Дисертації з теми "FSCW"
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Oliveira, Pedro Henrique Freiria de. "Estudo das propriedades e desempenho mecânico de juntas soldadas por fricção pontual de poli (metacrilato de metila) (PMMA)." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/899.
Повний текст джерелаUniversidade Federal de Minas Gerais
Polymeric components have been replacing traditional materials such as glass or metals in a wide range of applications due to their advantages, such as optimized specific strength (weight-to-strength ratio), reduced fabrication time and costs, and design flexibility. The increasing use of polymeric materials in engineering requires efficient and environmental friendly fabrication and processing technologies. Initially developed for metals, the Friction Stir Spot Welding (FSSW) is a joining technique with short process cycles, low energy consumption and no need of consumables. Friction Stir Spot Welding has excellent performance in welding of lightweight alloys, showing promising results in thermoplastic welding. This study investigates the relationships between friction stir spot welding parameters (tool rotational speed, plunge rate and dwell time) and weld properties (joint geometry, process temperature, microstructure, lap shear resistance and failure mechanisms) in polymethylmethacrylate (also known as PMMA) single-spot joints. PMMA friction stir spot welds showed similar mechanical performance in comparison to other current welding techniques, with equal or shorter welding cycle times. Differential scanning calorimetry and gel permeation chromatography analysis demonstrated that polymer degradation level in the weld region was negligible. The statistical models proposed for FSSW of PMMA showed good repeatability and reproducibility for the investigated material and welding ranges. Moreover, the feasibility of the Friction Spot Welding (FSpW) a new joining technology developed as a further improvement of the friction stir spot welding was successfully demonstrated in thermoplastic polymers for the first time worldwide. Sound FSpW-single lap joints on PMMA were produced and their properties studied within an exploratory study.
A busca por eficiência econômica e tecnologias ecologicamente corretas tem sido observada em praticamente todos os setores da produção industrial, desde o desenvolvimento de materiais, design de produtos e inclusive na área da soldagem. A soldagem ponto por fricção e mistura mecânica, FSSW (do inglês Friction Stir Spot Welding) e a Friction Spot Welding FSpW são técnicas de soldagem recentes e que têm sido amplamente empregadas na união de ligas metálicas leves, em que as soldas geralmente apresentam excelentes propriedades mecânicas. Além disso, ciclos de soldagem curtos, baixo consumo de energia e ausência de necessidade de adição de material ou elementos de soldagem são características positivas encontradas nesses novos processos. Na área de materiais poliméricos, entretanto, este é um novo e promissor assunto. Neste trabalho buscou-se investigar a relação entre os parâmetros do processo de soldagem por FSSW (velocidade de rotação da ferramenta, taxa de penetração e tempo de recalque) e as propriedades das juntas (geometria da solda, máxima temperatura processual, área afetada termicamente, resistência mecânica ao cisalhamento sob tensão e mecanismos de fratura) em placas de poli (metacrilato de metila). Foi possível observar a formação de juntas com resistência mecânica ao cisalhamento semelhante a outros processos atualmente utilizados na indústria, com tempos de ciclo de soldagem iguais ou inferiores a esses processos. As análises via calorimetria diferencial exploratória (DSC) e cromatografia por permeação em gel (GPC) demonstraram que os níveis de degradação termomecânica encontrados nas amostras foram insignificantes. A modelagem estatística do processo demonstrou a boa repetibilidade e reprodutibilidade dentro das condições estudadas. Nesse trabalho, também foi investigado através de um estudo exploratório, pela primeira vez, a viabilidade da nova técnica FSpW na soldagem de termoplásticos, demonstrando, com sucesso, a capacidade de obtenção de juntas de boa qualidade em PMMA.
Gonçalves, Joel. "Soldagem pontual por fricção (FSpW) de poliamida 6." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/7314.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Friction Spot Welding (FSpW) is an innovative technique developed and patented in 2005 by the Helmholtz Zentrum Geesthacht (HZG) research center in Germany. FSpW uses the friction between a rotating tool and the workpieces to generate heat enough to cause diffusion across the interface to consolidate the weld. This new welding technology has been tested and optimized with the objective of produce overlap weld joints between two polyamide 6 plates. Full factorial design of experiments (24) and analysis of variance (ANOVA) allowed to explain the effects of weld parameters as rotational speed (RS), welding time (WT), plunge depth (PP), holding pressure time (HPT) and the interactions between these main parameters on the microstructural characteristics and mechanical strength of the joints. The rotational speed (RS) and welding time (WT), within the limits studied, had greater influence on the mechanical single lap shear strength of the joints that achieved up to 26 MPa. This behavior was related to the higher heat generation during the weld, reaching temperatures of up to 275°C, thereby increasing the welded area. The parameter holding pressure time (HPT), designed in this study allowed the cooling and solidification of the polymer under pressure, improving the weld surface finishing and avoiding defects as voids in the weld area. The most common failure for the joints with higher mechanical strength was the fracture of one of the plates while the joints with lower mechanical strength showed interface shear failure. The degree of crystallinity of PA6 in the welded area did not show a significant difference as compared to the base material. The molecular weight of PA6 in the welded area was reduced in the worst case 7% as compared to the base material (Mv = 41.800 g/mol), and that reduction occurred linearly with the increase of the temperature during the welding; however, that low degree of degradation was not found to affect the mechanical strength of the joints. These characteristics emphasize the potential of this FSpW as an alternative to the current welding methods for polyamide 6.
A Soldagem Pontual por Fricção (FSpW) foi desenvolvida e patenteada pela Helmholtz-Zentrum Geesthacht (HZG), na Alemanha. A FSpW é uma técnica de soldagem pontual que ocorre por meio da fricção de uma ferramenta, com movimentos rotacional e axial, através das amostras, gerando aquecimento suficiente para fundir e misturar localmente o(s) polímero(s), com posterior consolidação sob pressão. Este estudo teve como principal objetivo investigar o uso da FSpW na fabricação de juntas pontuais entre chapas de poliamida 6 (PA6) sobrepostas. Experimentos do tipo fatorial completo (24) e análise de variância (ANOVA) possibilitaram a compreensão dos efeitos dos parâmetros de soldagem, velocidade de rotação (VR), tempo de soldagem (TS), profundidade de penetração da ferramenta (PP), tempo de consolidação (TC), e de suas interações, sobre características microestruturais e a resistência mecânica das juntas. Os parâmetros velocidade de rotação (VR) e tempo de soldagem (TS), dentro dos limites estudados, apresentaram maior influência sobre a resistência mecânica das juntas, alcançando 26 MPa. Este comportamento foi relacionado à maior geração de calor durante a soldagem, atingindo temperaturas de até 275oC, consequentemente, aumentando a área soldada. A utilização do parâmetro tempo de consolidação (TC), idealizado neste estudo, possibilitou o resfriamento e solidificação do polímero sob pressão, melhorando o acabamento superficial da solda e evitando a formação de defeitos. Juntas com maiores valores de resistência ao cisalhamento sob tração apresentaram maior probabilidade de falha por fratura de uma das chapas, enquanto que juntas menos resistentes falharam por separação das chapas. O grau de cristalinidade da PA6 nas soldas não sofreu variação significativa e observou-se um decréscimo de até 7% na massa molar da PA6 em relação ao material de base (Mv = 41.800 g/mol) que ocorreu de forma linear com o aumento da temperatura durante a solda, porém essa alteração não comprometeu a resistência mecânica da solda.
Kennard, Kirtis Frankland. "A Simple Method for Evaluating Wear in Different Grades of Tooling Applied to Friction Stir Spot Welding." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5529.
Повний текст джерелаZiegler, Daniel (Daniel M. ). "Compiling Gallina to go for the FSCQ file system." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113460.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 85-87).
Over the last decade, systems software verification has become increasingly practical. Many verified systems have been written in the language of a proof assistant, proved correct, and then made runnable using code extraction. However, due to the rigidity of extraction and the overhead of the target languages, the resulting code's CPU performance can suffer, with limited opportunity for optimization. This thesis contributes CoqGo, a proof-producing compiler from Coq's Gallina language to Go. We created Go', a stylized semantics of Go which enforce linearity, and implemented proof-producing compilation tactics from Gallina to Go' plus a straightforward translation from Go' to Go. Applying a prototype of CoqGo, we compiled a system call in the FSCQ file system, with minimal changes to FSCQ's source code. Taking advantage of the increased control given by CoqGo, we implemented three optimizations, bringing the system call's CPU performance to 19% faster than the extracted version.
by Daniel Ziegler.
M. Eng.
Matchett, Michael William. "Resolution of enantiomers using cyclodextrins in HPLC, FSCE and NMR." Thesis, University of Bath, 1996. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307070.
Повний текст джерелаHeinrich, Bernd. "Auswirkungen der FSC-Zertifizierung auf die Waldrestholzbereitstellung." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-202319.
Повний текст джерелаAli, Khaled Yousif. "Friction Stir Welding Between Similar and Dissimilar Materials." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1513857047779233.
Повний текст джерелаKarlsson, Alexandra. "Attityder till certifieringssystemen FSC och PEFC i skogsbranschen." Thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-38481.
Повний текст джерелаOlika grupper i skogsbranschen riskerar att ha olika syn när det gäller ansvaret för ett miljömässigt hållbart skogsbruk och nyttan med certifiering och den här studien gjordes för att undersöka vilka inställningar som fanns i skogsbranschen till certifieringssystemen FSC och PEFC. Arbetet gjordes med avseende på tre grupper: skogsägare, skogsentreprenörer och anställda som arbetar på skogsföretaget Södra med certifiering i sitt dagliga arbete. I studien skickades en enkät och ett frågeformulär ut. Undersökningen visade att de tre grupperna värderade miljömässigt hållbart skogsbruk med certifiering högt. Som skogsägare fick man en certifieringspremie för det certifierade virke som man sålde. Skogsägarna såg också en ekonomisk vinning med certifiering. Skogsentreprenörerna ansåg att certifiering i högre grad gav ordning och reda i deras arbete men att det fanns en ekonomisk kostnad med att vara certifierad. Skogsföretagsgruppen menade att certifierade produkter gav tillgång till en större marknad för skogsföretaget. Grupperna var överens om att ansvaret för ett miljömässigt hållbart skogsbruk låg på de/den som ägde skogsmarken. Samtidigt uppskattade hälften av skogsägarna att deras kunskaper om certifieringarna var otillräckliga medan skogsentreprenörerna och skogsföretagsgruppen ansåg att deras kunskaper var tillräckliga. Detta kunde bero på att skogsägarna fick mindre utbildning av certifiering än de andra två grupperna. Det här arbetet har visat att grupperna inte har olika syn när det gäller vikten av att ett miljömässigt hållbart skogsbruk bedrivs.
Reese, Gregory A. "Dissimilar Friction Stir Welding Between Magnesium and Aluminum Alloys." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955097/.
Повний текст джерелаReilly, Aidan. "Modelling of friction stir spot welding." Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/244946.
Повний текст джерелаMakrickas, Evaldas. "FSC forest management certification analysis in Lithuaniua and Russia." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110601_115619-77809.
Повний текст джерелаPagal FSC standartus miškai pradėti sertifikuoti nuo 1993 metų. Patogi sertifikavimo sistema leido minėtam standartui išplisti visame pasaulyje. Bolivijoje, Brazilijoje, Indonezijoje FSC sertifikavimas vis dar plečiamas (Claros, 2009). Sertifikacijos dėka gerinama miškų valdymo kokybė, biologinės įvairovės apsauga, sprendžiamos darbuotojų saugos problemos. Šio standarto visapusišku naudingumu neabejoja daugelis FSC rėmėjų: LEED Lumber, IKEA, bei didžiausios miško produktus superkančios ar nevyriausybinės organizacijos, Pasaulio gamtos fondas (World wild Fund WWF), Green peace (www.fsc.org). Mokslinių darbų, nagrinėjančių miškų sertifikaciją objektyviai, yra nedaug ir miškų sertifikavimo tema nėra plačiai nagrinėjama palyginus su socialiniais, miško gyvosios ir negyvosios gamtos sąveikos tyrimais. Miškų sertifikavimo standartų palyginamųjų darbų taip pat yra negausu. Šio darbo sukūrimo pagrindas – galimybė išanalizuoti skirtumus tarp FSC sertifikuotų kaimyninių šalių (Lietuvos ir Rusijos) miškų tvarkymo vienetų ir naudojimo standartų (MTV – Lietuvoje valstybinių miškų įmonių urėdijų ir Rusijoje miškų ūkių ir miškų nuomotojų). Taip pat norima sužinoti, ar Lietuvoje ir Rusijoje susiduriama su skirtingais sertifikavimo pažeidimais. Šių pažeidimų koregavimo veiksmų reikalavimų (KVR) aspektų pagalba palyginti Lietuvos ir Rusijos FSC miškų valdymo sertifikacijos standartus bei su standartais susijusi šalių miškų teisė. Kita šio darbo dalis, skirta ištirti kokią įtaką ekonominės... [toliau žr. visą tekstą]
Souza, Henrique Cezar. "Projeto de dispositivo para ensaio de solda FSW sobreposta." Instituto Tecnológico de Aeronáutica, 2011. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2995.
Повний текст джерелаQuercetti, Giovanni. "Analisi delle problematiche della FSW di leghe eleggere avanzate." Doctoral thesis, Università Politecnica delle Marche, 2014. http://hdl.handle.net/11566/242841.
Повний текст джерелаThe subject of this doctoral research was to study the weldability using the FSW process of light alloys of aluminum and magnesium. In particular, after a first phase illustrative of FSW technology is has undertaken a series of experimental work summarized below. It started with the welding of butt joints by analyzing three main topics, the first of which has studied the weldability of a joint between dissimilar alloy AZ31 and AA6061 through a macro and microstructural characterization. The results showed a welding without defects with the area of the nugget characterized by widespread phenomena of recrystallization in both alloys and phenomena of interdiffusion of aluminum in magnesium and magnesium in aluminum, in the form of secondary precipitation. In the second work was investigated the creep strength of a magnesium alloy AZ31 welded FSW. Following the creep tests performed , the observations of the curves showed that the beginning of the tertiary stage of the samples FSW occurs for lower values than the base material. The research for the butt joint configurations ended with a new welding technique which involved the double-pass, i.e. the weld on both sides of the sheets. A comparison of the AZ31 alloy welded joints on one side with those from two sides showed that the samples welded with technique from two sides, show a trend toward the elimination of discontinuities obtained with single pass, in addition, in the welded joints with technical double pass, there is an increase in the hardness values of the mixing zone similar to the single-pass and slightly higher, but there is a better fitting in the decrease of the valuesuntil arrive in the area of the unaffected base material. From tensile tests it was found that the samples welded with double-pass had an increase of tensile strength (UTS) of about 9%. The research has been followed with the analysis of welding of lap joints and with dissimilar thicknesses to vary the process parameters and the configuration of the tool. In this regard, we have tried to assess the weldability of an aluminum alloy AA5754 with dissimilar thicknesses. It has made the analysis of variance for the three factors considered as variables of the process and has assessed the effect of individual factors and give them a percentage on the importance of control of the process. The results obtained showed a high variability, in particular with the decrease of the rotation speed and with the increase of the translation speed.
Ražauskaitė, Rita. "Lietuvos valstybinių miškų urėdijų sertifikavimo pagal FSC programą poveikio analizė." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120620_151755-00560.
Повний текст джерелаThe aim of this paper is to analyze the main impacts of the FSC. In order to achieve this goal, the survey was the Lithuanian state forest enterprises as the main subject of the certification. For added reliability analysis was performed to achieve the rangers and the pilot survey. The survey results were compared and analyzed. To further investigate the impact of certification on external stakeholders were interviewed by the four groups. Structured interviews and summarized results. The study found that the certification had no significant effect on forest management. Enterprises and district staff responses were similar. The most significant positive changes were found in the social sphere. Extra points were assessed positively associated with easily discernible, measurable and comparable developments. The more complex and more difficult to assess changes were evaluated as almost neutral. For example. "State forest composition”. This can be attributed to the specifics of forest ecosystems. Economic impact analysis revealed that after certification of enterprises, and the price of goods and demand has changed very slightly. Economic incentives are a key factor leading to certification, so it can be stated that Lithuanian owners are not encouraged to certify their holdings. The certification effect analysis of different stakeholders showed the significant differences between public and private groups opinion. The Private organizations were less active and the means of... [to full text]
Gratecap, François. "Études du procédé de soudage par frottement et malaxage (FSW)." Nantes, 2007. http://www.theses.fr/2007NANT2139.
Повний текст джерелаFriction stir welding is a relatively new process, but already has a large number of theoretical and experimental studies. However, at the scientific level, many questions remain including the mixing dynamics, the compounds formation in heterogeneous welding, induced and intrinsic thermal fields, coupling thermal dynamic structural fields. Moreover, the welding speeds and tool geometry choice takes mostly place in an empirical manner without real theoretical basis. Finally, the short tool life remains the major technological lock for hard alloys. It is in this research context that this thesis aimed at improving our understanding of the FSW process. The main objective of this work is to advance in the FSW physical phenomenon understanding and to develop a hybrid FSW assisted diode laser manipulation to start tests on hard alloys. The first point concerns the influence of a tool kinematics disruption on the material movement. First, at a macroscopic scale where we study the material flow and then at a microscopic scale where we study the effect of the tool vibration on the material mixing. The second point concerns the methodology development based on an optimization algorithm for defining the tool geometry and the optimal welding speeds for a given material. This method can result in a process window. The third point concerns the FSW hybrid assisted laser diode study. We present the thermal models used to define the laser parameters and discuss the first testing in steel and titanium alloys as well as for dissimilar aluminum-steel
Gastebois, Sabrina. "Simulation numérique du soudage FSW à l'aide d'une formulation ALE." Thesis, Paris, ENMP, 2015. http://www.theses.fr/2015ENMP0040/document.
Повний текст джерелаSince the invention of Friction Stir Welding (FSW) in 1991 by The Welding Institute (TWI), aeronautics industry has been investigating the possibility to use this process instead of riveting with the objective to lighten its structures and more particularly the aircrafts structure panels. Aircraft panels are often straightened with stringers and profiles which are joined to the outer skin. The qualification of FSW process in aeronautics requires producing very high quality joints with the longevity of tools, which requires fine tuning of process parameters such as the geometry of the welding tool (shoulder and pin dimensions, threads on pin and shoulder) and the advancing and rotating speeds. The aim of this work is to support the design of the process by numerical simulation. It has three parts: (1) developing an efficient and accurate Arbitrary Lagrangian or Eulerian (ALE) formulation within the parallel version of Forge® software, (2) modelling the FSW process and (3) calibrating the F.E. model and validating simulation results thanks to FSW experiments on lap joints.This work is based on the parallel ALE formulation developed in Forge® to model the different possible defects taking place in FSW (flashes and worm holes). The transport algorithm of continuous fields, required by the Eulerian frame, is enhanced to take the special characteristics of the FSW's flow into account (nodes located in input plan or flashes or in contact with the tool). A new time integration scheme based on cylindrical coordinates, which are best suited for this process, is introduced. Finally, the pin and shoulder threads are modelled by introducing a new friction law at the tool / material interface.This general and parallel ALE formulation is robust enough to model the FSW process. Thermomechanical results obtained are in agreement with previous results validated by experiences. And the numerical tool demonstrated its ability to model flashes formation and losses of contact behind the pin. Finally industrial welding lap joints configuration was studied. Experimental tests were conducted with several process parameters and type of lap joint. And measure of torque and forces in tool, and temperature in tool and sheet metal allowed to calibrate model parameters (friction, behavior law, thermal coefficients) and to validate FE results
Schreiber, Rafael Gustavo. "Estampagem incremental e soldagem FSW para fabricação de coletor solar." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/183075.
Повний текст джерелаThis work presents an innovative model of flat plate solar collector, with absorber plate manufactured using Incremental Sheet Forming (ISF) and Friction Stir Welding (FSW). This absorber plate consists of two AA1200-H14 aluminum sheets with a thickness of 1 mm, stamped and welded in symmetry, in order to leave channels for the passage of water. In this study the characterization of the material by Nakajima Test and Traction Test was performed. In order to determine the parameters of ISF, 16 experiments were performed with a tool of diameter df = 9.5 mm, varying the rotation speed of N = 50 rpm at 800 rpm and the step down of Δz = 2 mm to 0.2 mm, maintaining the feed rate at = 250 mm/min. Also, 3 experiments with tool df = 22 mm were performed, varying the step down of Δz = 2 mm to 0.5 mm, maintaining the rotation speed at N = 50 rpm and the feed rate at = 250 mm/min. For determination of FSW parameters, 4 experiments with 8 mm diameter shoulder tool and M3x0.5 pin were performed, maintaining the rotation speed at N = 1500 rpm and varying the feed rate from = 100 mm/min to 400 mm/min. A prototype solar collector absorber plate with a 0.12 m² area was then manufactured. In the experiments carried out, it was found that it is possible to obtain greater deformations in the ISF than in the Conventional Stamping and that the deformations are higher when using smaller diameters, higher rotations and smaller step downs of the tool. In FSW, no influence was observed in the quality of the weld bead in relation to the variation of the tool feed rate. In this study it was also verified that it is possible to manufacture prototypes of solar collector absorber plates by the processes of ISF and FSW. However, for commercial size collectors, further studies are needed to improve the way the plates are fixed during FSW.
Huang, Dong Fang. "Investigation of Heterogeneity of FSW Inconel 718 Coupled with Welding Thermal Cycle." BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1914.
Повний текст джерелаDardouri, Fawzia. "Dispositif d’assistance associé à des robots manipulateurs utilisés dans des procédés de fabrication/FSW." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0036/document.
Повний текст джерелаNowadays industrial robots are used in many manufacturing applications because of their versatility and easy applicability. Notwithstanding their performance these robots are not suitable for some manufacturing processes where uniform and high forces together with suitable precision of position are required. The present research is focused on the robotization of one of the high-thrust operations, the friction stir welding (FSW). This method for connecting two parts works while the connected materials are in the solid phase. For this reason a very high axial force is needed to soften the material during the welding process. Due to these high forces the position of the tool of a serial robot deviates from the desired trajectory. In this PhD work, the possibility of using a parallel structure device is investigated to improve the load capacity and stiffness of a heavy loadmanipulator robot. In a first part, the geometric, kinematic and dynamic modeling and the flexibility of an industrial robot, Kuka KR500-2MT are developed by locating flexibility at the joints. The second part is to improve the performance of the FSW process using an industrial robot. So different methods are examined: the modification of the gravity compensation system, the addition of an additional mass on the tool, the addition of a parallel structure and the use of a cooperative system. The last two solutions exert forces directly on the process tool. In this way the movement of the tool is mainly generated by the industrial serial robot, while the assistive device (either the parallel structure or the second robot used in the cooperatif system) ensures the generation of very high axial forces. Optimization algorithms are developed to minimize deviations and thus reduce welding defects. Finally, a study of the workspace is studied using Catia software. Knowledge of the system workspace with the proposed solutions allows to estimate the possible welding applications that can be achieved using these systems
Miyazaki, Marcos Hideki. "Desenvolvimento de novo conceito de junção de reforçadores aeronáuticos por FSW." Instituto Tecnológico de Aeronáutica, 2009. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1278.
Повний текст джерелаBrumbaugh, David. "DISC, FSC, and the cost of capital in the export sector." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/74513.
Повний текст джерелаMaster of Arts
Rosendo, Tonilson de Souza. "Estudo do desempenho mecânico de solda(s) ponto por fricção (FSpW) da liga AA6181-T4." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/18981.
Повний текст джерелаA new welding technique referred to as Friction Spot Welding (FSpW) suitable to produce overlap joints uses a spindle to transfer mechanical and thermal energy to the material being welded. Although initially developed for lightweight alloys this welding technique is suitable to virtually any material presenting some degree of plasticity. The process has shown potential applicability to complementary use together with other well established techniques such as resistance and LASER spot welding and riveting. In this work a study of the application of the FSpW process for the automotive aluminium alloy 6181-T4 was performed. Overlap joints were produced with different welding conditions by using different combinations of tool rotation speed and welding time. The objectives were the assessment of the welding parameters on the strength, microstructure and geometry of the joints, as well as the optimization of the process. The welded joints were assessed mechanically and metallurgically aiming the investigation of the mechanisms of joint formation and the optimization of the welding parameters. The methodology used for the optimization of the welding parameters was the fracture mechanisms of the joints under shear and tension loads. The results revealed that sound welds with high strength and toughness are possible to be produced with the 6181-T4 alloy using this process. Moreover, the metallurgical investigation revealed that the spot joint is comprised by three elements: Primary Union, Secondary Union and Rim. It was found that the characteristics of these three elements in addition to the metallurgical transformations imposed to the material play a fundamental role on the fracture behaviour of the joints and thus, on its mechanical behaviour.
Atcherley, Christopher Wade. "Voltammetric Measurements Of Tonic And Phasic Neurotransmission." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/338965.
Повний текст джерелаPlaine, Athos Henrique. "Soldagem por fricção e mistura (FSW) no aço inoxidável austenítico AISI 304." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/900.
Повний текст джерелаFinanciadora de Estudos e Projetos
Stainless steels are an important class of engineering materials with attractive properties such as high mechanical and corrosion resistance and thereby widely used in a variety of industries and environments due to its outstanding properties such as mechanical and corrosion resistance. These materials, which are usually considered difficult to weld by conventional fusion welding processes, have demonstrated outstanding performance when joined by Friction Stir Welding (FSW), a solid-state joining process. FSW input energy regulates the magnitude of the thermal cycle and the intensity of deformation during the process, and it can be controlled by the welding parameters, which affects the grain features and consequently the mechanical properties of the joints. The aim of this work is to evaluate the feasibility of producing friction stir welds of a 304 austenitic stainless steel and correlate this process to the microstructures and mechanical properties in these joints. The samples were produced using a polycrystalline cubic boron nitrides (PCBN) tool and four different rotational speeds. Microstructural investigation showed that all joints presented, besides the base material (BM), the three typical FSW zones: stir zone (SZ), termomecanically affected zone (TMAZ) and heat affected zone (HAZ). The ZTA exhibited a microstructure similar to MB, while ZTMA and ZM were characterized by dynamic recovery and recrystallization, respectively. In the advancing side of ZM was observed the formation of sigma phase, a brittle and undesirable phase. The welding parameters variation affected mainly the deformation experienced by the material, the average grain size and length of the weld zones. The mechanical tests were consistency with the observed microstructures, being the mechanical properties of joints higher than BM, which is very attractive from the technological point of view.
Os aços inoxidáveis são uma importante classe de materiais de engenharia que possuem propriedades atrativas, como a alta resistência mecânica e a corrosão, sendo extensamente aplicados em muitas indústrias e em diversos ambientes. Esses materiais, frequentemente considerados difíceis de serem soldados pelos métodos de soldagem por fusão convencionais, têm demonstrado um excelente desempenho quando unidos pela técnica de soldagem por fricção e mistura (FSW Friction Stir Welding), um processo de soldagem no estado sólido. Na FSW, a energia do processo determina a magnitude do ciclo térmico e a intensidade da deformação que ocorre no material durante o processo energia essa controlada pelos parâmetros de soldagem afetando características do grão e consequentemente as propriedades mecânicas das juntas. O presente estudo tem por objetivo avaliar a viabilidade de união de placas de aço inoxidável austenítico AISI 304 e relacionar processo, microestruturas e propriedades mecânicas nestas soldas. As amostras foram produzidas utilizando-se uma ferramenta de nitreto de boro cúbico (PCBN) e quatro diferentes velocidades de rotação da ferramenta. A observação microestrutural mostrou que as soldas produzidas apresentam além do metal de base (MB), três zonas típicas do processo FSW: zona de mistura (ZM), zona termomecanicamente afetada (ZTMA) e zona termicamente afetada (ZTA). A ZTA apresentou uma microestrutura similar ao MB, enquanto que ZTMA e a ZM foram caracterizadas por recuperação e recristalização dinâmica, respectivamente. No lado de avanço da ZM houve a formação de fase-, frágil e indesejada. A variação dos parâmetros de processo afetou principalmente o tamanho médio de grãos, a deformação sofrida pelo material e a extensão das zonas de soldagem. Os resultados dos ensaios mecânicos demonstraram coerência com as microestruturas observadas, de forma que as propriedades mecânicas das juntas soldadas foram superiores ao MB, sendo dessa forma atraentes do ponto de vista tecnológico.
Demmouche, Younes. "Étude du comportement en fatigue d'assemblages soudés par FSW pour applications aéronautiques." Phd thesis, Paris, ENSAM, 2012. http://pastel.archives-ouvertes.fr/pastel-00838617.
Повний текст джерелаGranat, Simon. "Naturvårdsuppföljning vid slutavverkningar : En jämförelse mellan FSC-certifierade bolag i södra Sverige." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-54015.
Повний текст джерелаAlmeida, Renato Caldas Vasconcellos de. "Análise numérica de falha de vigas de KUHN fabricadas com soldagem FSW." Instituto Tecnológico de Aeronáutica, 2012. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=3324.
Повний текст джерелаLorrain, Olivier. "Analyses expérimentales et numériques du procédé de soudage par friction malaxage fsw." Paris, ENSAM, 2010. https://pastel.archives-ouvertes.fr/pastel-00515112.
Повний текст джерелаThe Friction Stir Welding (FSW) is a solid state welding process, without melting. The weld is fabricated thanks to the action of tool made of a shoulder and a pin, positioned at the interface of the two pieces to be welded. The tool as two roles : heating of the material by friction of the shoulder, mixing of the material due to the pin. This thesis work is made within the partnership between Arts et Métiers ParisTech and Institut de Soudure. Its goal is to develop a FSW simulation model in order to decrease experimental trials required to optimize the process. Therefore, some points have been treated in this manuscript. Experimental analysis of thermal cycles and material movements in the case of unthreaded tools has been carried out. This situation allows (1) to make the comparison with numerical simulation easier and (2) to be in the case of worn tools. Formulations (lagrangian, eulerian, ALE) analysis in order to choose the more appropriate to take material flow into account has allowed to select an eulerian formulation (implemented in the FLUENT software) to estimate thermal and kinematical fields in the steady state. The set up of the numerical model in the FLUENT software is presented. We have studied the influence of numerical parameters on the results and proposed an identification strategy for some parameters which are not reachable experimentally. A detailed comparison between our experimental results and the ones from our simulations have been performed with success. The study of the influence of the process parameters (feed rate, rotating speed) and of the pin geometry on the kinematical and thermal fields has highlighted the link between velocity field and the presence of tunnel type defects
Huang, Dongfang. "Investigation of heterogeneity of FSW Inconel 718 coupled with welding thermal cycles /." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd2750.pdf.
Повний текст джерелаMorrone, Ericka Pardini. "Contribuições da auditoria ambiental para a comunicação do desempenho de empresas com certificação FSC : análise das não conformidades evidenciadas no resumo público de auditoria." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/100/100136/tde-20042016-184147/.
Повний текст джерелаThe study aimed to analyze how companies communicate to the public through the public summary of audit their difficulties (represented by the non-conformities) to meet the environmental requirements of FSC certification. The influence of the configuration of the audit was considered on the results obtained in the process, results these communicated to external parties. We collected secondary data from 95 public summaries carried out between 2010 and 2015, analyzed by the content analysis technique in order to identify the main thematic areas which non-conformities referred, and mapped a total of eleven thematic areas. Based on descriptive statistical analysis (Kruskal Wallis test and Chi square) sought to identify the relationship between the characteristics of the audits defined (Size of the audit team, Diversity in the training of staff, Audit time, Certifying company and Audit event) and thematic areas identified. The Compliance with labor legislation; Management plan; Quality of system monitoring; Communication and relationship with the public were the thematic areas with the highest number of non-conformities. It was found that, except for specific cases, there is no significant relationship between the characteristics of the audits and the disclosure of non-conformities. However, this does not mean that the way the audit happen not influence the quality of the results, as there are other factors such as the quality and truthfulness of non-compliances identified to be considered. Public reports represent a breakthrough in communication of socioenvironmental results obtained, converging with the need for transparency in the certification. However, is necessary to evolve in pursuit of disseminating results in a more clear and organized way and at the relation with the communities that surrounding enterprise
Grund, Olof. "Modification of a transient EPR and photoluminescence detection setup." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328896.
Повний текст джерелаHasan, Ahmed Falh. "Modelling of tool wear and metal flow behaviour in friction stir welding (FSW)." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/36154/.
Повний текст джерелаYeung, Wai-man Violet, and 楊慧敏. "The popularity of FSC timber products in the consumer market in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207622.
Повний текст джерелаpublished_or_final_version
Environmental Management
Master
Master of Science in Environmental Management
Terreros, Iñigo. "Modélisation DEM thermo-mécanique d'un milieu continu. Vers la simulation du procédé FSW." Phd thesis, Ecole nationale supérieure d'arts et métiers - ENSAM, 2013. http://pastel.archives-ouvertes.fr/pastel-00996971.
Повний текст джерелаSonne, Lehnberg Ida. "Privata skogsägares uppfattning om FSC- och PEFC-certifiering : att bli och vara certifierad." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-76666.
Повний текст джерелаFioravanti, Artur Suárez. "Soldagem por FSW de ligas de alumínio Alcalad AA2024-T3 e AA7075-T6." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/14373.
Повний текст джерелаThe welding of AA2024-T3 and AA7075-T6 clad aluminum alloys was always an obstacle to the industry due to cracking susceptibility during arc welding process. These alloys are largely used in the aeronautical industry because of their high mechanical strength and low density, being riveting the most widely used method to join them. The advent of friction stir welding (FSW) presents itself as a new opportunity to join these alloys and the present research demonstrates excellent mechanical properties of the joint. Friction stir welding is a welding technique that was developed in 1991 at The Welding Institute (TWI) in England. This welding method has the advantage to be a solid state process that preserves the mechanical properties of alloys, to the contrary of conventional fusion welding techniques that produce microstructures with low mechanical properties. In the FSW process a high strength tool with a given profile is rotated in order to generate friction in the parts to be welded. This friction generates enough heat to soften and stir the material, joining them without fusion. The objective of this work is to determine a set of parameters using the FSW process to weld a 1,8 mm thick AA2024-T3 and AA7075-T6 aluminum clad sheet using a stiff milling machine. For this purpose, development of two tool geometries with a set of parameters to obtain defect-free welded joints was utilized. These welded joints were investigated using microhardness, bending and tension testing to verify the mechanical properties in comparison with the base metal. It was noted that, dependent upon the parameters and tools used for welding, the joints did not show adeq uate ductility during the bending testing, even if the macrographic analysis demonstrate no defects. In the same way, the joint mechanical strength is 70% of base metal, showing that this technique is a good alternative for riveting method. Finally, for the AA2024-T3 aluminum alloy, it was obtained the desired properties for the joints, with no defects, good ductility and tension strength.
Mattiello, Rafael. "As trajetórias da certificação florestal dos standards do Conselho de Manejo Florestal - FSC." Florianópolis, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/100992.
Повний текст джерелаMade available in DSpace on 2013-06-26T00:35:06Z (GMT). No. of bitstreams: 1 309742.pdf: 13033173 bytes, checksum: ac8bfde8d663de50cb4036054912e8e1 (MD5)
O objetivo geral desta tese é contribuir ao crescente corpo teórico da sociologia ambiental. A teoria da modernização ecológica trata da necessidade de readequação ambiental oriunda dos principais atores envolvidos nos processos de crescimento e desenvolvimento industrial do capitalismo contemporâneo. Argumentamos que a modernização ecológica está relacionada à emergência de práticas responsáveis por intermédio da construção de standards por autoridades privadas especializadas. Analisamos as transformações sociais que permitiram a introdução de mecanismos privados de manejo florestal responsável e suas implicações político-sociológicas através de um estudo de caso dos processos e conflitos em torno dos standards do Conselho de Manejo Florestal - FSC. Defendemos que a (alta)modernidade sob uma condição de globalização se caracteriza por riscos e incertezas, demandas e expectativas, necessidades e oportunidades intrínsecas à própria dinâmica de reflexividade deste fenômeno, o que gera novas possibilidades e reanálises em todos os âmbitos. As empresas standards foram criadas, implementadas e cada vez mais legitimadas por todos para estabelecer novas práticas econômicas/administrativas/fabris/ socioambientais que dessem conta da expectativa da sociedade como um todo. Dentro desta abordagem caracterizada pelos fluxos, redes e pela modernização reflexiva/ecológica é analisada a emergência e o desenvolvimento do standard de manejo florestal mais respeitado e amplamente utilizado pela indústria de madeira, papel, celulose e embalagens, gráficas - os standards do FSC, com seus conflitos e discrepâncias nesta ampla rede de atores sociais in-the-making, através de duas etapas de certificação florestal: a definição de normas e a implementação delas. São analisadas as certificações da Klabin (realizada pelo Imaflora) e da Veracel (realizada pela SGS) e ao mesmo tempo as características reflexivas, conflituosas, ideológicas e discursivas destes standards. Por fim são dadas algumas recomendações para serem debatidas visando o aprimoramento característico e contínuo do sistema FSC.
The aim of this thesis is to contribute to the growing body of literature on environmental sociology. The theory of ecological modernization exposes the need for environmental adjustment of the main actors involved in the processes of industrial growth and development of contemporary capitalism. We argue that ecological modernization is related to the emergence of responsible practices through the construction of private standards by specialized authorities. Hence, we analyze the social changes that allowed the introduction of private mechanisms for responsible forest management and its implications in a political-sociological study of the processes and conflicts involved in a case study of the Forest Stewardship Council standards. We contend that the (high)modernity under a condition of globalization is characterized by risks and uncertainties, demands and expectations, needs and opportunities inherent to the dynamics of this phenomenon of reflexivity, which creates new possibilities and reanalysis in all areas. Specifically business standards were created, implemented and increasingly legitimized to establish new economic/administrative/ manufacturing/socioenvironmental practices that account to the expectation of the entire society as a whole. Within this approach characterized by flows, networks and through the theory of reflexive/ ecological modernization we analyze the emergence and development of the forest management standard that is most respected and widely used by the wood, pulp and paper, packaging and printing industries - the standards of the FSC. We focused in the conflicts and discrepancies of this extensive network of social actors in-the-making through the two stages of forest certification: setting the standards and its implementation. Thus, it is considered the certification of Klabin performed by Imaflora (SmartWood/Rainforest Alliance) and Veracel conducted by SGS, while it analyzes the reflexive, conflicted, ideological and discursive characteristics of those standards. Finally some recommendations are given to be discussed aiming at the characteristic continuous improvement of the FSC system.
Tchein, Gnofam Jacques. "Étude des couplages thermomécaniques et microstructuraux d’un alliage de titane au cours du soudage FSW." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0344/document.
Повний текст джерелаFriction Stir Welding (FSW) is a solid state welding process used today in the aerospace, naval and rail transport sectors. It has the advantage of providing welds with better mechanical properties than fusion welding processes. Most of studies carried out on this process concern aluminum alloys. This work focuses on the study of thermomechanical and metallurgical phenomena during FSW of the Ti-6Al-4V alloy. The influence of the initial microstructure on the mechanical properties and the final microstructure is studied through an experimental study. The HAZ and TMAZ of the welds are very thin and the welds didn’t present any weak zone. The genesis of the microstructure during the process has been identified and is made up with three main steps: α → β phase change, continuous dynamic recrystallization of the β phase and formation of α grains within the recrystallized β grains. In order to set up a model to predict the microstructure in the weld nugget, hot torsion tests were performed to determine the rheological properties of TA6V. These tests also made it possible to set up an analytical behavior law of Ti-6Al-4V. The velocity fields during FSW are formulated analytically from the equations of fluid mechanics and thermal fields are determined numerically from a eulerian formulation
Saunier, Valentin. "Microélectrodes nanocomposites implantables couplant enregistrement-stimulation neuronale et détection électrochimique de neurotransmetteurs." Thesis, Toulouse 3, 2021. http://www.theses.fr/2021TOU30023.
Повний текст джерелаElectrophysiology is the physiology field that aims at recording the electrical activity of biological tissues. Using microelectrodes in or on the brain, electrophysiology helped make crucial advancements in the understanding of major neurological mechanisms like memory, language, learning by recording the brain electrical signals. Through these advances, it promised and helped develop treatments and therapeutic devices to cure the major neurological diseases like Parkinson's, Alzheimer's or epilepsy. However, recently the need for other sources of information to combine with electrophysiological recordings has raised, as the research and therapeutic approaches over-relying on these recordings did mostly lead to dead-ends. As the brain electrical activity is molecularly supported by a class of molecules called neurotransmitters, their detection in real-time is proposed as a high-potential complementary brain study technique to integrate along with electrophysiological recordings during neural interfacing. During this PhD, we developed a new generation of nanocomposite microelectrodes made of both PEDOT and oxidized carbon nanofibers to meet this combined integration. These electrodes displayed a key characteristics combination in-vitro, with low impedance, high charge injection limit, making them promising candidates for bidirectional electrophysiology, while being capable to detect dopamine (one key neurotransmitter) using two complementary techniques, chronoamperometry and fast-scan cyclic voltammetry. Moreover, these electrodes keep a sufficiently low spatial profile to interface with single cells, making them promising candidates for multifunctional neural interfacing, adding neurochemical detection to electrical recordings. Integrated on flexible implants, these electrodes were first tested in-vivo in brain slices as recording and stimulating electrodes (realizing bidirectional electrophysiology). They showed high performances, being capable to record brain electrical signals on a wider frequency range than standard microelectrodes, with a higher Signal to Noise Ratio (SNR). They also allowed to electrically stimulate brain slices tissues, generating measurable outputs with low inputs compared to standard electrodes. In conclusion, the modified electrodes developed in this thesis showed promising properties for multifunctional neural interfacing at a single cell level, enabling the coupling between electrophysiological recording and electrical stimulation of tissues in-vivo, while also being capable of neurotransmitter electrodetection in-vitro. Through these properties, they constitute meaningful candidates for long-term simultaneous recording of the brain electrical and neurochemical activities for research and therapeutic applications
Silva, Erenilton Pereira da. "Fundição, laminação e soldagem por fricção e mistura mecânica de ligas de magnésio com adição de Mischmetal." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-09022017-081216/.
Повний текст джерелаThe growing scarcity of renewable energy resources, as well as the continued rise in costs has required in recent decades a dramatic reduction in energy used for transportation freight and passenger, which is increasing daily all over the world. An alternative is to weight reduction with the use of light alloys, this concept the use of magnesium alloys is justified by their low density, about 1/3 lower than that of aluminum. Among the magnesium alloy, the matrix is ZK type that has greater mechanical strength and the addition of rare earth elements (RE) to increase corrosion resistance, working temperature and yield strength due to the formation of thin films and density oxides, and intermetallic of the high melting point and higher hardness. The formation of intermetallic of the MgZn type, which has a low melting point, makes alloys with matrix of the ZK type susceptible to formation of hot crack during the welding, making impossible the use of conventional welding processes, an alternative is the friction stir welding (FSW) that the union is made below the melting point. This work shows the studies the addition of 1.5% wt. of mischmetal (Mm) in the ZK60 alloy and effects of the casting process with mechanical mixing in the semi-solid state. Were produced the alloys: ZK60, ZK60-1.5RE with conventional casting and ZK60-1.5RE Tixo with mechanical mixing in the semi-solid state, all were hot-rolled in a symmetrical laminator and welded with friction stir welding (FSW) process. The methods of casting and cooling gave resulted in materials free of defects and chemical homogeneity, and the mechanical mixing provides homogeneous microstructure with globular grains. The alloy with mischmetal addition had an average grain size of about 22% lower than ZK60 alloy, when compared to the casting method the ZK60- 1.5RE Tixo alloy had an average grain size of about 26% lower than ZK60-1.5RE alloy. The rolling process gave rise to a partially recrystallized microstructure with average grain size of between 3.3 and 4.23 μm, the intermetallic network were broken, however, kept continuous for alloys with Mm addition. As for mechanical strength was higher for ZK60 alloy, due smaller amount and intermittent network of the intermetallic. The alloys with Mm addition had better thermal stability during welding and showed better surface quality, being possible to do a welding with rotation of 1200 rpm and advancing speed of 400 mm/min while the ZK60 alloy only was possible the welding with advancing speed of 200 mm/min. The analyzes of residual stresses had similar values and profiles and follow the flow of material as well as the texture of the weld beads. The micro hardness maps in the cross section of the weld bead showed a higher hardness in the mixing zones, and higher and more homogeneous values for ZK60 alloy, and can thus affirm that the intermetallic MgZn type has higher hardness than the MgZnRE type.
Ökshei, Jorunn, and Hannah Eriksson. "Certifieringens betydelse för naturvärden i skogen." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-85925.
Повний текст джерелаVergara, Mesina Benjamín. "Modelamiento acoplado térmico y de deformación en soldadura por fricción-agitación." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/148355.
Повний текст джерелаLa presente memoria tiene como objetivo el corroborar, reformular y combinar ecuaciones asintóticas para obtener expresiones explícitas útiles para la soldadura por fricción-agitación (FSW). Para ello se crea una base de datos y se rede ne el modelo asintótico asociado a esta, para plantear ecuaciones fundamentales y corroborar las diferentes aproximaciones que las de nen, además de agregarles factores de corrección. La FSW aprovecha el calor generado por el roce entre las placas a soldar y la herramienta giratoria usada, para generar la unión entre los metales. Su ventaja es que se obtienen mejores propiedades mecánicas y por lo mismo, está siendo ampliamente utilizada; pero dado que se estudia por ensayo y error, es necesario que se desarrolle mayor conocimiento teórico sobre ella. Por ello, varios investigadores han desarrollado modelos para representar los fenómenos que gobiernan esta soldadura y en el caso de esta tesis, se utiliza el método de escalamiento adimensional. Se observa que las aproximaciones presentan variaciones menores al 12% por lo que son aceptables, excepto para el caso de Zener-Hollomon en que es necesario estudiar la tasa de deformación usada. Por otro lado, los factores de corrección en general presentan valores menores a 4, lo que se considera satisfactorio para el nivel de aproximación y resultados trabajados. Además, no se puede de finir un solo epsilon para AA5059 y AA7075, por lo que se debe estudiar más materiales, pero sí se concluye que se logran modelar los fenómenos asociados a esta soldadura, con resultados útiles para la ciencia.
Este trabajo ha sido parcialmente financiado por el Gobierno Canadiense a través de la Beca "Emerging Leaders in the Americas Program"
Bozzi, Sandrine. "Optimisation du procédé FSSW (Friction Stir Spot Welding) pour des assemblages homogènes A1/A1 et hétérogènes A1/Acier." Paris 11, 2009. http://www.theses.fr/2009PA112314.
Повний текст джерелаFriction Stir Spot Welding (FSSW) is a thermomechanical joining process : a tool constituted by a retaining wall and by a pawn is put in fast rotation and penetrates into both sheet stacked to assembly. The heat produced by the friction of the tool on sheets provokes a softening of the material. The rotation of the pawn allows then to mix the material of both sheets. The tool withdraws then by leaving an imprit. Therefore the FSSW allows the joining of aluminium alloys thanks to a mixing between both sheets. The flow of the material in the stir zone was able to be indentified. There are exactly two different streams : external rises of material and an internal mix along the wall f the pawn. It results the appearance of streaks in the stir zone, which correspond to films of melted material resulting from the bottom of the pawn. From a microstructural point of view, the mechanism of dynamic continous recrystallisation was identified, so that the stir zone corresponds to a zone of small recristallized grains about 5 µm of diameter, interrupted of streak with finer grains about 1 µm, and of different chemical composition. As for the mechanical properties, they are strongly bound to the flow of material and to the microstructure which results from it, as shows it in particular the mechanism of break. The break take place by the distribution of the crack situated at the end of the interface between both sheets. This crack propagates generally by contourning the stir zone, which presents a strong hardness due to the refinement of grains, by taking the way marked by the contraction of sreak. S, an evident means to delay the break is to obtain the widest possible stir zone. But it is not about the only factor to optimize the mechanical strength. The slope of the crack a the end of the interface is another very influential datum. The assembly between aluminium and steel, as for its, is possible thanks to a hhok, that is to say an ascent of steel into the aluminium sheet. There is then formation of intermetallic compounds in the interface between the steel hook and the aluminium, thanks to a thermochemical effect. The intermetallic precipitates present a size about 250 nm, and a hardness which differs strongly according to their nature, until 1100 to HV. These intermetallic areas become the very fragile zones which can damage the welds mechanical behaviour. When these precipitates are on a too important quantity, and when their microhardness is raised, the hook rupture results from numerous cracks. But those intermetallic compounds remain necessary, because if they are almost non-existent, the mechanical strength is very weak : the fracture taking place by a fast separation between steel and aluminium. So, for an optimal mechanical strength, a certain quantity of intermetallic compounds is necessary, what also corresponds to a surface of sticks more important. In that case, hooks being more strong, the fracture takes place by a tear of the aluminium sheet. All the results allowed to show the strong potential of the FSSW for homogeneous applications of aluminium as well as for heterogeneous applications between aluminium and steel
Kittipanya-ngam, Pichawadee. "Downstream food supply chain (FSC) in manufacturing firms : operating environment, firm's strategy, and configuration." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608839.
Повний текст джерелаMiyaura, Edson Haruo. "Efeito das tensões residuais sobre a propagação de trincas em juntas soldadas por FSW." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265149.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Inúmeros trabalhos de pesquisa tem sido feitos em torno de um processo de soldagem por atrito conhecido por FSW, ou Friction Stir Welding. A proposta deste trabalho é determinar o efeito das tensões residuais resultantes de tal processo sobre a propagação de trincas na região próxima à junta soldada. Este efeito é considerado calculando-se fatores de intensidade de tensão residual pelo uso de funções ponderadoras e pelo método de elementos finitos. Técnicas numéricas e equações de taxa de propagação modificadas são empregadas para determinar a vida residual em fadiga de sólidos com trincas que atravessam transversalmente a região da solda. É abordado e aplicado um meio de determinar uma curva de tensão residual longitudinal a partir de uma curva de fatores de intensidade de tensão residual. Finalmente, o ensaio cut compliance é apresentado como uma técnica experimental eficaz na determinação de uma curva de fatores de intensidade de tensão residual. A aplicação de tal método exige o conhecimento prévio ou o cálculo de funções de influência. Demonstra-se que o método de elementos finitos é eficaz na determinação de tais funções
Abstract: Numerous research papers have been published on a process known as friction stir welding or FSW. The purpose of this work is to determine the effect of residual stresses resulting from such process on the propagation of a crack near the weld. This effect is taken into account by calculating residual stress intensity factors using weight functions and finite elements. Numerical techniques and crack propagation rate equations are employed to determine residual fatigue life of solids with cracks that traverse across the weld region. A way to determine a longitudinal residual stress curve from a residual stress intensity factor curve is discussed and applied in this work. Finally, the cut compliance method is presented as an effective experimental technique to determine residual stress intensity factor curves. The application of such method requires calculation of influence functions. It is shown that the finite element method is effective in determining those functions
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
Michels, Michel. "Solda topo de placa em liga AA 7050t7451 pelo método friction stir welding (FSW)." Instituto Tecnológico de Aeronáutica, 2013. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=3401.
Повний текст джерелаCórdova, Thais Gabriele Zamboni. "Impactos da certificação FSC SLIMF nos meios de vida de grupos de pequenos produtores." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-26072018-134213/.
Повний текст джерелаSocio-environmental certifications, in order to become more accessible to small producers, provide alternative methods of obtaining the acreditation. The FSC, in addition to the possibility of group certification, has offered the Small and Slow Intensity Managed Forests (SLIMF) certification standard since 2004. Brazilians forestry companies, in order to meet the market\'s high demand and to remain competitive, not only have established outgrower schemes, but also have encouraged and assisted small producers to certificate. Certification can contribute to the diversification of smallholders\' livelihoods. The present study had as objectives: i) to characterize the factors that generate changes in groups of certified forest smallholders\' livelihoods; and ii) to verify the influence of time of certification on the change of livelihood assets of these groups. Four groups of FSC SLIMF certified smallholders outgrowers, and a not certified smallholder outgrower group were selected to this study. These groups are located in the Brazilian regions of the extreme south of Bahia and north of Espirito Santo, and the Tibagi river valley in Paraná. The groups were characterized by interviews and bibliographic surveys. The certifications\' impacts on the smallholders\' livelihoods were measured using a questionnaire based on an adaptation of the Sustainable Livelihoods approach. Scenarios on the certification\'s influence on each group\'s livelihoods were developed and the interactions between livelihood capitals were interpreted. The certification\'s positive performance was influenced by the market demand for certified products, the smallholders groups previous situation on the social capital and their socioeconomic conditions. The FSC SLIMF certification promoted positive changes in all livelihoods\' capitals, but at different intensities in each group. The perception of higher change in the natural capital was unanimous. The financial capital, considered to be the main participation motivator in the certification, did not present the Premium Price expected by the producers. Certification time positively influenced outcomes across all livelihoods, however engagement and participation of group members in management is key to successful certification. Aspects such as schooling and income influenced the interest in pursuing certification and perceiving improvements.
Basso, Vanessa Maria. "Desafios e oportunidades da certificação do manejo florestal pelo sistema FSC no continente americano." Universidade Federal de Viçosa, 2015. http://www.locus.ufv.br/handle/123456789/6777.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A certificação florestal é uma ferramenta de mercado, voluntária e não governamental que está sendo utilizada como mecanismo de garantia para o “bom manejo florestal”, sob o cumprimento de princípios ambientais, econômicos e sociais. São vários os fatores que levam uma organização florestal a buscar uma certificação, tais como: exigências de mercados, críticas socioambientais da sociedade, requerimentos legais, necessidade de melhoria da imagem institucional, dentre outros. Um dos principais sistemas de certificação florestal reconhecido mundialmente é o FSC – Forest Stewardship Council, atuante desde de 1993. Ao reconhecer que o continente americano é um grande produtor e exportador de produtos florestais no mercado mundial e, também, possui extensas áreas com florestas naturais e plantações florestais, viu-se a necessidade de entender como a certificação florestal vem sendo impulsionada em seus países. Assim, buscou-se com a presente pesquisa analisar as influências, contribuições, oportunidades e desafios da certificação florestal pelo sistema FSC nos principais países com produção florestal no continente. O estudo foi dividido em três capítulos e desenvolvido a partir de metodologias da pesquisa social, em específico a pesquisa descritiva por meio de análise de documentos oficiais. Como resultados, verificou-se que apesar do aumento de certificados de manejo florestal, na última década, o percentual de área certificada ainda é baixo se comparado com a área de florestas nativas e de produção florestal dos países americanos. Os países com maior número de certificados são Estados Unidos, Canadá e Brasil. Entretanto, os fatores que influenciaram cada país foram diferentes. O Canadá apresentou a maior área certificada impulsionados por incentivos e exigências de seu governo e indústrias. Os Estados Unidos apresentaram o maior número de certificados de Unidades de Manejo florestal (UMF), que possivelmente foram impulsionados pelas críticas da sociedade e suas organizações florestais buscaram a certificação como evidência de suas boas práticas socioambientais. Já no Brasil, dois fatores contribuíram para que os empreendimentos florestais buscassem a certificação: as críticas da sociedade e as exigências de mercado, principalmente, da União Europeia. Com relação à certificação de pequenas propriedades têm-se destaque as iniciativas na Guatemala, Honduras e México, que contaram com apoio de seus governos e de ONGs internacionais. Contudo, de forma geral, na maior parte dos países analisados, o mercado interno ainda não requer a certificação florestal, o que acaba por não gerar demanda para que as demais organizações do setor se certifiquem. Quanto aos desvios, verificou-se um menor percentual de não conformidades entre as organizações dos Estados Unidos e do Canadá, o que sinaliza melhor preparo nas atividades de manejo. Nestes países os maiores desvios estavam relacionados às questões ambientais. Já nos demais países da América Latina, independente da escala, os percentuais de não conformidades por organização foram bem maiores e prevaleceram sobre os quesitos trabalhistas, seguidos das questões ambientais. Com relação aos benefícios econômicos, estudando se casos no Brasil, verificou-se que as contribuições da certificação florestal foram baixas. Acredita-se que uma análise aprofundada, em que sejam considerados as contribuições socioambientais indiretas, poderá evidenciar melhor os benefícios econômicos. Por fim, verifica-se como ponto positivo, em todos os casos, é que a adesão à certificação florestal exigiu a implementação de modelos de gestão ambiental e social mais rigorosos que os aplicados anteriormente à decisão da certificação. Um ponto fundamental para que os números de certificados florestais aumentem nos países americanos é a geração de demanda em seus mercados internos. Assim, é importante que o sistema de certificação FSC e as partes envolvidas no processo amplie sua divulgação e imagem do que realmente significa a sua logomarca para os consumidores finais.
Forest certification is a marketing strategy, voluntary and non-governmental that has been used a guarantee mechanism for the "good forest management", according to the environmental, economic and social principles. There are many factors that contribute to a forestry organization to seek for a product certification, such as markets requirement, society environmental criticism, legal requirements and/or necessity to improve the institutional reputation. One of the main globally recognized forest certification system is the FSC - Forest Stewardship Council, founded in 1993. Taking account that American Continent is the greatest producer and exporter of forest products and has extensive areas with natural forests and forest plantations, we notice the necessity to understand how forest certification has been promoted in these countries. Thus, this study aimed to analyze the current influences, contributions, opportunities and challenges of the forest certification by the FSC system in the major forest producer countries located in American Continent. The study was divided in three chapters and was developed utilizing methods of social research, in particularly, the descriptive research using data from official documents. Even though we observed an increment of forest management certificates in the last decade, the percentage of certified area is still low compared with the area of native forests and forest production. United States, Canada and Brazil are the countries with the highest numbers of certificates and the factors that influenced the certification demand among countries were different. Canada has the largest certified area driven by incentives and requirements of its own government and industries. The United States has the highest number of Forest Management Units certificates (UMF), which might be driven by society criticism leading its forestry organizations sought by certification, as evidence of their good social and environmental practices. In Brazil, two mainly factors contributed to the certification of forest organizations: the society criticism and market demands, mainly from the European Union. Regarding to small farms certification, we observed important initiatives in Guatemala, Honduras and Mexico, supporting by their own governments and some international ONGs. Generally, for the most of the countries analyzed, the internal market still does not require forest certification, which ends up not generating demand for other sector organizations to be certificated. In the United States and Canada organization, we observed the lower percentage of non-compliances between organizations indicating the better preparation of the management activities. In these countries, the largest deviations were related to environmental questions. In the Latin American countries, the percentage of non-compliance by the organization was bigger and related to labor questions, followed by environmental issues. Regarding to economic benefits, studying specific cases in Brazil, it was found that the contributions of forest certification were low. We believe that a detailed analysis, considering the indirect social and environmental contributions of certification should be considered and possibly could demonstrate the economic benefits to the society. Finally, as a positive result in all cases, we observed that the forest certification induced to an implementation of more rigorous environmental management and social models compared to the utilized before the certification process. A fundamental point for increasing the forest certificate numbers in American countries is the generation of demand in their domestic markets. In this way, it is important that the all certification FSC system involved in this process expanding its outreach and image of the final product reaching the final consumers.
Allred, Jacob D. "An Investigation into the Mechanisms of Formation of the Hard Zone in FSW X65." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3806.
Повний текст джерелаOliveira, Jaqueline José Silva. "O PADRÃO DE CERTIFICAÇÃO DO FSC (FOREST STEWARDSHIP COUNCIL) PARA O MANEJO DE PLANTAÇÕES DE TECA NO BRASIL Na Perspectiva da Racionalidade Ambiental e do Capitalismo Natural." Pontifícia Universidade Católica de Goiás, 2010. http://localhost:8080/tede/handle/tede/2781.
Повний текст джерелаThe environmental problem is characterized essentially by a frenetic search to change the current economic model to a new stage of capitalism, called Natural Capitalism. This presents four principles as indispensable ways of maintaining the Earth and its species, without the naïve vision of non-development, limits to growth and the don quixotic cries to save the Earth from the obvious high global temperatures which provoke climate change. These changes are caused by polluting activities, especially those which increase the greenhouse effect, and by the lack of energetic measures to preserve the environment. A less romantic view of the proposals of Natural Capitalism will be discussed in this study which could lead to the reappropriation of nature, through the sustainable development discourse, which has attracted international agreements to guarantee sustainability (highlighting the Quioto Protocol and CON 15 in Copenhagen). This dissertation, for reasons which will become apparent, focuses on the question of environmental sustainability, based on the tripod (Triple Bottom Line) including economic, social and environmental dimensions. A significant issue that must be observed is the fact that in order to effectively guarantee a permanent adaptation of the new model of development being proposed, it is not sufficient that business leaders assimilate the concept of sustainability and produce without degrading the environment. Consumer awareness must be heightened in order to move towards an ethical market. It is up the consumer to get to know the economic, environmental and social impact of products which s/he rewards by purchase. The identification of products coming from politically correct companies will be carried out through stamps or certification, especially the green stamp, from the Forest Stewardship Council (FSC). It aims to justify the guarantee and differentiation which the FSC offers to the investor, in this case, though the plantation Teak on Brazilian land, as compared to different kinds of forest certification around the world and in Brazil.
A presente dissertação objetiva, valendo-se de subsídios multidisciplinares, analisar e demonstrar a importância do Padrão de Certificação do FSC (Forest Stewardship Council) para o manejo de plantações de teca no Brasil, bem como confrontar as questões teóricojurídicas controvertidas que deverão alcançar o âmbito diferenciado deste programa de certificação florestal, comparado aos demais sistemas existentes. O trabalho orienta-se através dos métodos hipotético-dedutivo e comparativo, apropriados ao objeto de estudo, para sanar as questões levantadas e de técnicas de investigação seguras, notadamente histórica e a monográfica. Para tanto, fez-se uso de referenciais teóricos obtidos pelas pesquisas bibliográficas e em websites, dos esquemas de certificação florestal. No transcorrer do desenvolvimento deste trabalho, destaca-se a problemática ambiental, que se caracteriza, primordialmente, pela frenética busca de mudança do modelo econômico atual para uma nova era do capitalismo: o Capitalismo Natural (Natural Capitalism). Este apresenta quatro princípios como via imprescindível na manutenção do globo e suas espécies, sem a ingênua visão (do não-desenvolvimento e dos limites ao crescimento), ofuscada pela ideologia salvacionista do planeta em relação às evidentes elevações da temperatura média global, que ocasionaram alteração climática, provocada pelas atividades poluidoras, sobretudo, as que aumentaram o efeito estufa, somadas à falta de medidas enérgicas, com o propósito de preservação ambiental. A óptica menos romântica da proposta fundamentada nos quatro princípios do capitalismo natural, que serão citados ao longo deste estudo, desemboca na reapropriação da natureza, através do discurso de desenvolvimento sustentável, em que as dificuldades em resguardar o planeta atraíram acordos internacionais (destacando o Protocolo de Quioto e a Convenção 15, em Copenhague), para garantir a sustentabilidade. A abordagem deste tema, por razões que se tornarão evidentes, está voltada para a questão ambiental, no conceito de sustentabilidade, fundamentado no tripé (Triple Bottom Line) que abrange o econômico, o social e o ambiental. Um ponto importante a ser observado consiste no fato de que a garantia de uma efetiva adaptação ao novo modelo de desenvolvimento proposto não se encontra apenas no processo de as lideranças empresariais assimilarem o conceito de sustentabilidade e produzirem sem degradar o meio ambiente, mas, especialmente, na conscientização do consumidor, o qual norteará um mercado ético. Cabe a ele saber qual é o impacto econômico, ambiental e social, que geram os produtos que premia com a sua compra. A identificação dos produtos de empresas politicamente corretas será feita através de selos ou certificações, no caso específico, do selo verde - FSC (Forest Stewardship Council), almejado pelos empreendedores madeireiros, em particular, os de plantio da tectona grandis no Brasil.