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Eksik, Ömer. "Structural performance of GRP top hat stiffened marine structures". Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431952.
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Nunes, Eliana Ferreira. "Qualitative investigation of the performance of a structural membrane roof project". reponame:Repositório Institucional da UFOP, 2012. http://www.repositorio.ufop.br/handle/123456789/6036.
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Programa de Pós Graduação em Engenharia Civil. Departamento de Engenharia Civil, Escola de Minas, Universidade Federal de Ouro Preto.Submitted by Oliveira Flávia (flavia@sisbin.ufop.br) on 2016-01-14T15:41:06Z No. of bitstreams: 1 TESE_QualitativeInvestigationPerformance.pdf: 28313982 bytes, checksum: 7fa9b21301ee73fcec79f7676cdc021f (MD5)
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This paper provides a qualitative investigation about the structural performance of the membranes, surface structures (with double curvature in opposite directions) with minimum thickness and weight, which absorb forces in form of tensile stresses in its own plane, considering two aspects: structural and design procedure. Initially, it involved the analyses of lightweight structure buildings and the observation of constructive work process in membrane roofs. These investigations allowed identifying strategies that contribute to achieve optimum system performance and the challenges encountered along the stages of designing and building. They also guided the qualitative analysis of the performance of a structural membrane roofing project, i.e., a particular situation, as example. This qualitative analysis was developed in two stages, guided by experimental and numerical data. The first stage involved the optimization procedure of the structural system under load action. This analysis showed that the flexible system performance is a result of the three-dimensional stability of the structural system (arrangement and geometry of all components), membrane surface stiffness (membrane geometry), as well as the cooperation of all components in pre-tension state. The second stage comprised the experimental investigation of the membrane material behaviour within the structure context in order to analyze the flattened membrane geometry. Such evaluation enabled to verify the difference between the theoretical model (shape of equilibrium) and the actual shape (consisting of flat panels), enabling the proper adjustment of the surface geometry so that the final shape can reveal not only the path of the forces, but also the best use of the material. The investigations, analyses and working procedure here adopted broadened the understanding of this system pointing possibilities to increase its performance and to minimize failures during the preliminary stage of design.
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Carboni, Julia L. "Structural Predictors of Contract Performance". Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/255195.
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Government increasingly contracts out public functions to the private sector. While theory about contract performance management is abundant, there is little empirical evidence on contract performance. Additionally, the public management contract literature emphasizes management strategies to produce desired performance but largely disregards how the structure of ex post contract settings influences individual contract performance. In this dissertation, I develop theory and measures to assess how structural variables influence contract performance on quality dimensions. I focus on networked structures of exchange between contracted programs and government funders and the way exchange is situated in a larger environment. The empirical basis for my dissertation is a set of government funded residential services programs for delinquent youth. The outcome variable is a measure of program quality created by the government funder. Predictor variables include competition at the program and parent organization level and the overall presence of public and nonprofit programs in the contract network. I also examine the effects of organizational form on performance. Most programs are contracted to nonprofit and for-profit organizations with a small number of programs directly provided by government. The mixed market provides an opportunity to test existing theory about organizational form and performance. I use hierarchical linear models (HLM) and qualitative comparative analysis (QCA) to examine how structural variables influence performance. In the HLM analysis, I find some support for my hypotheses about structural predictors of performance. In the QCA analysis, I find that effects of organizational form are conditional upon structural variables. It appears that nonprofit and public programs perform well under a variety of conditions while for-profit programs are more likely to perform acceptably when they are constrained by structural factors like competition. This dissertation makes theoretical, empirical and practical contributions to the field of public management. Following recent, scholarly tradition, I examine the changing role of government and its increasing use of the nonprofit and for-profit organizations to deliver government services. I incorporate structural theory into the contract management literature and demonstrate the structure of contract settings influences performance. I also develop formal measures of competition in contract settings. I also find that HLM and QCA can be complementary analytical tools and provide a richer picture of causal processes when used on the same dataset.
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Tannert, Thomas. "Structural performance of rounded dovetail connections". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/694.
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The structural performance of Rounded Dovetail Connections (RDC) has been studied experimentally and numerically to provide information needed for connection structural design.
RDC are mainly used to transfer vertical shear forces, but test results show that they can carry considerable load in tension and bending. Geometric parameters, such as dovetail flange angle and dovetail height are shown to significantly effect affect the structural performance of RDC. Results show that it is impractical to determine a set of empirical equations to describe the structural performance of RDC based on basic wood material properties. RDC manufactured and tested with low and constant moisture content outperformed those evaluated under other climatic conditions, and test results demonstrate that RDC should be produced at low machine speed and with minimal a gap between the connecting members. RDC in laminated strand lumber have higher capacity and fail under larger deformations compared to RDC in western hemlock.
A three-dimensional finite element method model is presented and validated with experimental tests. Good agreement is achieved between the load deformation response predicted by the model and the experimentally observed load deformation response. Therefore the model is deemed suitable for estimating the stresses needed to develop failure criteria. A failure criterion for the analysis of RDC is presented taking into account size effect in the strength of wood. Based on the experimental and numerical studies, a design equation for RDC is presented that provides the engineering community with a new design tool. Finally, self tapping screws as reinforcement have been studied and are shown to significantly improve the structural performance of RDC under vertical shear loading.
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Ghisbain, Pierre. "Seismic performance assessment for structural optimization". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82833.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 223-228).
The economic impact of earthquakes has spurred the implementation of performance-based design to mitigate damage in addition to protecting human lives. A developing trend is to consider damage directly as a measure of seismic performance. In spite of the ability to estimate the cost of future earthquakes, adjusting the investment in seismic upgrades is impeded by the computational requirements of the probabilistic damage assessment. In this dissertation, we develop the damage assessment tools needed to implement structural optimization with an estimate of lifetime seismic damage in the objective function. A parametric study of the procedure to predict damage from earthquake simulation results is presented. By varying the procedure and analyzing the effects on the damage estimate, we identify simplifications that are beneficial for practical applications without losing important information about the behavior of the structure under seismic loads. The runtime of the probabilistic damage assessment is dominated by the response analysis of the structure to a range of earthquake scenarios. We consider alternatives to the standard but expensive nonlinear dynamic analysis, and we evaluate the error introduced by the faster analysis methods. The applicability of linear dynamic analysis is further investigated by detailing the effects of structural nonlinearities on the lifetime damage assessment. We determine that these effects are limited for the performance-based designed buildings, whose responses to the moderate but more frequent earthquakes remain essentially elastic. An application to the placement and sizing of viscous dampers in building frames is presented. A first procedure seeks the optimal trade-off between the investment in damping and the losses due to future earthquakes. For each level of damping considered, another optimization problem is solved to determine the most efficient damper layout considering the results of the damage assessment in a true performance-based design process.
by Pierre Ghisbain.
Ph.D.
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Bianchi, Gabriel. "Structural performance of spacecraft honeycomb panels". Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/333288/.
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Honeycomb sandwich structures (commonly referred to as honeycomb sandwich panels) have found wide spread application in the aerospace industry thanks to their excellent properties, in particular their high strength-to-weight and high stiffness-to-weight ratios. Surrey Satellite Technology Ltd. (SSTL), like many other space companies, often use honeycomb sandwich panels as part of the primary and secondary structures of the small satellites they develop. Although honeycomb panels have been used for the past 50 years gaining a better understanding of these sandwich structures, and the methods and solutions used to produce structural assemblies from them is still a major concern in the aerospace industry. Whether directly or indirectly, there are still significant research efforts ongoing that affect these areas. This work focuses on some of these issues and covers several research fields including material science, tribology and adhesive bonding technology. The first area of focus of this work deals with the structural performance of honeycomb panels alone and mainly concentrates on hexagonal honeycomb cores. An experimental investigation using the rail shear test was conducted to study the shear behaviour of hexagonal honeycomb cores. This involved both static and fatigue tests using numerous honeycomb panel test samples with the loading direction at various angles to the core ribbon. From these tests it was found that core shear strength did not have a linear relationship with loading orientation and that contrary to what is commonly assumed the transverse direction (to the ribbon) is not always necessarily the weakest orientation. The optimal design and performance of the load introduction points was the second area of focus for this work which covers equipment inserts and bolted joints. Two types of inserts where investigated in this work: hot bonded inserts and cold bonded inserts. A study on hot bonded and cold bonded inserts was conducted to assess their performance and effectively compare the two insert systems. A large portion of the study was experimental and involved carrying out numerous insert pull-out tests to measure static pull strength capability. From the study it was found that contrary to what was expected cold bonded potted inserts outperformed the hot bonded inserts in terms of static strength capability. Using finite element it was found that this was due to the different filler materials used for the two insert systems. The last area covered in this work concerns friction grip bolted joint between honeycomb panels. Here a simple method to analyze the efficiency of shear joint units is proposed. An extensive test campaign was also carried out to determine the influence of various parameters on the friction coefficient. Surface abrasion was found to be a reliable way of achieving high values of friction coefficient.
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Zhu, Junqing. "Structural Performance Analysis of Underground Stormwater Storage Chamber". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1338490426.
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Mattingly, James E. "Stakeholder salience, structural development, and firm performance : structural and performance correlates of socio-political stakeholder management strategies /". free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3099618.
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O'Sullivan, Donald Quinn 1970. "Structural elements with mathematically defined surfaces for enhanced structural and acoustic performance". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8664.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 205-209).
Two design methods are explored to reduce vibration, minimize unwanted acoustic noise, and increase stiffness in structures. The first design approach is to create nearly isotropic panels with increased stiffness using two-dimensional curvature. These quasi-isotropic designs can be used in lieu of typical panel reinforcements, and can provide an inexpensive alternative to honeycomb sandwich designs. The second approach is to design panels formed into the shape of a mode shape to reduce detrimental modal dynamics. The effects of combining the two-dimensionally curved designs with constrained layer damping is also investigated. Further, it is also the goal of this research that these panels can be inexpensively manufactured with current manufacturing methods (e.g. stamping, rolling, thermoforming, etc.), resulting in a more effective structural element that does not require significant extra cost or weight. Initial analysis was performed using geometric modeling and finite element analysis. Experimental analysis involved both static and dynamic system identification. The experimental results indicate that quasi-isotropic designs can be accomplished with two-dimensional curvature.
(cont.) These quasi-isotropic designs increase the stiffness of a panel and raise the natural frequency by a factor of 2 (compared to a flat panel of the same mass). Although the quasi-isotropic designs have no acoustic benefit, they were shown to be effective replacements as honeycomb cores. The mode-shaped designs demonstrated the unique quality of simultaneously reducing vibration and acoustic noise over a broad frequency range (50-10,000 Hz). The mode-shaped panels demonstrated a factor of 3 increase in the natural frequency, a ten-fold reduction in dynamic deflection displacements, and a 3 to 4 dB RMS reduction in the radiation index over a broad frequency range.
by Donald Quinn O'Sullivan.
Ph.D.
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Lingblad, Mats Axel. "The structural determinants of innovation project performance". Thesis, London Business School (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429936.
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Kim, Harry M. Eng Massachusetts Institute of Technology. "Structural performance of spoke wheel roof systems". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111513.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 65-66).
A spoke wheel roof system consists of tension rings, compression rings, and radial spokes and resists loads mainly through axial forces. Due to its light weight and ability to achieve a column-free, long span, it has been a popular solution to structures such as stadia since its first use in 1960s. However, there has been lack of information on the performance of a spoke wheel roof system depending on its geometry. This thesis explores the history and general behaviors of a spoke wheel roof system. A representative model is created and tested in Rhino-Grasshopper-Karamba, and the geometric variations to the structure and their influence are evaluated. Configuration of the rings, inner and outer ring radii, aspect ratios of the rings, spoke spacing and slope are chosen to be variables, and load path is used as an evaluation criterion for structural performance or efficiency. Results show that the choice between different ring configurations depends on architectural needs and climate conditions. Assuming that minimal load path implies high structural performance, roof span and size are inversely related to the structural performance. They have a greater influence than the aspect ratios of the rings. Smaller spacing and larger slope of the spokes lead to a more efficient structure.
by Harry Kim.
M. Eng.
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Weber, Matthias. "Structural Performance Comparison of Parallel Software Applications". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-216133.
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With rising complexity of high performance computing systems and their parallel software, performance analysis and optimization has become essential in the development of efficient applications. The comparison of performance data is a key operation required in performance analysis. An analyst may conduct different types of comparisons in order to understand the performance properties of an application. One use case is comparing performance data from multiple measurements. Typical examples for such comparisons are before/after comparisons when applying optimizations or changing code versions. Besides comparing performance between multiple runs, also comparing performance characteristics across the parallel execution streams of an application is essential to detect performance problems. This is typically useful to detect imbalances, outliers, or changing runtime behavior during the execution of an application. While such comparisons are straightforward for the aggregated data in performance profiles, only limited solutions exist for comparing event traces. Trace-based analysis, i.e., the collection of fine-grained information on individual application events with timestamps and application context, has proven to be a powerful technique. The detailed performance information included in event traces make them very suitable for performance analysis. However, this level of detail also presents a challenge because it implies a large and overwhelming amount of data. Currently, users need to perform manual comparison of event traces, which is extremely challenging and time consuming because of the large volume of detailed data and the need to correctly line up trace events.
To fill the gap of missing solutions for automatic comparison of event traces, this work proposes a set of techniques that automatically align traces. The alignment allows their structural comparison and the highlighting of differences between them. A set of novel metrics provide the user with an objective measure of the differences between traces, both in terms of differences in the event stream and timing differences across events.
An additional important aspect of trace-based analysis is the visualization of performance data in event timelines. This has proven to be a powerful approach for the detection of various types of performance problems. However, visualization of large numbers of event timelines quickly hits the limits of available display resolution. Likewise, identifying performance problems is challenging in the large amount of visualized performance data. To alleviate these problems this work proposes two new approaches for event timeline visualization. First, novel folding strategies for event timelines facilitate visual scalability and provide powerful overviews of performance data at the same time. Second, this work presents an effective approach that automatically identifies and highlights several types of performance critical sections in an application run. This approach identifies time dominant functions of an application and subsequently uses them to analyze runtime imbalances throughout the application run. Intuitive visualizations present the resulting runtime variations and guide the analyst to performance hot spots.
Evaluations with benchmarks and real-world applications assess all introduced techniques. The effectiveness of the comparison approaches is demonstrated by showing automatically detected performance issues and structural differences between different versions of applications and across parallel execution streams. Case studies showcase the capabilities of the event timeline visualization techniques by demonstrating scalable performance data visualizations and detecting performance problems and code inefficiencies in real-world applications.
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Pye, Andrew John. "The structural performance of glass-adhesive T-beams". Thesis, University of Bath, 1998. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275417.
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Jang, Jae Won. "Characterization of live modeling performance boundaries for computational structural mechanics /". Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10178.
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Sazak, Hasan. "STRUCTURAL HEALTH MONITORING OF A STADIUM FOR EVALUATING HUMAN COMFORT AND STRUCTURAL PERFORMANCE". Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4473.
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Light and rapid constructions as well as considerations such as improved line of sight and increased capacity for modern stadium structures make them vulnerable for vibration serviceability problems. These problems are also observed at convention centers, large shopping malls, concert halls and ballrooms. Especially when the individuals in a crowd are involved in some sort of coordinated motion, this type of loading creates the most potential for high levels of vibration. In order to understand the causes of vibration, vibration levels, service and safety levels, Structural Health Monitoring (SHM) can be implemented to track and evaluate performance of a structure during events such as games at football stadia. SHM becomes a critical need especially when decisions such as repair and retrofit are to be made for the structure. The main objectives of this study are a) to determine the impact of vibration to human comfort levels; b) to identify dynamic loading for the coordinated motion; c) to determine the structural performance by means of a detailed model validated using experimental data. In order to achieve these objectives, a football stadium was monitored for three years to establish the vibration levels during different games and different events in each game such as goals, interceptions, playing a particular song. It is seen that certain events and long periods of playing particular songs induced vibration levels that are at the threshold of human comfort based on the design codes. To simulate the crowd motion due to this song, a laboratory study was designed and conducted to experimentally determine the forcing functions due to jumping with the rhythm of the song. The spectral analysis of the stadium data and the song also revealed that the first mode frequency of the stadium and the dominant frequency of the music are very close, creating resonance conditions. Further investigative studies were conducted by developing a finite element (FE) model of the stadium, which was validated using the results of the modal analysis from the ambient vibration data. Subsequently, the FE model was employed to simulate forcing functions obtained from the laboratory studies to explore the vibration levels, dynamic response as well as the response of the structure when it is retrofitted by additional elements. In addition, different aspects of model development, with respect to the physical model of the stadium were outlined in terms of design considerations, instrumentation, finite element modeling, and simulating dynamic effect of spectators. Finally, the effectiveness of the retrofit by adding elements to the steel structure of the stadium was explored by simulating the crowd motion with the FE model.M.S.
Department of Civil, Environmental, and Construction Engineering;
Engineering and Computer Science
Civil, Environmental, and Construction Engineering
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Mwafy, Aman Allah Mohamed Abdel-Rahman. "Seismic performance of code designed RC buildings". Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/7285.
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Alvarez-Valencia, Daniel. "Structural Performance of Wood Plastic Composite Sheet Piling". Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/AlvarezValenciaD2009.pdf.
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Hellqvist, Kjell Maria. "Performance of Conventional and Structural Lithium-Ion Batteries". Doctoral thesis, KTH, Tillämpad elektrokemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122875.
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Lithium-ion batteries have, in recent years, experienced a rapid development from small everyday devices towards hybrid electric vehicle (HEV) applications. Due to this shift in application area, the battery performance andits degradation with time are becoming increasingly important issues to besolved.In this thesis, lithium-ion batteries are investigated with focus on lifetime performance of an existing battery chemistry, and development of electrodes for so-called structural batteries. The systems are evaluated by electrochemical methods, such as cycling and electrochemical impedance spectroscopy (EIS),combined with material characterization and modeling. Lifetime performance of mesocarbon microbeads (MCMB)/LiFePO4 cells was investigated to develop an understanding of how this technology tolerates and is influenced by different conditions, such as cycling, storage and temperature.The lifetime of the LiFePO4-based cells was found to be significantly reduced by cycling at elevated temperature, almost five times shorter compared to cycle-aged cells at ambient temperature. The calendar-aged cells also showed major signs of degradation at elevated temperatures. The overall cause of aging was electrolyte decomposition which resulted in loss of cyclable lithium, i.e. capacity fade, and impedance increase. Commercially available polyacrylonitrile (PAN)-based carbon fibers were investigated, both electrochemically and mechanically, to determine their suitability as negative electrodes in structural batteries. The electrochemical performance of carbon fibers was found to be excellent compared to other negative electrode materials, especially for single or well-separated fibers. The mechanical properties, measured as changes in the tensile properties, showed that the tensile stiffness was unaffected by lithium-ion intercalation and cycling. The ultimate tensile strength, however, showed a distinct variation with state-of-charge (SOC). Overall, carbon fibers are suitable for structural battery applications.QC 20130529
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Abukari, Mohammed Hashim. "The performance of structural screws in Canadian Glulam". Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110664.
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The development of engineered wood products (EWPs), such as glued laminated timber, has led to the production of structural members with increased strength and spanning capabilities compared with solid sawn lumber and timber, and similar to what one could attain with commonly sized steel and reinforced concrete members. An important reason for the underutilisation of wood for heavy construction is the limitation of the CSA O86 Wood Design Standard especially as it applies to the design of fastenings for highly loaded connections. This thesis addresses the connection design of glulam and sawn wood using structural self-tapping/self-drilling screws from Europe.The CSA–O86 Standard provides formulas for the design of both lag and wood screws in Canada. Recently in Europe structural screws have been developed which combine the advantages of both lag and wood screws. These screws have high load carrying capacities and withdrawal strengths and are also self-tapping/self-drilling, hence in most cases do not need lead holes. However CSA O86 has no specific design provisions for these screws. To assess their viability for use in Canada, two test programs were carried out; the first on the withdrawal resistance of the screws and the second on the performance of inclined screws in joist-to-header connections. Douglas fir Larch(20f-E), Spruce Pine (20f-E) and Nordic Lam (24f-1.9E) glulam in conjunction with a variety of 6, 8, 10 and 12mm diameter European structural screws were used for the withdrawal tests, while the joist to header connections were made of No.2 white pine timber connected by double threaded 8.2mm WT-T screws from SFS intec. In all 1960 withdrawal test were carried out. The test setup and procedure was modelled after ASTM D1761.The joist to header test set-up, involving 14 tests was modelled after ASTM D7147. The main aim of the withdrawal test program was to recommend a generic equation for use in the design of these screw connections with Canadian glulam. In the process the effects of Canadian wood density, depth of penetration, screw diameter and lead holes on the withdrawal resistance of the screws were assessed. The aim of the joist to header connection test program was to compare the performance of dry specimen with that of the same connection in wet timber.The test results demonstrated that the withdrawal strength per unit length increases with denser wood, except 6mm and 8mm in Nordic Lam glulam. The depth of penetration affects the withdrawal strength, where for larger screws an increase of slightly more than double was obtained for 12d penetration compared to 6d.The orientation of the glulam, that is either top or side, was insignificant other than the effect it had on the scatter of the strength results. The use of lead holes was shown for both the 8mm and 10mm not to influence the withdrawal strength. However the lead holes improved the ease of installation for the larger screws, especially in the dense glulam.The tests results were compared with the predicted characteristic and average withdrawal resistance values, which were calculated using formulas found in timber codes around the world, namely CSA O86 (Canada), NDS (USA), Eurocode 5 (Europe), DIN 1052 (German) and from other researchers including Frese and Blaβ (GER), Pirnbacher and Schickhofer (AUT) and McLain (USA). All methods resulted in a reasonable prediction of the withdrawal resistance except for the CSA O86 formula for lag screws which was very conservative. The McLain formula for lag screws provided the closest prediction of the test result, but bearing in mind the variability of wood, all the other methods could be considered as acceptable except for the CSA O86 lag screw equation. Regarding the joist-to-header cross screw connections, the dry tests were measured to have a 35% increase in resistance compared with the wet specimens; furthermore, the Kevarinmäki formula provided the most accurate prediction of the resistance.Le développement de produits de bois d'ingénierie a entrainé la production d'éléments de structure de la résistance et de portée supérieures, et similaires à ce qu'il pourrait être atteint avec de l'acier de taille commune et des éléments porteurs en béton armé. Une raison importante pour la sous-utilisation de bois pour la construction lourde est la limitation des règles de calcul des charpentes en bois CSA O86, en particulier lorsqu'elles s'appliquent au design d'assemblages soumis à de charges importantes. Cette thèse étudie la conception des assemblages en bois lamellé-collé et bois scié utilisant des vis auto perçantes européennes.La norme CSA O86 fournit des formules pour la conception de tire fond et des vis à bois au Canada. En Europe, des vis qui présentent à la fois les avantages de tire fond et des vis à bois ont été récemment développées. Ces vis ont de résistance latérale et à l'arrachement élevée, et sont auto-perçantes. Toutefois, la norme CSA O86 ne contient aucune disposition spécifique pour la conception de ces vis. Pour évaluer la viabilité de leur utilisation au Canada, deux séries de test ont été réalisées: la première sur la résistance à l'arrachement des vis et la seconde sur la performance de vis inclinées dans les connexions entre solive et poutre. Du lamellé-collé Douglas-Mélèze (20f-E), Épinette-Pin (20f-E) et Nordic Lam (24f-1.9E) ont été utilisés avec des variétés de vis européennes de 6, 8, 10 et 12 mm de diamètre pour les essais d'arrachement, tandis que les connections solive-poutre étaient faites de pin blanc no 2 relié par des vis WT-T à double filetage 8.2mm. Au total, 1960 tests d'arrachement ont été effectués d'après ASTM D1761 tandis que 14 du test solive-poutre mis en place ont été effectués d'après ASTM D7147. L'objectif principal du programme de tests d'arrachement était de recommander une équation générique à utiliser dans la conception de ces connexions de vis avec du lamellé-collé canadien. Les effets de la densité du bois, de la profondeur et du diamètre de la vis et des trous pilotes sur la résistance à l'arrachement des vis ont été évalués. Test de connexion solive-poutre était de comparer la performance de l'échantillon sec avec celle de la même connexion en bois humide.Les résultats montrent que la résistance à l'arrachement augmente avec la densité du bois, à l'exception de vis 6 et 8 mm dans le lamellé-collé Nordic Lam. La résistance à l'arrachement est influence par la profondeur de pénétration et pour les plus grandes vis, il a été un peu plus que doublée pour une pénétration 12d par rapport à 6d. L'orientation du lamellé-collé, qui peut être transversale ou latérale, n'a pas d'importance autre que son effet sur la dispersion des valeurs de résistance. Il a été montré que trous pilotes n'influence pas la résistance à l'arrachement pour les diamètres 8 mm et 10 mm mais elles améliorent la facilité d'installation pour les vis plus grandes, en le bois lamellé-collé dense.Les résultats des tests ont été comparés avec les valeurs caractéristiques prédites par calculs selon des formules trouvées dans cette codes ; CSA O86 (Canada), NDS(USA), l'Eurocode 5 (Europe),DIN 1052(Allemagne) et de chercheurs, dont Frese et Blaβ, Pirnbacher et Schickhofer, et McLain. Toutes les méthodes ont conduit à une prédiction raisonnable de la résistance à l'arrachement, à l'exception de la formule de CSA O86 pour les vis de compression, qui est très conservatrice. La formule de McLain pour les vis à compression donne la prédiction la plus proche des résultats des essais, mais compte tenu de la variabilité du bois, toutes les autres méthodes peuvent être considérés comme acceptables, à l'exception de celle de la CSA O86 pour les tire fond. En ce qui concerne les connexions solive-poutre par des vis inclinées,les essais à sec montrent une augmentation de 35% de la résistance par rapport aux spécimens humides;en outre la formule de Kevarinmäki donne la prédiction de résistance la plus précise.
20
Wu, G. P. "Structural performance of multi-layered laminated glass plates". Thesis, Swansea University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636698.
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The work presented in this thesis focus on analysing the structural performance of multi-layered laminated glass places subjected to uniform pressure loading. Numerical simulations using ANSYS finite element software has been performed to analyse the behaviour of laminated glass plates. Theoretical laminated glass beam models that represent the interaction of forces between PVB interlayer and glass have been presented. Based on the formulation of theoretical models, a new modelling technique using shell and link elements has been proposed. The behaviour of glass plate is captured by the shell element and the shearing behaviour of PVB interlayer is simulated by a structure constructed of link elements. The shearing behaviour of PVB interlayer can be modelled as linear, if the shear strain does not reach the non-linear limit. The modelling technique has been applied to model experimental results provided by the Public Services Agency and close agreement of results have been obtained. Parametric studies have been carried out on laminated glass models and discussions have been made. Using two non-dimensional parameters, design equations for 3-ply, 5-ply and 7-ply laminated glass plates have been proposed. For the case of 3-ply laminated glass plates, it is discovered that the design equations with 40MPa and 45MPa design stresses predicted close agreement to experimental results. For the case of 5-ply and 7-ply laminated glass plates. 28MPa and 33MPa design stresses predicted close agreement to experimental results. For samples with standard interlayer thickness, same plate dimensions and glass thickness, laminated glass plates can be stronger than monolithic glass plates. Additionally in most cases, the load bearing capacity of laminated glass plates with more layers is higher or comparable to laminated glass plates with fewer layers. This is caused by the redistribution of bending and membrane stresses due to early or late development of membrane effect.
21
Mays, Geoffrey Charles. "Fatigue performance and durability of structural adhesive joints". Thesis, University of Dundee, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334180.
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Friis, Jesper. "Structural performance of confined high strength concrete columns". Thesis, City University London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397864.
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Kalombaris, A. "Structural maintenance assessment and performance of minor roads". Thesis, University of Hertfordshire, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276181.
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Arnaout, S. "The structural performance of egg-shaped sewer linings". Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/46943.
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Thomson, Andrew. "The structural performance of non-metallic timber connections". Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544513.
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Reducing the amount of metal used within a timber structure has many advantages, particularly when dealing with connections. Fire resistance and durability are commonly cited benefits. In addition the use of alternative connector materials minimises thermal bridging and can also provide a lighter weight structural solution. Existing contemporary forms of non-metallic timber connections are commonly provided through the use of adhesives. However, these connections are reliant on a need for careful offsite, prefabricated construction. Traditional green oak carpentry connections provide a mechanically fastened non-metallic solution. However, carpentry connections are not widely compatible with contemporary architectural design or with the use of modern engineered timber products such as glulam. Building upon research completed at the University of Bath, the aim of this thesis was to develop a mechanical, non-metallic connection system suitable for contemporary applications. Specific objectives were to investigate the structural performance of a defined connection system and to develop analysis methods to facilitate design. A review of the literature demonstrated a lack of uptake and use of mechanical non-metallic connections. Guidance for the design of mechanical fasteners reflects the lack of innovation and research into the use of non-metallic materials. Following an initial experimental investigation of non-metallic materials, an experimental testing programme was completed to investigate the use of glass fibre reinforced plastic (GFRP) dowels in conjunction with densified veneer wood (DVW) plates. The findings of the experimental study demonstrate that the use of these materials can provide a robust connection system for contemporary applications. The results of the experimental work provide guidance on dowel spacing requirements, connection response to load and connection failure modes. The failure modes of the proposed connection system were shown to be unique to the materials used and specific strength analysis methods have been developed to predict connection yield and ultimate strength. A method for predicting initial connection stiffness was also developed through the use of a beam on elastic foundation model.
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Chow, Yi-Mei Maria 1974. "Computational fluid dynamics for high performance structural facilities". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50366.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.Includes bibliographical references (leaves 104-106).
by Yi-Mei Maria Chow.
M.Eng.
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Al-Khudairi, Othman. "Structural performance of horizontal axis wind turbine blade". Thesis, Kingston University, 2014. http://eprints.kingston.ac.uk/32197/.
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The power output from a wind turbine is proportional to rotor swept area and as a result in the past 30 years continuous effort has been made to design larger blades. In this period, the blade length has been increased about 10 times since 1980s to present time. With the longest blade currently measuring more than 100m in length, wind turbine blade designers and manufacturers face enormous challenges to encounter the effect of increased weight and other loads on fatigue durability of the blade. Wind turbine blades are mainly made from glass fibre reinforced plastic (GFRP) composite. materials. As a result, in the design of various parts of wind turbine blades such as the shear web, spar cap and the aerofoil the fatigue behaviour of F RP materials is required. The performance of these parts as well as the adhesively bonded joint under fatigue loading is crucial for structural integrity of a long lasting blade. During operation, delamination can initiate and propagate shortening blade life; hence, characterisation of failure envelope of GFRP laminates under different loading mode is necessary. In this regard in this project, quasi-static tests were carried out to find mode 1, mode 11 and mixed mode I/11 delamination fracture toughness using DCB, ENF and MMB tests and the fracture envelope was established for various mode mixity. In the next stage, the stress-lifetime (S-N) diagrams of the GFRP was studied. Fatigue-life experiments on three different types of loading, i.e. tension-tension at R=0.1, 0.5, tension- compression at R=-1 and compression-compression at R=2 and R=10 were performed. From the results of S-N diagrams, the constant life diagrams (CLD) for 90 degree and 0 degree fibre directions were constructed. CLD diagrams are useful for prediction of fatigue lifetime for loading condition that no experimental data available. The analysis of delamination crack propagation under cyclic loading was next area of the research. The onset life and propagation delamination crack grth of 0//0 interface of GR P laminate in mode I loading using DCB specimens was investigated and the Gm. from the onset life test was determined. From the fitted curve to mode I experimental propagation data the Paris’ law coefficient for the laminated GFRP in mode I was determined. The mode II fatigue crack growth in laminated 0//0 GFRP material was also investigated using ENF specimens. The fatigue behaviour in this mode is analysed based on application of Paris’ law as a function of energy release rate for mode II loading. From the fitted curve to experimental data, the Paris’ law coefficient for the laminated GFRP in mode II was determined. The effect of fatigue delamination growth on fracture surface was studied by fractography analysis of SEM images of fracture surfaces. Studying the behaviour of GFRP under cyclic loading and delamination under static and dynamic load led to full-scale testing of wind turbine blade to establish damage tolerance of the blade under cyclic loading. The sensitivity of wind turbine blade to damage has considerable interest for turbine operators and manufacturers. For full-scale fatigue testing, calibration test and modal analysis of a 45.7m blade has been done and moment-strain diagram and natural frequencies of the blade were obtained. Next, the blade sensitivity to damage under fatigue loading was investigated. The blade has been damaged intentionally by initially inserting a crack of 0.2m between the shear web and spar cap and later it was extended to 1m. The effect of these damages on the modal shape, natural frequencies and strains at various locations of the blade were investigated. The damaged blade fatigue tested, the structural integrity and growth of damage were monitored, and the results were discussed. Finally for the improvement of delamination resistance for joints between spar beam and aero-shell stitching method was used. T-beam and box beam joint were chosen as the platform for testing the stitching effect on the delamination. Various pattern of stitching was applied and the optimum pattern was determined.
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Ulu, Erva. "Enhancing the Structural Performance of Additively Manufactured Objects". Research Showcase @ CMU, 2018. http://repository.cmu.edu/dissertations/1188.
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The ability to accurately quantify the performance an additively manufactured (AM) product is important for a widespread industry adoption of AM as the design is required to: (1) satisfy geometrical constraints, (2) satisfy structural constraints dictated by its intended function, and (3) be cost effective compared to traditional manufacturing methods. Optimization techniques offer design aids in creating cost-effective structures that meet the prescribed structural objectives. The fundamental problem in existing approaches lies in the difficulty to quantify the structural performance as each unique design leads to a new set of analyses to determine the structural robustness and such analyses can be very costly due to the complexity of in-use forces experienced by the structure. This work develops computationally tractable methods tailored to maximize the structural performance of AM products. A geometry preserving build orientation optimization method as well as data-driven shape optimization approaches to structural design are presented. Proposed methods greatly enhance the value of AM technology by taking advantage of the design space enabled by it for a broad class of problems involving complex in-use loads.
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Murambadoro, Daniel K. "The structural performance of egg-shaped sludge digesters". Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/5019.
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Faghih, Faezeh. "Structural performance of nano concrete-steel sandwich wall". Thesis, City, University of London, 2018. http://openaccess.city.ac.uk/19774/.
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Concrete is extensively used in the construction of infrastructures, however formation and development of cracks undermines the integrity of the structure. Thus, both improving the mechanical properties of this construction material as well as structural health monitoring of structures are essential tasks to be tackled. The research covered in this thesis is concerned with mechanical properties of carbon nanofiber reinforced concrete and the effect of this type of concrete on structural performance of the composite steel-concrete sandwich (SC) system. The use of nanofibers such as Carbon Nanofiber (CNF) within cementitious materials is found to be effective in enhancing the mechanical properties of the cementitious material as well as enhancing the sensing ability of the cementitious composites. Despite the abundant experimental work on nanofiber reinforced cementitious composites by researchers, their use within concrete has not been fully addressed. Therefore, the significance of this research is to assess mechanical properties of nanoreinforced concrete along with its sensing capability. The steel-concrete sandwich system consists of thick concrete core with exterior steel faceplates acting as reinforcement. The steel faceplates are anchored to the concrete core with shear connectors. This study presents the structural performance of the SC element with fiber reinforced concrete (FRC) core using both single fiber and hybrid fiber (i.e. consisting of two types of fibers) in the core. For this study carbon nanofiber and steel fiber, which is conventionally used in practice, are used for the FRC. Static tests were conducted on eight SC beams with different concrete types. In addition to studying the structural performance of the SC element with fiber reinforced concrete, the self-sensing capability of beams with CNF reinforced concrete core were assessed. Furthermore, finite element analysis was conducted to evaluate the effect of some design parameters on the behaviour of SC element. The outcome of this thesis enhances the current knowledge on the use of nanofibers in civil engineering industry as nano reinforcement and nanofilaments within cementitious materials, typically concrete and it will contribute to the understanding of the effect of CNF on concrete mechanical properties. This research laid the groundwork for additional in-depth study on using carbon nanofiber reinforced concrete within structural members and determination of their effect as nanofilaments on the self-sensing capability of the structural element.
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Yoo, Jung Han. "Analytical investigation on the seismic performance of special concentrically braced frames /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/10115.
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Goodman, Joseph Neal. "Performance measures for residential PV structural response to wind effects". Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54910.
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This thesis applies structural reliability measures for the performance based design of residential PV system structures. These measures are intended to support designers in delivering systems with quantified and consistent reliability. Existing codified practices prescribe global factors (allowable stress design) and partial factors (load and resistance factor design) intended to provide an acceptable level of reliability as defined by historical practice. When applied to residential PV systems this prescriptive approach has two flaws, (1) calibration efforts needed to ensure consistency across structural system types have not kept up with the commercially available system types and (2) the actual expected reliability is not quantified and available to support decisions. The proposed reliability measures include probability of failure conditioned to wind speed in a fragility curve and the reliability index β, both of which are commonly used in performance based design. The approach is demonstrated through the application of the reliability measures to code compliant designs. Diverse system types are utilized to demonstrate how the existing code prescribed approach may lead to non-uniform structural performance. For each of the system types on which the reliability measures are demonstrated, a code compliant design is developed for three roof slopes, wind tunnel testing is conducted to provide an experimental measure of wind pressure coefficients, system specific fragility curves are generated to quantify the probability of failure conditioned to a set of wind speeds, and then, a site specific wind model is applied to produce a probability of failure and reliability index β. Through the performance based approach proposed in this thesis, two key outputs show non-uniform and unanticipated structural performance of PV systems designed according to the prescriptive code method. The two key outputs which illustrate this finding are fragility curves which illustrate the probability of failure over a range of wind speeds and reliability index, β values which couple the structural and wind distributions for a single measure of reliability.
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Adams, Scott Michael. "Performance-Based Analysis of Steel Buildings: Special Concentric Braced Frame". DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/389.
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The performance-based analysis methods and evaluation criteria in ASCE 41-06 were used to evaluate a special concentric braced frame building based on the design standards in ASCE 7-05. A rectangular, six-story office building was evaluated using linear static, linear dynamic, nonlinear static, and nonlinear dynamic procedures. The results showed that the linear procedures underestimated damage compared to the nonlinear procedures, with the building performing to Life Safety for the linear procedures, and the nonlinear procedures indicating component damage beyond the intended Life Safety limit for the 2/3 maximum considered earthquake (MCE) hazard. This trend continued to the maximum considered earthquake hazard as well, under which the overall building performance for the linear procedures did not reach the Collapse Prevention level, which occurred in the nonlinear procedures.
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Abdi, Meisam. "Evolutionary topology optimization of continuum structures using X-FEM and isovalues of structural performance". Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/31226/.
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In the last three decades, advances in modern manufacturing processes, such as additive manufacturing (AM) on one hand and computational power on the other hand, has resulted in a surge of interest in topology optimization as a means of designing high performance components with high degrees of geometrical complexity. Topology optimization seeks to find the best design for a structure by optimally distributing material in a design space. Therefore not only the shape and size of the structure, but also the connectivity of the structure changes during the topology optimization process. As a result, the solution of a topology optimization problem might be represented with a high degree of geometrical complexity as it is not dependent on the initial geometry. The finite element method (FEM) is a powerful numerical analysis technique that was developed to solve complex solid mechanics problems. Many topology optimization approaches use FEM to calculate the response of the structure during the optimization process and some of them, called “element based-methods”, are integrated with FEM to use the properties of finite elements as design variables in the optimization. The solutions of such approaches are usually represented by a uniform finite element mesh that bears no relation to the final geometry and hence they don’t provide an accurate representation of the design boundary. The solution from topology optimization must therefore go through further post processing stages to obtain a manufacturable design. The post processing stages which can include smoothing and shape optimization are costly and time-consuming and may result in the structure becoming less optimal. With traditional manufacturing processes this is acceptable as the manufacturing constraints prevent the optimized design from being manufactured so some re-analysis is necessary. With additive manufacturing, however, this restriction is removed, which means a topology optimization resulting in a manufacturable design is highly desirable. Evolutionary structural optimization (ESO) is an element based topology optimization approach which operates by systematically removing inefficient material from the structure until the optimization objective achieves convergence. Due to the intuitive nature of ESO, this method is simple to be programed and can be easily integrated with FEM or other numerical analysis techniques; thus it is suitable for complex geometries represented with FEM. During the last two decades ESO and its extensions, such as bi-directional ESO (BESO), have been successfully used for many topology optimization problems such as stiffness design, design of compliant mechanisms, heat conduction problems and frequency problems. However, being an element based method, the drawback of poor boundary representation remains. The extended finite element method (X-FEM) is an extension of the classical FEM that was developed to represent discontinuities, such as cracks and material-void interfaces, inside finite elements. X-FEM can be employed in topology optimization problems to handle the material-void discontinuity introduced by the evolving boundary during the optimization process which potentially enables a sub-element boundary representation. This requires an implicit boundary representation, such as level-set method with the benefits of better computational accuracy through the optimization, more optimized solution and smoother boundaries for direct to manufacture. In this work a new method of evolutionary structural optimization is proposed in which X-FEM is employed for the more smooth and accurate representation of the design boundary. Linear finite elements are used to discretize the design space. These include 4-node quadrilateral elements in 2D modelling and 8-node hexahedral elements in 3D modelling. To implement the X-FEM, an implicit boundary representation using isoline and isosurface approaches is used. The proposed method which is called “Iso-XFEM” is implemented for various topology optimization problems, including the stiffness design of 2D and 3D structures, stiffness design with additional displacement constraint and topology optimization of geometrically nonlinear problems. The solutions of the Iso-XFEM method are compared with those obtained using BESO, as a representative FE based method. The results confirm a significant improvement in boundary representation of the solutions when compared against BESO, and also demonstrate the feasibility of the application of the proposed method to complex real-life structures and to different objectives. All the programs used to generate topology optimised solutions using the proposed method and its modifications are developed by the author. These include topology optimization codes, linear and non-linear FEA, and 2D and 3D X-FEM integration schemes.
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Kim, Do-Hwan. "Seismic performance of PR frames in areas of infrequent seismicity". Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/20738.
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Cullen, Gavin William James. "Performance of stabilised top-hat sections in portal frames". Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359060.
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Crewe, Adam J. "The characterisation and optimisation of earthquake shaking table performance". Thesis, University of Bristol, 1998. http://hdl.handle.net/1983/47c8d984-04b8-4c21-9491-e74829e561ed.
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Parkinson, David L. "Performance based design of structural steel for fire conditions". Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-0821102-115014.
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Wu, Tianyi. "Structural performance of timber rivets in engineered wood products". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/48418.
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Timber Rivets are oval-shaped nails made from high-strength steel that allow for strong and ductile timber connections. Timber Rivets have been successfully used in the construction industry for over 40 years. Both the Canadian design code (CSA-O86) and the American design code (NDS), however, only specify Timber Rivets to be used with Glulam and solid sawn timber of certain species. In recent years, significant research has been conducted in New Zealand regarding the application of Timber Rivets to Laminated Veneer Lumber. As a result, the Johansen Yield Model, which is verified as a valid approach to predict the ductile failure of Timber Rivet connections, has been complemented with new failure models and design equations that predict brittle failure modes.
The objective of the research was to evaluate the feasibility of using the novel models to predict the failure modes and capacities of Timber Rivet connections in Laminated Veneer Lumber and Cross Laminated Timber. The experimental investigations carried out as part of this thesis consisted of 29 test series (with three or five replicates each) of Timber Rivet connections in these structural composites made from North American species. Quasi-static monotonic and cyclic tests with loading parallel and perpendicular to the grain were conducted in the Wood Mechanics Laboratory at the University of British Columbia Vancouver. The quasi static tests were used to validate the prediction models; the cyclic tests were used to assess the seismic performance of the connections.
The results showed that the recent New Zealand model provides good predictions for Timber Rivet connections in Laminated Veneer Lumber. Furthermore, it was shown that cyclic loading does not severely weaken the performance of Timber Rivet connections. The existing models, however, do not provide accurate predictions for Timber Rivet connections in Cross Laminated Timber and more research is deemed necessary before such connections can be safely designed.Forestry, Faculty of
Graduate
40
Hong, Kwan Eui Marcel. "Structural performance of nail-laminated timber-concrete composite floors". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62710.
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Nail-laminated timber-concrete composite (TCC) is a system composed of a nail-laminated timber (NLT) panel connected to a concrete slab through shear connections. When used as flexural elements such as floors, the concrete and NLT are located in the compression and tension zones, respectively. NLT panels, being constructed out of inexpensive lumber planks nailed on their sides, offer an economical advantage in mass-timber constructions that complement the structural and building physics advantages of TCC. However, the performance of nail-laminated TCC as well as efficient shear connectors for this system have not been investigated.
This thesis presents the experimental study conducted on the performance of TCC panels constructed out of NLT, mechanical fasteners, and cast-in-place concrete. First, nine different sizes of truss-plates and two configurations of self-tapping screws installed in small-scale TCC specimens were tested under shear load. The connections’ strength and stiffness were determined to evaluate its performance as TCC shear connectors. Second, four truss-plate configurations were selected for implementation in full-scale TCC panels. Two panels for each shear connection systems were tested under impact loading and a quasi-static monotonic loading to determine the vibration bending properties, respectively. Panel specifications and layouts of the connectors were designed based on the established γ-method. The test results show that nail-laminated TCC panels reached slightly higher fundamental natural frequency and elastic bending stiffness than predicted. Furthermore, failure did not occur until loading reached 5 to 7 times the serviceability requirements. The selected truss-plates shear connection demonstrated to be an efficient solution for nail-laminated TCC panels.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Reeves, Eric E. "Structural reliability of ultra-high performance concrete in flexure". Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1177090784.
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Quinn, D. F. "Panel Skin Sub-stiffening Concepts for Improved Structural Performance". Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527892.
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Ahmad, Zulkifli Bin. "Synthetic and structural investigations of high performance aromatic polymers". Thesis, University of Reading, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424256.
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Violette, Franck Luc Marcel. "On the fatigue performance prediction of ship structural details". Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388346.
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Brandon, Daniel. "Fire and structural performance of non-metallic timber connections". Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.665417.
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Recent studies showed the need for timber connections with high fire performance. Connections of members in timber structures commonly comprise steel connectors, such as dowels, screws, nails and toothed plates. However, multiple studies have shown that the presence of exposed metal in timber connections leads to a poor performance under fire conditions. Replacing metallic fasteners with non-metallic fasteners potentially enhances the fire performance of timber connections. Previous studies showed that Glass Fibre Reinforced Polymer (GFRP) dowels can be a viable replacement for steel dowels and that Densified Veneer Wood functions well as a flitch plate material. However, as the resin matrix of GFRP dowels is viscoelastic, connection creep, which is not studied before, can be of concern. Also no research has been carried out on the fire performance of these connections. Therefore, a study of the creep behaviour and the fire performance of non-metallic timber connections comprising GFRP dowels and a Densified Veneer Wood flitch plate was performed, as is discussed in this thesis. Predictive models were proposed to determine the connection slip and load bearing capacity at ambient and elevated temperatures and in a fire. The material properties and heat transfer properties required for these models were determined experimentally and predictions of these models were experimentally validated. Furthermore, an adjustment of the predictive model of connection slip at ambient temperature allowed approximating the creep of the connection. The material properties, required for the creep model, were determined experimentally and predictions of the model were compared to results of longterm connection tests. The study confirmed that timber members jointed with non-metallic connectors have a significantly improved fire performance to timber joints using metallic connections. Models developed and proposed to predict fire performance gave accurate predictions of time to failure. It was concluded that non-metallic connections showed more creep per load per connector, than metallic connections. However, the ratio between initial deflection and creep (relative creep) and the ratio between load level and creep were shown to be similar for metallic and non-metallic connections.
46
Dodds, Wayne J. "Durability performance of coarse crushed concrete aggregate structural concrete". Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/27534.
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Crushed or recycled concrete aggregates (CCA/RCA) is an increasingly popular material as a replacement for natural aggregates in concrete due to industry demands for more recycled, lower carbon and responsibly sourced materials. In the UK, the majority of CCA is utilised in non-structural applications such as: a general fill material, road base/subbase or in low-grade concrete. Recycled aggregate producers however, are seeking new ways to incorporate CCA into higher value applications such as structural concrete to increase profits. Opportunities to incorporate CCA into structural concrete may also arise because of project demands for sustainability or in situations where natural aggregates are in short supply. Limited research has been published regarding the effect of coarse CCA on the durability of structural concrete, particularly in respect to water and chloride ion ingress and possibility of corrosion initiation. The aim of this EngD research programme was to investigate the effect of coarse CCA and supplementary cementitious materials (SCMs) on the durability performance of structural concrete, with particular emphasis on the key liquid transport mechanisms within concrete, namely absorption by capillary action, diffusion and migration. This addressed an industry concern regarding the detrimental effect of coarse CCA which has resulted in a limit on replacement levels of coarse natural aggregates in structural concrete, as defined in Eurocodes and local national standards for concrete. In this study, structural concrete was produced with varying levels of coarse CCA replacement (up to 100%), from five different sources and/or structural elements across the UK, with various combinations of SCMs to replace in part the Portland cement. Petrographic analysis was used as an innovative technique to characterise the coarse CCA sources to determine suitability which yielded positive results. The durability performance of the resultant concrete was analysed by exposing the concrete to aggressive chloride environments. The results indicate that the inclusion of coarse CCA, even as low as 20%, had a detrimental effect on the durability performance of structural concrete, in relation to absorption by capillary action, diffusion and migration. This effect however, can be offset through the use of SCMs, which have been shown to outperform control Portland cement concrete with 100% natural aggregates in durability performance tests. The results also suggest that cementitious materials had a greater influence on durability performance than the type and source of coarse aggregates used. It is recommended that the replacement of natural aggregate with coarse CCA be limited to 30% in cases where compliance with the 28 day characteristic strength is of particular importance. If the criterion for compliance at 28 days can be relaxed and the compressive cube strength of concretes with SCMs tested at later ages for conformity (56 or 90 days), then higher quantities of coarse CCA may be incorporated up to 60% to produce a more sustainable structural concrete. It is recommended that Portland cement is partially replaced with 50% ground granulated blast-furnace slag (GGBS) to produce a CEM III/A concrete. This is a significant step towards the potential wider implementation of coarse CCA in structural concrete, provided a suitable quantity of SCM is adopted along with a reliable and consistent source of coarse CCA.
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Kashi, Mohsen Gholam-Reza. "A performance analysis of the hi-plan structural apparatus". Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/50031.
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Visual experience is a powerful pedagogic tool. Extensive use of experimental studies prior to design and construction has made conceptualization of complex structures possible. Experiments on reduced-scale structures and specimens are also vital tools for teaching structural mechanics. As such, the Department of Civil Engineering at Virginia Tech has acquired a new apparatus for use as an educational demonstration tool in the area of structural mechanics. This work presents the results of a detailed study on the performance of this device as related to its accuracy and operation.
To fulfill such objectives, two structural models (a continuous beam and a portal frame) were extensively tested under several loading and support configurations. The models were analysed using STRUDL as well as a computer program developed by the author. The comparison of the results (deformations) obtained in the two phases of the study have indicated that the apparatus is reasonably accurate to meet the requirements of a structural teaching model and adapting to a variety of structural models.Master of Science
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Punyamurthula, Deepthi. "Structural performance of low-profile FRP composite celluar modules". Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3815.
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Thesis (M.S.)--West Virginia University, 2005Title from document title page. Document formatted into pages; contains xi, 91 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 83-85).
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Prescott, A. T. "The performance of end-plate connections in steel structures and their influence on overall structural behaviour". Thesis, University of Hertfordshire, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377587.
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Tagawa, Hiroyuki. "Towards an understanding of seismic performance of 3D structures : stability & reliability /". Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/10192.
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