Orientador: Cecilia Amélia de Carvalho Zavaglia / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-28T04:10:25Z (GMT). No. of bitstreams: 1 Corredori_PauloCesar_M.pdf: 3624543 bytes, checksum: 7dff308f63100edb2b9d157d780f91b3 (MD5) Previous issue date: 2015 / Resumo: Este mundo que vivemos está se tornando extremamente competitivo dia após dia, a apenas cinquenta anos, os motores ciclo Otto permaneciam quase os mesmos quando foram inventados pelo engenheiro alemão Nikolaus August Otto no final do século 19. Foi somente no final da década de 1970 que os antigos motores começaram a ganhar apelos tecnológicos, como injeção eletrônica, ignição eletrônica, controle de emissões e gás carbônico, etc., com isso, todas as montadoras começaram a buscar soluções que fizessem do seu veículo, o melhor ou o mais econômico e menos poluente. Face às novas exigências governamentais ao redor do mundo, todas as montadoras e autopeças estão trabalhando incansavelmente na busca de várias soluções, soluções estas que vão desde a diminuição de emissões evaporativas, redução do consumo de combustível, seja em função de um motor mais econômico quanto a melhorias de aerodinâmica, que resulta em menor fenômeno de arraste e consequente economia de combustível. Sabe-se também que redução de peso impacta diretamente na redução do fenômeno de arraste, portanto, gera um menor consumo de combustível, por isso, estamos vendo o crescente interesse das indústrias automotivas em substituir as antigas e atuais peças em metal que são normalmente pesadas, para peças extremamente mais leves em plásticos de engenharia e com alta resistência térmica, mecânica, etc., e quem nem por isso não mantenham a mesma qualidade funcional das peças em metal. Plásticos de engenharia como a Poliamida 6 com 35% de fibra de vidro (PA6 GF35), já estão sendo aplicados no mercado automotivo a pelo menos quase 20 anos, pois os primeiros coletores de admissão e filtro de ar em plástico nasceram utilizando esta matéria prima, hoje em dia, nesta busca por redução de peso e consequentemente preço, um material plástico chamado Polipropileno com 35% de fibra de vidro (PP GF35), que até não muito tempo atrás era de segunda linha, passa a ser de suma importância para alcançar objetivos que técnicos e monetários que até outro dia, somente era possível com a Poliamida 6 com 35% de fibra de vidro (PA6 GF35). Hoje em dia o polipropileno é um polímero de destaque no setor automotivo, pois ele se destaca pela alta resistência química e solvente, boa estabilidade dimensional, flexibilidade, durabilidade, excelente balanço entre impacto e rigidez. Sendo assim, uma matéria prima que era utilizada na fabricação de fios de tecelagem, embalagens flexíveis, brinquedos, copos plásticos, corpo de eletrodomésticos, está sendo usado em peças de alto valor agregado, alto e com tal desempenho técnico como um coletor de admissão e em quase todas as peças de acabamento interno e externo da maioria das empresas automotiva do Brasil e do mundo / Abstract: Due to strong competition among automotive companies around the world, and also by the incessant search in order to reduce weights in vehicles, reducing fuel consumption and therefore reduce carbonic gas emissions, the automakers are working on several fronts in order to reach the targets already defined through the government¿s laws. Given these several requests, the automotive parts industries, together with the raw materials industry, are working to achieve these goals. Thus, reductions in power cell consequently the numbers of cylinders in the engines are already a reality, for example three cylinders engines are replacing the four cylinder engines, and the most important comment, and they are keeping the same driving force. In addition, we are working so hard in order to replace the current Intake Manifold in Polyamide 6 with 35% glass fiber (PA6 GF35), for Polypropylene with 35% glass fiber (PP GF35), so is being reduced around 15% of weight, changing only the raw material. Polypropylene (PP), who was a second-line raw material in the past at the automotive world, becomes to move of other excellent quality of baseline of importance, as well, as reducing the weight of the piece, how it reduces the price piece value, as also the polypropylene is cheaper around of 15% more than the polyamide 6. This new polypropylene for Intake Manifold needs to be heat stabilizer, but needs not to be flame retardant. Many characteristics had been considered very important in the decision matrix in order to reach a good polymer, as well, mechanical resistance to the tensile and impact, density, water absorption, thermal resistance, chemical resistance regarding fuel, injection process and the availability of mass production. Only twenty years ago, all engines Cycle Otto were manufactured, using Intake Manifold in aluminum material, due to the aluminum caused a chemical reaction in physical contact with the alcohol, it was invented the Intake Manifold in Polyamide 6. Today all the automotive world uses Intake Manifold in Polyamide 6 for Cycle Otto application, but due to the excellent results using the polypropylene raw material, all automakers are moving to this new raw material, which in a not so distant past, was regarded as the second line in the automotive industry / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Glass fiber core Vacuum Insulation Panels (VIPs) have thermal performance per unit thickness of about 5-10 times higher than the traditionally used building insulation materials such as mineral wool, XPS, EPS, foam, etc. This advantage of VIP has made it very attractive new option for innovative building designs. Especially in Canada, where some of the areas have long and very cold winters. Confidence in the service life of a building material is necessary before putting a product to market. Extensive research has been conducted on the product development, quality improvement, and field application of VIPs around the world. However, there is lack of consistent and simple prediction method for the long-term thermal performance of VIPs. This paper discussed the process and performance of a field project using glass fiber VIPs to retrofit a commercial building in Yukon, Canada. The thermal performance of the VIPs used in this project was continuously monitored and critically analyzed since the start in 2011. The results have shown satisfactory thermal performance of VIPs for the past 8 years. The findings were also used to validate glass fiber core VIP accelerated aging tests conducted by the National Research Council Canada (Ottawa), and the aging rate of VIPs in a cold and dry climate was determined. The second part of this study investigated the monitored performance results from two sets of simplified accelerated laboratory aging tests, the results were analyzed with the aim to separate the impact of air diffusion from water vapour on the long-term thermal performance of glass fiber VIPs. In addition, this study also investigated the potential application of VIPs in balcony constructions to reduce heat transfer through thermal bridges. Computer modeling exercises, using a benchmarked (EN ISO 10211) three-dimensional transient and steady-state heat transfer simulation tool HEAT3, were carried out on the most optimal (thermal performance) balcony assemblies of wood framed buildings using VIP as insulation. This niche application of VIPs can significantly increase the energy efficiency of building envelopes/skins in extreme climates of Canada and elsewhere in the world. / Graduate / 2021-11-06

Diploma thesis is focused on production technology of the glass fibre polyester part. It introduces characteristics of the composite materials and their dividing by the reinfocement geometry, reinforcement dimensions, reinfocement material and matrix materiál. In the final chapters thesis describes production technologies and proces of launching new part from 3D data to data and drawings of the mould including creation of the technological process.

The diploma thesis is aimed at an influence of surface modifications of fibrous reinforcements on mechanical properties at the fiber-matrix interface in fiber reinforced composites. Glass fibers were used as reinforcements and polyester resin was the matrix. The sample of composite consisted of polymer matrix in a form of cylindrical body placed on bundle of glass fibers. The design of the sample was constructed with respect to results of Finite Element Analysis (FEA). The tensile test using a materials testing machine (Zwick) was employed to evaluate adhesion at the fiber-matrix interface. Untreated glass fibers, fibers with commercial sizing, and fibers modified by deposition of plasma polymer film using Plasma-Enhanced Chemical Vapor Deposition (PECVD) at different deposition conditions were used for fabrication of composite samples. The fibers and composite samples were analyzed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM).

No description available.

This research investigated effect of submicron glass fiber modification on mechanical performance of short carbon fiber reinforced vinyl ester resin. Firstly, the mixture of resin and glass fiber was made by mixing submicron fiber into resin in a homogenizer at the speed of 5000 rpm in 30 minutes. Then, this modified resin was reinforced by short carbon fiber at the length of 1 mm, 3mm and 25 mm. The modifying effects were accessed by evaluating mechanical properties such as: bending, tensile, impact test as well as dynamic mechanical analysis. To explain some manners of material caused by adding glass fiber into resin, some techniques were also used (IFSS, SEM, laser microscope scanner, ultrasonic S-scan, X-ray ...). / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

No description available.

Yes / The flexural performance of geopolymer concrete (GPC) T-beams reinforced longitudinally with GFRP bars under a four-point static bending test was investigated. Six full-scale simply supported T-beams were cast and tested; one control specimen was made with ordinary Portland cement concrete (OPCC), while the other five beams were made of geopolymer concrete. The G-GPC2 was designed to attain the same theoretical moment capacity as the G-OPCC6 control beam. The main parameters investigated were the reinforcement ratio of ρ_f/ρ_b= 0.75, 1.05, 1.12, 1.34 and 1.34 for G-GPC1, G-GPC2, G-GPC3, G-GPC4, and G-GPC5, respectively, and compressive strength of geopolymer concrete. Based on the results of the experiments, the ultimate strain of GPC did not show the same behaviour as that of OPCC, which affects the mode of failure. The beam capacity and deflection were, respectively, overestimated and underestimated using the ACI 440 2R-17 predictive equations.

Yes / This paper presents the experimental results of five large-scale hybrid glass fiber reinforced polymer (GFRP)-steel reinforced concrete continuous beams compared with two concrete continuous beams reinforced with either steel or GFRP bars as reference beams. In addition, two simply supported concrete beams reinforced with hybrid GFRP/steel were tested. The amount of longitudinal GFRP, steel reinforcements and area of steel bars to GFRP bars were the main investigated parameter in this study. The experimental results showed that increasing the GFRP reinforcement ratio simultaneously at the sagging and hogging zones resulted in an increase in the load capacity, however, less ductile behaviour. On the other hand, increasing the steel reinforcement ratio at critical sections resulted in more ductile behaviour, however, less load capacity increase after yielding of steel. The test results were compared with code equations and available theoretical models for predicting the beam load capacity and load-deflection response. It was concluded that Yoon's model reasonably predicted the deflection of the hybrid beams tested, whereas, the ACI.440.1R-15 equation underestimated the hybrid beam deflections. It was also shown that the load capacity prediction for hybrid reinforced concrete continuous beams based on a collapse mechanism with plastic hinges at mid-span and central support sections was reasonably close to the experimental failure load. / Higher Education of Libya (972/2007).

This dissertation presents the first reported identification and analyses of the phase relations in the YBa2Cu3O7-x (YBCO)-SiO2 system at elevated temperatures. In this regard, a rigorous characterization study of the reaction phases within YBCO glass fibers, heat-treated YBCO+SiO2 pellets, rapid thermally annealed YBCO+SiO2 rods and rapid thermally annealed YBCO powder inside a fused silica tube is provided. These analyses are based on a vast set of generated novel results obtained using energy dispersive spectroscopy analyses on an environmental scanning electron microscope, X-Ray diffraction analyses, Raman spectroscopy, X-ray photoelectron spectroscopy analyses and a cross-polarized light study. First, original drawings of YBCO into glass fibers using the molten-core approach on a fiber draw tower in air and oxygen atmospheres are presented and analyzed. The performed analyses reveal the occurrence of reactions between the YBCO core and the silica cladding in as-drawn fibers as well as after additional heat-treatments. A detailed analysis and characterization of the occurring dissolution and diffusion based reaction processes is, then, provided along with the identification of the arising phase separation. Moreover, in order to analyze drawing YBCO glass fibers at lower temperatures, the use of borosilicate as the preform material is also investigated. This varied set of experiments and associated analyses reveal that the as-drawn YBCO fibers contain an amorphous core and that cuprite (Cu2O) is the first phase to crystallize out of the amorphous silicate matrix upon heat-treatment. Furthermore, the obtained results demonstrate the dissolution of the fused silica cladding into Si4+ and O2- ions and their subsequent diffusion into the molten YBCO core, leading to phase separation due to an occurring miscibility gap in the YBCO-SiO2 system as well as to silicate formation and amorphization of the YBCO core. This, as a result, prohibits the formation of the superconductive YBCO (Y-123) phase upon annealing. In addition, heat-treatment analyses show that higher temperatures or prolonged dwelling times at lower temperatures lead to the formation of barium copper and yttrium barium silicates. The analysis focusing on the use of borosilicate as the preform material reveals that drawing at lower temperatures reduces the dissolution and diffusion based reactions, but does not prevent them. Furthermore, the analysis on YBCO glass fibers with a fused silica cladding drawn in oxygen atmosphere shows that a higher oxygen content increases the dissolution of the fused silica cladding into its ions and their subsequent diffusion into the molten YBCO core. In addition, the performed heat-treatments on YBCO+SiO2 pellets in air and oxygen atmospheres demonstrate the gradual decomposition of the Y-123 phase with an increase in SiO2 content. Moreover, the rapid thermal annealing experiments with a subsequent quenching step on YBCO+SiO2 rods and on YBCO powder inserted inside a fused silica tube show the decomposition of the Y-123 phase and the formation of phases similar to the phases obtained in the YBCO glass fiber study, thus corroborating the results thereof. In summary, this dissertation enables the determination of the phase relations and reaction processes within the YBCO-SiO2 system, the identification of the direct effects of the silicon content on the Y-123 phase decomposition, as well as a rigorous characterization of the dissolution and diffusion based reactions within the YBCO-SiO2 glass-clad fiber system. The generated results and drawn conclusions build a fundamental understanding of phase relations in the YBCO-SiO2 system, which enables a definite assessment of the feasibility of manufacturing long-scale purely superconductive YBCO glass fibers using the molten-core approach and introduces advanced contributions to general glass-clad fiber systems manufactured using this method. / Doctor of Philosophy / This dissertation provides the first reported identification and analysis of the phase relations in the YBa2Cu3O7-x (YBCO)-SiO2 system at high temperatures. In this regard, a thorough characterization study of the reaction phases within YBCO glass fibers drawn using the molten-core approach on a fiber draw tower is provided. In addition, heat-treatment analyses considering YBCO+SiO2 pellets, rapid thermally annealed YBCO+SiO2 rods and rapid thermally annealed YBCO powder inside a fused silica tube are performed to gain further fundamental insights. The performed analyses are based on a wide set of characterization methods including energy dispersive spectroscopy on an environmental scanning electron microscope, X-Ray diffraction analyses, Raman spectroscopy, X-ray photoelectron spectroscopy and a cross-polarized light study. Our experimental results and performed analyses identify the phase relations and reaction processes within the YBCO-SiO2 system at elevated temperatures, demonstrate the direct effects of the silicon content on the superconductive YBCO phase decomposition, enable drawing definite conclusions regarding the feasibility of manufacturing long-scale purely superconductive YBCO glass fibers using the molten-core approach, and, characterize the dissolution and diffusion based reactions occurring within the YBCO-SiO2 glass-clad fiber system. In a nutshell, this dissertation provides a fundamental understanding of phase relations in the YBCO-SiO2 glass-clad system as well as key insights covering general glass-clad fibers drawn using the molten-core approach, paving the way for improved glass-clad fiber manufacturing using this method.