Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-08-25T19:22:50Z No. of bitstreams: 1 DissIFC.pdf: 1376434 bytes, checksum: c70895a8516bc9a3019f119a79b65a96 (MD5) / Approved for entry into archive by Ronildo Prado (bco.producao.intelectual@gmail.com) on 2018-01-24T12:27:49Z (GMT) No. of bitstreams: 1 DissIFC.pdf: 1376434 bytes, checksum: c70895a8516bc9a3019f119a79b65a96 (MD5) / Approved for entry into archive by Ronildo Prado (bco.producao.intelectual@gmail.com) on 2018-01-24T12:28:00Z (GMT) No. of bitstreams: 1 DissIFC.pdf: 1376434 bytes, checksum: c70895a8516bc9a3019f119a79b65a96 (MD5) / Made available in DSpace on 2018-01-24T12:35:42Z (GMT). No. of bitstreams: 1 DissIFC.pdf: 1376434 bytes, checksum: c70895a8516bc9a3019f119a79b65a96 (MD5) Previous issue date: 2017-04-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No summary / Essa pesquisa tem como objetivo analisar os fatores que influenciam uma gestão da intersetorialidade do Programa Bolsa Família (PBF) com elevados índices de desempenho nos municípios do estado de São Paulo. Foram construídas três hipóteses: a primeira é referente ao alcance de altos valores do IGDM a partir da institucionalização da intersetorialidade por meio dos documentos oficiais (decretos, normas operacionais e portarias) do PBF. A segunda hipótese, na qual levantamos que o desempenho da gestão do PBF pode ser resultado da inovação na gestão local. A terceira hipótese, destacamos que as condições socioeconômicas como porte populacional e índice de Gini (concentração de renda) refletiriam no resultado do IGDM. Hipótese testada através da comparação entre o IGDM e o IDHM (medido em 2000 e 2010) dos municípios pesquisados, a fim de observar se aqueles que possuem altos valores de IDHM também possuiriam altos valores para o IGDM. Os resultados da pesquisa apontam que a institucionalização em si da intersetorialidade não acarreta com que todos os municípios obtenham uma gestão no mesmo patamar de qualidade. Nesse sentido a atuação dos gestores locais e das características municipais, principalmente o porte do município e concentração de renda afetam mais no resultado de uma gestão considerada mais satisfatória em detrimento dos demais resultados alcançados de gestão.

The Powder Bed Fusion using Electron Beam (PBF-EB) process is a highly complex additive manufacturing process. There are a very limited number of materials that have been used successfully, which limits the applications of the process, despite its well-documented advantages over conventional manufacturing. However, the development of new materials is hindered due to a lack of understanding of the fundamental phenomena in the process. The goal of this work has been to develop a model that is able to predict the process parameters that will lead to the manufacture of a fully dense component.   The model is based on 1285 empirical datasets of process parameters and the physical properties of the printed materials. Nine different materials were included in the data. By inputting a pre-defined set of process parameters and materials properties the model will output the beam power at which it is predicted a dense component may be manufactured. This novel approach will shorten the development of new process parameters by providing a first approximation of suitable parameters to iterate from. A tool steel powder supplied by Uddeholms AB was printed, using parameters proposed by the model. Two sets of pre-defined process parameters were used with several beam velocities and resulted in a number of correct predictions.   This model is a first step in predicting process parameters and presents a simple, transparent and new method of obtaining the process window for novel materials in Powder Bed Fusion using Electron Beam. / Powder Bed Fusion med Electron Beam (PBF-EB) är en mycket komplex additiv tillverkningsprocess. Det finns ett fåtal antal material som går att använda i processen. Detta är ett förhinder för applikationer trots processens väldokumenterade fördelar över konventionell framställning. Framtagning av nya material är dock hejdad på grund av okunskap kring de grundläggande fenomenen inom processen. Målet med detta arbete har varit att utveckla en modell som kan förutse processparametrar vilka ger helt kompakta komponenter.   Modellen är baserad på totalt 1285 data uppsättningar av processparametrar och de fysiska egenskaperna av de printade materialen. Data på nio olika material har samlats in. Genom att mata in ett par förbestämda processparametrar och materialets specifika materialegenskaper så beräknar modellen kraften på strålen vid vilken det förutspås att goda resultat framställs. Denna nya metod kortar ned tiden inom traditionell processparameterutveckling genom att bistå med en första iteration att arbeta utifrån. Ett verktygsstålspulver tillverkat av Uddeholms AB vart printat med hjälp av modellen. Två uppsättningar av förbestämda processparametrar användes vid flera olika stråles hastigheter och resulterade i åtskilliga lyckade förutsägelser.   Denna modell är ett första steg i att förutspå processparametrar och presenterar en simpel, transparant och ny metod till att finna process fönstret för nya material i Powder Bed Fusion med Electron Beam processen.

This study analyses and examines the hybrid printing process at Uddeholms AB in Hagfors.The objective of this study is to present recommended parameters to achieve optimal printingresults in a newly developed steel as well as a steel powder material designed for additivemanufacturing.The study showed that the best results occurred when printing on metal in a delivery state,with a thin layer thickness and double exposure. This resulted in full density in the fusion zoneand a gradient hardness change compared to a linear hardness change which was achievedwhen using single exposure. This leads to a lower chance of crack initiation due to internalstresses in the material.Additionally, a fixture system is presented that can fixate a variety of geometriessimultaneously. The use of this fixture system leads to a reduction in lead time by up toapproximately 85% comparing to the fixture solution in use today. Another benefit is theincreased economic sustainability since the operator does not need bespoke fixturing solutionsfor specific jobs.To achieve optimal properties of the printed detail, the parameters presented in this studyshould be used in conjunction with the fixture system.

This thesis aims to investigate whether additive manufacturing is applicable in manufacturing the 1N thruster option that Bradford Ecaps offers. Therefore, the nozzle design is of particular interest as AM provides accessibilities to manufacturing complex structures. The current Ecaps 1N thruster has an operating thrust lifespan that exceeds the required lifespan commonly needed for the majority of customers. With AM, an increase in production throughput and optimization of nozzle design is possible. A candidate material, a platinum group metal, was picked for a future 1N thruster prototype concerning the limiting operating constraints. Computational fluid analysis was performed to investigate different contour nozzles to investigate the possibility of improving the performance of the Bradford ECAPS 1N thruster. AMATLAB code was developed to model the contour nozzles, and ANSYS Fluent was used for the computational analysis. Three different nozzle geometries were evaluated to investigate the overall performance of the expanding exhaust gas and thrust properties in vacuum conditions. Configuration 1. which had an extended nozzle was selected as a solution since it eliminatedthe interferences with the continuum. The Nasa CEA code was used to generate the fluid gas properties. No substantial performance gain was observed for the 1N thruster. This was found to be due to the boundary-dominated flow exhibited in the nozzle. A conical nozzle was found to work comparatively well. / Detta examensarbete syftar till att undersöka om additiv tillverkning (AM) är tillämplig vid tillverkning av Bradford Ecaps 1N raketmotor. Därför är munstycksdesignen av särskilt intresse eftersom AM ger möjlighet för tillverkning av komplexa strukturer. Den nuvarande Ecaps 1N-motorn har en livslängd som överstiger den livslängd som krävs för de flesta kunder. Med AM är ökning av produktionsgenomströmningen och optimering av munstycksdesign möjlig. Ett kandidatmaterial, en metall i platinagruppen, valdes ut för en framtida 1N prototyp med hänvisning till de begränsande driftsbegränsningarna. Beräkningsflödesanalys utfördes för att undersöka olika konturmunstycken för att undersöka möjligheten till att förbättra prestandan hos Bradford ECAPS 1N framdrivningssystem. En MATLAB-kod utvecklades för att modellera konturmunstyckena och ANSYS Fluent användes för beräkningsanalysen. Tre olika munstycksgeometrier utvärderades för att undersöka den totala prestandan hos de expanderande avgaserna och dragkraftsegenskaperna under vakuumförhållanden. Konfiguration 1. som hade ett förlängt munstycke valdes som en lösning eftersom detta eliminerade interferenserna med kontinuumet. Nasa CEA-koden användes för att generera fluidens gasegenskaper. Ingen betydande prestandaökning observerades för 1N motorn. Detta visade sig bero på det gränsskiktsdominerade flödet som uppvisades i munstycket. Ett koniskt munstycke visade sig fungera relativt bra.

This thesis focuses on the topic of PBF-LB applied to titanium alloys. Of allalloys, an α + β is chosen, named Ti-6Al-4V. The selection of this particular alloy is driven by its current widespread use in many industrial applications where high strength coupled with low density are both desirable properties. For the last 50 years, parts made with this alloy have been cast or forged and then machined to achieve the final geometry. There is now an opportunity totransform this process chain by additive manufacturing, hence reducing material waste and achieving near net shape from powder feedstock. The process is summarised as follows: a laser selectively melts areas on a build plate where powder is pre-placed. Then a successive powder layer is spread and the process is repeated until completion. Upon removal of the part from the build plate, loose powder in the chamber is collected and recycled whenever possible. The design freedom provided by powder bed fusion methods enables production of intricate geometries and added functionality, despite the need for post-build consolidation and/or microstructural adjustments. Today’s fine and narrow powder cuts (e.g., 15-50μm) are designed to be coupled with low layer thicknesses (i.e., 30μm) to achieve smooth surfaces and high resolutions of small features e.g., internal cooling channels. However, costs associated with production of fine and narrow powder cuts are substantial as refinement of batches requires multiple sieving steps. In addition, resulting building times are considerably long (i.e., days), therefore a beneficial alternative could be that of exploring higher layer thicknesses together with wider and coarser powder cuts. The main idea of this work is to investigate the effects of employing a powder with a wider size distribution 15-90μm. The aim is to reduce the sievingrequired and consequently decrease the costs of developing and building parts made by PBF-LB. An extensive microstructural investigation is conducted on single tracks and cubes built with 27 different process parameter combinations, which also attempts to establish correlations between characteristics of tracks and responses measured in cubes. As a second step, the amount of residual porosity of asbuilt cubes is chosen as the discriminant for further mechanical testing of sub and super-β transus high-pressure heat treated material. / Den här avhandlingen fokuserar på additiv tillverkning av titanlegeringar med laser pulverbädd metoden. Den legering som främst är i fokus är Ti-6Al-4Vsom är en α+β legering. Anledningen till valet av denna titanlegering är att det är den vanligast förekommande titanlegeringen och att den används i ett antal olika industriella tillämpningar där hög styrka i kombination med låg vikt är önskvärda egenskaper. Under de senaste 50 åren har komponenter utav denna legering tillverkats med gjutning eller smide, följt av bearbetning till slutlig geometri. Med hjälp av additiv tillverkning finns nu en möjlighet att förändra tillverkningskedjan i vilket minskat materialspill och en mer nära-slutgeometri kan erhållas direkt genom användning av metallpulver som utgångsmaterial. Processen kan summeras enligt följande: en laser smälter ett förbestämt område på en byggplatta som täckts mer pulver. Därefter adderas ytterligare ett lager med metallpulver ovanpå, på vilket samma process sker igen, och igen osv, tills hela detaljen är färdigtillverkad. När detaljen ska tas loss ifrån byggplattan samlas det kvarvarande icke-smälta pulvret upp och återanvänds i så stor utsträckning som möjligt. Frihetsgraderna vid design i processen möjliggör tillverkning av komplexa geometrier och adderade funktionaliteter, även fast efterbehandling och/eller justeringar av mikrostrukturen kan behövas. Dagens smala pulverstorleksfördelning (tex 15-50μm) är avsedd att ge tunna lagertjocklekar (tex 30μm) för att åstadkomma en fin yta och hög upplösning av små geometrier, såsom exempelvis interna kylkanaler. Men kostnaderna som det innebär att framställa och sortera ut fina och smala kornstorleksfördelningarär avsevärd eftersom det innebär flera steg med silning. Vidare leder de tunnalagertjocklekarna till långa byggtider (typiskt dagar). Ett alternativ, som därför vore fördelaktigt, är att undersöka möjligheten med att bygga tjockare lager med en bredare och större pulverstorleksfördelning. Huvudfokuset i detta arbete fokuserar på att undersöka effekterna av att använda en bredare pulverpartikelstorleksfördelning 15-90μm, med syfte at minska silningsbehovet och därmed reducera kostnaden för att utveckla och tillverka detaljer med laser pulverbädd additiv tillverkning. En omfattande mikrostrukturundersökning har gjorts på enkelsträngar och kuber byggda med 27 olika processparameter-kombinationer, vilket samtidigt försöker identifiera korrelationer mellan enkelsträngarnas karaktäristik med resultaten uppmätta hos kuberna. I ett nästa steg har material, som tillverkats med processparametrar som renderade i minst/mest porer hos kuberna, mekaniskt provats efter att det högtrycksvärmebehandlats över- respektive under β-transus. / <p>Paper A is not included due to the copyright.</p><p>Paper B and C are to be submitted.</p>

This thesis work was done to get a fundamental knowledge of the mechanical and microstructural properties of 316L stainless steel fabricated with the additive manufacturing technique, laser powder-bed fusion (L-PBF). The aims of the thesis were to study the mechanical and microstructural properties in two different building orientations for samples built in two different machines, and to summarize mechanical data from previous research on additive manufactured 316L. Additive manufacturing (AM) or 3D-printing, is a manufacturing technique that in recent years has been adopted by the industry due to the complexity of parts that can be built and the wide range of materials that can be used. This have made it important to understand the behaviour and properties of the material, since the material differs from conventionally produced material. This also adds to 316L, which is an austenitic stainless steel used in corrosive environments. To study the effect of the building orientation, samples of 316L were built in different orientations on the build plate. The density and amount of pores were also measured. Tensile testing and Charpy-V testing were made at room temperature. Vickers hardness was also measured. Microstructure and fracture surfaces were examined using light optical microscope (LOM) and scanning electron microscope (SEM). The microstructure of the 316L made with L-PBF was found to have meltpools with coarser grains inside them, sometime spanning over several meltpools. Inside these coarser grains was a finer cellular/columnar sub-grain structure. The tensile properties were found to be anisotropic with higher strength values in the orientation perpendicular to the building direction. Also high dense samples had higher tensile properties than low dense samples. The impact toughness was found to be influenced negatively by high porosity. Hardness was similar in different orientations, but lower for less dense samples. Defects due to lack of fusing of particles were found on both the microstructure sample surfaces and fracture surfaces. The values from this study compare well with previous reported research findings.

This thesis analyzes the influence of process gases on the formation and the characteristics of process byproducts that emerge during additive manufacturing of an aluminum alloy belonging to the 2000 series.  In order to address the influence, four pure gases, argon, nitrogen, helium, and carbon dioxide, were used as a shielding gas on the same parameter sets.  The interaction of the laser beam with the powder bed under each shielding condition was recorded by a camera.  The humidity, particle size distribution, and chemistry of the spatters produced after each job was analyzed.  The chemistry of small cylinders printed, was determined.  The density of the produced cubic samples was determined following the Archimedes principle, as well as through the analysis of the  cross-section.   Lastly,  the  embedded  and  polished  samples  were  etched,  and  the penetration depth of the laser was determined.  Under argon and nitrogen shielding, the process looked the same and the produced spatters show similar results.  Under helium shielding, less incandescent spatters were seen, and the particle size distribution is smaller than under argon or nitrogen. Carbon dioxide resulted in the highest number of incandescent particles and a change of the color of the rays from red to yellow.  The chemical analysis shows that a slight increase of nitrogen in the spatters and the bulk material can be seen under nitrogen shielding.  Oxygen and hydrogen content was sim- ilar under argon, nitrogen, and helium shielding.  Carbon dioxide shielding resulted in the highest oxygen content in the spatter and the bulk material. The density is highest under helium shielding, and lowest under carbon dioxide shielding.  Under argon and nitrogen shielding, the density was similar.  The study concluded that the choice of a process gas is not an arbitrary one but should be selected with care. / Denna avhandling analyserar processgasernas påverkan på bildandet och egenskaperna hos process biprodukter som uppstår vid additiv tillverkning av en aluminiumlegering som tillhör 2000-serien. För att hantera inflytandet användes fyra rena gaser, argon, kväve,  helium  och  koldioxid  som  skyddsgas  på  samma  parameteruppsättningar. Interaktionen mellan  laserstrålen och  pulverbädden under  varje skärmningsförhållande registrerades  av  en  kamera.  Fuktigheten, partikelstorleksfördelningen  och  kemin  hos stänkarna som producerades efter varje jobb analyserades. Kemien hos de små cylindrarna  som  trycktes  bestämdes. Densiteten  hos  de  producerade  kubikproven  bestämdes enligt Archimedes princip, liksom genom analys av tvärsnittet. Slutligen etsades de inbäddade och polerade proverna och laserns penetrationsdjup bestämdes. Under argon- och kväveavskärmning såg processen likadan ut och de producerade stänkarna visar liknande resultat. Under heliumskärmning sågs mindre glödande stänk och partikelstorleksfördelningen är mindre än under argon eller kväve. Koldioxid resulterade i det högsta antalet glödande partiklar och en förändring av strålarnas färg från rött till gult. Den kemiska analysen visar att en liten ökning av kväve i stänkarna och bulkmaterialet kan ses under kväveavskärmning. Syre- och väteinnehållet var liknande under argon-,  kväve-  och  heliumskärmning. Koldioxidavskärmning  resulterade  i  det  högsta syreinnehållet i stänk och bulkmaterial. Densiteten är högst under heliumskärmning och lägst under koldioxidskärmning. Under argon- och kväveavskärmning var densiteten densamma. Studien drog slutsatsen att valet av en processgas inte är godtyckligt utan bör väljas med omsorg.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-01T19:19:42Z No. of bitstreams: 1 SandroDeOliveiraPimentel_DISSERT.pdf: 2186593 bytes, checksum: c24db079ddfff6411e75d866fb4d76c3 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-06T20:11:55Z (GMT) No. of bitstreams: 1 SandroDeOliveiraPimentel_DISSERT.pdf: 2186593 bytes, checksum: c24db079ddfff6411e75d866fb4d76c3 (MD5) / Made available in DSpace on 2016-04-06T20:11:55Z (GMT). No. of bitstreams: 1 SandroDeOliveiraPimentel_DISSERT.pdf: 2186593 bytes, checksum: c24db079ddfff6411e75d866fb4d76c3 (MD5) Previous issue date: 2015-02-04 / Esta pesquisa tem como objetivo analisar as condi??es habitacionais e socioecon?micas de benefici?rios do Programa Bolsa Fam?lia ? PBF da Zona Norte de Natal. Para tanto, foi necess?rio um levantamento das origens dessa regi?o e de como ocorreu sua expans?o no contexto do desenvolvimento urbano local, considerando sua evolu??o demogr?fica, em especial, a partir da constru??o dos conjuntos habitacionais e loteamentos formais e informais. A partir da pesquisa de campo, composta de um piloto in loco com algumas fam?lias residentes, tornou-se poss?vel iniciar a an?lise das condi??es habitacionais que culminou em um estudo detalhado do Cadastro ?nico do governo federal (Cad?nico), em rela??o a 100% (cem por cento) dos benefici?rios do Programa Bolsa Fam?lia (PBF) de Natal, com informa??es qualitativas e quantitativas. A partir desse levantamento geral, fez-se um recorte contemplando apenas os benefici?rios residentes na Zona Norte da cidade. Para melhor compreender essa realidade, a pesquisa verificou o d?ficit habitacional brasileiro, considerando suas origens, contextos hist?ricos e os conceitos utilizados pelas seguintes institui??es: Funda??o Jo?o Pinheiro (FJP), Instituto Brasileiro de Geografia e Estat?stica (IBGE), Instituto de Pesquisa Econ?mica Aplicada (IPEA), al?m do Plano Local de Habita??o de Interesse Social (PLHIS) e do Programa das Na??es Unidas para os Assentamentos Humanos (UNHABITAT). Ademais, foram comparados os diversos conceitos de cidade e sua respectiva evolu??o, considerando a import?ncia do planejamento como instrumento de pol?ticas p?blicas necess?rias ?s a??es governamentais e pol?ticas permanentes de Estado. Aponta-se, como resultado, para a import?ncia da utiliza??o do Cadastro ?nico do governo federal como instrumento eficaz para mensurar as condi??es de habitabilidade dos munic?pios brasileiros. / This research aims to analyze the housing conditions and socioeconomic of beneficiaries of the Bolsa Fam?lia Program ? PBF of the North side of Natal city. For that, it is necessary a survey of this region's origins and how its expansion has occurred in the context of local urban development, considering demographic evolution, in particular, from the construction of housing complex and formal and informal allotments. From the field research, consisting of a pilot in loco with some households, it became possible to start the analysis of housing conditions that culminated with a detailed study of the Single Register form of the federal Government (Cad?nico), in relation to 100% (one hundred percent) of the beneficiaries of the Bolsa Familia program (PBF) of Natal city, with qualitative and quantitative information. From this general survey, a cut was done, contemplating only beneficiaries residing in the north of the city. To better understand this reality, the survey found the Brazilian housing deficit, considering its origins, historical contexts and concepts used by the following institutions: Jo?o Pinheiro Foundation (FJP), Brazilian Institute of Geography and Statistics (IBGE), Applied Economics Research Institute (IPEA), and Local Plan Housing of Social Interested (PLHIS) and the United Nations Centre for Human Settlements (UN-HABITAT). Furthermore, were compared the various concepts of city and its respective evolution, considering the importance of planning as an instrument of public policy necessary to governmental actions and permanent policy of State. As a result, there are a detach about the deficit and housing conditions in the city of Natal, mainly North Zone, pointing out the importance of using the Unified Register of the federal government as an effective tool to measure the living conditions of Brazilian municipalities.

The capabilities of various metal Additive Manufacturing (AM) processes, such as Powder Bed Fusion – Laser (PBF-L) and Direct Energy Deposition (DED) are increasing such that it is becoming ever more common to use them in industrial applications. The ability to print atop a substrate broadens that scope of applications. There is ongoing research regarding the mechanical properties of additively processed materials, but little regarding the interaction between additive material and its substrate. An understanding of the mechanical and performance properties of the AM/substrate interface is imperative. This paper describes a study of the strength properties of AM/substrate interfaces, with respect to torsion and tension, and compares them to their fully wrought and fully additive counterparts. PBF-L and DED are used to produce tensile and torsion test specimens of two different materials, SS316L and M300 steels. This provides sufficient variety in testing for a confident analysis to be made.

No description available.