms involved. Thermomechanical analysis (TMA) was utilized to investigate the thermal behavior of the adhesives. Finally, the laboratory plywood or particleboard were prepared for evaluating the bonding performances of adhesives. (2) A novel biomass-based wood adhesive was prepared with commercial mimosa tannin extract and glycerol diglycidyl ether (GOE) by convenient mechanical mixing. GOE served as the crosslinker of the tannin without any aldehyde addition yielding hardened threedimensional networks. Oifferent weight ratios of tannin/GOE were investigated by several techniques to determine their influence on final properties. Two kinds of lignin-based adhesives were prepared, i.e., ( i ) glyoxal modified lignin and dialdehyde starch cross-linked by urea; ( ii ) periodate oxidation by two-steps. The molecular species formed and the reactions mechanism involved were determined by FT-IR, 13C NMR and MALDI-ToF mass spectrometry. The adhesives based on this reaction were tested by bonding laboratory plywood or particleboard, by differential scanning calorimetry (DSC), and thermomechanical analysis (TMA). (3) A tannin-based non-isocyanate polyurethane (NIPU) rigid foam was obtained. Citric acid and glutaraldehyde mixture served as a blowing and crosslinker agent used to provide foaming energy and cross-link the tannin-based resin to prepare the NIPU foams. The reaction mechanism of the tannin-based NIPU foams were investigated by FT-IR, MALDI-TOF, and 13C NMR. Additionally, tannin was also used as a natural tire-retardant to improve the final properties of glucose-based NIPU foams, including fire retardancy and compression strength. (4) A biorefinery waste, humins, and soybean protein insolate (SPI) were selected as formaldehyde substitute bio-sourced crosslinkers for two kinds of tannin-based foam formulations. As expected, the properties were improved by using these bio-sourced crosslinkers. The basic properties of series tannin foams were investigated. The morphology and structure characteristics were observed by scanning electron microscopy (SEM). Additionally, the crosslinking reaction mechanisms between tannin with the two bio-sourced crosslinkers, i.e., humins and SPI, were determined by MALDE-ToF and FTIR spectrometry. Finally, the thermal stability, mechanical properties, fire retardancy and formaldehyde emission were evaluated by the relevant techniques
Paget, Baptiste. "Étude du renforcement de mousses syntactiques à matrice polyuréthane." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1202.
Повний текст джерелаSyntactic foams synthesized from an elastomeric matrix and soft-shell microspheres have shown interesting acoustical properties. They open new perspectives for the manufacturing of stealthy submarines or ships, but the industrialization of such material is held back by their great compressibility: hydrostatic pressure tends to crush the microspheres, which leads to a loss of the damping properties. We are therefore interested in studying the reinforcement of syntactic foams with polyurethane matrix. Scientific literature being scarce on this subject, a reference syntactic foam has been synthesized in the laboratory to allow a better characterization of this material and its components. In particular, an innovative test of hydrostatic compression has been developed to characterize the behavior under pressure of the microspheres and foam. A model of the literature simulating the compression of syntactic foams has been used thanks to the material parameters collected; it allowed us to test the influence of various parameters on this compression. This model could also predict the characteristics of the components of a foam whose compressibility would meet a set of specifications. These different analyses have shown that the main parameter governing the compression of syntactic foams is the Young's modulus of the matrix. In addition, a compression reinforcement can only be obtained using a chemical reinforcement of the matrix; the presence of fillers (fibers, MWCNTs) does not bring significant changes
Furtwengler, Pierre. "Synthèse et caractérisation de nouveaux synthons et mousses biosourcés, à partir de sorbitol." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAE005.
Повний текст джерелаIn a context of renewable molecules valorization, new molecular architectures and polyols have been developed from sorbitol and various biobased building-blocks with respect to the green chemistry principles. Several polyesters polyol have been synthesized from controlled esterification reactions in bulk conditions. Thanks to the used of variable size diols (C2 to C12) monomers, polyols final viscosity and hydroxyls values were tuned until the obtaining of suitable properties for polyurethanes foams elaborations. Thus, semi-flexible polyurethane foams and rigid polyisocyanurate foams were formulated with fast foaming kinetic profiles (less than 3 min). Rigids polyisocyanurates foams exhibit excellent mechanical and thermal properties, in great agreement with building insulating application requirement. Otherwise, transesterifications reaction involving sorbitol and dimethyl carbonate were studied in order to develop a new bi-functional chemical platform, a bis-cyclocarbonate. Ring opening polymerization and aminolysis reactions were investigated from this chemical platform to the elaboration of cross-linked polyether and non-isocyanate polyurethanes (NIPU). NIPU syntheses were performed with short and long diamines in order to study the relationships between monomers choice and the resulting polymer material temperature of glass transition
Persenot, Théo. "Fatigue of Ti-6Al-4V thin parts made by electron beam melting." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI117/document.
Повний текст джерелаNowadays, reducing the energy consumption is crucial for most of the industries. For transportation industries, it can be achieved through weight reduction. In this context, cellular structures turn out to be one of the most efficient solution. Thanks to the development of additive manufacturing, producing such complex geometries is no longer an issue. However, their use will remain limited as long as their fatigue performances are not known. This PhD work aimed at understanding the mechanisms that govern the fatigue behaviour of such cellular structures. It was first decided to focus on their unitary element, i.e. a single strut. Single struts samples were manufactured by Electron Beam Melting and then characterized in as-built conditions using different experimental techniques (X-ray tomography, optical and electron microscopy, etc.). Their static and cyclic tensile properties were then evaluated. The rough surface and in particular notch-like defects were found to be responsible for the knockdown of the mechanical properties. Regarding the fatigue resistance, their detrimental impact was predicted using Kitagawa diagrams. It also enabled to explain the impact of the build orientation. Different post-treatments were used in order to improve these mechanical properties. Chemical etching and ultrasonic shot peening (USP) significantly reduced the severity of surface defects of as-built thin struts and thus increased their mechanical properties. After USP, the fatigue properties of machined samples were almost matched. Hot Isostatic Pressing lead to the closure of all internal defects and to the coarsening of the microstructure. When combined with one of the surface treatments, the fatigue properties were further improved. Finally, a method enabling to systematically and automatically extract from the surface the most critical defects and quantitatively analyze their influence on fatigue life was proposed and discussed. It was successfully applied to chemical etched samples but improvements are mandatory for other surface conditions
Thébault, Marion. "Développement de trois différents types de matériaux innovants à base de tannins." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0202/document.
Повний текст джерелаTannins are chemical extracts which represent a natural alternative to chemicals as phenol or resorcinol which are from oil resources. They are already used industrially for the synthesis of adhesives used for the manufacture of wood-based products such as particleboards and plywood, but generally always used with formaldehyde as a hardener to improve their mechanical strengths. The first products developed in this thesis are adhesive resins for the manufacture of particleboards, synthesized from Radiata Pine tannins and less hazardous aldehydes obtained by reacting sunflower oil with ozone then with a reducing agent. The study has focus first on the conditions of the ozonolysis, whose parameters are numerous, and the analysis of the oils obtained, then on the synthesis of resins with solutions of tannins. Some of these resins have been used to manufacture particleboards that have been tested in dry internal bond strength. Then the subject has been oriented toward the development of rigid tannin/furanic-based foams as part of an industrial multi-material project. Several formulations have been tested to achieve the objectives of a specification, whose first purpose is to obtain foam panels homogeneous, low in density and with good mechanical properties. The innovation has been to make these foams in a particleboard press. Finally, a new route to manufacture tannin-based polyurethane polymers has been tested by using less hazardous chemicals in replacement of isocyanates, conventionally used in the industry. The synthesis is made by a first carbonatation step of tannins hydroxyl groups and then by a reaction with hexamethylenediamine. Spectrometric analyzes have shown that the products obtained do have urethane linkages. The study led to the exploration of the use of tannins reacted with ammonia to replace hexamethylenediamine to obtain new "non isocynates" polyurethanes with more bio-based and environment-friendly chemicals
Cerdan, Florent. "Etude du vieillissement hydrique et des effets de couplages hygro-thermo-mécaniques sur le comportement d'une mousse polyuréthane renforcée par des fibres de verre au sein d'une membrane Mark III." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2017. http://www.theses.fr/2017ESMA0028/document.
Повний текст джерелаThe insulation of containment membrane of liquid natural gas carrier using the MarkIII membrane system, consists of load-bearing system made of panels in glass fiber reinforced polyurethane foam. The membrane is designed to resist to mechanical and thermal service load cases. As stated by IGC code regulation, and more specifically in some critical safety scenario, it has to be demonstrated that the cargo containment system will keep its integrity and main functions when subjected to water leakage through the inner hull wall (ballast).The challenge of this study is to appreciate the behavior of the reinforced polyurethane foam in immersion, which could widen the understanding of both water diffusion mechanisms and the impact of water penetration on the properties of the material.The setting up of water sorption tests at ambient temperature, according to three conditioning "free", "blocked" and "coupled" has allowed to identify a swelling law, a loading law and a damage law.In "free" conditioning, the cellular structure and the orientation of glass fibers in XY planes induce an anisotropic hygro-mechanical coupling. The swelling of Z direction has an important impact on the water solubility levels.In "blocked" conditioning, the blocking of the displacement of the faces perpendicular to the Z direction induces an increase in the internal stress levels as a function of the progression of the penetration front. In "coupled" conditioning, the sequence of the water aging and the cryogenic aging causes several damages. The damage degree is proportional to the hygroscopic swelling level of the cellular structure.The impact of these different conditionings on the durability of the material mechanical properties has been evaluated
Amani, Yasin. "Modélisation basée sur données de tomographie aux rayons X de l'endommagement et de la conductivité thermique dans les matériaux cellulaires métalliques." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI036/document.
Повний текст джерелаThe properties of cellular materials depend on their architecture and casting defects. The architecture refers to shape and distribution of the solid phase. Defects correspond to the presence and distribution of cavities or intermetallic particles in the solid phase due to the fabrication procedure. Two types of materials produced by different fabricating routes are studied in this manuscript. On the one hand, two ERG foams with different cell sizes were chosen to study the effect of the presence of intermetallic particles on the plasticity and damage. Micro-tensile tests and nanoindentation experiment were also performed on the struts extracted from the foam to determine their micro elastoplastic behaviour. On the other hand, two structures with the same shape and repetitive pattern but different struts and nodes thicknesses were produced by selective laser melting manufacturing route to study the effect of porosity on plasticity and damage. This PhD-work aimed at developing a generic image-based finite element procedure to take into account the effect of the local porosity and the presence of intermetallic particles into the finite element simulations of the cellular materials. The initial state of the samples was pictured by performing high resolution "local" tomography and "stitching" methods. The 3D geometries were meshed and the local porosity and elastic-plastic properties of each element were directly informed according to high-resolution 3D images. The deformation and fracture procedures of the samples were pictured by performing in-situ/ex-situ experiments coupled with low-resolution tomography scanning. 3D image-based finite element models were developed for the simulation of the tension/compression tests. The microstructurally informed FE models better capture the mechanical behaviour of the cellular structures, especially for the prediction of the fracture. The study also aimed at determining the thermal conductivity of a highly porous ERG foam using image-based finite element calculations. The results were verified by comparing with the measured thermal conductivity from guarded hot plates experiments
Jmal, Hamdi. "Identification du comportement quasi-statique et dynamique de la mousse de polyuérathane au travers de modèles de mémoire." Phd thesis, Université de Haute Alsace - Mulhouse, 2012. http://tel.archives-ouvertes.fr/tel-01017088.
Повний текст джерела