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Lap splice in glass fiber reinforced polymer‐reinforced concrete rectangular columns subjected to cyclic‐reversed loadsNaqvi, Syed 27 October 2016 (has links)
This study presents the experimental results of nine full-scale lap spliced glass-fiber reinforced polymer (GFRP) reinforced concrete (RC) columns, and one additional reference steel-RC column with lap splices, under axial and cyclic-reversed loads. The test parameters included type of reinforcement, lap splice length of longitudinal reinforcement, transverse reinforcement spacing, and the effect of using steel fiber-reinforced concrete (SFRC). Test results indicated that a splice length of 60 times the diameter of the longitudinal column bar was adequate in transferring the full bond forces along the splice length and were able to maintain the lateral load carrying capacity when subjected to higher levels of axial loads and drift ratios. In addition, lap spliced GFRP-RC columns with closely spaced transverse reinforcement achieved high levels of deformability. Furthermore, the use of SFRC in columns with inadequate splice increased the peak lateral strength and the energy dissipation of the specimens. / February 2017
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Protection de fibres base SiC pour composites à matrice céramiqueDelcamp, Adrien 19 December 2008 (has links)
Les composites à matrice céramique (CMC) sont des matériaux constitués d’une matrice céramique renforcée par des fibres céramiques continues (généralement à base de SiC ou de C). Le travail de thèse présenté, réalisé en collaboration avec Snecma Propulsion solide et l’Agence De l’Environnement et de la Maîtrise de l’Energie, a pour objectif d’introduire des matériaux CMC au sein de pièces de moteurs d’avions civils, concurrençant ainsi les alliages métalliques actuellement utilisés. Pour ce faire, les matériaux CMC devront répondre aux exigences propres à l’aéronautique civil, à savoir qu’ils devront présenter une longue durée de vie en atmosphère oxydante dans une gamme de basse température (400-600°C) et avoir un coût compétitif. Dans ce contexte, des matériaux CMC constitués de fibres SiC de première génération, de coût moins élevé, sont étudiés, mais leur inconvénient majeur est leur plus grande sensibilité à l’oxydation. Des matrices auto-cicatrisantes multicouches à base de Si, B, et C ont été développées ces dernières années afin d’assurer une tenue à l’oxydation des fibres, mais elles ne sont pas opérantes dans la gamme de température imposée. Compte tenu d’études précédemment réalisées et des exigences requises pour l’application visée, l’objectif du travail présenté dans ce mémoire est de proposer des solutions pour améliorer la tenue à l’oxydation de renforts fibreux à base de fibres de SiC de première génération, dans la gamme de température 400-600°C, en évitant un surcoût de production trop important. / Continuous fiber-reinforced ceramic matrix composites (CFCCs) are an important class of materials for structural applications at elevated temperatures because of their improved flaw tolerance, large fracture resistance, improved toughness by crack deflection and crack bridging mechanism, low density and noncatastrophic mode of failure comparing with metallic materials. Fibers play a critical role in both the processing and performance of CFCCs. SiC-based fibers are considered leading candidate materials in the aerospace application, such as engine turbines. However, the major shortcoming of SiC-based fibers is their oxidative embrittlement and degradation, which is caused by the oxygen ingression from the micro cracks and interstitials in the composites, is the dominant life-limiting phenomenon of non-oxide composites. This study carried out with the financial supply of both Snecma Propulsion Solide and Agence De l’Environnement et de la Maîtrise de l’Energie has for objective to integrate SiC-based as reinforcement in CFCCs for civil aircraft engine application. In order to reach this objective, it is imperative to find a novel approach to diminish the oxygen ingression by developing protective fiber coatings.
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Experimental model for predicting cutting forces in machining carbon fiber reinforced polymer compositesAhmadian, Amirali 15 May 2019 (has links)
The demand for materials with high mechanical performances such as Carbon Fiber Reinforced Plastics (CFRP) is increasing. However, there are major challenges in machining CFRP as it involves delamination, fiber pullouts, and extreme cutting tool wear. Analysis of chip formation mechanisms and prediction of associated cutting forces in CFRP machining enables one to address these challenges. This study proposes a mechanistic cutting force model for milling operations of the CFRP workpiece, considering its non-homogeneity and anisotropy, by taking into account variations of fiber cutting angle during machining. A mechanistic model of cutting force constants is obtained from a number of experimentally measured unidirectional CFRP milling forces. The obtained mechanistic force model predictions are verified against experimentally measured milling forces with arbitrary tool path indicating the accuracy of the proposed mechanistic model in predicting cutting forces. The proposed mechanistic cutting force model is capable of being integrated into the manufacturing process to allow optimized machining of quality certified CFRP work-pieces. / Graduate
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Synthetic Fiber Reinforced Concrete in Marine Environments and Indirect Tension TestUnknown Date (has links)
An experiment was conducted to evaluate the durability, toughness, and strength
of Synthetic Fiber Reinforced Concrete after being immersed in five separate
environments for one year at FAU SeaTech. The specimens were molded and reinforced
with two-inch Polypropylene/Polyethylene Fibers in a concrete aggregate matrix and
were cut into identical sizes. Some of these environments had accelerated parameters
meant to increase degradation to simulate longevity and imitate harsh environments or
seawater conditions. The environments consisted of: a high humidity locker (ideal
conditions), submerged in the Intracoastal Waterway (FAU barge), seawater immersion,
a wet and dry seawater immersion simulating a splash/tidal zone, and another in low pH
seawater. The latter three were in an elevated temperature room (87-95°F) which
produced more degradative properties. The specimens were monitored and the
environments were controlled. The specimens were then evaluated using the IDT test
method using force to initiate first-cracking and post-cracking behaviors. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
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Fine particulate filled polymeric material and the investigation of its friction and wear propertiesSu, Kwai-Yung Benjamin January 1980 (has links)
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Includes bibliographical references. / by Kwai-Yung Benjamin Su. / Sc.D.
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A utilização de GRC na renovação de edifícios : caso de estudo: centro de I&D do IPCAPereira, Ana Cláudia Costa January 2013 (has links)
Tese de Mestrado Integrado. Mestrado em Engenharia Civil (Construções). Faculdade de Engenharia. Universidade do Porto. 2013
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Large-scale experimental and analytical seismic studies of a two-span reinforced concrete bridge systemJohnson, Nathan Stuart. January 2006 (has links)
Thesis (Ph. D.)--University of Nevada, Reno, 2006. / "May, 2006." Includes bibliographical references (leaves 105-107). Online version available on the World Wide Web.
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Autonomous unmanned ground vehicle for non-destructive testing of fiber reinforced polymer bridge decksMercer, Anthony Scott. January 2006 (has links)
Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains x, 100 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 83-86).
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Seismic performance of self-centering frames composed of precast post-tensioned concrete encased in FRP tubesSha'lan, Ahmad Abdulkareem Saker. January 2009 (has links) (PDF)
Thesis (M.S. in civil engineering)--Washington State University, December 2009. / Title from PDF title page (viewed on Feb. 4, 2010). "Department of Civil Engineering." Includes bibliographical references (p. 134-135).
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Processing and characterization of long fiber thermoplasticsParthasarathy, Krishnan Balaji Thattai. January 2008 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Title from PDF title page (viewed Feb. 8, 2010). Additional advisors: J. Barry Andrews, Kathryn Brannon, Derrick R. Dean, Gregg M. Janowski, Mark L. Weaver. Includes bibliographical references (p. 158-161).
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