Tesis: "Tests sandwich"

1

Martin, James David. "Sandwich Plate System Bridge Deck Tests". Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/31648.

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Three series of tests were conducted on a sandwich plate bridge deck, which consisted of two steel plates and an elastomer core. The first series of testing was conducted by applying a static load on a full scale sandwich plate bridge deck panel. Local strains and deflections were measured to determine the panelâ s behavior under two loading conditions. Next, fatigue tests were performed on the longitudinal weld between two sandwich plate panels. Two connections were tested to 10 million cycles, one connection was tested to 5 million cycles, and one connection was tested to 100,000 cycles. The fatigue class of the weld was determined and an S-N curve was created for the longitudinal weld group. Finally, a series of experiments was performed on a half scale continuous bridge deck specimen. The maximum positive and negative flexural bending moments were calculated and the torsional properties were examined. Finite element models were created for every load case in a given test series to predict local strains and deflections. All finite element analyses were preformed by Intelligent Engineering, Ltd. A comparison of measured values and analytical values was preformed for each test series. Most measured values were within five to ten percent of the predicted values. Shear lag in the half scale bridge was studied, and an effective width to be used for design purposes was determined. The effective width of the half scale simple span sandwich plate bridge deck was determined to be the physical width. Finally, supplemental research is recommended and conclusions are drawn.
Master of Science

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2

Grigg, William Reid. "Post-Injection Welded Joint Fatigue Tests of Sandwich Plate System Panels". Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/44900.

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The Sandwich Plate System (SPS) is created by bonding two steel plates together with an elastomer core that is injected into a cavity formed by the steel plates and perimeter bars. The result is a stiffer and lighter panel that can be used for plate-like structures such as bridge decks, stadium risers or ship decks. For more versatility, the effects of welding post-injection to the SPS panels were investigated. Three post-injection welded joints were tested to determine fatigue resistance and the effects of cyclic loading on the localized debonding of the heat affected zone at the post-injection welded joint of a SPS bridge deck. Seven panels containing one of three post-injection weld configurations were investigated. Each panel was fatigue tested to ten million cycles or until failure, by applying remote bending to the post-injection welded joint. Experimental deflections and strains were compared to finite element analyses. Fatigue-life predictions were made using code based S-N curves, and a relatively new mesh-insensitive structural stress method with a master S-N curve approach. The post-injection welded joint demonstrated good fatigue resistance to recommended AASHTO loading when shims were used under the middle support to offset the camber in the SPS panels. It was also found that stresses caused by draw down of the camber had an adverse affect on the post-injection welded joint and greatly reduced its fatigue resistance.
Master of Science

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3

Foster, Andrew. "Understanding, predicting and improving the performance of foam filled sandwich panels in large scale fire resistance tests". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/understanding-predicting-and-improving-the-performance-of-foam-filled-sandwich-panels-in-large-scale-fire-resistance-tests(3dc4bf07-82f0-4e3e-9cab-37e9244fe2a2).html.

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This thesis presents the results of research on sandwich panel construction, with the aims of developing tools for modelling sandwich panel fire performance and hence to use the tools to aid the development of sandwich panel construction with improved fire resistance. The research focuses on sandwich panels made of thin steel sheeting and a polyisocyanurate (PIR) foam core. For non-loadbearing sandwich panel construction, fire resistance is measured in terms of thermal insulation and integrity only. However, these two parameters are affected by mechanical performance of sandwich panel construction due to the high distortion and large deformation nature of sandwich panel construction under fire attack. Therefore, it is necessary to consider both thermal and mechanical performances of sandwich panels under fire conditions. The work in this thesis includes development of a thermal conductivity model for PIR foam as this thermal property is one of the key values in determining heat transfer through sandwich panels; this thermal conductivity model is based on the effective thermal conductivity of porous foams proposed by Glicksman (1994) and includes the effects of polymer decomposition and increases in foam cell size. It is validated against fire tests carried out on PIR sandwich panels 80mm and 100mm thick with steel facings of thickness 0.5mm. A large 3D sequentially coupled thermal-stress model of a full scale fire test has been developed in the commercial finite element analysis (FEA) software ABAQUS to provide insight into the way sandwich panels behave in a fire resistance test and also to assess different modelling techniques. Aspects and stages of the simulation that agree well with test data are explained. Limitations of the ABAQUS software for simulating sandwich panel fire tests are highlighted; namely, it is not possible to simulate the correct radiation heat transfer through panel joints, as cavity radiation cannot be specified in a fully coupled thermal-stress analysis. Joints are key components of sandwich panel construction. In order to obtain temperature development data for modelling joints, a number of fire tests have been carried out. These fire tests were conducted with different joint configurations and panel thicknesses under realistic fire conditions using timber cribs. The joint fire tests revealed significant ablation of the foam core within the joints of sandwich panels at high temperatures. At the beginning of fire exposure, the joint temperature on the unexposed surface was lower than that on the panel due to the better insulation property of air compared to the foam. However, as the joint gap increased due to ablation of the foam, the joint temperatures became higher than in the panel. A numerical simulation model has been created to investigate this behaviour. Using the aforementioned thermal model, numerical simulations have been carried out to examine the influences of possible changes to sandwich panel design on sandwich panel construction fire performance. It was suggested that if the maximum gap in the joints can be limited to 5mm, for example, by applying intumescent coating strips within the sandwich panel joints to counter the increasing gap formed due to core ablation, then the joint temperature on the unexposed surface would not exceed that of the panel surface, hence the joint would cease to be the weak link. To increase the panel fire resistance, the use of graphite particles in the PIR foam formulation may be considered to lower the contribution of radiative heat transfer within the foam cells by reducing the transmissivity of the cell walls. Graphite particles may offer considerable increases in the thermal resistance of PIR foam at high temperatures by limiting the radiation contribution which dominates heat transfer above 300oC.

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4

Freitas, Nuno Rodolfo Gomes. "Sandwich test para avaliação de grouts". Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14959.

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Mestrado em Engenharia Civil
A presente dissertação visa estudar métodos de ensaio para avaliar as características de grouts não estruturais a utilizar na consolidação de revestimentos de edifícios com destacamento de uma/várias camadas. Neste sentido, foi realizado o ensaio sandwich para simulação de destacamento de camadas. É introduzida uma nova variante deste ensaio seguindo as normas europeias e realizados os ensaios de referência. Apresenta-se a metodologia adotada e faz-se a exposição, comparação, análise e justificação dos ensaios e retiram-se as conclusões bem como os desenvolvimentos futuros.
This thesis aims to study test methods for evaluating the characteristics of non-structural grouts to be used for consolidation of buildings coatings with detachment of one or several layers. Thus, we performed the sandwich trial for layers detachment simulation. A new variant of this essay following the European standards is introduced and reference trials are done. The methodology adopted, exposure, comparison, analysis, trials justification, conclusions taken and future developments are shown.

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5

Lien, Fredrik. "Modelling and Test Setup for Sandwich Radomes". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26233.

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Sandwich radomes are structures providing communication- and radar antennas with protection from the environment. The sandwich materials are designed to affect the electromagnetic radiation as little as possible with respect to transmission- and reflection loss, boresight error, boresight error slope, increased sidelobe levels and depolarization. In order to match the frequency response of the radome material to the specifications, simulation and optimization of the thickness and dielectric properties of the individual sandwich layers is done.To simulate the transmission- and reflection coefficients for sandwich materials a Matlab scripts has been developed. The script calculate the response for up to 10 different layers for incidence angles and frequencies defined by the user. Verification of the results has been done by comparing the simulated data to results in Kozakoff (2010) and show that the script works correctly.Waveguide measurement and calibration components have been designed and manufacturedin order to measure samples of dielectric materials and samples of complete radome sandwich materials. The results have been compared to results from simulations done in CST Microwave Studio and show a good match for complete sandwich materials and thicker dielectrics. However the measurement results for thin material samples show more deviation compared to the simulation results. The deviation seems to be dependent on the thickness of the sample.Two optimization routines have been developed in Matlab. The first compare the measuredresults from measurements to the simulated results from Matlab. Least square optimization is used to adjust the dielectric properties (relative permittivity and dielectric loss tangent) used by the simulation script in order to match the simulation values to the measured values. The results show good match of the optimized relative permittivity for a 22 mm thick sample of Teflon with the optimized value deviating 1.3% from the specified permittivity value. With decreasing thickness of the test samples the deviation increased to approximately 3-12%. The optimized loss tangent values however show very large deviation from the specified values and should be treated as invalid. The main reasons are believed to be the low loss of the materials combined with the thickness relative to the measurement wavelength.The second optimization routine adjust the thickness of the individual layers to achieveminimum loss for one- or more predefined frequency bands. The results show that theoptimization work as intended. To investigate the effect of production errors/productiontolerances the core thickness of an A-sandwich has been adjusted with +/-10% from theoptimized thickness. The result show that the thickness deviation has a bigger impact onhigh frequencies.

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6

Krödel, Jonsson Viktor. "Burst test analysis of metal sandwich wall panels". Thesis, KTH, Lättkonstruktioner, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180456.

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In this report, an investigation of some of the most common damage models available in literature is performed. Their ability to predict ductile failure of metals will be compared and a specific focus is put on burst failure prediction of the cooling channels inside a sandwich wall structure. This structure is intended to be used at future versions of the Ariane rocket nozzles developed at GKN-Aerospace in Trollhättan, Sweden. Currently GKN-Aerospace uses a prediction method of burst failure based on the Rice and Tracey damage model but it has been shown to sometimes deviate from experimental results, why they seek for a new method to predict ductile failure. Hence the objective of this project is to find a more accurate method to predict burst failure of the sandwich wall than the one used today at GKN-Aerospace. This will be done by both a literature research and performing simulations with the studied damage models. The project was demarcated to investigate four damage models; the Gurson-Tvergaard-Needleman, Johnson-Cook, the Extended Mohr Coulomb criterion and the currently used damage model at GKN-Aerospace. Further the simulations were delimited to the softwares ANSYS APDL and LS-DYNA, for which burst test simulations was only performed in ANSYS APDL. It was found that only the Gurson-Tvergaard-Needleman and the Rice and Tracey based model could be used for prediction of burst failure in ANSYS APDL, why only those damage models could be evaluated against the objective of the project. The burst test simulation results showed that the Rice and Tracey based model gave predictions of burst pressure closest to experimental results, why the objective of the project was not met since a more accurate prediction method was not found. However important conclusions could be drawn and valuable recommendations for future work could be given.

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7

Melrose, Paul Thomas. "Elastic Properties of Sandwich Composite Panels Using 3-D Digital Image Correlation with the Hydromat Test System". Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/MelrosePT2004.pdf.

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8

Bois-Grossiant, Philippe Carleton University Dissertation Engineering Mechanical and Aerospace. "Boundary element fracture mechanics analysis of sandwich test specimens". Ottawa, 1994.

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9

Li, Nan. "Identification des paramètres mécaniques de plaque sandwich cousue par essais vibratoires". Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2361.

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L'objectif des travaux exposés dans cette thèse est d'identifier les différentes propriétés des constituants du sandwich cousu in-situ. Cette identification est indispensable pour simuler le comportement de ce type de matériau composite à différentes sollicitations statiques ou dynamiques. Nous proposons dans cette thèse de faire Une identification dynamique faite sur un échantillon représentatif (une plaque) qui prend en compte l'hétérogénéité et complexité de la structure. Cette identification est basée sur la corrélation ent.re un essai vibratoire et un calcul par éléments finis. La corrélation se fait en minimisant une fonction coût qui porte sur le décalage entre fréquences propres expérimentales et numériques. Cette minimisation est précédée par une identification du couple (fréquence propre/mode propre) numérique et expérimental en utilisant le MAC (Modal Assurance Criterion). Pour optimiser, nous passons, dans un premier temps; par une analyse de sensibilité qui permet de classifier les paramètres en fonction de• leur importance et ainsi ne lancer le processus d'identification que sur un nombre réduit de paramètres. Nous avons appliqué cette approche sur une poutre sandwich cousue et une plaque sandwich cousue. Dans une deuxième partie de ce travail de thèse, nous avons pu mettre au profil l'aspect périodique de ces structures composites sandwichs cousues, en utilisant le théorème de Floquet-Bloch, et cela sur deux plans : l'aspect numérique pour la réduction du modèle et du temps de calcul et sur le plan physique par l'étude des bandes d'arrêt ('stopband') qui ont un intérêt applicatif assez intéressant
The sandwich structures are well known for their high bending stiffness. This type of structure is also capable of including acoustic and thermal functionalities. However, they also have weaknesses such as the connection between the faceplate and the core and the weakness in the transverse direction due to the property of the core. The core is usually made of soft materials like foam for acoustic functionality. To overcome these weaknesses, it is possible to connect the different layers of the sandwich by transverse stitches. This is the concept of ‘stitched sandwich’. The stitch will deeply change the behavior of the structure and complicate the determination of its properties. The objective of this thesis is to identify the properties of the constituents of the stitched sandwich in situ. These properties are essential to simulate the behavior of this type of composite material under static or dynamic excitation. The identification of the properties of the constituents by mechanical tests is difficult for various reasons: the heterogeneity makes it complex to extract representative specimen; the behaviors of the constituents may change in non-in-situ tests; several different types of mechanical test, such as tensile-compression and torsion, are necessary to determine all the engineering constants in the case of orthotropic material which is common for composite materials. To overcome all these difficulties, we propose in this thesis a dynamic identification method conducted on the structure (the whole plate for example). Compared to mechanical test which is based on a sample, this method takes into account the heterogeneity and complexity of the structure. This method is based on the correlation between the vibration test and a finite element model of stitched sandwich. The parameters are identified by minimizing a cost function which can measure the gap between the experimental frequencies and the calculated frequencies. The correspondence of experimental mode and calculated mode is guaranteed by MAC (Modal Assurance Criterion). Before the optimization, we propose firstly a sensitivity analysis to classify the parameters according to their importance. Then the identification process is only conducted on a reduced number of parameters. We have applied this dynamic identification method to both a stitched sandwich beam and a stitched sandwich plate. 9 parameters of different constituents are identified in the case of plate. In the second part of this thesis, based on the theorem of Floquet-Bloch, we have profited from the periodic characteristic of the stitched sandwich structures in two aspects: in the numerical aspect, the periodicity has served to reduce the calculation of forced response of periodic structure; in the physical aspect, we have studied the stop band of stitched structures

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10

Junior, Mauricio Francisco Caliri. "Modelos de material para espumas poliméricas aplicadas a estruturas aeronáuticas em material compósito sanduíche". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-15082011-223452/.

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Estruturas aeronáuticas são em sua grande parte fabricadas em material compósito para que sejam atendidas as especificações de projeto. Entre essas estruturas destaca-se a estrutura sanduíche. A utilização desse tipo de estrutura requer estudos extensos em novos materiais, bem como na aplicação dos mesmos. Uma atenção especial para o núcleo dessas estruturas é necessária, pois este material é na verdade uma estrutura celular, como as espumas poliméricas. Esta dissertação busca concatenar a literatura com a prática ao estudar a calibração de modelos de material para descrever o comportamento mecânico de espumas poliméricas, bem como avaliar suas potencialidades e limitações. Estas espumas são estruturas celulares cujos mecanismos de falha consistem em respostas micro e macroscópicas. A identificação e quantificação desses comportamentos podem ser feitas através da investigação de modelos de material micro-mêcanicos ou fenomenológicos (macro-mecânicos) associados a ensaios e análises experimentais tanto do material celular quanto da estrutura na qual este material é utilizado. Cada abordagem, micro ou macro-mecânica, possui vantagens e desvantagens que no presente trabalho são discutidas para o material estudado (espuma polimérica rígida de PVC, poli-cloreto de vinila, com estrutura de células fechada e densidade de 60kg/m³). Uma série de ensaios experimentais com bases em normas é realizada e os dados coletados são comparados com dados obtidos simultaneamente através de uma técnica de correlação de imagens. Todas as informações experimentais são confrontadas e associadas aos mecanismos de falha da espuma polimérica. Finalmente, os dados experimentais são utilizados nas identificações de parâmetros de modelos de material disponíveis em um programa comercial de elementos finitos - ABAQUS. Com os modelos de material calibrados, o presente trabalho investiga a representatividade e as limitações dos mesmos quando aplicados a estruturas aeronáuticas submetidas a cargas localizadas, monotônicas ou não. Observou-se que há uma forte dependência da resposta macroscópica da espuma com sua estrutura celular quando submetida a cargas localizadas e/ou não-monotônicas. Ademais, o uso de modelos de material simplificados, e/ou com hipóteses de implementação, gera resultados duvidosos quando estes modelos são aplicados a materiais celulares com respostas complexas (mecanismos micro-mecânicos, anisotropia, viscosidade, etc.). Todavia, o presente trabalho mostra que uma calibração estratégica relevando as hipóteses de implementação e as limitações do modelo de material, fornece bons resultados macroscópicos que são fortemente influenciados pelos mecanismos de falha micro-mecânicos.
Aircraft structures are mostly made of composite material in order to achieve the specifications of a project. Among these structures one highlights the sandwich structure. The usage of this structure requires extensive studies on new materials as well as on the application of these very materials. A special attention for the cores material of these structures is needed because it is in fact a cellular structure, as the polymeric foams. This dissertation seeks to concatenate the literature and practice, studying the calibration of material models to describe the mechanical behavior of polymeric foams, as well as to analyse their potentials and limitations. These foams are cellular structures whose failure mechanisms comprise micro and macro responses. The identification and quantification of these behaviors can be done through micro-mechanical or phenomenological (macro-mechanical) material models along with experimental tests and analyses of both the cellular material and the structure in which this material is used. Each approach, micro or macro, has advantages and disadvantages that in the present work are discussed for the studied material (PVC, poly-vinyl-chloride, rigid closed-cell polymeric foam with a density of 60kg/m³). A series of experimental tests based on standard procedures are carried out and the data collected are compared with data obtained simultaneously through an image correlation technique. All the experimental information are confronted and associated to the failure mechanisms of the polymeric foam. Finally, the experimental data are used for the identification of material models parameters, currently available in the commercial finite elements software - ABAQUS. With the material models calibrated, the present work investigates the representativeness and the limitations of these very models when applied to aircraft structures submitted to monotonic or not localized loads. One has observed that there is a strong dependence of the foams macroscopic response with its cellular structure when it is submitted to localized and/or non-monotonic loads. Moreover, the usage of simplified material models, and/or with some implementation hypotheses, renders doubtful results when these models are applied to cellular materials with complex responses (micro-mechanical mechanisms, anisotropy, viscosity, etc.). Nevertheless, the present work shows that a strategic calibration taking into account the implementation hypotheses and the limitations of the material model, yields good macroscopic results that are strongly influenced by the micro-mechanical failure mechanisms.

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11

Tardieu, Jean-Luc. "Caractérisation d'anticorps monoclonaux dirigés contre l'ACTH : mise au point d'un test IRMA". Compiègne, 1992. http://www.theses.fr/1992COMPD549.

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Ce travail porte sur la sélection d'anticorps monoclonaux en vue de la mise au point d'un dosage immunoradiométrique de la corticotrophine (ACTH). Afin d'obtenir un immunogène efficace, nous avons réalisé des couplages d'ACTH entière et de différents fragments N et C terminaux sur des protéines porteuses telles l'albumine bovine, la thyroglobuline ou l'hémocyanine. Une étude systématique de ces différents immunogènes a ensuite été réalisée. De bonnes réponses immunitaires ont été obtenues chez la souris. Mais cependant les anticorps monoclonaux produits chez cette espèce n'ont pas été de haute affinité. Des immunisations effectuées chez le rat ont permis d'obtenir de bonnes réponses immunitaires. Les travaux réalisés sur les hétérohybrides nous ont incités à envisager la fusion de rate de ces animaux avec le myélome de souris X-63. Nous avons optimisé ce protocole en étudiant tous les paramètres de la fusion lymphocytaire entre ces deux espèces. Cette mise au point a permis de caractériser des anticorps monoclonaux de rat dirigés contre quatre épitropes de l'ACTH (ACTH 1-6, ACTH 6-13, ACTH 18-24 et ACTH 34-39). Tous ces anticorps ont été testés de manière systématique afin de vérifier leur possibilité d'utilisation soit en phase solide, soit comme traceur radiomarqué. Pour l'étude de phases solides, nous avons fait varier le type de polymère ainsi que la quantité d'anticorps utilisé. Le copolymère ABS (Acrylonitrile Butadiène Styrène) permet d'augmenter le signal de plus de 10 %. Par ailleurs, le processus de revêtement du polymère est complété par une phase de désorption à 37°C ce qui permet de gagner 45 % de signal spécifique. Nous avons également montre l'intérêt d'utiliser en phase solide deux anticorps N terminaux (ACN3 et ACN35) reconnaissant des épitopes différents, et comme traceur un troisième anticorps (ACC17) qui reste stable à 20 microcurie/microgramme pendant plus de 40 jours à 20° C. Une limite de détection proche de 4 pg/ml est obtenue. La caractérisation de ces anticorps ouvre donc la voie au développement d'une trousse de dosage de l'ACTH présentant une bonne sensibilité.

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12

Riccò, Federico. "Design and engineering of 100% polyurethane sandwich structure for sanitary application". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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This work is based on a team research project developed at DUNA-Corradini SpA. The project consists in design and characterization of innovative composite structure, used principally for the production of shower trays for sanitary application. Starting from a set of existing PUR materials trademark of DUNA-Corradini SpA, DUNAPOL® T products, we worked to combine them to obtain a new composite sandwich structure for 100% PU based shower trays manufacturing, avoiding the use of glass fibres and styrene-based materials in the final product. The final prototype must be able to satisfy costumer’s requirements in terms of mechanical properties, weight, and production cost. A brief literature review is presented, regarding polyurethane chemistry, studied materials and sandwich structures. Mechanical tests were performed to study mechanical behaviour and to classify DUNAPOL® T products for sandwich production. Impact tests were performed on different sandwich structures to identify best materials for both “skin” and “core”, studying the main parameters that affect impact resistance of polyurethanes. Optimization procedure was applied working on PU formulation, core density and skin thickness principally. Materials for sandwich structures production able to withstand requirements in terms of impact resistance, were identified. Final sandwich structure obtained is characterized by high weight saving (up to 60%), good dimensional stability and low cost related to raw materials used. Finally, production of shower tray prototypes with different coatings was performed. Production process suitable for 100% PU-based shower trays was defined, exploiting DUNA-Corradini know-how in PU industry. Production process steps are then validated at DUNA-Corradini laboratories, to obtain shower tray prototypes. Then, a FMEA, failure mode and effect analysis, is applied on the production process considered, based on sandwich and shower tray production carried out in laboratory.

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13

Oluwabusi, Oludare E. "Assessing the In-plane Shear Failure of GFRP Laminates and Sandwich Structures". University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1544528074090494.

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Cornillon, Amandine. "Test de génotypage plaquettaire in vitro à base de sandwichs de microparticules biofonctionnalisées : détection par capteur de fluorescence à ondes évanescentes, imagerie de fluorescence et cytométrie en flux". Thèse, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/6024.

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Résumé : Cette thèse porte sur l’élaboration d’un outil de capture d’ADN permettant d’identifier une mutation génétique (SNP) grâce à la formation de sandwichs avec des particules de carboxylatex biofonctionnalisées avec des oligonucléotides couplée à une détection de la fluorescence. Le modèle biologique choisi pour ce projet est le génotypage plaquettaire et plus particulièrement la recherche du gène biallélique HPA-1. Le principal objectif de ce travail a été d’optimiser un outil de capture préalablement développé dans l’équipe (Trévisan, 2011) afin de réduire le nombre d’étapes et de simplifier la mise en œuvre globale du test en modifiant les interactions moléculaires utilisée pour capturer l’ADN cible et en utilisant des particules fluorescentes comme élément de détection. En présence d’ADN cible, des sandwichs sont formés entre les particules fluorescentes et les particules magnétiques biofonctionnalisées. Ces sandwichs sont purifiés par séparation magnétique et la fluorescence est détectée par trois méthodes : la cytométrie en flux, l’imagerie de fluorescence et l’Evareader (détection par ondes évanescentes). Dans un premier temps, les paramètres de fonctionnalisation chimique et biologique des différentes particules (magnétiques et fluorescentes) ont été déterminés et optimisés ainsi que les conditions d’hybridation pour la capture de l’ADN cible. Ensuite, la formation des sandwichs et leur détection ont été suivies par des mesures de fluorescence en utilisant trois méthodes différentes : la cytométrie en flux, l’imagerie de fluorescence et l’Evareader (capteur à ondes évanescentes). Les résultats obtenus avec les différentes méthodes de détection sont concordants et montrent que l’outil de capture d’ADN développé permet de capturer la cible synthétique (oligonucléotide) HPA-1 en réduisant le temps d’analyse de 45 min. Dans nos conditions, le test permet de discriminer l’allèle a de l’allèle b du gène HPA-1 qui ne diffère que d’un nucléotide. Le rapport des signaux de fluorescence issus du sandwich spécifique et du sandwich non spécifique est d’environ 2,5 à 3. Ce rapport devra être amélioré par la suite, en optimisant les conditions de formation des sandwichs. La prochaine étape consistera à optimiser le système de capture d’ADN développé pour gagner en spécificité et déterminer la limite de détection du test. Ce test devra également être validé avec des échantillons biologiques. A plus long terme, la fluorescence pourra être détectée par un photodétecteur miniaturisé actuellement développé à l’Université de Sherbrooke. Des études préliminaires présentées dans ce manuscrit montrent les potentialités de ce nouveau transducteur. // Abstract : This thesis is about the development of a new assay to capture DNA. This assay is based on the formation of sandwiches between biofunctionnalized with oligonucleotides carboxylatex microparticles combined with fluorescence detection. It should be able to discriminate single nucleotide polymorphism (SNP). This assay is designed to be applied to platelet genotyping for the research of the gene HPA-1. The main goal of this work was to improve an assay previously developed (Trévisan, 2011) by INL and EFS Rhône-Alpes. The objectives are to reduce the number of steps and to simplify the test. To do so, the molecular interactions used in order to capture target DNA are modified and fluorescent microparticles are used for the detection. In the presence of target DNA, sandwiches are formed between both biofunctionnalized fluorescent and magnetic particles. Those sandwiches are purified through magnetic separation. Then, fluorescence is detected by three methods: flow cytometry, fluorescence imaging and Evareader (detection with an evanescent wave). First, chemical and biological parameters for the functionalization of the different particles (magnetic and fluorescent) are determined. The conditions for the capture of target DNA were optimized. Then, the formation and the detection of the sandwiches were estimated by measuring the fluorescence using three different methods: flow cytometry, fluorescence imaging and Evareader. The results obtained with the three methods are consistent. They show that the new system enables to capture synthetic target (oligonucleotide) HPA-1 with a reduction of total time analysis of 45 min. In our conditions, SNP can be discriminated for HPA-1 gene. For this discrimination, the fluorescence signal ratio about 2.5 to 3. This ratio should be improved by optimizing the conditions of sandwiches formation. Next step will consist in the optimization of the system developed to capture DNA in order to gain specificity and to determine the limit of detection. This test should also be validated with biological samples. In the long term, fluorescence could be detected by a miniaturized photodetector developed in the University of Sherbrook. Preliminary studies presented in this manuscript show the potentialities of this new transducer.

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15

Flor, Felipe Rendeiro. "Damage monitoring in composite structures via vibration based method: metal-composite bonded joints and sandwich structures". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-04042016-161659/.

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The present document covers the studies over Structural Health Monitoring systems via vibration based methods. The topic is organized in two parallel studies. The first one analyzes the integrity of metal-composite single lap bonded joints. The second one approaches similar analyses for sandwich structures. The monitoring was made by investigating the dynamic response both computationally and experimentally to verify the reliability of applying vibration based SHM procedures, specifically with the objective of identifying the presence of debonding damage. The dynamic responses were obtained via accelerometers and piezoelectric sensors placed on top of the investigated structures (on the outward surface). The purpose for the accelerometers is to provide reference data for the analyses involving the piezoelectric sensors. Different metrics of damage identification were investigated, all working over a determined frequency range. They quantify the damage by analyzing either the magnitudes or phase angles of the dynamic responses among the undamaged and damage structures. This present work proposed modifications to some methodologies of damage quantification found in the literature and compared the results. The new metrics offered more reliable values for the damage quantification on several of the analyses. It was verified that the metrics are valid for the scenarios observed in the present study. The experimental analyses showed also the influence on the dynamic response due to the position of small elastomeric elements. In regards to the finite element analyses, the computational models showed similar results to the experimental data, the more accurate ones being the models for the bonded joints. For the computational models, improvements can be applied into the piezoelectric sensor (e.g. by using new finite element formulations), as well as the region of debonding (e.g. by using contact algorithms). It is important to highlight that the elastic properties of the skins for the sandwich structure were obtained by the literature, so the model can be improved in the future by applying properties obtained experimentally.
Esta dissertação aborda os estudos realizados no campo de Sistemas de Monitoramento da Integridade Estrutural por meio de métodos baseados em vibrações. O tópico abordado é organizado em dois estudos paralelos. O primeiro é relativo ao monitoramento da integridade de juntas coladas metal-compósito. O segundo versa sobre análises semelhantes em estruturas sanduíche. O monitoramento foi executado através das análises das assinaturas dinâmicas das estruturas, tanto computacionalmente quanto experimentalmente, visando avaliar a capacidade de metodologias vibracionais de SHM em detectar dano de descolamento. As respostas dinâmicas foram obtidas por meio de acelerômetros e sensores piezelétricos dispostos sobre a superfície das estruturas avaliadas. Os acelerômetros fornecem dados de referência para as análises realizadas com base nas respostas do sensor piezelétrico. Diferentes métricas de identificação de dano são abordadas, sendo que todas estão baseadas em análise no domínio da frequência, utilizando parâmetros de magnitude ou ângulo de fase das estruturas danificadas e intactas. O presente trabalho propôs alterações em algumas das metodologias encontradas na literatura e comparou os resultados das métricas originais com as modificadas. As métricas modificadas apresentaram resultados mais consistentes em vários cenários de análise. Constatou-se também que as métricas abordadas mostram-se válidas para os casos observados no presente estudo. As análises experimentais também evidenciaram a influência na assinatura dinâmica da estrutura sanduíche causada pelo posicionamento de pequenos elementos elastoméricos. Com relação às análises via elementos finitos, os modelos computacionais apresentaram resultados similares aos obtidos experimentalmente, sendo os da junta colada os mais precisos. Tais modelos computacionais podem ser melhorados no futuro por meio de uma modelagem mais detalhada dos elementos piezelétricos (por exemplo: por meio de novas formulações), como também da região de descolamento (por exemplo: por meio da implementação de algoritmos de contato). Deve-se ressaltar também que as propriedades elásticas das lâminas externas da estrutura sanduíche foram obtidas da literatura, assim sendo, o modelo poderá ser melhorado em estudos futuros por meio do emprego de propriedades obtidas experimentalmente.

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16

Cornillon, Amandine. "Test de génotypage plaquettaire in vitro à base de sandwich de microparticules biofonctionnalisées : Détection par capteur de fluorescence à ondes évanescentes, imagerie de fluorescence et cytométrie en flux". Thesis, Ecully, Ecole centrale de Lyon, 2014. http://www.theses.fr/2014ECDL0052/document.

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Cette thèse porte sur l’élaboration d’un outil de capture d’ADN permettant d’identifier une mutation génétique (SNP) grâce à la formation de sandwichs avec des particules de carboxylatex biofonctionnalisées avec des oligonucléotides couplée à une détection de la fluorescence. Le modèle biologique choisi pour ce projet est le génotypage plaquettaire et plus particulièrement la recherche du gène biallélique HPA-1. Le principal objectif de ce travail a été d’optimiser un outil de capture préalablement développé dans l’équipe (Trévisan, 2011) afin de réduire le nombre d’étapes et de simplifier la mise en oeuvre globale du test en modifiant les interactions moléculaires utilisée pour capturer l’ADN cible et en utilisant des particules fluorescentes comme élément de détection. En présence d’ADN cible, des sandwichs sont formés entre les particules fluorescentes et les particules magnétiques biofonctionnalisées. Ces sandwichs sont purifiés par séparation magnétique et la fluorescence est détectée par trois méthodes : la cytométrie en flux, l’imagerie de fluorescence et l’Evareader (détection par ondes évanescentes). Dans un premier temps, les paramètres de fonctionnalisation chimique et biologique des différentes particules (magnétiques et fluorescentes) ont été déterminés et optimisés ainsi que les conditions d’hybridation pour la capture de l’ADN cible. Ensuite, la formation des sandwichs et leur détection ont été suivies par des mesures de fluorescence en utilisant trois méthodes différentes : la cytométrie en flux, l’imagerie de fluorescence et l’Evareader (capteur à ondes évanescentes). Les résultats obtenus avec les différentes méthodes de détection sont concordants et montrent que l’outil de capture d’ADN développé permet de capturer la cible synthétique (oligonucléotide) HPA-1 en réduisant le temps d’analyse de 45 min. Dans nos conditions, le test permet de discriminer l’allèle a de l’allèle b du gène HPA-1 qui ne diffère que d’un nucléotide. Le rapport des signaux de fluorescence issus du sandwich spécifique et du sandwich non spécifique est d’environ 2,5 à 3. Ce rapport devra être amélioré par la suite, en optimisant les conditions de formation des sandwichs. La prochaine étape consistera à optimiser le système de capture d’ADN développé pour gagner en spécificité et déterminer la limite de détection du test. Ce test devra également être validé avec des échantillons biologiques. A plus long terme, la fluorescence pourra être détectée par un photodétecteur miniaturisé actuellement développé à l’Université de Sherbrooke. Des études préliminaires présentées dans ce manuscrit montrent les potentialités de ce nouveau transducteur
This thesis is about the development of a new assay to capture DNA. This assay is based on the formation of sandwiches between biofunctionnalized with oligonucleotides carboxylatex microparticles combined with fluorescence detection. It should be able to discriminate single nucleotide polymorphism (SNP). This assay is designed to be applied to platelet genotyping for the research of the gene HPA-1. The main goal of this work was to improve an assay previously developed (Trévisan, 2011) by INL and EFS Rhône-Alpes. The objectives are to reduce the number of steps and to simplify the test. To do so, the molecular interactions used in order to capture target DNA are modified and fluorescent microparticles are used for the detection. In the presence of target DNA, sandwiches are formed between both biofunctionnalized fluorescent and magnetic particles. Those sandwiches are purified through magnetic separation. Then, fluorescence is detected by three methods: flow cytometry, fluorescence imaging and Evareader (detection with an evanescent wave). First, chemical and biological parameters for the functionalization of the different particles (magnetic and fluorescent) are determined. The conditions for the capture of target DNA were optimized. Then, the formation and the detection of the sandwiches were estimated by measuring the fluorescence using three different methods: flow cytometry, fluorescence imaging and Evareader. The results obtained with the three methods are consistent. They show that the new system enables to capture synthetic target (oligonucleotide) HPA-1 with a reduction of total time analysis of 45 min. In our conditions, SNP can be discriminated for HPA-1 gene. For this discrimination, the fluorescence signal ratio about 2.5 to 3. This ratio should be improved by optimizing the conditions of sandwiches formation. Next step will consist in the optimization of the system developed to capture DNA in order to gain specificity and to determine the limit of detection. This test should also be validated with biological samples. In the long term, fluorescence could be detected by a miniaturized photodetector developed in the University of Sherbrook. Preliminary studies presented in this manuscript show the potentialities of this new transducer

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17

Bhustalimath, Sanhgarsh. "Development and verificationof a method to determine theshear properties of Hybrix core". Thesis, KTH, Lättkonstruktioner, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-290084.

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This thesis helps develop a material model for a novel Fiber Core SandwichSheet construction. A test method was used to determine the mechanicalproperties of the sandwich material. Standard three point bendingtests coupled with digital image correlation was used. Results wereextracted from the digital image data. These results supplemented thedevelopment and tuning of an FE model of the sandwich material. Conclusionswere drawn about the feasibility of the method in studying sucha material.
Denna avhandling genomfördes mot utvecklingen av en homogeniseradmaterialmodell för en ny sandwich-konstruktion med fiberkärna. En testmetodanvändes för att bestämma de mekaniska egenskaperna hos sandwichmaterialet.Testmetoden involverade trepunkts i kombination meddigital bildkorrelation. Resultaten extraherades från den digitala bilddatanvid genomförande av trepunkts. Dessa resultat användes utvecklingenav en FE-modell av sandwichmaterialet. Slutsatser drogs om tillämplighetenav metoden för att studera ett sådant material.

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18

Webster, Keith Gordon. "Investigation of Close Proximity Underwater Explosion Effects on a Ship-Like Structure Using the Multi-Material Arbitrary Lagrangian Eulerian Finite Element Method". Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31077.

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This thesis investigates the characteristics of a close proximity underwater explosion and its effect on a ship-like structure. Finite element model tests are conducted to verify and validate the propagation of a pressure wave generated by an underwater explosion through a fluid medium, and the transmission of the pressure wave in the fluid to a structure using the Multi-Material Arbitrary Lagrangian/Eulerian method. A one dimensional case modeling the detonation of a spherical TNT charge underwater is investigated. Three dimensional cases modeling the detonation of an underwater spherical TNT charge, and US Navy Blast Test cases modeling a shape charge and a circular steel plate, and a shape charge and a Sandwich Plate System (SPS) are also investigated. This thesis provides evidence that existing tools and methodologies have some capability for predicting early-time/close proximity underwater explosion effects, but are insufficient for analyses beyond the arrival of the initial shock wave. This thesis shows that a true infinite boundary condition, a modified Gruneisen equation of state near the charge, and the ability to capture shock without a very small element size is needed in order to provide a sufficient means for predicting early-time/close proximity underwater explosion effects beyond the arrival of the initial shock wave.
Master of Science

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19

León, janampa Nancy. "Development of a test associated with magnetic nanoparticles for the diagnosis of tuberculosis". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0272.

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Mycobacterium tuberculosis provoque l'une des maladies qui présentent le taux de mortalité et de morbidité le plus élevé des Amériques et du monde. Dans les pays en développement, le diagnostic de la tuberculose (TB) repose sur la microscopie des frottis et des cultures bactériologiques. La première méthode a une faible sensibilité et la seconde met plusieurs semaines à atteindre un diagnostic de confirmation. L'absence de diagnostic rapide compromet les efforts de lutte contre la tuberculose, favorisant ainsi sa transmission à la population vulnérable. Actuellement, les nanoparticules magnétiques (MNP) fonctionnalisées par des biomolécules sont utilisées en biomédecine, en raison de leurs propriétés magnétiques, électriques et optiques. De cette manière, en appliquant des champs magnétiques externes, les MNP bio-fonctionnalisées sont utilisées pour détecter et concentrer les cellules et les biomolécules à partir d'échantillons biologiques.Dans ce travail, nous présentons la synthèse, la caractérisation et la bio-fonctionnalisation de nanoparticules magnétiques afin de développer un test ELISA en sandwich associé aux MNP, afin de détecter les antigènes de M. tuberculosis. À cette fin, des nanoparticules magnétiques ont été synthétisées par une méthode de co-précipitation. La surface des MNP a été amino-silanisée (MNP@Si@NH2) et caractérisée par des méthodes physico-chimiques.Les antigènes MTB évalués dans cette étude étaient: Hsp16.3, CFP10, ESAT6, MTC28, MPT64, protéine de 38 kDa, Ag85B et MoeX. Le clonage et l'expression de protéines recombinantes ont été réalisés dans le système de E. coli BL21 (DE3) pLysS. Des anticorps polyclonaux ont été produits chez des lapins Nouvelle-Zélande et des souris BALB/C, préalablement immunisés avec des antigènes recombinants purifiés. Des anticorps spécifiques (ab) ont été immobilisés sur les surfaces des MNP amino-silanisées. Les MNP@Si@ab ont été associées dans un test ELISA sandwich colorimétrique pour capturer et détecter les antigènes natifs du MTB à partir d’échantillons d’expectorations.La XRD, la spectroscopie Mössbauer, le potentiel zêta, la TEM et le FTIR ont validé l'obtention des MNP montrant un diamètre de cristal de diffraction de ~ 12,5 nm (10,48 ± 2,56 nm), une charge nette superficielle de +23,57 ± 2,87 mV, des profils caractéristiques de magnétite et une structure sphérique. De plus, une saturation en aimantation de 37,06 emu.g-1 a été observée. Pour la fonctionnalisation des surfaces de nanoparticules avec des anticorps, une méthode via l'utilisation d'ester activé (agent de couplage EDC/NHS) a été utilisée pour la formation de liaisons peptidiques. Des paramètres tels que le temps d'incubation, la concentration des agents de couplage et le niveau de saturation de surface des MNP amines silanisées (MNP@Si@NH2) ont déjà été standardisés.Enfin, des anticorps fonctionnalisés sur des MNP ont été utilisés pour capturer et détecter les antigènes recombinants et natifs de M. tuberculosis dans un test sandwich ELISA-MNP@Si@ab (dans un temps de réaction <4 h). Les antigènes ESAT6 et CFP10 ont été mieux différenciés dans les expectorations des patients atteints de tuberculose (fold value ~ 1,8). L'utilisation de MNP@Si@ab a amélioré la détection des antigènes du MTB dans des échantillons biologiques. Nos résultats sont encourageants, mais des évaluations supplémentaires sont nécessaire telles que la détermination de réactions croisées avec des échantillons d'expectorations provenant de patients atteints d'autres infections, la réalisation du test avec les expectorations fraîches de patients tuberculeux et la détermination de la sensibilité et de la spécificité de la méthode
Mycobacterium tuberculosis causes one of the diseases with the highest mortality and morbidity rate in the Americas and around the world. In developing countries, the diagnosis of tuberculosis (TB) is based on smear microscopy and bacteriological cultures. The first method has low sensitivity, and the second take several weeks to reach a confirmatory diagnosis. The lack of a rapid diagnosis compromises the efforts to control TB, favoring its transmission to the susceptible population. Currently, magnetic nanoparticles (MNPs) functionalized with biomolecules have been used in biomedicine, due the magnetic, electrical and optical properties. In this way, applying external magnetic fields, bio-functionalized MNPs is used to detect and concentrate cells and biomolecules from biological samples.In this work we present the synthesis, characterization and bio-functionalization of magnetic nanoparticles, to develop a sandwich ELISA assay associated to MNPs to detect antigens from M. tuberculosis. For this purpose, magnetic nanoparticles were synthesized by co-precipitation method. The MNP surface was amine-silanized (MNP@Si@NH2) and characterized by physical-chemical methods.The MTB antigens evaluated in this study were: Hsp16.3, CFP10, ESAT6, MTC28, MPT64, 38 kDa protein, Ag85B and MoeX. Cloning ad expression of recombinant proteins were made in E. coli BL21 (DE3) pLysS system. Polyclonal antibodies were produced in New Zealand rabbits and BALB/C mice, previously immunized with purified recombinant antigens. Specific antibodies (ab) were immobilized in the amine-silanized MNP surfaces. The MNP@Si@ab were associated in a colorimetric sandwich ELISA assay to capture and detect native MTB antigens from sputum samples.The XRD, Mössbauer spectroscopy, zeta potential, TEM and FTIR demonstrated the successful preparation of the MNPs showing a diffraction crystal diameter of ~12.5 nm (10.48 ± 2.56 nm), superficial net charge of ᶎ: +23.57 ± 2.87 mV, characteristic patterns of magnetite and a spherical structure. Additionally, a magnetization saturation of 37.06 emu.g-1 was observed. For the functionalization of nanoparticle surfaces with antibodies, active ester method (coupling agent EDC/NHS) were used for peptide bond formation. Parameters such as time of incubation, concentration of coupling agents and surface saturation level of amine-silanized MNPs (MNP@Si@NH2), were previously standardized.Finally, antibody functionalized on MNPs were used to capture and detect recombinant and native M. tuberculosis antigens in an ELISA-MNP@Si@ab sandwich test (in a reaction time <4 h). The ESAT6 and CFP10 antigens were better discriminated in sputum pooles from patients with TB (fold value ~ 1.8). The use of MNP@Si@ab improved the detection of MTB antigens in biological samples. Our results are encouraging, but the essay requires additional evaluations such as determining cross-reactions with sputum samples from patients with other infections, performing the test with fresh sputum of TB patients, and determining the sensitivity and specificity of the method
Mycobacterium tuberculosis causa una de las enfermedades con la tasa más alta de mortalidad y morbilidad en las Américas y en todo el mundo. En países en vías de desarrollo, el diagnóstico de tuberculosis (TB) se basa en microscopía de frotis y cultivos bacteriológicos. El primer método tiene baja sensibilidad y el segundo toma varias semanas para llegar a un diagnóstico confirmatorio. La falta de un diagnóstico rápido compromete los esfuerzos para controlar la TB, lo que favorece su transmisión a la población susceptible. Actualmente, las nanopartículas magnéticas (MNP) funcionalizadas con biomoléculas se han utilizado en biomedicina, debido a las propiedades magnéticas, eléctricas y ópticas. De esta manera, aplicando campos magnéticos externos, se utilizan MNP bio-funcionalizadas para detectar y concentrar células y biomoléculas a partir de muestras biológicas. En este trabajo presentamos la síntesis, caracterización y bio-funcionalización de las nanopartículas magnéticas para desarrollar un ensayo ELISA sándwich usando MNPs para detectar antígenos de M. tuberculosis. Para este propósito, las nanopartículas magnéticas fueron sintetizadas por el método de co-precipitación. La superficie de MNP fue amino-silanizada (MNP@Si@NH2) y se caracterizada por métodos físico y químicos. Los antígenos de MTB evaluados en este estudio fueron: Hsp16.3, CFP10, ESAT6, MTC28, MPT64, proteína de 38 kDa, Ag85B y MoeX. La clonación y la expresión de las proteínas recombinantes se realizaron en el sistema de E. coli BL21 (DE3) pLysS. Se produjeron anticuerpos policlonales en conejos de Nueva Zelanda y ratones BALB/C, inmunizados previamente con antígenos recombinantes purificados. Se inmovilizaron anticuerpos específicos (ab) en las superficies de MNP amino-silanizadas (MNP@Si@ab). El MNP@Si@ab fue utilizado en un ensayo ELISA sándwich colorimétrico para capturar y detectar antígenos de MTB nativos en muestras de esputo. La XRD, espectroscopia de Mössbauer, la potencial zeta, TEM y FTIR demostraron la preparación exitosa de los MNP, el cual mostró un diámetro de difracción del cristal de ~ 12.5 nm (10.48 ± 2.56 nm), carga neta superficial de ᶎ: +23.57 ± 2.87 mV, patrones característicos de magnetita y una estructura esférica. Además, una saturación de magnetización de 37.06 emu.g-1 fue observada. Para la funcionalización de superficies de nanopartículas con anticuerpos, se utilizó el método del éster activo para la formación de enlaces peptídicos. Parámetros tales como el tiempo de incubación, la concentración de los agentes de acoplamiento y el nivel de saturación de la superficie de las MNPs aminosilanizadas (MNP@Si@NH2) fueron estandarizadas. Finalmente, se usaron MNP funcionalizados con anticuerpos para capturar y detectar antígenos nativos y recombinantes de M. tuberculosis en una prueba sándwich de ELISA-MNP@Si@ab en un tiempo de reacción <4 h. Los antígenos ESAT6 y CFP10 se discriminaron mejor en las muestras de esputo de los pacientes con TB (fold value ~ 1,8). El uso de MNP@Si@ab mejoró la detección de antígenos de MTB en muestras biológicas con respecto a un sELISA convencional. Nuestros resultados son alentadores, pero el ensayo requiere evaluaciones adicionales, como determinar reacciones cruzadas con muestras de esputo de pacientes con otras infecciones, realizar la prueba con esputo frescos de pacientes con TB y determinar la sensibilidad y especificidad clînica del método

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Portela, Alexandre Machado Aguiar. "Inspeção por ressonância magnética nuclear de painéis-sanduíche compósitos de grau aeronáutico". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-18012012-145718/.

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O presente trabalho objetivou desenvolver e implementar, em escala laboratorial, uma rotina experimental com base em Imageamento por Ressonância Magnética Nuclear (IRMN) de modo a verificar seu potencial como metodologia não-destrutiva aplicável à inspeção quali- e quantitativa de água e hidrocarbonetos líquidos aprisionados no interior de células de núcleos-colméia utilizados na confecção de painéis-sanduíche compósitos estruturais de grau aeronáutico. Tentativas foram também realizadas no sentido de se observarem e caracterizarem danos por amassamento de núcleos-colméia, assim como de se detectar a presença de resina polimérica na forma sólida, visando, desta feita, verificar o uso do IRMN na inspeção de componentes previamente reparados e/ou contendo excesso de resina por falha do processo de manufatura. Concluiu-se que IRMN é uma poderosa ferramenta para a detecção e a quantificação de líquidos puros e compostos, ricos em hidrogênio, contidos nas células de núcleos de amostras extraídas de painéis-sanduíche compósitos. O potencial do IRMN na identificação, e, portanto, na discriminação entre os diversos fluidos se mostrou bastante promissor, desde que se empreguem ferramentas de processamento e análise computadorizada de imagens a partir de programas computacionais de reconhecimento de padrões via redes neurais artificiais e/ou sistemas com base em conhecimento. A técnica de IRMN utilizada neste estudo não permitiu a captura de imagens de resina polimérica sólida, nem mesmo quando à esta foram adicionadas cargas de elementos intensificadores de sinais de RMN, tais como ferro e gadolíneo. Danos no núcleo-colméia tão pequenos quanto 1,0 mm de profundidade e 1,8 mm de diâmetro foram clara e inequivocamente imageados e delineados pela técnica IRMN, desde que estivessem permeados por fluido hidrogenado (ex. água). A quantificação de líquidos nos núcleos-colméia por intermédio de ferramentas computacionais simples (processadores e analisadores de imagens) foi muito bem sucedida no caso dos líquidos com relativamente alto ponto de fulgor, pois as massas fluidas se mantiveram constantes por períodos de tempo significativamente longos no interior das células analisadas.
This work intended to develop and implement in laboratorial scale an experimental routine funded in Nuclear Magnetic Resonance Imaging (NMRI) in order to verify its potential as a non-destructive methodology for quali- and quantitative inspection of liquid water and hydrocarbons entrapped in honeycomb core cells utilized to build up aeronautical grade structural composite sandwich panels. Attempts were also carried out to observe and characterize crush damage of honeycomb core, as well as to detect solid polymer resin towards the use of NMRI to assess previously repaired components and/or containing in excess resin amount due to manufacturing process faults. It has been concluded that NMRI is a powerful tool in detecting and quantifying hydrogen-rich pure and compound liquids contained in core cells of composite sandwich samples. The NMRI potential in identifying and, therefore, discriminating several fluids has shown very promising as long as computed image processing and analysis tools are employed from pattern recognition software via artificial neural networks and/or knowledge-based systems. The utilized NMRI technique failed in imaging solid polymer resin, even when the latter was loaded with NMR-signal intensifier elements such as iron and gadolinium. Honeycomb core damages as small as 1.0 mm in depth and 1.8 mm in diameter were clearly and unambiguously imaged and delineated by the NMRI technique since they were permeated with hydrogenated fluid (ex., water). The quantification of liquids in honeycomb cores by means of simple computational tools (image processor and analyzer) was very successful in case of relatively high flash point fluids, insofar as their masses remained constant within the analyzed cells for significantly long periods of time.

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Mendonça, Cristiane Gonçalves de. "Características das superfícies foliares de algumas plantas daninhas e estudo da absorção de translocação de 2,4-D em Memora peregrina (Miers) Sandwith". Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-22112004-163522/.

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O objetivo desta pesquisa foi avaliar a densidade estomática, a porcentagem de compostos polares e apolares das ceras epicuticulares e observar as características ultra-estruturais da cutícula foliar de Peschiera fuchsiaefolia (A. DC.) Miers, Vernonia polyanthes Less., Vernonia westiniana Less., Memora peregrina (Miers) Sandwith, Tecoma stans (L.) Juss. ex Kunth, Ipomoea grandifolia (Dammer) ODonell, Ipomoea purpurea (L.) Roth., Euphorbia heterophylla L., Sida rhombifolia L. e Sida glaziovii K. Schum.. Outro objetivo foi avaliar a absorção e translocação do herbicida 2,4-D radiomarcado em plantas de Memora peregrina. A densidade estomática foi determinada aderindo a epiderme foliar em lâmina de vidro. As ceras epicuticulares foram extraídas com clorofórmio e fracionadas em compostos apolar e polar usando uma coluna de sílica gel. A análise ultra-estrutural foi realizada por meio de Microscopia Eletrônica de Varredura. A absorção e a translocação do herbicida 14C 2,4-D foram determinadas no 2,4-D sozinho (DMA 806 BR) e na mistura de 2,4-D e picloram (DMA 806 BR+Padron), nos intervalos de tempo de 1, 2, 4, 8, 24 e 48 horas após as aplicações. P. fuchsiaefolia apresentou densidade estomática de 11,8 e 209,4 estômatos/mm2 de área foliar (adaxial e abaxial), tricomas curtos na superfície adaxial e 41,9 µg de cera/cm2 (88,8 % de compostos polares). A densidade estomática em V. polyanthes foi 36,5 e 99,7 estômatos/mm2 e em V. westiniana 45,2 e 154,9 estômatos/mm2. Em V. polyanthes encontrou-se 31,1 µg de cera/cm2 (15% compostos apolares e 85% polares), enquanto a espécie V. westiniana apresentou 42,9 µg de cera/cm2 (7,6% apolares e 92,4% de polares). A espécie M. peregrina apresentou 368,0 estômatos/mm2 na superfície abaxial e estavam ausentes na adaxial, enquanto que T. stans apresentou 9,7 estômatos/mm2 na adaxial e 78,2 na abaxial. A porcentagem de compostos polares foi 58,5% em M. peregrina, com 22,8 µg de cera/cm2 e T. stans apresentou 16,8 µg/cm2, sendo 59,5% compostos polares. A densidade estomática de I. grandifolia foi 44,0 estômatos/mm2 na adaxial e 156,0 na abaxial e na espécie I. purpurea foi 62,8 estômatos/mm2 na adaxial e 131,2 na abaxial. As espécies do gênero Ipomoea apresentaram maiores quantidades de compostos polares, tricomas unicelulares e ceras epicuticulares em forma de estrias nas superfícies adaxiais. A densidade estomática de E. heterophylla foi 140,5 estômatos/mm2 na superfície adaxial e 215,2 na abaxial, com depósito em forma de cristais e com 46,0 µg de cera/cm2 (48,9% compostos apolares e 51,1% polares). A densidade estomática de S. rhombifolia foi 101,1 estômatos/mm2 (adaxial) e 212,6 (abaxial), e em S. glaziovii foi 118,6 e 187,3 estômatos/mm2. As espécies S. rhombifolia e S. glaziovii apresentaram maiores porcentagens de compostos polares (75,9% e 62,1%, respectivamente). As porcentagens de absorção do 14C 2,4-D uma hora após a aplicação foram 8,22% e 9,63%, para os tratamentos com 2,4-D e 2,4-D + picloram, respectivamente. E 48 horas após a aplicação, a absorção foi 23,81% no tratamento 2,4-D e 24,26% com 2,4-D + picloram e deste total absorvido 98,44% permaneceu na folha tratada no tratamento com o 2,4-D e 99,50% quando se usou a mistura 2,4-D+picloram, caracterizando translocação muito pequena deste herbicida.
The objective of this research was to evaluate the stomatal density, the percentage of polar and apolar compounds of the epicuticular waxes and to observe the ultra-structural characteristics of the foliar cuticle of Peschiera fuchsiaefolia (A. DC.) Miers, Vernonia polyanthes Less., Vernonia westiniana Less., Memora peregrina (Miers) Sandwith, Tecoma stans (L.) Juss. ex Kunth, Ipomoea grandifolia (Dammer) ODonell, Ipomoea purpurea (L.) Roth., Euphorbia heterophylla L., Sida rhombifolia L. and Sida glaziovii K. Schum.. Other objective was to evaluate the absorption and translocation of the radiolabelled herbicide 2,4-D in plants of Memora peregrina. The stomatal density was determined by the impression of the foliar epidermis in sheet of glass. The epicuticular waxes were extracted with chloroform and they divided in apolar and polar compounds using a column of silica gel. The ultra-structural analysis was realized using the Scanning Electronic Microscopy. The absorption and translocation of the 14C 2,4-D were evaluated using the 2,4-D alone (DMA 806 BR) or the mixture of 2,4-D plus picloram (DMA 806 BR+Padron), in different time after the applications (1, 2, 4, 8, 24 and 48 hours). P. fuchsiaefolia presented stomatal density of 11.8 and 209.4 stomatas/mm2 of foliar area (adaxial and abaxial), short trichomes in the adaxial surface and 41.9 µg of wax/cm2 being 88.8% of polar compounds. The stomatal density in adaxial and abaxial surfaces of V. polyanthes was 36.5 and 99.7 stomatas/mm2, respectively, and in V. westiniana was 45.2 and 154.9 stomatas/mm2. In leaves of V. polyanthes were removed 31.1 µg of wax/cm2 (15.0% apolar compounds and 85.0% polar compounds), whereas in the specie V. westiniana were extracted 42.9 µg of wax/cm2 (7.6% apolar and 92.4% polar). The specie M. peregrina had 368.0 stomatas/mm2 in the abaxial surface and in to adaxial they were absent, in plants of T. stans were achieved 9.7 stomatas/mm2 in the adaxial surface and 78.2 in the abaxial. The percentage of polar compounds was 58.5% in M. peregrina, with 22,8 µg of wax/cm2 and the plants of T. stans presented 16.8 µg/cm2, being 59.5% of polar compounds. The stomatal density of I. grandifolia was 44.0 stomatas/mm2 in the adaxial and 156.0 in the abaxial and in the specie I. purpurea was 62.8 stomatas/mm2 and 131.2 in the abaxial. The species of the Ipomoea genus had great amounts of polar compounds, unicellular trichomes and epicuticular waxes in the form of ridge in the adaxial surfaces. The stomatal density of E. heterophylla was 140.5 stomatas/mm2 in at adaxial surface and 215.2 in the abaxial, with deposit in the form of crystals and with 46.0 µg of wax/cm2 (48.9% apolar compounds and 51.1% polar). The stomatal density of S. rhombifolia was 101.1 stomatas/mm2 (adaxial) and 212.6 (abaxial) and in S. glaziovii the stomatal density was 118.6 and 187.3 stomatas/mm2. The species S. rhombifolia and S. glaziovii presented great percentages of polar compounds, 75.9% and 62.1%, respectively. The percentage of absorption of the 14C 2,4-D one hour after the application were 8.22% and 9.63%, for the treatments with 2,4-D and 2,4-D + picloram, respectively. The absorption 48 hours after the application was 23.81% in the treatment with 2,4-D and 24.26% with 2,4-D+picloram. In this same interval of time, 98.44% absorbed total stayed in the treated leaf in the treatment with 2,4-D and 99.50% with mixture 2,4-D+picloram, then the translocation of this herbicide was considered insignificant.

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DE, LA PIERRE DES AMBROIS STEFANO. "Advanced joined materials development and their shear strength evaluation for aerospace, energy and structural applications". Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2845790.

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Marassa, Ana Maria. "Identificação de fonte sanguínea em dípteros da Família Culicidae, em áreas de epizootia da febre amarela silvestre". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/6/6132/tde-20072009-153444/.

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A importância em conhecer o padrão alimentar em mosquitos da Família Culicidae permite esclarecer alguns aspectos relacionados à transmissão de zoonoses e estimar o grau de contato humano-vetor que é fator relevante em estudos epidemiológicos. Com o objetivo de explorar o comportamento alimentar dessa Família, em área epizoótica de febre amarela silvestre, foram coletados exemplares nos municípios de Santo Antônio das Missões e Garruchos, Estado do Rio Grande do Sul. Fêmeas ingurgitadas foram obtidas por aspiração em ambiente de mata, no período de setembro de 2005 a abril de 2007 e identificadas segundo fonte de sangue ingerido através da técnica imunoenzimática ELISA de captura no sistema avidinabiotina. Foram testadas seis fontes de alimento: ave, bovino, eqüino, humano, macaco e rato. Os resultados obtidos mediante a padronização de anticorpos monoclonais possibilitaram demonstrar pela primeira vez o reconhecimento de sangue humano ingerido nesses mosquitos pelo emprego da subclasse IgG1 e comprovar a sensibilidade e especificidade da técnica ELISA de captura. No município de Santo Antônio das Missões, de um total de 190 amostras, 60,9% reagiram para sangue de boi, 23,6% para humano, 9,9% para ave, 1,9% para macaco e 3,7% para combinações de dois hospedeiros. Quanto às amostras referentes ao município de Garruchos, das 158 fêmeas capturadas na área Cachoeirinha pode-se observar reatividade para ave (16%), boi (29,6%), humano (36,8%), cavalo (4%), macaco (0,8%) e combinações de hospedeiros (12,8%), enquanto que para as 149 fêmeas pertencentes à área de São José, detectou-se sangue ingerido de boi em (51,5%), ave e humano (11,5%), macaco (6,2%), cavalo (0,8%) e mistos (18,5%). Aedes scapularis, Aedes crinifer, Culex (Culex) spp., Haemagogus leucocelaenus apresentaram maior número de fêmeas ingurgitadas nos dois municípios. Os resultados obtidos com Aedes scapularis sugerem ecletismo, conforme combinações detectadas em amostras de sangue de diferentes fontes. Haemagogus leucocelaenus apresentou a maior proporção de amostras contendo sangue humano em relação às demais fontes e essa característica traz implicações, por ser espécie incriminada na transmissão e por se tratar de área de ocorrência de epizootias de febre amarela.
The knowledge of mosquitoes Culicidae host feeding patterns permits to clarify some aspects related to zoonosis transmission and to estimate the degree of human-vector contact which is relevant in epidemiological studies. Aiming to explore the feeding behavior of these mosquitoes, specimens were collected in the municipalities of Santo Antônio das Missões and Garruchos, Rio Grande do Sul, an epizootic area of sylvatic yellow fever. Engorged females were collected by aspiration from forested areas from September 2005-April 2007 and their blood meals were identified using the avidin-biotin system of immunoenzymatic ELISA capture. Six blood meal sources were tested: bird, cattle, horse, human, monkey and rat. The result achieved with the species-specific IgG1 mAb was unprecedented for mosquito blood meal identification and reinforced the sensibility and specificity of the immunoenzymatic ELISA capture. Of the 190 samples from Santo Antônio das Missões, 60.9% reacted to cattle, 23.6% to human, 9.9% to bird, 1.9% to monkey and 3.7% to mixed blood meals. In Garruchos, of the 158 females collected in Cachoeirinha, 16.0% reacted to bird, 29.6% to cattle, 36.8% to human, 4.0% to horse, 0.8% to monkey and 12.8% to mixed blood, while of the 149 engorged females from São José, blood from cattle accounted for 51.5%, of blood identified, bird and human 11.5%, monkey 6.2%, horse 0.8% and mixed blood 18.5%. Blood engorged females of Aedes scapularis, Aedes crinifer, Culex (Culex) spp., Haemagogus leucocelaenus predominated in the two municipalities. The results obtained with Aedes scapularis suggests its eclecticism, according to the combinations of blood which were detected from different sources. Haemagogus leucocelaenus was found to have the highest proportion of samples containing human blood in comparison with other sources, which has implications, on account of being incriminated in the transmission and also for taking into consideration the outbreaks reported that underline the risk of yellow fever.

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Bertini, Alexandre Araújo. "Análise do comportamento à flexão de painéis sanduíche com faces de argamassa armada e núcleo de espuma rígida de poliuretano derivado de óleo de mamona". Universidade de São Paulo, 1995. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-24042018-122409/.

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Recentemente, tem se verificado aplicações de painéis sanduíche como elementos estruturais e não estruturais na Construção Civil, principalmente empregados em edificações. Painéis sanduíche, com faces de argamassa armada e núcleo de espuma rígida de poliuretano derivado de óleo de mamona, são estudados visando o emprego em edificações. O comportamento à flexão destes painéis, é estudado através de ensaios de flexão com vigas submetidas a carregamentos nos terços do vão. Alguns modelos teóricos para o cálculo do deslocamento são propostos e comparados com os deslocamentos obtidos nos ensaios. Ensaios de cisalhamento da espuma são feitos a fim de se determinar o seu módulo de deformação transversal, bem como a resistência ao cisalhamento. Obtém-se da análise dos resultados dos ensaios, parâmetros para projeto deste elemento.
Sandwich panels have been used as structural or nonstructural elements in the Civil Construction, mainly in building. A kind of sandwich panel, with ferrocement faces and stiff foam core of castor oil polyurethane, is studied aiming its use in building. The bending behavior of these panels is studied through bending tests with beams loaded at the third parts of the span. Some theoretical models for the deflection calculation are proposed and compared with the experimental values obtained in the tests. Shear tests on the polyurethane foam were done to determinate its shear modulus and its shear strength. Design parameters are obtained from the analysis of the experimental results.

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Bertini, Alexandre Araújo. "Estruturas tipo sanduíche com placas de argamassa projetada". Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-09062006-150602/.

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Elementos tipo sanduíche, com placas de argamassa projetada, têm sido utilizados na construção de edificações em alguns países, inclusive no Brasil, apresentando boas características de resistência mecânica, térmica e acústica. De maneira geral, a aplicação desse tipo de elemento tem se restringido a obras de edificações, sendo utilizado principalmente como painéis de fechamento, portantes ou não, existindo ainda um potencial a ser explorado em obras de infra-estrutura, tais como: muros de arrimo, canais, galerias e reservatórios de água. Apesar de ser um método utilizado na construção de edificações, existem dúvidas, tais como: resistência efetiva da argamassa projetada, colaboração entre as placas resistentes em função do tipo de núcleo, modo de combater os efeitos de retração da argamassa, etc. Apresenta-se neste trabalho um estudo sobre a resistência efetiva da argamassa projetada, no qual se obteve que a sua resistência é de aproximadamente 80% da resistência à compressão de corpos-de-prova cilíndricos. Realizaram-se ainda ensaios para analisar a ligação entre elementos tipo sanduíche e seu comportamento à flexão, que comprovam o bom desempenho estrutural. Acredita-se que essa técnica de construção sanduíche possa ser aplicada em obras de infra-estrutura de interesse social, trazendo vantagens tecnológicas e econômicas em relação a sistemas tradicionais
Sandwichtype elements, with plates made of projected mortar, have been used in the construction of buildings in some countries, including Brazil, showing expressive thermical, acoustical and mechanical strength characteristics. In general, the application of this kind of element have been limited to buildings, mainly used as cladding panels, with carrying load capacity or not, and have other potential uses in infra-structural works to be explored such as bearing walls, channels, and water reservoirs. Although it is a method that have been conventionally applied in the construction of buildings, there are uncertainties in some parameters, like the effective strength of the projected mortar, interaction between the plates related to the type of core, the mode against shrinkage of the mortar etc. It is showed in this work a study concerning the effective strength of the projected mortar. As a result of a series of tests in walls made of projected mortar, it is determined that the effective strength of the projected mortar is 80% of that one measured from cylindrical specimens in compression tests. As well, some tests have been executed to analise the bending behaviour and the connections between the plates of the sandwich-type specimens, which demonstrated a relatively high structural performance. It is believed that this technical solution can be well applied to public works of social interest, and can offer technological and economical advantages in contrast to the traditional systems

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Andrade, Bruna Fuzzer de. "PADRÕES NORMATIVOS, ENSAIOS EXPERIMENTAIS E ANÁLISE DA PERFORMANCE ACÚSTICA DE TELHAS SANDUÍCHE". Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/7920.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
In urban areas, where noise is significant, the facades and roofs must submit a performance capable of ensuring insulation required for the acoustic comfort of the users. The roof, although important elements of the envelope of buildings, has been little studied in Acoustics. The validity of ISO 15575 Residential Buildings - Performance impacted mainly the construction industry suppliers, who needed to characterize their products and systems. Also in 2015 came the NBR 16373 - tiles and thermoacoustic panels - Performance requirements. This Thesis aimed to establish a methodology to analyse the acoustic performance for sandwich tiles considering regulatory standards and experimental trials. It started from the requirements of ISO 16373 for performing absorption tests and sound transmission loss of sandwich type of shingle tiles + EPS. The experimental procedure used to determine the sound absorption coefficient (α) was the method of the reverberation chamber in a diffuse field standardized by ASTM C423. The results showed behaviour with greater absorption (0.29) in a narrow band around 250 Hz and stabilized above 1600 Hz, with values similar to 0.06. These factors mean rank 1 according to the NBR 16373, in other words, the worst performance scale. Regarding the sound insulation test, performed according to ISO 10140 in reverberation room, it was quantified the Weighted Sound Reduction Index, Rw = 20 dB, above the expected performance because resulted close to the performance of other more valued tile commercially. The information given on NBR 16373: 2015 for the experimental analysis of sandwich tile are very incomplete, so difficult the tests. To facilitate implementation, minimizing errors due to erroneous interpretations of the techniques involved standards, we established a specific analysis methodology for trials in shingles or tiles. Therefore, it is proposed that the adequacy of samples of the tests, the individual analysis of each material that compose the shingle and evaluation of the two faces of the composite tiles, in order that they may have different types of finish (liner, liner-film, perforated panel, among others) and therefore the analysis of the lower tile becomes effective in assisting in the determination of the acoustic conditioning of the interior environments. Another suggestion is the evaluation of the rain impact noise on tiles. Finally, we reiterate the importance of the technical product information are clear and complete, allowing consumers to obtain adequate acoustic performance in their buildings.
Em áreas urbanas, onde o ruído é significativo, as fachadas e coberturas devem apresentar um desempenho capaz de garantir a isolação necessária para o conforto acústico dos usuários. As coberturas, embora sejam elementos importantes da envoltória das edificações, tem sido pouco estudadas na área de Acústica. A vigência da NBR 15575 Edificações habitacionais Desempenho impactou, principalmente, o setor de fornecedores da construção civil, que necessitaram caracterizar seus produtos e sistemas. Além disso, em 2015, surgiu a NBR 16373 Telhas e painéis termoacústico Requisitos de desempenho. A presente Dissertação teve como objetivo principal estabelecer uma metodologia de análise da performance acústica para telhas sanduíche, considerando padrões normativos e ensaios experimentais. Partiu-se das exigências da NBR 16373 para a execução dos ensaios de absorção e perda de transmissão sonora das telhas sanduíche do tipo telha + EPS. O procedimento experimental utilizado para a determinação do Coeficiente de Absorção Sonora (α) foi o método da câmara reverberante em campo difuso, normatizado pela ASTM C423. Os resultados mostraram um comportamento com maior absorção (0,29) numa faixa estreita em torno de 250 Hz e uma estabilização acima de 1600 Hz, com valores similares a 0,06. Tais coeficientes significam classificação 1, de acordo com a NBR 16373, ou seja, o pior desempenho da escala. No que tange ao ensaio de isolamento sonoro, executado de acordo com a ISO 10140, em câmara reverberante, foi quantificado o Índice de Redução Sonora Ponderado, Rw= 20 dB, desempenho acima do esperado, pois resultou próximo ao desempenho de outra telha mais valorizada comercialmente. As informações constantes na NBR 16373:2015 para a análise experimental da telha sanduíche são muito incompletas, por isso dificultam a realização dos ensaios. Para facilitar a execução, minimizando os erros decorrentes de interpretações equivocadas das normas técnicas envolvidas, estabeleceu-se uma metodologia de análise específica para ensaios realizados em telhas ou coberturas. Assim, propõe-se a adequação das amostras dos ensaios, a análise individual de cada material que compõe a telha e a avaliação das duas faces das telhas compostas, tendo em vista que elas podem possuir diferentes tipos de acabamento (forro, forro-filme, painel perfurado, entre outros) e, por isso, a análise da parte inferior da telha torna-se eficaz no auxílio da determinação do condicionamento acústico no interior de ambientes. Outra sugestão é a avaliação do ruído de impacto da chuva em telhas. Por fim, reitera-se a importância de que as informações técnicas sobre os produtos sejam claras e completas, permitindo que os consumidores finais possam obter um adequado desempenho acústico em suas edificações.

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Bucňák, Ondřej. "Návrh demonstrátoru konstrukce z kompozitních materiálů pro kalibraci simulace pohlcení energie". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254336.

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This master thesis focuses on a scaled fuselage design made from composite material. The first part deals with a description of composite materials and used material models in an explicit FEM simulation. Two types of scaled structures were designed that were subjected to drop test. Test results were compared with FEM simulation. Finally the calibration of models was carried out.

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Junior, Mauricio Francisco Caliri. "Contribuição para teoria de placas: análises estruturais de compósitos laminados e estruturas sanduíches via formulações unificadas". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-26072016-101122/.

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Em engenharia, a quantidade de problemas geométricos complexos que precisam ser resolvidos empregando teorias de placas ou cascas é notável. Esta é a razão por que há tantas teorias que buscam simplificar os problemas tridimensionais em outros menos custosos computacionalmente. Além disso, o aumento atual do uso de estruturas sanduíche requer que as formulações bidimensionais sejam mais precisas. Esta tese, num primeiro momento, compila a maioria das teorias de placa, comentando as principais diferenças, vantagens e desvantagens de cada uma. As formulações bidimensionais de placas laminadas são classificadas principalmente de acordo com o tratamento da coordenada na direção normal a superfície da mesma: Camada Única Equivalente (ESL), ESL refinada (teorias Zig-Zag) e Teorias Discretas ou de Camada (LW). Cada uma destas teorias é revista juntamente com as hipóteses de placas que são feitas para cada uma das camadas ou para o laminado como um todo. Para resolver tais problemas estruturais em engenharia, métodos numéricos são normalmente utilizados. Portanto, num segundo momento, alguns métodos de solução são citados e revisados, mas o foco é dado ao Método dos Elementos Finitos (MEF). A contribuição deste trabalho consiste na implementação de um novo método de solução de compósitos laminados e estruturas sanduíche com base em um sistema unificado de Formulação Generalizada (GUF) via MEF. Um elemento quadrilátero de 4 nós foi desenvolvido e avaliado com um código de Elementos Finitos desenvolvido pelo presente autor. Os requisitos para continuidade do tipo C-1 são respeitados para a variável de deflexão da placa. Esse método é nomeado de Formulação Generalizada do Caliri (CGF). Resultados para placas isotrópicas, placas de laminado compósito e estruturas sanduíche consideradas finas ou espessas são comparados com dados da literatura e soluções via Abaqus. Os resultados obtidos ao longo da espessura reforçam a necessidade de soluções de placa não-lineares para placas espessas (laminadas ou não). Mostrou-se que as soluções estáticas e dinâmicas empregando o método proposto fornecem resultados coerentes quando comparados com outros métodos de solução. Dentre os diversos estudos de caso investigados, verificou-se que é possível se obter resultados com alta concordância. Para uma estrutura sanduíche com núcleo macio, o resultado de deslocamento previsto para um carregamento estático chega a 99.8% de concordância e o resultado de uma análise modal da mesma estrutura mostra uma concordância de 99.5% com os resultados de um modelo feito com elementos 3D em um programa comercial de elementos finitos.
In engineering, the amount of complex geometrical problems, which need to be solved by using plates and shells theories, is remarkable. This is the reason why there are so many plate and shell theories which attempt to simplify three dimensional problems into ones with low computational cost. Additionally, the current increasing use of sandwich structures requires that the two dimensional formulations be accurate enough. First, this thesis compiles most of the plate theories from the literature and quotes the main differences, advantages and weaknesses of each one. The bi-dimensional laminated plate formulations are mainly classified according to the treatment of the variable in the normal direction of the plate surface: Equivalent Single Layer (ESL), Refined ESL (Zig-Zag theories) and Layer-Wise (LW) theories. Each one of these theories is reviewed along with the plate hypotheses which are made for each ply and/or laminate. To solve such complex structural engineering problems, numerical methods are normally used. Second, few solution methods are reviewed and quoted, but focus is given to the Finite Element Method (FEM). The contribution of this work is the implementation of a new solution method for laminated composites and sandwich structures based on a Generalized Unified Formulation (GUF) via FEM. A quadrilateral 4-node element was developed and evaluated using in-house Finite Element program. The C-1 continuity requirements is fulfilled for the transversal displacement field variable. This method is tagged as Caliri\'s Generalized Formulation (CGF). Results for isotropic plates, laminated composite plates and sandwich structures for thin and thick laminates are compared with literature data and solutions via Abaqus. The through-the-thickness profile results reinforce the need for non-linear plate (laminated or not) solutions. It was shown that the static and dynamic solutions employing the proposed solution method yield coherent results when compared with other solution methods. Among the different case studies investigated, it was verified that it is possible to obtain results with high agreement. For a soft-core sandwich structure, the displacement result for a static loading is reported as high as 99.8% and the result of a modal analysis of the same structure shows an accuracy of 99.5%, comparing to the results from a 3D finite element model built with a commercial software.

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Veselý, Martin. "Příprava realizace výrobního a administrativního objektu v Moravanech". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392183.

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The diploma thesis deals with the elaboration of a building-technological project for the construction of a hall in Moravany u Brna. The work includes comprehensive studies of implementation including timetable, financial plans and technological regulations. It also deals with the design of the main building mechanisms, building equipment, control and test plan. There are also three drawings of the construction site equipment for the implementation stages.

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30

Sartori, Ana Paola. "Desenvolvimento e caracterização de compósitos sanduíche para isolamento térmico". reponame:Repositório Institucional da UCS, 2009. https://repositorio.ucs.br/handle/11338/453.

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Um painel sanduíche consiste essencialmente em duas faces, podendo inclusive possuir reforços metálicos e um núcleo formado normalmente por um polímero celular. As faces deste tipo de painel podem estar unidas por um adesivo estrutural, ou por espuma rígida de poliuretano (PU) injetado diretamente sobre os substratos, quando a união ocorrerá naturalmente. A propriedade de maior relevância que o painel sanduíche deve ter para o transporte de cargas congeladas (0ºC a -30ºC) ou refrigeradas (7ºC a 1ºC) é a condutividade térmica (k). Dentro deste contexto o objetivo deste trabalho foi propor e caracterizar painéis sanduíches que possam ser utilizados em câmaras frigoríficas. Este trabalho apresenta as seguintes alternativas para compósito sanduíche: amostra 1 (PRFV/PU/PRFV); amostra 2 (AG/PU/AG); amostra 3 (Frisado/PU/PRFV); e amostra 4 (Al/PU/Al), onde PRFV é poliéster reforçado com fibra de vidro, PU é espuma rígida de poliuretano, AG é aço galvanizado, Frisado é alumínio frisado, e Al é alumínio. Estes painéis foram caracterizados quanto às propriedades físico-mecânicas, térmicas, morfológicas e custo. Foi possível concluir que o sistema (AG/PU/AG) mostrou o melhor custo versus desempenho dentre os compósitos propostos.
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A sandwich panel consists essentially of two face sheets and may even have metal reinforcements and a core formed, usually by a cellular polymer. The faces of this type of panel may be joined by a structural adhesive or in cases where the core is a rigid polyurethane foam injected directly on the substrates the union will occur naturally. The most relevant property of the sandwich panels for the transport of frozen (0ºC a -30ºC) or chilled (7ºC a 1ºC) cargo is thermal conductivity (k). Within this context the objective of this work is to obtain and characterize sandwich panels which can be used in refrigerated chambers. This work presents four alternatives for composite sandwich, sample 1 (PRFV/PU/PRFV), sample 2 (AG/PU/AG), sample 3 (Al Crimpy/PU/PRFV) and sample 4 (Al /PU/Al), were PRFV is a glass fibre reinforced plastics, PU is a rigid polyurethane, AG is galvanized steel, Al Crimpy is crimpy aluminum and Al is aluminum. These composites were characterized by physicalmechanical, thermal, morphologic and cost. It could be concluded that the AG/PU/AG showed the best cost versus performance.

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31

Gajdoš, Nikola. "Stavebně technologický projekt montované haly v Olomouci". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-371916.

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In my diploma thesis I document the construction of administrative, commercial and warehouse building in Olomouc. In particular, I deal with selected parts of the construction and technological preparation of the facility. I deal more closely with the technological regulations for the assembly of reinforced concrete skeleton and sheeting. My diploma thesis includes building site design, set of machinery, control and test plans, budget, schedules, personnel and machine deployment, variation of sheet metal finishing and drawing on the budget.

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32

Boček, Milan. "Rekonstrukce prodejny ve Vyškově - stavebně technologický projekt". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265420.

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This master´s thesis deals with a complete renovation of a shop in Vyškov. A part of this thesis represents a technical report of the worksite facilities, technological standard, inspection and test plan, machine design, plan of safety and protection of environment, contract for work, budget and schedule.

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33

Márquez, Costa Juan Pablo. "Caractérisation et modélisation des interfaces dans les composites organiques stratifiés à haute température : Application à la tenue au feu des structures aéronautiques PhyFire LOT 2 - Développement de modèles de comportement du composite Caractérisation en température de la ténacité en mode II des interfaces des CMO en utilisant l’effet Joule Caractérisation du comportement visqueux des interfaces CMO et influence sur la propagation de délaminage Convention PhyFIRE 2 - LOT 2 : Développement d’un cadre de modélisation pour les matériaux composites Durabilité des matériaux composites en conditions extrêmes : vers la prédiction des propriétés de tenue au feu Durability of Composite Materials under Severe Temperature Conditions : Influence of Moisture Content and Prediction of Thermo- Mechanical Properties During a Fire Towards the Prediction of Sandwich Composites Durability in Severe Condition of Temperature : A New Numerical Model Describing the Influence of Material Water Content during a Fire Scenario". Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2021. http://www.theses.fr/2021ESMA0004.

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Dans le cadre de la tenue au feu des matériaux composites, il est nécessaire d’évaluer la dégradation de leurs propriétés thermiques et mécaniques due à des pertes de masse, de la fissuration matricielle et/ou des délaminages. Néanmoins, peu d’études dans la littérature sur la tenue en température des composites aéronautiques concernent le comportement mécanique et la rupture des interfaces avant toute dégradation thermique, sujet qui est l’objet principal de ce travail. Ainsi, l’objectif est de proposer un modèle de prévision de rupture concernant tant l’amorçage que la propagation du délaminage pour des chargements thermomécaniques. Ce travail a porté en grande partie sur la caractérisation des propriétés d’interfaces à l’aide d’une analyse d’essais de propagation de fissure en mode II pour des éprouvettes chauffées par effet Joule. Ces analyses numériques montrent que le comportement du pli n’explique pas la réponse macroscopique pseudo-ductile observée expérimentalement. Ainsi, une méthode de dialogue essai-calcul, comparant les champs cinématiques mesurés par corrélation d’images numériques et ceux simulés par éléments finis, souligne l’importance du comportement visqueux à l’échelle de l’interface.C’est par une approche similaire de type FEMU que les paramètres d’une loi de rupture de type cohésif ont été identifiés en température et en tenant compte des différentes sources d’incertitude. Ce travail met en évidence la similitude entre le cisaillement plan et hors plan, tant sur le comportement que sur la rupture. En parallèle, l’analyse d’essais de tenue en température par impact laser a permis d’établir un critère d’amorçage par une approche couplée en contrainte et en énergie. Une confrontation de ce critère aux paramètres de la loi de zone cohésive identifiés précédemment permet de discuter de l’échelle de modélisation de l’interface
Within the framework of the fire resistance of composite materials, it is necessary to assess the degradation of their thermal and mechanical properties due to mass losses, matrix cracking and/or delamination cracks. Nevertheless, few studies in the literature about the temperature resistance of aeronautical composites concern the mechanical behaviour and the rupture of interfaces before any thermal degradation,subject which is the main topic of this work. Thus, the objective is to propose a failure model concerning both the delamination crack initiation and growth under thermomechanical loads. Much of this work has focused on the characterisation of interface properties using an analysis of mode II crack propagation tests for Joule heated specimens. These numerical analyses show that the ply behaviour does not explain the macroscopic pseudo-ductile response observed experimentally. Thus, a test-calculation dialog method, comparing the kinematic fields measured by digital images correlation and those simulated by finite elements, underlines the importance of the viscous behaviour at the interface scale. By a similar FEMU approach the parameters of a cohesive-type fracture law have been identified in temperature and taking into account the different sources of uncertainty. This work highlights the similarity between plane and out-of-plane shearing, both on behaviour and on failure. In parallel, the analysis of temperature resistance tests by laser impact made it possible to establish a crack initiation criterion by a coupled stress and energy approach. A comparison of this criterion with the parameters of the cohesive zone law previously identified makes it possible to discuss about the modeling scale of the interface

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34

Malý, Martin. "Skladová hala v Měříně, příprava a organizace stavby". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372192.

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The aim of this work is the processing of the technological project for the ,,Skladová hala v Měříně“, which addresses the preparation and organization of construction. Construction technology the project involves the processing of time plans, economic evaluation, design of pumping sources for construction, working procedures, construction site equipment, and design of major machines and mechanisms. Further, it is processed a detailed technological regulation and inspection and test plan for a prefabricated reinforced concrete skeleton. All technological procedures are processed with regard to work safety and environment.

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35

Yalew, Wubete Mengist y Wubete Mengist Yalew. "Behavior of Geotextile-Reinforced Clay and Improvement with Sandwich Technique under Unconsolidated-Undrained Triaxial Tests". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/6287rs.

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碩士
國立臺灣科技大學
營建工程系
102
Reinforced soil structures, in which reinforcement is embedded in soil mass, have a number of distinct advantages over conventional retaining structures because of their ductility, high tolerance to differential settlement without structural distress, rapid method of construction, cost effectiveness, and adaptation to different site conditions. For effective performance of reinforced earth structures, the design practices limited the soil to be well-graded, free draining coarse-grained materials as backfills. If it is difficult to find the materials commonly specified in design guidelines, locally available soils which may be fine grained or low permeable might be used as backfills, then the behavior of reinforced fine-grained or poorly draining soils needs to be evaluated. A series of standard compaction and unconsolidated-undrained (UU) triaxial compression tests were conducted to investigate the behavior of geotextile-reinforced clay. Effects of inclusion of nonwoven geotextile to clay were investigated and evaluated by varying the magnitude of confining pressures, and number of geotextile layers. The response of single layer reinforced clay with provision of thin layers of sand around the reinforcement (sandwich technique) to undrained loading was also examined. In sandwich technique, confining pressure and thickness of sand layer were all varied to quantify its effect on clay-geotextile interaction. The investigations were conducted on clay specimens prepared at their maximum dry unit weight and optimum moisture content, as well on sand specimens prepared at relative density of 70%. The mobilized tensile strain of reinforcements was estimated from the residual tensile strain using a digital image-processing technique. The compaction test results indicated the benefit of reinforcing clay with geotextile to increase the dry unit weight of soil, which were determined for pure compacted soil between geotextile layers. The UU test results showed that geotextile reinforcement improves the response of clay by enhancing the peak shear strength, and reducing the loss of post-peak shear strength. Failure patterns were gradually changed from apparent classical failures for unreinforced soil specimens to bulging failures between adjacent layers (barrel-shaped) for geotextile-reinforced specimens without sand around the reinformcent. As the number of geotextile layers increased, failure patterns for reinforced specimens was getting uniform. This demonstrates that the increase in number of geotextile layers, the more constraint to later deformation of clay specimen. As the number of geotextile layers increases, the strength ratio increases and with increasing confining pressure, the peak strength ratio also decreases. Effectiveness of reinforcing clay without providing sand around reinforcement was due to the increase in the cohesion of the reinforced specimen. In addition, the mobilized tensile strain of reinforcement increases as the number of geotextile layers, confining pressure and showed direct proportionality to strength difference between reinforced and unreinforced soil. In sandwich technique, the investigations revealed that thin layers of sand provided around the reinformcent could enhance the strength and deformation behavior of reinforced clay particularly under high confining pressure and large thickness. The failure patterns were bulging of reinforced clay specimen and the thin sand layers almost appeared undeformed. This provides an evidence that sand layer around reinforcement is effective in improving the interfacial shearing resistance with geotextile and clay, by penetrating in to it and consequently, the failure is forced away from sand-geotextile as well as clay-sand interface to clay. The increase in shear strength was due to an increase in the internal friction angle. Similar to reinforced clay without sand, in sandwiched specimen the mobilized reinforcement tensile strain increases with the thickness of sand layers. In addition, the strength differences increases with thickness of sand layers. The negative strength differences observed at smaller thickness of sand layers were attributed to the thickness of shear band. This implies that the thickness of sand layers around the reinforcement should be large than the estimated thickness of shear band.

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Sousa, Christoph Fernandes. "Development of a multifunctional composite sandwich panel for the rehabilitation of building façades". Doctoral thesis, 2021. http://hdl.handle.net/1822/75853.

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Tese de doutoramento em Civil Engineering
This PhD thesis presents a research work aiming at the development of a sustainable and multifunctional composite sandwich panel for the rehabilitation of reinforced concrete (RC) buildings from the 1960s to the mid-1980s. The sandwich panel retrofit solution developed in the thesis comprises four main components: (i) thin outer layers of Recycled Steel Fibre Reinforced micro Concrete (RSFRC); (ii) a lightweight core made of polystyrene; (iii) internally distributed glass fibre reinforced polymer (GFRP) connectors; and (iv) steel anchors for fixing the panel to the existing structure. The first part of this work’s experimental program encompassed pushout and pullout tests, carried out on reduced-scale specimens representative of the sandwich panel solution; these tests aimed at assessing the overall composite behaviour of the sandwich panel and analysing the influence of the type of core insulation layer, and of the anchoring conditions and diameter of the GFRP connectors. The tests showed that the adopted structural GFRP connectors are able to adequately ensure shear load transfer between RSFRC layers. The second part of the experimental program involved testing intermediate-scale RC frame specimens, representative of the target building typology, under in-plane cyclic loading conditions. The cyclic tests were performed on different variations of the referred RC frames: (i) a bare RC frame; (ii) an RC frame with a masonry infill wall; and (iii) an RC frame with the incorporation of the sandwich panel prototype developed in the scope of this research work. The results of the tests show that, in comparison with the traditional masonry infill wall solution, the proposed rehabilitation solution enabled a significant improvement of the RC frame’s cyclic performance, providing higher levels of load carrying capacity and energy dissipation. The numerical part of this study included numerical simulations conducted to assist the sandwich panel design process and, more specifically, the modelling of the failure mechanisms observed at the interface between the RSFRC layers and the polystyrene core; good agreement was obtained between experimental and numerical results, with important conclusions being drawn regarding the cohesion and friction angle between these components of the sandwich panel.
Esta tese apresenta um trabalho de investigação relativo ao desenvolvimento de um painel sanduíche compósito sustentável e multifuncional concebido para a reabilitação de edifícios porticados de betão armado (BA) construídos entre 1960 e meados da década de 1980. Este painel é composto essencialmente por quatro componentes principais: (i) finas camadas exteriores em microbetão reforçado com fibras de aço recicladas (BRFR); (ii) núcleo em poliestireno; (iii) conetores poliméricos reforçados com fibras de vidro (GFRP); e (iv) ancoragens metálicas para ligação do painel à estrutura a reabilitar. A primeira parte do programa experimental do presente trabalho envolveu a realização de ensaios de corte e ensaios de arrancamento em provetes de escala reduzida, representativos do painel em desenvolvimento; com estes ensaios, pretendeu-se avaliar o funcionamento compósito do painel através da análise da influência do tipo de camada de isolamento e do comprimento de ancoragem e diâmetro dos conetores em GFRP. Os resultados obtidos revelaram que os conectores em GFRP de cariz estrutural são eficazes na transmissão de esforços de corte entre as camadas de BRFR. A segunda parte do programa experimental consistiu na realização de ensaios cíclicos em pórticos de BA de escala intermédia, representativos da tipologia de edifícios a reabilitar. Os ensaios foram realizados utilizando três variantes dos referidos pórticos: (i) pórtico de BA isolado; (ii) pórtico de BA com parede de enchimento em alvenaria; e (iii) pórtico de BA reforçado com um protótipo do painel sanduíche desenvolvido no âmbito deste trabalho. Os resultados mostraram que, em comparação com a solução tradicional com enchimento em alvenaria, a solução de reabilitação proposta produziu uma melhoria significativa no comportamento cíclico do pórtico em termos de capacidade de carga e energia dissipada. A parte numérica do presente estudo incluiu a realização de simulações de apoio ao processo de dimensionamento do painel e, mais especificamente, no auxílio à interpretação do mecanismo de rotura observado na interface entre as lâminas de BRFR e o núcleo em poliestireno. Registou-se uma boa concordância entre as respostas numérica e experimental, o que permitiu obter conclusões importantes relativamente aos valores de coesão e ângulo de atrito que caraterizam a interface entre estes componentes do painel sanduíche.
Fundação para a Ciência e a Tecnologia (FCT)

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Mawella, Nadeesha R. "A robust test of homogeneity in zero-inflated models for count data". Diss., 2018. http://hdl.handle.net/2097/38877.

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Doctor of Philosophy
Department of Statistics
Wei-Wen Hsu
Evaluating heterogeneity in the class of zero-inflated models has attracted considerable attention in the literature, where the heterogeneity refers to the instances of zero counts generated from two different sources. The mixture probability or the so-called mixing weight in the zero-inflated model is used to measure the extent of such heterogeneity in the population. Typically, the homogeneity tests are employed to examine the mixing weight at zero. Various testing procedures for homogeneity in zero-inflated models, such as score test and Wald test, have been well discussed and established in the literature. However, it is well known that these classical tests require the correct model specification in order to provide valid statistical inferences. In practice, the testing procedure could be performed under model misspecification, which could result in biased and invalid inferences. There are two common misspecifications in zero-inflated models, which are the incorrect specification of the baseline distribution and the misspecified mean function of the baseline distribution. As an empirical evidence, intensive simulation studies revealed that the empirical sizes of the homogeneity tests for zero-inflated models might behave extremely liberal and unstable under these misspecifications for both cross-sectional and correlated count data. We propose a robust score statistic to evaluate heterogeneity in cross-sectional zero-inflated data. Technically, the test is developed based on the Poisson-Gamma mixture model which provides a more general framework to incorporate various baseline distributions without specifying their associated mean function. The testing procedure is further extended to correlated count data. We develop a robust Wald test statistic for correlated count data with the use of working independence model assumption coupled with a sandwich estimator to adjust for any misspecification of the covariance structure in the data. The empirical performances of the proposed robust score test and Wald test are evaluated in simulation studies. It is worth to mention that the proposed Wald test can be implemented easily with minimal programming efforts in a routine statistical software such as SAS. Dental caries data from the Detroit Dental Health Project (DDHP) and Girl Scout data from Scouting Nutrition and Activity Program (SNAP) are used to illustrate the proposed methodologies.

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38

Gonçalves, Cláudia Sofia Costa. "Estudo do comportamento de elementos de conexão em GFRP (Glass Fiber Reinforced Polymer) para utilização em painéis sandwich de betão". Master's thesis, 2012. http://hdl.handle.net/1822/29588.

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Dissertação de mestrado integrado em Engenharia Civil
O trabalho a desenvolver nesta dissertação decorre no âmbito do projeto de investigação “LEGOUSE – Pré-fabricação Modular de Edifícios de Custos Controlados”, em desenvolvimento no Departamento de Engenharia Civil da Universidade do Minho, que visa criar uma solução inovadora para a construção de casas modulares, recorrendo a painéis sandwich de betão pré-fabricados. Os painéis sandwich de parede, propostos como solução mais funcional e económica, são constituídos por duas camadas externas de Betão Autocompactável Reforçado com Fibras de Aço (BACRFA), uma camada interna de material isolante e conectores em GFRP (Glass Fiber Reinforced Polymer). Os painéis sandwich devem garantir o correto funcionamento estrutural a que se destinam, mas também devem garantir bom comportamento térmico e resistir às cargas de manuseamento, armazenamento e transporte. Os conectores em GFRP estabelecem a ligação física entre os panos de betão, assumindo uma função fundamental na transmissão de esforços entre eles e garantindo o funcionamento conjunto do painel sandwich. O GFRP permite ainda a redução das pontes térmicas que são originadas quando se aplicam conectores metálicos. Os conectores propostos são placas lisas perfuradas de GFRP, que são embebidos nos elementos de betão. Para efeitos de comparação, são preparados e ensaiados provetes com Betão Autocompactável Reforçado com Fibras de Aço (BACRFA) e Betão Autocompactável (BAC). A fim de avaliar o comportamento do conector ao corte e ao arranque são realizados ensaios em escala reduzida com provetes tipo push-out e tipo pull-out, respetivamente. São testados provetes, onde se faz variar o tipo de mantas de fibras de vidro usadas na produção dos conectores, a espessura dos conectores e o número de furos por conector. A avaliação do comportamento isolado dos furos no conector é efetuada através de ensaios de rasgamento em provetes com um único furo. Com base nos resultados experimentais da capacidade resistente do conector em GFRP são desenvolvidas expressões analíticas preliminares para a avaliação da capacidade resistente do conector.
The work here presented is developed within the research project “LEGOUSE – Préfabricação Modular de Edifícios de Custos“, currently in development at the Civil Engineering Department of University of Minho. This project aims to create an innovative solution for the construction of modular housing, by using precast sandwich panels. Sandwich wall panels are proposed as a more functional and economic solution and consist of two outer wythes made of Steel Fiber Reinforced Self Compacting Concrete (SFRSCC), an internal layer of insulating material and GFRP (Glass Fiber Reinforced Polymer) connectors. The sandwich panels must guarantee the correct structural functioning, a good thermal behavior and should also resist to loads that result from handling, storage and transportation. GFRP connectors establish the physical connection between the concrete wythes, assuming a fundamental role in the transmission of loads between them and ensuring the global behavior of the panel. GFRP also reduces the effect of thermal bridges that exist when metal connectors are applied. The proposed connectors consist on perforated GFRP flat plates that are embedded in concrete elements. For comparison purposes, test specimens are prepared and tested with Steel Fiber Reinforced Self Compacting Concrete (SFRSCC) and Self Compacting Concrete (SCC). To evaluate the behavior of the connector, tests are performed on small scale specimens prepared for push-out tests and pull-out tests. The tested specimens’ variation consists on the type of glass fiber layers used to produce the connectors, on its thickness and on the number of holes per connector. The performance evaluation of isolated holes in the connector is done by testing strips with a single hole. Preliminary analytical expressions are developed in order to evaluate the strength capacity of the connector. These equations are based on the experimental results obtained.

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39

Machado, Joana Maria Leal. "Estudo da ligação entre componentes estruturais de GFRP (glass fiber reinforced polymer) e componentes estruturais em betão". Master's thesis, 2015. http://hdl.handle.net/1822/40687.

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Dissertação de mestrado integrado em Engenharia Civil
O trabalho desenvolvido nesta dissertação decorreu no âmbito do projeto de investigação RehabGFRP que decorreu no Departamento de Engenharia Civil da Universidade do Minho. No âmbito deste projeto, foi desenvolvido um novo sistema estrutural em laje sandwich formada por camada inferior de tração e nervuras transversais em material polimérico reforçado com fibra de vidro (GFRP- glass fiber reinforced polymer), núcleo em material leve com propriedades de isolamento térmico (espuma de poliuretano) e camada superior de compressão realizada em argamassa. Esta argamassa tem como finalidade aumentar a rigidez à flexão da laje, aumentar a resistência à encurvadura local das nervuras transversais de GFRP, contribuir para a resistência e a ductilidade no comportamento estrutural da laje e melhorar o seu desempenho termo-acústico. O painel sandwich proposto tem como principal aplicação a reabilitação estrutura de edifícios de alvenaria onde se preservam as paredes resistentes e se pretende remodelar os pavimentos. Trata-se de um tipo de laje com peso próprio muito inferior a qualquer outra solução construtiva existente. Neste trabalho, pretende-se estudar soluções otimizadas que garantam a ligação entre as nervuras de GFRP e a camada superior de argamassa. Para tal, são avaliadas três tipologias diferentes de conexão, nomeadamente o conector liso, o conector perfurado e o conector indentado. Todos estes conectores são realizados nas nervuras de GFRP. Para cada tipologia de conectores em estudo avalia-se também a influência de considerar duas espessuras diferentes, neste caso de 4 e de 6 mm. Para estudar as ligações mencionadas, são efetuados ensaios experimentais de tipo pull-out, que permitem avaliar a capacidade resistente da ligação ao arranque. Esta configuração de ensaio permite avaliar a resistência e adequabilidade do GFRP utilizado, a contribuição da aderência entre as superfícies de GFRP e de argamassa, a contribuição dos pinos de betão que se mobilizam nas aberturas do conector e a contribuição da forma das aberturas. Previamente à realização dos ensaios experimentais é efetuado o fabrico e a produção dos diversos provetes que são utilizados no estudo. São também realizados ensaios de caraterização mecânica da argamassa de ultra elevada ductilidade (DHCC - Deflection Hardening Cement Composites) utilizada e ensaios de caracterização das soluções de GFRP definidas para a camada inferior e para as nervuras.
The work presented in this master's thesis was developed as part of the research project RehabGFRP which took place in the Department of Civil Engineering on University of Minho. A new structural sandwich slab system that consists of a lower GFRP tensile skin and GFRP transversal ribs made with polymeric material reinforced with glass fibers (GFRP - glass fiber reinforced polymer), an internal core made that uses lightweight material with thermal insulation properties (polyurethane foam) and a compression top layer made with special mortar. This mortar is used to increase the bending stiffness of the slab, to increase resistance to local buckling of the transverse ribs of GFRP, to contribute to the strength and ductility of the slab structural behavior and to improve their thermo-acoustic performance. The main application of the proposed sandwich panel is in the structural rehabilitation of masonry buildings which preserve the resistant walls. It is intended to be used in the refurbishment of these buildings floors. It is a type of slab whose dead weight is lower than any other existing constructive solution. In this work, it is intended to study optimized solutions that are able to provide the connection between the ribs of GFRP and the upper layer of mortar. As such, three different types of connection are evaluated: the plane connector, the perforated connector and the indented connector. All these connectors are made in the ribs of the GFRP. For each type of connectors under study, two different thicknesses are evaluated by considering, in this case, thicknesses of 4 mm and 6 mm. Experimental tests of pull-out type are performed in order to assess the bearing capacity of the connection. This test configuration allows to evaluate the resistance and the suitability of the used GFRP, the contribution of the adhesion between the surfaces of GFRP and mortar, the contribution of concrete pins that are mobilized in the connector openings and the contribution of the shape of the openings. The manufacture and production of many samples used in the study is performed previously to the execution of experimental tests. Mechanical characterization tests of ultra high ductility mortar (DHCC - Deflection Hardening Cement Composites) and characterization of GFRP solutions defined for the lower layer and the ribs tests, are also performed.

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Oliveira, André Manuel Correia. "Caracterização de painéis sanduíche híbridos para a reabilitação de pisos de edifícios". Master's thesis, 2018. http://hdl.handle.net/1822/70881.

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Dissertação de mestrado integrado em Engenharia Civil
Nos últimos anos, o crescente interesse e investimento na área da reabilitação justificou uma crescente necessidade de elementos estruturais leves, de elevada rigidez, resistência e durabilidade. Como consequência, houve necessidade de desenvolver novas soluções, tendo-se verificado que as soluções compósitas, nas quais se incluem os painéis sanduíche, apresentam vantagens face a outras tipologias. A presente dissertação insere-se no âmbito do Projeto de Investigação “EasyFloor”, desenvolvido pelo consórcio que inclui a Universidade do Minho, o Instituto Superior Técnico (IST) e a empresa ALTO-Perfis Pultrudidos, Lda. Este projeto tem por objetivo o desenvolvimento de painéis sanduíche totalmente compósitos e painéis sanduíche híbridos inovadores que serão utilizados na substituição de pisos degradados em edifícios antigos. No âmbito desta dissertação, pretende-se efetuar um conjunto de tarefas associadas ao desenvolvimento e à caracterização mecânica destes painéis sanduíche híbridos. Os painéis são constituídos por uma lâmina inferior em G/CFRP (glass/carbon fiber reinforced polymer), duas almas laterais também em G/CFRP, uma lâmina superior em SCSFRMC (self-compacting steel fiber reinforced micro concrete) e um núcleo em PUR (Polyurethane) ou em PIR (Polyisocyanurate). Por razões técnicas, entre o SCSFRMC e o núcleo existirá uma lâmina de GFRP. O processo de produção dos painéis será por pultrusão, estando prevista uma ligação mecânica por encaixe entre painéis. De modo a assegurar uma adequada ligação entre a lâmina de GFRP e a camada de SCSFRMC foi avaliada a influência i) do tipo de preparação da superfície da lâmina e ii) do tipo de adesivo que procura melhorar a dita ligação, por intermédio de ensaios de “pull-off”. De forma a proceder à otimização do painel sanduíche nas suas diversas vertentes, foi necessário determinar as propriedades mecânicas das diferentes componentes do painel. Desta forma, numa primeira fase procedeu-se à caraterização mecânica do SCSFRMC, através de ensaios de compressão e flexão. Por intermédio de ensaios de flexão e de tração uniaxial, foi ainda caraterizado o comportamento das lâminas de GFRP. Finalmente, foi também caracterizado o núcleo (PUR e PIR) por intermédio de ensaios de compressão e corte. Estes resultados foram posteriormente utilizados como dados iniciais das simulações numéricas efetuadas ao painel sanduíche, recorrendo ao método dos elementos finitos. Estas simulações permitiram prever a resposta estrutural dos painéis sanduíche para diferentes configurações de carregamento e diferentes condições fronteira, previstas no projeto “EasyFloor”.
In recent years, the increasing interest and investment in rehabilitation has justified a growing need for light structural elements of high stiffness, strength and durability. As a consequence, new solutions were investigated, and it became clear that composite solutions, including sandwich panels, have advantages over other types. This master’s dissertation is framed in the research project “EasyFloor” developed by a consortium comprising University of Minho, Instituto Superior Técnico (IST) and the company ALTO-Perfis Pultrudidos, Lda. The aim of this project is to develop innovative fully composite panels and hybrid sandwich panels which will be used to replace ruined floors of old buildings. In the scope of this dissertation it is intended to carry out a set of tasks associated to the development and the mechanical characterization of hybrid sandwich panels. The panels are composed of a lower strip made of G/CFRP (glass/carbon fiber reinforced polymer), two side webs also made of G/CFRP, a top strip made of SCSFRMC (self-compacting steel fiber reinforced micro concrete) and a core made of PUR (Polyurethane) or PIR (Polyisocyanurate). For technical reasons, between SCSFRMC and the core there will be a GFRP slide. The panels will be produced by pultrusion. A mechanical connection between panels will be provided. In order to ensure an adequate connection between the GFRP slide and SCSFRMC layer, it was decided to assess the influence i) the slide surface preparation technique and ii) the type of adhesive that improves the already mentioned connection by means of pull-off tests. In order to optimize the sandwich panel in a global manner, it was necessary to determine the mechanical properties of the different components of the panel. Thus, in a first phase, the mechanical characterization of SCSFRMC was carried out through compression and bending tests. By means of flexural and uniaxial tensile tests, the behaviour of the GFRP slides was also characterized. Finally, the core (PUR and PIR) was characterized with compression and shear tests. These results were later used as initial data of the numerical simulations based on the sandwich panel, using the finite element method. These simulations were developed to obtain the predictive structural responses of the sandwich panels for the different test configurations foreseen in the “EasyFloor” project.
Este trabalho foi desenvolvido no âmbito o projeto “EasyFloor – Desenvolvimento de painéis sanduíche composto para reabilitação de pavimentos”, envolvendo a empresa ALTO – Perfis Pultrudidos, Lda., CERIS / Instituto Superior Técnico e ISISE / Universidade do Minho, apoiada por fundos FEDER através do Programa Operacional de POCI (Programa Operacional de Competitividade e Internacionalização) e da Agência Nacional de Inovação (ANI) – projeto no. 3480 (POCI-01-0247-FEDER-003480).

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Cruz, Fábio Quintas. "Desenvolvimento e caraterização de painéis sanduíche híbridos para a reabilitação de pisos de edifícios". Master's thesis, 2017. http://hdl.handle.net/1822/49794.

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Dissertação de mestrado integrado em Engenharia Civil (área de especialização em Perfil de Estruturas e Geotecnia)
Nos últimos anos, com a crescente necessidade de elementos estruturais leves, de elevada rigidez e resistência na Engenharia da Construção, nomeadamente na área da reabilitação, tem havido um enorme interesse no estudo e desenvolvimento de soluções compósitas, nas quais se incluem os painéis sanduíche. A presente dissertação insere-se no projeto de investigação “EasyFloor”, que tem como objetivo o de contribuir para o desenvolvimento de painéis sanduíche inovadores que constituem o elemento central de uma nova técnica de reabilitação de pavimentos de piso de edifícios existentes ou em construção nova. Estes painéis serão constituídos por uma lâmina inferior em GFRP ou G/CFRP (glass/carbon fiber reinforced polymer), uma lâmina superior em matriz cimentícia reforçada com fibras de elevado desempenho e um núcleo em espuma de poliuretano (PUR). O trabalho incluí componentes experimentais e numéricas. De modo a proceder à conceção e otimização do painel sanduíche nas suas diversas vertentes, foi necessário conhecer completamente as propriedades de todos os materiais envolvidos. Desta forma, numa primeira fase procedeu-se à caraterização mecânica do PUR à compressão, tração e corte. No que respeita aos ensaios de compressão e tração, foram seguidas as recomendações normativas existentes. Relativamente aos ensaios de corte, tendo por base a bibliografia existente, foi desenvolvida e analisada uma configuração de ensaio alternativa. Na análise da configuração de ensaio proposta foi avaliada a influência da geometria do provete na resposta ao corte do PUR. Posteriormente, a geometria e a metodologia desenvolvidas foram empregues para caraterizar experimentalmente o comportamento ao corte do PUR. Por intermédio de ensaios de tração uniaxial e de flexão, foi ainda caraterizado o comportamento de provetes de GFRP e C/GFRP sob o efeito de tensões normais. Realizaram-se diversas simulações numéricas dos ensaios experimentais efetuados com o objetivo de complementar a análise de resultados e de calibrar modelos numéricos para os estudos paramétricos realizados. Em geral, os resultados experimentais obtidos estão de acordo com o reportado na bibliografia. Relativamente ensaios de corte do PUR constatou-se que existe um efeito de escala nos resultados obtidos, tendo-se observado que quanto maior é a relação comprimento/espessura (L/t) dos provetes, mais elevados são os valores da resistência ao corte. Complementarmente, observou-se que a rigidez inicial é pouco influenciada por este parâmetro (L/t), contrariamente ao que acontece com os modos de rotura observados experimentalmente, que consistentemente se mostraram dependentes desta relação. Quanto aos resultados obtidos a partir dos ensaios de tração e de flexão em lâminas de GFRP, as duas configurações de provetes de GFRP ensaiadas não apresentaram diferenças significativas em termos das respostas experimentais observadas. Por outro lado, os provetes híbridos C/GFRP ensaiados à flexão apresentaram, em geral, um modo de rotura prematuro condicionante da resposta experimental, observando-se a delaminação ao nível da camada de transição entre os dois materiais. Por último, as simulações numéricas conducentes ao dimensionamento do painel sanduíche mostraram que o uso de uma camada superior com melhores propriedades mecânicas aumenta significativamente a rigidez à flexão do painel.
In recent years, with the growing need for light structural elements, of high stiffness and resistance in Construction Engineering, particularly in the rehabilitation domain, there has been a great deal of interest in the study and development of composite solutions, including sandwich panels. The present dissertation is part of the research project "EasyFloor", which aims to contribute to the development of innovative sandwich panels that constitute the central element of a new technique for the rehabilitation of floors in existing buildings or new constructions. These panels will comprise a lower GFRP or G/CFRP (glass / carbon fiber reinforced polymer) flange, a top flange made of a cementitious matrix reinforced with high performance fibers, and a polyurethane foam core (PUR). The work includes experimental and numerical research components. In order to proceed with the design and optimization of the sandwich panel in its several aspects, it was necessary to characterize the properties of all the materials involved. In this way, in a first phase the mechanical characterization of the PUR in compression, tension and shear was carried out. For the compression and tension tests, the existing normative recommendations were followed. With regard to the shear tests, based on the existing literature an alternative testing configuration was developed and analysed. In the analysis of the proposed test configuration, the influence of the geometry of the specimen in the shear response of the PUR was evaluated. Subsequently, the developed geometry and methodology were used to experimentally characterize the shear behaviour of PUR. By means of uniaxial tensile and flexural tests, the behaviour of GFRP and C / GFRP specimens under the effect of normal stresses was also characterized. Numerical simulations of the experimental tests were performed with the objective of complementing the analysis of results and of calibrating numerical models for the parametric studies. In general, the experimental results obtained are in agreement with the ones reported in the literature. With regards to the PUR shear tests, it was found that there is a scale effect on the results obtained, since the higher the length / thickness ratio (L / t) of the test specimens, the higher the shear strength values obtained. Complementarily, it was observed that the initial stiffness of the experimental responses is almost not influenced by this parameter (L / t), in contrast to the experimentally observed rupture modes, which have consistently shown to be dependent on this ratio. As for the results obtained from the tensile and flexure tests on GFRP samples, the two configurations of GFRP specimens tested did not present significant differences in terms of the observed experimental responses. On the other hand, the flexural test on C/GFRP hybrid test specimens showed, in general, that a premature failure mode tends to occur, which consists on the delamination at the level of the transition layer between the two materials. Finally, the numerical simulations leading to the design of the sandwich panel showed that the use of an upper layer with better mechanical properties significantly increases the flexural rigidity of the panel.

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PENG, CHI-HUA y 彭基華. "A Bending Test Study for Glass Fiber/Epoxy Resins Composite Sandwich Structure". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/08964168197791242253.

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碩士
中華大學
機械工程學系碩士在職專班
99
The demand for high degree of strength, corrosion-resistant, and lightweight materials has been rapidly increased in the field of aerospace, automotive and engineering. Due to their good resistance to bending, high strength, and more flexible to be redesigned, composite materials have very wide range of applications. This study focus on how the composite materials are utilized in the sandwich-structure, and to be analyzed for their performance. To construct the sandwich-structure with composite materials, glass fiber/epoxy layer are stacked up as both the top and bottom layer of the structure, while the 30k-ps high-density polystyrene foam is used as the core layer the structure. The experiment on sandwich-structure was conducted by changing several variables, such as the stacking layers of glass fiber, and the thickness of polystyrene foam in the middle layer. Furthermore, the same test was performed again with adding new variables, such as single I beam and double I beam, in order to do the comparison between those two tests. The bending tests were performed to evaluate the performance of sandwich-structure. The results indicate that, when the stacking layers of glass fiber material increase, the specimens can correspondingly withstand greater loading, bending moment, and stress. In addition, the specimens can also withstand greater loading and bending moment when the thickness of core material increases, but not the stress. It is because the same material with the same stack of layers of glass fiber can generate the same value of stress. Furthermore, the sandwich-structure with single I beam and double I beam can tolerate greater loading, bending moment and stress as well. Keywords: glass fiber, epoxy, composites, sandwich structures, bending test.

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Tsai, Wen-Jing y 蔡文璟. "Development and Cyclic Tests of Cross-Anchored Dual-Core Self-Centering Sandwiched Buckling-Restrained Braces (SC-SBRBs)". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/50093595947521808336.

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碩士
國立臺灣大學
土木工程學研究所
103
Self-Centering Brace (SCB) uses tendons to constrain steel compression member of the brace and provides self-centering properties under brace in tension and compression that is restored to zero residual deformation. Conventional dual-core SCB is two times brace deformation capacity than conventional single-core SCB under same strain of tendons (or reduce to half the additional strain of tendons under same brace deformation capacity) that effectively reduce the elastic strain demand of tendons.The Energy dissipating members experience serious wear, which reduces their energy dissipating efficiency and results in a need for replacement. Sandwiched Buckling-Restrained Brace (SBRB) uses two identical restraining members that sandwich the Energy Dissipative core with fully tensioned high-strength bolts to prevent core buckling and have stable hysteretic response. This study presents a cyclic behavior and self-centering behavior of Cross-Anchored Dual-Core Self-Centering Sandwiched Buckling- Restrained Brace (SC-SBRB). A SC-SBRB consists of a SBRB system, which provide energy dissipation, and self-centering system, which provide self-centering. The SC-SBRBs were Designed and tested two specimens (7490 mm long) with different member settings, tendons of two SC-SBRBs used same D16 mm steel strand. The objective was to compare the difference of seismic performance of SC-SBRBs. Test results indicate that the mechanism of SC-SBRBs is consistent with prediction. Under drift 2% of phase 1 test, two SC-SBRBs maintained good hysteretic response in self-centering behavior. Maximum brace strain of two SC-SBRBs were 1.1% corresponding to maximum tendons strain 0.80% and maximum load 1648 kN and 1705 kN, respectively. SBRB Systems can develop stable hysteretic responses up to a maximum core axial strain 1.5%, and cumulative plastic ductility 1090-1129 that is much higher than that specified the value of 200 in AISC seismic provisions (2010).

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Ling, Yu-Ting y 凌郁婷. "Seismic Performances of Actual High-Rise Buildings with Dual-Core SCBs and Sandwiched BRBs in Taiwan：Nonlinear Time History Analyses and Brace Tests". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/76qe46.

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碩士
國立臺灣大學
土木工程學研究所
104
To evaluate the seismic performances and effects that dual-core self-centering braces (DC-SCBs) and sandwiched buckling-restrained braces (SBRBs) would make in high-rise buildings, two actual high-rise buildings in Taiwan were selected and modeled with installing of DC-SCBs and SBRBs. In order to avoid the pretension force of tendons in DC-SCB losing during earthquake excitation, an external friction device (EFD) was designed as a fuse in series with the main brace, slipping before the axial strain of tendon exceeded its yield strain. To estimate seismic parameters of actual high-rise buildings and to validate the dynamic response of analytical model under earthquake excitation, long-term vibration monitoring of a selected Hsinchu high-rise factory building was conducted. A full-scale DC-SCB+EFD and a full-scale SBRB were tested to validate their seismic cyclic performances. Nonlinear time history analyses were conducted on two sets of SMRFs, SMRF+SBRBFs and SMRF+DC-SCBFs to evaluate their seismic demands under both design and maximum considered level of earthquake motions. Analysis results showed that DC-SCB provided well seismic effect in reduction of both maximum and residual drift of frames. SBRB provided well seismic effect in reduction of maximum drift of frames, while might make the residual drift larger.

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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.

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Tese no âmbito do Doutoramento em Engenharia Civil, apresentada à Faculdade de Ciências Tecnologia da Universidade de Coimbra
A 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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