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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Development of a Procedure to Evaluate the Shear Modulus of Laminated Glass Interlayers

Brackin, Michael S. 2010 May 1900 (has links)
Laminated glass is comprised of multiple glass plates coupled together in a sandwich construction through the use of a polymorphous interlayer that acts as a bonding agent between the glass plates. Laminated glass offers several advantages over monolithic glass including the ability to resist post fracture collapse, improved sound insulation, lower ultraviolent light trans-mission, and improved thermal insulation. Because the stiffness of the interlayer is often many orders of magnitude less than that of the glass, plane sections prior to loading do not remain plane throughout the laminate?s thickness after load is applied. The behavior of laminated glass is controlled by the stiffness of the interlayer. This behavior rules out the use of classical theoretical formulations for thin plates. In such cases, it is necessary to use specially formulated equations or finite element analyses to evaluate the performance of laminated glass. Previous attempts have been made to develop procedures to quantify the interlayer stiffness for use in laminated glass design. However, there is no widely accepted technique that can be referenced for use. It is known that the interlayer stiffness is a function of both temperature and load duration. The primary objective of this thesis is to formalize a standard procedure to estimate the in situ interlayer shear modulus through the use of nondestructive testing. Physical experiments were carried out on simply supported laminated glass beams subject to three point loading in a temperature controlled environmental testing chamber. Strains and temperatures were recorded as a function of time. These data were used in combination with results from finite element analyses to quantify the variation of the interlayer stiffness as a function of temperature and load duration for a given laminated glass beam. This procedure was applied to three common types of interlayer materials: freshly man-factured polyvinyl butyral (PVB), over a decade old PVB, and freshly manufactured SentryGlas Plus (SGP). Results from these efforts provide specific design guidance for laminated glass that incorporates these interlayer materials. Further, the procedure was applied to various data presented in open literature by previous researchers. In addition, a standardized procedure to estimate interlayer stiffness is provided for the development of additional interlayer properties as required.
2

Experimental Analysis Of Curved Laminated Beam

Uzhan, Tevfik 01 May 2010 (has links) (PDF)
ABSTRACT EXPERIMENTAL ANALYSIS OF CURVED LAMINATED GLASS BEAM Uzhan, Tevfik M.S., Department of Engineering Sciences Supervisor: Prof. Dr. M. Z&uuml / lf&uuml / ASik May 2010, 33 Pages In this thesis, experimental studies are carried out on curved laminated glass beams to form a database for the scientists who may like to test their mathematical models. Beams which are only free to rotate and constrained in radial direction at both ends are tested to make the data available for further calculations. Test setup is prepared to minimize error that could occur due to test setup and data readings. Material testing machine and 4 channel data collecting machine are used to measure the signals at the strain gauges located over the glass beam. Within the range of force applied to the specimens, laminated curved beam shows linear behavior without any fracture. Data collected from the specimens are in conformance with each other. Results obtained from experiments are compared with the results obtained from the mathematical model developed by ASik and Dural (2006). As it is observed from the graphs presented, experimental results from the tests and numerical results from the mathematical model are in good agreement.
3

ESTUDO DA INCORPORAÇÃO DE VIDRO DE PARA-BRISA EM MASSA DE PORCELANA SILICOSA E ALUMINOSA

Santos, Araldo Augusto Tisque dos 08 August 2012 (has links)
Made available in DSpace on 2017-07-21T20:42:38Z (GMT). No. of bitstreams: 1 Araldo Augusto Tisque dos Santos.pdf: 3494228 bytes, checksum: 10aa5475f02c7ee4a3913a8571815ebc (MD5) Previous issue date: 2012-08-08 / The glass is not a biodegradable material, which causes an environmental problem when it is discarded. However, it is a material that can be 100% recycled, or even re-used, but the laminated glass (glass windshields) is not accepted for recycling, this because it is a glass of low particle size and also by the difficulty of separating the glass polymer film, while this type of glass consisting of two or more layers of glass held together by one or more layers of a polymer called polyvinyl butyral (PVB). Thus it is necessary to find alternative means which allow recycling. In this thesis was studied the possibility of incorporating laminated glass in the ceramic bodies of siliceous and aluminous porcelain, replacing feldspar which acts as a flux these two ceramic bodies. The objective of this research is to verify the changes that the incorporation of glass windshields because the glassy phase of siliceous and aluminous porcelain and reflections that these changes have on the ceramic properties. Was chosen for this particle sizes of two glass laminate, and a thin, rough and added to another ceramic body in amounts of 5%, 10% and 15%, by weight replacing the same amount of feldspar. The powders of these mixtures were pressed and sintered at three different temperatures. Sintered porcelains were characterized through measurements of porosity, bulk density, water absorption, modulus of rupture by three point bending, X-ray diffraction, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS). The compositions siliceous and aluminous porcelain were introduced laminated glass of finer showed very similar results to those of composition without addition of laminated glass. / O vidro não é um material biodegradável, causando um problema ambiental quando o mesmo é descartado. Entretanto é um material que pode ser 100% reciclado, ou até mesmo reutilizado, mas o vidro laminado (vidro de para brisas) não é aceito para a reciclagem, isto por se tratar de um vidro de baixa granulometria e também pela dificuldade de separar o vidro do filme polimérico, sendo que este tipo de vidro composto por duas ou mais camadas de vidro unidas por uma ou mais camadas de um polímero chamado de polivinil butiral (PVB). Assim se torna necessário encontrar meios alternativos que permitam a reciclagem desse material. Nessa dissertação foi estudada a possibilidade da incorporação do vidro laminado nas massas cerâmicas de porcelana aluminosa e silicosa, substituindo o feldspato que atua como fundente nessas duas massas cerâmicas. O objetivo dessa pesquisa é de verificar as mudanças que a incorporação do vidro de para brisas causa na fase vítrea da porcelana aluminosa e silicosa e os reflexos que essas mudanças apresentam nas propriedades cerâmicas. Para isso foi escolhido duas granulometrias de vidro laminado, sendo uma fina e outra grosseira e adicionadas à massa cerâmica nas quantidades de 5%, 10% e 15%, em peso substituindo a mesma quantidade de feldspato. Os pós dessas misturas foram prensados e sinterizados em três temperaturas diferentes. As porcelanas sinterizadas foram então caracterizadas através de medidas de porosidade aparente, densidade aparente, absorção de água, módulo de ruptura por flexão de três pontas, difração de raios X, microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS). As composições de porcelana aluminosa e silicosa que foram introduzidos o vidro laminado de granulometria fina apresentaram resultados muito próximos aos das de composição sem adição de vidro laminado.
4

Analysis Of Laminated Glass Arches And Cylindrical Shells

Dural, Ebru 01 January 2011 (has links) (PDF)
In this study, a laminated glass unit which consists of two glass sheets bonded together by PVB is analyzed as a curved beam and as a cylindrical shell. Laminated glass curved beams and shells are used in architecture, aerospace, automobile and aircraft industries. Curved beam and shell structures differ from straight structures because of their initial curvature. Because of mathematical complexity most of the studies are about linear behavior rather than nonlinear behavior of curved beam and shell units. Therefore it is necessary to develop a mathematical model considering large deflection theory to analyze the behavior of curved beams and shells. Mechanical behavior of laminated glass structures are complicated because they can easily perform large displacement since they are very thin and the materials with the elastic modulus have order difference. To be more precise modulus of elasticity of glass is about 7*104 times greater than the modulus of elasticity of PVB interlayer. Because of the nonlinearity, analysis of the laminated glass has to be performed by considering large deflection effects. The mathematical model is developed for curved beams and shells by applying both the variational and the minimum potential energy principles to obtain nonlinear governing differential equations. The iterative technique is employed to obtain the deflections. Computer programs are developed to analyze the behavior of cylindrical shell and curved beam. For the verification of the results obtained from the developed model, the results from finite element models and experiments are used. Results used for verification of the model and the explanation of the bahavior of the laminated glass curved beams and shells are presented in figures.
5

Method Development and Analysis of Tensile Stresses in Windscreens : A study on the dynamic stresses on windscreens subjected to random vibrations.

Reis, Philip, Murthy, Karthik January 2018 (has links)
The thesis work deals with the study and determination of static and dynamic stresses acting on windscreen structures during transportation from the manufacturing site to the production plant. To simulate the stress distribution affected by the transportation, a finite element model of the windscreen is development of the structure and tested. The evaluated results from the stress analysis are then verified against results from literature and by own experimental results. The constructed FE model is simulated for modal response, and the response is validated against data from the experimental modal analysis. The data from the experiment is also used to calibrate the material card in an effort to get the most realistic dynamic response. The dynamic stress experiment was carried out at RISE Borås in accordance to ASTM D4169-16 DC3. Strain gauges were mounted at areas of interest. The readings obtained from the strain gauges used in the analytical calculation of stress, which were used to verify the finite element stress results. The fundamental aim of both experiments was to evaluate the dynamic behaviour and validate the numerical model. The pre-processing software ANSA was used to construct the finite element model and MSC Nastran was used as the FE- solver to simulate static and dynamic stresses on the structure. Transport loads were simulated using the random vibration load case, where a input load is in form of Power Spectral Density (PSD) data which describes the distribution of power into frequency components for a given time series. The input PSD was also in accordance with ASTM D4169-16 DC3, which is used to simulate the same response as in the experiment. During the numerical analysis, the glass and the intermediate PVB layer is assumed to be linear and isotropic. A validation of the numerical model was carried out against the experimental results to evaluate the predictive capability of the developed numerical model. The finite element model leads to good correlation of natural frequencies and their corresponding mode shapes at the lower range of frequencies valid till 100 Hz. This study is thus intended to construct and develop a FE model in order to predict the dynamic response and stress states experienced during transportation. It is further extended to predict the critical areas on the windscreen and help optimize the packaging of windscreens. During the course of study, it was found that, windscreens in the current transport arrangement experienced high stresses at areas close to the supports. The simulated stress values near the top right spacer (holding area) were close to the elastic limit of glass. This therefore, presented a high chance of damage to the windscreen when subjected to the random vibration. / <p>The authors want to acknowledge that this work was written in collaboration between two Universities, Philip Oliver Reis from Jönköping University from the Master of Science program Product Development and Materials Engineering and Karthik Vasudeva Murthy from Chalmers University from the Master of Science program in Applied Mechanics. The authors of this report were assigned together by Volvo Car Corporation, to complete this research work.</p>
6

Verre feuilleté : rupture dynamique d'adhésion / Laminated glass : dynamic rupture of adhesion

Elzière, Paul 29 September 2016 (has links)
Il y a plus d'un siècle, les verres feuilletés ont été découverts. Ces structures sont formées d'un intercalaire polymère pris entre deux plis de verre. Cet intercalaire améliore considérablement les performances à l'impact de l'assemblage. Lorsque le verre se brise, la délamination et l'étirement de l'intercalaire dissipent une grande quantité d'énergie. Les personnes sont protégées de l'objet impactant qui ne traverse pas le verre et des projections potentiellement dangereuses. Nous avons identifié et caractérisé les mécanismes de dissipation d'énergie associés au décollement de l'intercalaire et à l'étirement qui s'en suit. Des tests de traction uniaxiale et des mesures de biréfringence ont permis de relier le comportement de l'intercalaire à sa structure chimique. Les différents mécanismes dissipatifs du comportement de ce polymère ont été identifiés et décris dans un modèle rhéologique. Nous avons utilisé une expérience modèle afin d'établir les sollicitations subies par l'intercalaire lors de sa délamination du verre. Cette expérience consiste en un essai de traction uniaxiale sur un verre feuilleté pré-entaillé. Nous avons montré l'existence d'un régime de délamination stationnaire dans une gamme limitée de température et de vitesse de déplacement imposée. Dans ces conditions stationnaires, nous avons identifié deux zones de dissipation d'énergie. La corrélation digitale d'image a permis de quantifier la dynamique de déformation de l'intercalaire en aval du front et d'expliquer la grande quantité d'énergie dissipée. Enfin un modèle éléments finis a confirmé les observations expérimentales et permis d'explorer le voisinage du front de délamination. / Laminated glass has been discovered more than a century ago. It is composed of a polymeric interlayer sandwiched in-between two glass plies. This interlayer dramatically enhances the performance during impact. Even if the glass breaks, partial delamination and stretching of the interlayer will dissipate a large amount of energy. This dissipation will protect people from the impacting object while the glass splinters will stick on the interlayer, preventing harmful projections. I have identified and characterized the dissipation mechanisms associated with the interlayer rheology and its delamination from glass.Using uniaxial traction tests combined with photoelastic measurements, a relationship between the polymer structure and its mechanical behavior has been provided. The different dissipating mechanisms of the interlayer rheology have been identified in a rheological model. To understand how the interlayer mechanical behavior is involved during the lost of adhesion at the glass interface, a model delamination experiment has been setup. This test consists in a uniaxial traction on a pre-cracked laminated glass sample. In a certain range of applied velocities and temperatures, a steady state delamination regime has been observed. In these steady state conditions, two zones of dissipation have been identified. Digital image correlation has been used to quantify the stretching dynamics of the interlayer ahead of the delamination fronts and to explain the large dissipation observed during impact. Finally a finite element model has been developed to confirm experimental observations and to explore the close vicinity of the delamination fronts.
7

Statická a dynamická analýza skleněných konstrukcí. / Statical and dynamical analysis of glass structures

Trojanová, Lenka January 2014 (has links)
Glass and the glass elements found thein way into almou all area sof human aktivity thanks to technological advances of the last 20 years. The are of construction i sof course no exeption, quite the contrary. These days it is difficult to imagine building without the glass element, whether it is a part of the interior or exterior. Yet the theory on this issue is at a very low level in the Czech Republic. The content of my work is static and dynamic analysis of structures of glass, when it is applied in practice, it will save money.
8

Characterisation of laminated glass for structural applications

Akter, Shaheda T., Khani, Mohammad January 2013 (has links)
Laminated glass (LG) consists of two or more glass layers bonded by an elasto-polymeric layer, the most commonly used being PVB (Polyvinyl Butyral). LG has improved safety properties compared with single layer glass because the interlayer prevents large sharp pieces from spreading when the glass is broken by impact. Even if one of the layers breaks, the other layer(s) still contribute in carrying the load. Through proper understanding of the interaction between the interlayer and the glass LG could be used in engineering as a load bearing material to a larger extent. This study aims at gaining a deeper knowledge of the behaviour of laminated glass by experimental investigations and by numerical model simulation. To pursue the proposed study, three point bending test with simple support conditions were performed for single layer glass and laminated glass units with three different types of interlayer materials. Corresponding finite element numerical models were created in the software ABAQUS to fit the model with experiment to obtain the bending stiffness and shear stiffness of the interlayer material. The PVB tested showed viscos-elastic material properties, whereas other two interlayer materials, Solutia DG 41 and Sentry Glass, showed linear elastic properties. PVB is the least stiff interlayer material among the three types. Solutia DG 41 and Sentry Glass have similar stiffness, about 13 to 15 times stiffer than the PVB. The behaviour of laminated glass lies in general between the two limits of a layered glass unit with no interaction and a monolithic unit of the same total thickness, depending on the stiffness of the interlayer material. Failure tests of the specimens were also carried out. The obtained strength of glass from four specimens is 80 MPa to 92 MPa with a variation of about 15%. The number of more performed experiments would have better outcome for strength of glass. The bending stiffness of the laminated glass as estimated with the numerical model fitted well with the experimental results with an error of about 2%. Hence the experimentally and numerically obtained results show a good correlation and are thought be possible to use in future larger scale modelling.
9

Transmission Loss Analysis of Laminated Glass with Porous Layers using Transfer Matrices for Automotive Applications

Suresh, Saurabh 26 September 2011 (has links)
No description available.
10

Design Of Glass Structures: Effects Of Interlayer Types On Heat-treated Laminated Glass

Akdeniz, Verda 01 September 2007 (has links) (PDF)
Glass is an inherrently strong and elastic building material that allows the enclosure of spaces to provide both comfort and &aelig / sthetic appeal. It is evidently due recognition of these properties that has resulted in the current propensity to use it in ever larger sizes / and then with minimum&ndash / if not total absence&ndash / of visible supporting structure. It is, however, its lack of plastic behavior under stress&ndash / leading to catastrophic failure without warning&ndash / that has been the main drawback preventing its use as a structural material on its own. Ergo, the development of composite configurations with plastic interlayers, commonly known as structural glass. Contemporary working methods for glass have also been able to provide better structural characteristics&ndash / particularly after heat treatments, which reduce its vulnerability to cracking and brittle failure. In com-bination, these methods offer designers the possibility of using glass panels capable of acting as load-carrying structural elements. The aim of this study was to investigate the performance of glass-adhesive-glass composite, or laminated, elements and the use of glass as a structural material in light of their inherent strength properties. Here, an attempt was made to define the be-havior of interlayers in structural glass and to then prepare a selection guide. To this end, it was necessary to first gather information about the materials and design methods used to create glass structures. As the literature notes that such stresses are particularly important to structural glass design due to the inability of the material to flow plastically and to thus relieve high stresses, pertinent simulation techniques (e.g., finite element analysis) were then used to investigate shear transfer between glass panes and interlayers. These simulations allowed determination of stiffness with different types of interlayer for panes of different dimensions and orien-tation in respect to loading conditions. It was the results of these analyses that were finally compiled into the selection guide already noted. It is expected that these results will make a worthwhile contribution to developing glass structure design and its application in practice.

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