Tesis sobre el tema "Friction joint"
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Zhang, Cheng. "Robotic 3D friction stir welding : T-butt joint". Thesis, Högskolan Väst, Avd för automationssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-8250.
Texto completoArinez, Jorge Francisco. "Reduction of friction in polymeric composites for artificial joint prostheses". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37044.
Texto completoIncludes bibliographical references (leaves 128-135).
Ultra-high molecular weight polyethylene has been used as a bearing material in artificial joints for more than thirty years. Despite this long period of use and the success which artificial implants have had, material failure and ultimately prosthetic failure still occurs as the result of mechanical wear of the bearing surface. Several wear mechanisms have been proposed as the main causes for failure; however, none is as dominant as the delamination wear of artificial knee prostheses. Delamination wear occurs mainly as the result of cyclic plastic deformation of the surface and subsurface layer which causes cracks to nucleate and propagate in the subsurface leading to the production of wear sheets. This research seeks a new alternative material to prevent the occurrence of delamination wear by the use of a fiber reinforced composite. The use of a fiber-reinforced composite having fibers oriented normal to the sliding direction is known to offer reduced plastic deformation resulting from the high stiffness of fibers and furthermore can inhibit crack nucleation and more importantly propagation since fibers are able to arrest the growth of cracks normal to the fiber axis. This new material has been called homo composite based on the fact that fiber and matrix are made from the same material, namely UHMWPE. This material has shown promising results in friction tests yielding coefficients of 0.05 in bovine lubricated sliding conditions. The optimization of material processing parameters with respect to friction and wear of the homocomposite is also presented.
by Jorge Francisco Arinez.
S.M.
KANTURA, JOHN JOSEPH. "TEST RIG DESIGN AND EVALUATION: CHARACTERIZING NONLINEARITY OF FRICTION JOINT". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1046378210.
Texto completoBlom, Arvid. "Speed dependent friction in bolt joints". Thesis, KTH, Maskinkonstruktion (Inst.), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141687.
Texto completoThis report examines the speed dependency of frictional behavior in zinc plated 8.8 M12x1.75 bolt joints with an 82 mm clamping length at a tightening torque of 120 Nm. A total of 84 test tightenings have been performed with new bolts, nuts and washers for each tightening. The tests are performed using equipment supplied by Atlas Copco and all data is imported and analyzed in Matlab. It is found that within one standard deviation of the mean value the clamping force can vary as much as 90% depending on where in the 10-200 rpm speed range the bolt is tightened. Furthermore it is concluded that the residual torque is also highly speed dependent, registering at ~5 Nm above the final torque at 10 rpm and ~20 Nm above at 200 rpm. An initial hypothesis was developed regarding the pressure distribution in the thread and under the bolt head in the hopes that better understanding and modeling of this aspect could help predict frictional behavior in the bolt joint. This hypothesis was abandoned after it is concluded that the impact of an improved pressure model would be much too small to be noticeable due to the already large scatter in frictional coefficients.
Schroeder, Matthew O. "Biotribology : articular cartilage friction, wear, and lubrication /". Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-12302008-063639/.
Texto completoSage, R. M. "The mathematical modelling of ball-joints with friction". Thesis, University of Leicester, 1987. http://hdl.handle.net/2381/34822.
Texto completoKantura, III John J. "Test rig design and evaluation characterizing nonlinearity of a friction joint /". Cincinnati, Ohio : University of Cincinnati, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1046378210.
Texto completoNykänen, Robin. "Simulation of Bolted Joint with Frictional Contacts". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74490.
Texto completoOwellen, Michael C. "Biotribology: The Effect of Lubricant and Load on Articular Cartilage Wear and Friction". Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36872.
Texto completoTwo loads (65 N and 20 N) and three lubricants (saline reference, reference + hyaluronic acid, and bovine synovial fluid) were tested and evaluated using several analysis techniques. These techniques included wear analysis by hydroxyproline measurement, scanning electron microscopy (SEM), histologic sectioning and staining, numerical analysis of friction and specimen displacement data, and Fourier transform infrared (FTIR) analysis.
Biochemical wear analysis showed that, under high load, the saline reference generated the most wear, hyaluronic acid produced less wear, and bovine synovial fluid produced the least. Wear was sensitive to load with all three lubricants, but was not significantly affected by the lubricant under low load.
SEM photographs and histologic sections showed evidence of plowing and surface delamination, as well as another wear mechanism that produced wear markings perpendicular to the direction of sliding.
Opaque films remained on the polished stainless steel
disks after saline and hyaluronic acid tests, but not after
synovial fluid tests. FTIR analysis of these films, as
well as fresh and worn cartilage, showed that the cartilage
experienced chemical changes during sliding.
Master of Science
JOHANNA, DOLK. "Rotary Joint Module for Lenses on Infrared Camera". Thesis, KTH, Maskinkonstruktion (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192635.
Texto completoThis work was done on the rotary joint module of handheld cameras in the T-series made by the company FLIR. The rotary joint module holds the lens and controls the angle in relation to the rest of the camera. FLIR’s current solutions for the rotary joint had various module solutions for different camera models and the solutions have individual problems in quality, tolerances and durability. The current solutions differ in which components that are used, in dimensions and what torque is required by the user. The company was looking for a new solution for the rotary joint module; a solution with scalability. This means that the new module were to fit in several camera models with different torques and with lenses of different weight. The torque needed by the user would be quantified by evaluating solutions used today, where these values would be applied when finding a new solution. The dimensions of the module would be in consideration to the dimensions of the earlier solutions and to the interface between the joint and the camera. In the beginning of the project a pre study was made by looking at the current solutions made by FLIR to form requirements. The tools used for this were MATLAB for calculations, SolidWorks for CAD drawings and workshop tools for manual measurements of the torque. To start forming concepts solving the problem a brainstorm was performed where the ideas were visualized using sketches, and later CAD drawings using SolidWorks. These concepts were calculated using MATLAB to find the right dimensions and components. The concepts were discussed using meetings with interested parties, to get feedback on the work and sort out the better concepts. A Pugh’s matrix was used to evaluate the concepts against each other. The final concepts were of two different models; one controlled by dimensions and steel balls, connected to compression springs, clicking into grooves, and the other controlled merely by the friction between two surfaces provided under load from compression springs, where there were no actual click positions. The intention was that these two would have the same torque and they were scalable in the same way; by pre-tensioning the springs in the application to give different loads.
Do, Nguyen Ba. "Modeling of Frictional Contact Conditions in Structures". Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7123.
Texto completoRen, Ying. "The analysis and identification of friction joint parameters in the dynamic response of structures". Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/8904.
Texto completoChang, Timothy C. (Timothy Chan) 1979. "Effects of select fluids on the friction of metal-on-polyethylene joint replacement surfaces". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30318.
Texto completoIncludes bibliographical references (leaves 57-61).
Lubricants are important factors in the tribology of total joint arthroplasty (TJA) surfaces, which are primarily comprised of a polished metallic or ceramic component articulating on an Ultra-High Molecular Weight Polyethylene (PE) surface. Wear particles released from the PE surface are the primary cause of TJA failure. The human body responds to the foreign, micro- scale particles by activating a cascade of cytokine responses that ultimately leads to osteolysis and aseptic loosening. Although research in the materials selection and design of TJA components is continually advancing, one of the major intrinsic components that affect the tribological response in joints is overlooked. In particular, the properties and composition of joint fluid directly affect the fluid film and boundary lubrication of artificial prostheses. Since the characteristics of joint fluids are likely to differ from patient to patient as a result of varying disease indications, age, health, gender, and activity level, tribological behavior is also likely to vary significantly. The primary objective of this thesis is to examine the effects of variation in joint fluid composition on tribology. Due to the relative high stresses applied to the knee, the tribological effects related specifically to total knee arthroplasty (TKA) are investigated in detail. Before any joint fluid samples are examined, however, an assay capable of determining appropriate tribological properties is adapted. A unidirectional pin-on-disk (POD) tribometer is therefore selected to measure friction between PE and cobalt-chromium-molybdenum alloy (Co-Cr). Its sufficient precision, short testing time-frame and low cost enables rapid evaluations.
(cont.) Preliminary friction data collected on fluids such as distilled water and bovine serum are used as standards and controls against lubricants in subsequent tests. From this data, the contributions to friction of boundary and fluid-film lubrication in PE on Co-Cr POD systems are discussed. Analysis of these friction properties in conjunction with previously published differences in wear between water and bovine serum leads to a rejection of a hypothesis directly correlating friction and wear. However, since ultimately wear is the important factor in the failure mechanism of TJA, an indirect relationship between friction and wear is investigated and proposed. Friction is then recorded using joint fluids as the lubricant and compared to the standards. Analysis of the joint fluid data demonstrates significance in frictional behavior, indicating that compositional properties affect friction. Moreover, examination of the data reveals large variation in joint fluids. Comparisons of the data to standard lubricants exhibit the potential for large variations in wear among joint fluids.
by Timothy C. Chang.
S.M.
Hedström, Gabriel. "Structural and tribological analysis of harvester crane joint". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-69653.
Texto completoSun, Tianzhu. "Residual stress development in AA7050 stationary shoulder friction stir welds". Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/residual-stress-development-in-aa7050-stationary-shoulder-friction-stir-welds(9c4066c2-f3cf-4a3d-bfd0-3f6842de1251).html.
Texto completoMartins, Jorge Miguel Ribeiro. "Joining copper to stainless steel by friction stir diffusion process". Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10723.
Texto completoOne of the major trends in welding and joining technology is to join dissimilar materials taking advantage of individual materials properties. Among these, copper to stainless steel joining has significant industrial applications and importance where e.g. the highest electrical and thermal conductivities are required to engineering materials associated to good corrosion resistance. However, joining these materials is difficult due to their very different chemical composition and thermo-physical properties. Additionally, they easily form intermetallic phases that deteriorate the mechanical strength of the joint. Thus investigating the feasibility of applying alternative processing technologies is relevant. Solid state processes have been investigated for this application, namely friction stir welding. Recently, a variant has been exploited where local diffusion is the fundamental joining mechanism triggered by friction stir. The advantage of friction stir diffusion process is the minimal detrimental effect on both materials, preventing some critical identified problems. Since this process is not well developed, this thesis aimed to study friction stir diffusion process (FSDP) to join copper to stainless steel. Lap joints were produced varying processing parameters, namely, rotation and travel speeds and axial forging force. The effect of processing parameters on the width of effective joining was studied, as well the joints characterization for mechanical resistance properties and microstructural features at the interface. The thermo-mechanical conditions and time during the FSDP resulted in an interface with diffusion between both materials below 3 μm. The shear strength of the lap joints depends on the material thickness involved, but joining efficiencies up to 73.8 % were achieved.
Olofsson, Johanna. "Friction and Wear Mechanisms of Ceramic Surfaces : With Applications to Micro Motors and Hip Joint Replacements". Doctoral thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-156801.
Texto completoFox-Kemper, Baylor 1973. "Eddies and friction : removal of vorticity from the wind-driven gyre". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/39405.
Texto completoThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 299-310).
Inertial terms dominate the single-gyre ocean model and prevent western-intensification when the viscosity is small. This occurs long before the oceanically-appropriate parameter range. It is demonstrated here that the circulation is controlled if a mechanism for ultimate removal of vorticity exists, even if it is active only in a narrow region near the boundary. Vorticity removal is modeled here as a viscosity enhanced very near the solid boundaries to roughly parameterize missing boundary physics like topographic interaction and three dimensional turbulence over the shelf. This boundary-enhanced viscosity allows western-intensified mean flows even when the inertial boundary width is much wider than the frictional region because eddies flux vorticity from within the interior streamlines to the frictional region for removal. Using boundary-enhanced viscosity, western-intensified calculations are possible with lower interior viscosity than in previous studies. Interesting behaviors result: a boundary-layer balance novel to the model, calculations with promise for eddy param- eterization, eddy-driven gyres rotating opposite the wind, and temporal complexity including basin resonances.
(cont.) I also demonstrate that multiple-gyre calculations have weaker mean circulation than single-gyres with the same viscosity and subtropical forcing. Despite traditional understanding, almost no inter-gyre flux occurs if no-slip boundary conditions are used. The inter-gyre eddy flux is in control only with exactly symmetric gyres and free slip boundaries. Even without the inter-gyre flux, the multiple-gyre circulation is weak because of sinuous instabilities on the jet which are not present in the single-gyre model. These modes efficiently flux vorticity to the boundary and reduce the circulation without an inter-gyre flux, postponing inertial domination to much smaller viscosities.
by Baylor Fix-Kemper.
Ph.D.
Ghods, Farzad. "Finite element modeling of single shear fastener joint specimens: a study of clamp-up, friction and plasticity effects". Thesis, Wichita State University, 2011. http://hdl.handle.net/10057/5168.
Texto completoThesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering.
Iyer, A. Vishwanath. "Effect of tool shoulder profile on the axial force and joint strength of friction stir spot welded aluminum alloys". Thesis, Wichita State University, 2012. http://hdl.handle.net/10057/5599.
Texto completoThesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering
Reardon-Smith, Mardi Jane. "Forces and Frictions of Belonging: Land, People and Changing Environments in Cape York, Australia". Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/25462.
Texto completoNiglis, Anton y Per Öberg. "Modelling High-Fidelity Robot Dynamics". Thesis, Linköpings universitet, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119640.
Texto completoPeterson, Rebecca Hilary. "Friction Bit Joining of Dissimilar Combinations of DP 980 Steel and AA 7075". BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/6030.
Texto completoSheedy, Patrick. "Alleviating concrete placement issues due to congestion of reinforcement in post-tensioned haunch-slab bridges". Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13251.
Texto completoDepartment of Civil Engineering
Robert Peterman
A flowable hybrid concrete mix with a spread of 17 to 20 inches was created with a superplasticizer to be used in post-tension haunch-slab (PTHS) bridges where rebar congestion is heaviest. The mix would allow for proper concrete consolidation. A conventional concrete mix with a slump of three to four inches was also created to be placed on top of the hybrid mix. The conventional mix would be used to create a sloping surface on the top of the concrete. The two mixes could be combined in the PTHS bridge deck and act as one monolithic specimen. Standard concrete tests such as compressive strength, tensile strength, modulus of elasticity, permeability, freeze/thaw resistance, and coefficient of thermal expansion were determined for the mixes and compared. Core blocks were cast using both mixes and composite cores were drilled. The cores were tested and their composite split-tensile strengths were compared to the split-tensile strengths of cylinders made from the respective mixes. A third concrete mix was made by increasing the superplasticizer dosage in the hybrid concrete mix to create a self-consolidating concrete (SCC) mix with a 24-inch spread. The SCC mix was created as a worst-case scenario and used in the determination of shear friction. Eighty-four push-off shear friction specimens were cast using the SCC mix. Joint conditions for the specimens included uncracked, pre-cracked, and cold-joints. Uncracked and pre-cracked specimens used both epoxy- and non-epoxy-coated shear stirrups. Cold-joint specimens used both the SCC mix and the conventional concrete mix. Joint-conditions of the cold-joint specimens included a one-hour cast time, a seven-day joint with a clean shear interface, and a seven-day joint with an oiled shear interface. The shear friction specimens were tested using a pure shear method and their results were compared to the current American Concrete Institute code equation.
Gilbert, Gregory S. Jr. "Scaling a Prismatic Revolute Joint (Pr) Manipulator Using Similitude and Buckingham Pi Techniques". Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36599.
Texto completoMaster of Science
Faivre, Jimmy. "Développement de liquides synoviaux synthétiques bioinspirés". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1230/document.
Texto completoBioinspiration consists in the design of materials inspired by biological systems which have developed ingenious solutions to suit their environment. This project deals with bioinspiration for joint lubrication and in particular for the development of treatments for patients suffering from osteoarthritis (OA). To do so, we took our inspiration from joints which are amongst the most efficient aqueous tribological systems. Their unique properties arise from the complex synergistic interactions between cartilage structure and the lubricant macromolecules of the synovial fluid (SF). However, during OA, inflammatory mechanisms as long as mechanical erosion result in the degeneration of cartilage and lubricant macromolecules (aggrecan and lubricin). Polymeric mimes of the SF have been synthesized based on the bottle-brush (BB) architecture of LUB and AGG which is responsible for the joint lubrication. Tribological tests (SFA, tribometer) showed that BB polymers provided mica surfaces with a low friction and a wear protection up to several megapascals, typically in the range of natural joints. This wear protection was essentially due to the incorporation of anchoring groups specific to mica tribopairs on the BB polymers and the intermolecular bridging and entanglements emerging between BB polymers and high molecular weight HA, another main SF component. Cartilage mimes composed of multilayered chitosan hydrogels were designed to mimic the basic features of cartilage. Along with our BB polymers, the hydrogels, which are poroelastic and fragile materials, provided a low friction and a great decrease of wear
Atwood, Lorne Steele. "Friction Bit Joining of Dissimilar Combinations of GADP 1180 Steel and AA 7085 – T76 Aluminum". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6400.
Texto completoRipard, Valentin. "Tribological characterization of greased drive-shaft : Evaluation of constant velocity joint durability". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI083.
Texto completoNew customer desires are leading car manufacturers to new challenges. Indeed, enhanced vehicles like SUV (Sport Utility Vehicle) becomes more and more popular, especially in Europe. These vehicles involve some modification over the usual mechanical transmissions designs. This vehicle type has a higher angularity than sedans for example. This desire modification has 2 impacts: the increase of slipping in the transmission and its influence on the durability of the components. The angularity modification remains one of the major lines of research in recent years for car manufacturers. Its increasing influences efficiency. Indeed, this axis of improvement is attractive for manufacturers due to new environmental standards but also an increase in oil price. In addition, a car must have a reliable transmission that does not require, in the case of constant velocity joints, any maintenance during vehicle life. The following work will focus on this objective. The main goal of this manuscript is to understand the wear mechanism of the tripod constant velocity joint (CVJ). An analysis of the kinematics was first conducted to reproduce contacts on test rigs. It relied on data from the bibliography but also a simulation of solid dynamics. In addition, the design of a new observation rig using additive manufacturing made it possible to experimentally reproduce slipping in tripod. Furthermore, a characterization of greases used in Groupe PSA transmissions was performed in order to know the friction coefficients inducing the shudder level of the CVJ. These are also essential in order to judge the efficiency of the component. Finally, a wear investigation is performed to explain the possible lubrication failure mechanisms with greases proposing different mechanical behaviour. This approaches enables the transmission designer to choose a grease ensuring maximum durability of transmission components. Looking ahead, a lubricant characterization rig specially designed for tripod joint contacts has been designed. It will thus allow a more complete characterization of further lubricants to this essential vehicle component
Wirström, Fredrik. "Development and Validation of Threaded Fastener Test Rig". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74502.
Texto completoBartošík, Jan. "Vliv velikosti hlavice na procesy tření a mazání v TEP kyčle". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231946.
Texto completoEhmaida, Mutyaa M. "Friction and lubrication behaviour of hip resurfacing metal-on-metal and ZTA ceramic on CFR peek implants with various diameters and clearances : friction and lubrication behaviour of hip resurfacing Co-Cr-Mo and zirconia toughened alumina ceramic heads against carbon fibre reinforced poly-ether-ether-ketone cups with various diameters and clearances have been investigated using serum-based lubricants". Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5665.
Texto completoBalounová, Hana. "Studium tření náhrad kyčelního kloubu". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230585.
Texto completoCrudu, Monica. "Étude expérimentale et numérique des joints hydrauliques". Thesis, Poitiers, 2012. http://www.theses.fr/2012POIT2283/document.
Texto completoThis work is a contribution to the study of reciprocating seals behavior. A numerical model, based on the inverse hydrodynamic lubrication theory, is developed to predict their performances. The main contribution consists in the treatment of the hydrodynamic effects in the entry region of contact. The numerical results are validated by comparison with experimentalones, obtained on an original experimental device, design and conceived in the laboratory INOE 2000 IHP of Bucharest. This bench reproduces actual operating conditions of a hydraulic seal and measures the friction force at constant pressure and speed. The comparison of experimental and numerical results was carried out for a "U" type rod seal at different operating pressuresvarying from 4 MPa up to 20 MPa and for two reciprocating speeds. Initially, we idealized the problem by assuming that the surfaces in contact are smooth. The numerical results obtained are in good correlation with experimental ones if the film thickness is greater than the rod roughness. Otherwise, the model must be improved. This improvement was undertaken in an original way. The inverse lubrication theory is applied to the dry frictionless contact pressure distribution, obtained from a FEM simulation of a rough seal and a smooth rod assembly. The average roughness (Ra) of the seal surface in contact with the rod is chosen equal to the measured average roughness of the studied seal. The results obtained significantly improve the correlationwith experimental measurements. The roughness distribution on the entry region of contact appears to have an important influence on the numerical results
Odehnal, Lukáš. "Vývoj součinitele tření a mazacího filmu v implantátu kolenní náhrady v průběhu cyklu chůze". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-442825.
Texto completoPlaine, Athos Henrique. "Estudo do processo de soldagem a ponto por fricção de juntas dissimilares entre ligas de alumínio e titânio". Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8598.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Multimaterial structures between aluminum and titanium alloys are a technologically attractive field of research and their increasing use in the transportation sector for weight and emission reduction is part of the motivation of this study. The currently used techniques are either too expensive or limited in performance, especially by excessive formation of undesirable intermetallic compounds, opening opportunities for innovation in this area. Friction spot welding (FSpW), a solid state joining process recently developed by Helmholtz Zentrum Geesthacht, has proven to be one of the promising technologies for joining dissimilar materials as it involves short steps and low thermal cycles, also with the advantages of adding no weight to the structure and having geometrical compatibility to replace rivets. The present work studies the feasibility in welding AA5754-H22/Ti6Al4V and AA6181-T4/Ti6Al4V joints through FSpW. In addition, it is intended to establish the microstructure/ properties / process relationships of the resultant joints, in order to understand the formation and growth of the joining interface and its consequences on the mechanical performance. The proposed joints are produced in overlap configuration through different combinations of parameters, which were established by statistical methods involving design of experiments, and later submitted to mechanical and metallurgical characterization. The results reveal that Al/Ti dissimilar joints with high strength and reproducibility can be produced by using FSpW. The mechanical behavior of the joints presents a strong dependence on the intermetallic thickness formed at the bounding interface, identified as TiAl3. Tool rotational speed and dwell time are key process parameters in controlling the resistance of welded joints. Moreover, the bending load associated to differences in stiffness and/or thickness of the welded specimen appears as an important variable influencing the crack propagation path during shear and fatigue tests.
Estruturas multimateriais entre ligas de alumínio e titânio são um campo de estudo atrativo tecnologicamente e seu uso crescente no setor de transportes, visando à redução de peso e de emissão de gases, faz parte da motivação deste trabalho. As técnicas de soldagem utilizadas atualmente na união de tais materiais são limitadas em certos aspectos, sobretudo pela formação excessiva de compostos intermetálicos indesejáveis, abrindo caminhos para inovação nesta área. A soldagem a ponto por fricção (FSpW) tem demonstrado ser uma das alternativas promissoras na união de materiais dissimilares, destacando-se principalmente por ser um processo de poucas etapas, sem adição de peso, com baixos ciclos térmicos e compatibilidade geométrica para substituir rebites. O presente trabalho estuda a viabilidade técnica da soldagem dissimilar das juntas AA5754-H22/Ti6Al4V e AA6181-T4/Ti6Al4V através do processo FSpW. Ao mesmo tempo busca estabelecer a relação microestrutura / propriedades / processamento, a fim de compreender a possível formação e crescimento dos compostos intermetálicos na região interfacial e as suas consequências no desempenho das juntas. As juntas foram produzidas em configuração de sobreposição por diferentes combinações de parâmetros, estabelecidas por metodologias estatísticas de planejamento de experimentos, e posteriormente submetidas à caracterização mecânica e metalúrgica. Os resultados obtidos demonstram que soldas de boa qualidade e reprodutibilidade podem ser produzidas através do processo de soldagem proposto. O comportamento mecânico apresenta uma forte dependência em relação à espessura dos compostos intermetálicos formados na camada interfacial, constituída principalmente por grãos alongados de TiAl3, sendo a velocidade de rotação da ferramenta e o tempo de mistura parâmetros de processo chaves no controle da resistência das juntas soldadas. Ademais, a carga de flexão associada à diferença de rigidez e/ou espessura entre as ligas de alumínio e titânio demonstra ser uma variável importante nos ensaios de cisalhamento e fadiga, influenciando o caminho de propagação das trincas.
Dhamari, Ruby Dharma Adji Aerospace Civil & Mechanical Engineering Australian Defence Force Academy UNSW. "The effects of water displacing corrosion preventatives on the fatigue behaviour of mechanically fastened aluminium joints". Awarded by:University of New South Wales - Australian Defence Force Academy. School of Aerospace, Civil and Mechanical Engineering, 2005. http://handle.unsw.edu.au/1959.4/38668.
Texto completoGadari, M’hammed El. "Étude expérimentale et numérique du comportement des joints à lèvre". Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2304/document.
Texto completoIt's about sixty years that we are interested in understanding and modeling the Elastohydrodynamic behavior (EHD) of rotary lip seals. However, we can consider that, until now, their modeling has not been accurately treated. Even though many studies have been devoted to this model, several questions have been raised and are still the subject of controversy among researchers, namely the parameters influencing on the rotary lip seals performance, such as: the shaft surface textured, the law adopted for the mechanical behavior of lip seals, the approach used to develop the matrix of compliance, the importance of assuming the smooth or rough shaft, and finally the ratio between the width of contact and the wavelength according the circumferential direction of the lip roughness.The main goal of this thesis is to answer rigorously these questions by developing and validating a numerical tool for EHD rotary lip seals modeling, that takes into account: the lip law behavior, the compliance matrix rigorously validated by assuming smooth shaft case, or rough and textured shaft case. In addition, an analytical approach is proposed, models the vibratory behavior of the "squeeze film". This implies a nonlinear comportment that is taken into account
Le-Tien, Luc. "Ansätze zur entkoppelten Regelung von mechanisch gekoppelten Doppelgelenken eines DLR-Medizinroboters". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-39460.
Texto completoNordlund, Erling. "Impact mechanics of friction joints and percussive drills". Doctoral thesis, Luleå tekniska universitet, Geoteknologi, 1986. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16974.
Texto completoGodkänd; 1986; 20070108 (mlk)
Mussa, Abdulbaset. "A study on wear characteristics of high strength steels under sliding contact". Licentiate thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik (from 2013), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-77660.
Texto completoComponents used in rock drilling and sheet metal forming operate under harsh contact conditions that result in an early-life component failure. Wear and fatigue are considered as the most common damage mechanism for these components. Commonly, the service life of a component is designed based on its fatigue life. However, wear might have a significant effect on the components life too. Wear results in a surface damage that in turn may cause a fatigue crack initiation. Therefore, knowledge about wear of materials and components is a key factor in design and prediction of the lifetime of the components. In order to predict wear of a certain component, a thorough understanding of the component with regards to its material properties, application loads and working environment, and damage mechanisms is required. The overall aim of the present work was to define the typical wear mechanisms occurred on machinery components used in rock drilling and sheet metal forming. A comparative analysis of the case studies and results from performed laboratory tests simulated wear mechanisms in the applications highlighted wear mechanisms and factors influencing severity of wear in the applications. Obtained information is crucial for ranking and selection of the best material in the applications.
The presentation will will be via zoom. PhD student will together with the supervisors will be in Karlstad while the opponent is in Luleå.
Karim, Yassine. "Caractérisation robuste de liaisons amortissantes avec dispositifs piezo-électriques pour la réduction de vibrations de structures". Phd thesis, Conservatoire national des arts et metiers - CNAM, 2013. http://tel.archives-ouvertes.fr/tel-00953330.
Texto completoEricsson, Mats. "Fatigue Strength of Friction Stir Welded Joints in Aluminium". Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160.
Texto completoTilaveridis, Ioannis. "Detection of friction variations in bolted joints during tightening". Thesis, KTH, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-213389.
Texto completoÅtdragning beskriver processen att rotera en skruv i syfte att binda två ytor ihop. Det tillämpas allmänt i monteringsprocessen av strukturer, där skruvförband används för att ansluta de olika delarna med varandra, t.ex. robotarmar, fordon, flygplan. Ett visst vridmoment appliceras med ett verktyg för att utveckla önskad klämkraft som håller ytorna ihop. En utmaning under denna process är att friktionsvariationer uppträder oväntat, vilket ökar risken för att inte uppnå den nödvändiga klämkraften för att säkerställa en framgångsrik åtdragning. I denna avhandling implementeras en diagnosmetod för att detektera friktionsvariationer vid hög dynamisk åtdragning. Olika detekterings algoritmer undersöks (t.ex. CUSUM, Partikelfilter, Linjärregression), och ett tillvägagångssätt som utnyttjar vridmoment- och vinkelsignalerna vid uppskattning av klämkraften implementeras. Undersökningar av signalbrus samt filtreringsoperationer under datautvinningen utförs, och signalerna utvärderas. Ett variabelt fönster används för att uppskatta vridmomentet, som används i detekteringsalgoritmen för att indikera variationer och utföra en diagnostisk rapport. Analysen utförs med en starkt dynamisk åtdragningsstrategi, programmerad i ett elektriskt åtdragningsverktyg, vilket gör att processen kan utföras på millisekunder. Undersökningar av parametrarna för detekteringsalgoritmen genomförs också, och värdetrösklarna identifieras. Slutligen utförs en statistisk analys av systemets beteende, liksom påverkan av operatören som håller verktyget, för utvärdering.
Doering, Kenneth Thomas Nathaniel. "Fatigue of friction stir welded lap joints with sealants". Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Doering_09007dcc80627994.pdf.
Texto completoVita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 9, 2009) Includes bibliographical references (p. 118-127).
Lång, Marcus. "Static Friction in Slip Critical Bolt Joints : Coefficient of Friction in Steel, Aluminium and ED Coated Steel". Thesis, Karlstads universitet, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-55223.
Texto completoWang, Na. "Greffage de polymères biomimétiques sur implants articulaires en polyéthylène : contrôle du comportement tribologique". Phd thesis, Université Claude Bernard - Lyon I, 2013. http://tel.archives-ouvertes.fr/tel-00966017.
Texto completoMahdavi, Shahri Meysam. "Fatigue Assessment of Friction Stir Welded Joints in Aluminium Profiles". Doctoral thesis, KTH, Materialteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92157.
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Vaziri, Mojgan. "Water Resistance of Scots Pine Joints Produced by Linear Friction Welding". Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10059/document.
Texto completoWood welding is a mechanical friction process allowing the assembly of timber without any adhesives. The process consists of applying mechanical friction, under pressure, alternately to the two wood surfaces to be welded. This process can be applied to weld two flat pieces of timber, originating from the same or different tree species, and can be used in the manufacture of furniture and wood joinery. The only limitation is that the joint is not exterior-grade, but only suitable for interior joints. Exterior use, or use in an environment with varying humidity demands water resistance of the welded joints. The main objective of this thesis is to study the water resistance of the welded wood. This is complemented with special attention to non-destructive test methods such as X-ray Computed Tomography (CT-) scanning and Magnetic Resolution Imaging (MRI). The influence of welding parameters and wood properties on crack formation and crack propagation in the weldline was investigated. The influence of these parameters on weldline density and water absorption in the weldline were also studied. Investigations in this thesis are based on welded samples of Scots pine (Pinus sylvestris) of the dimensions 200 mm × 20 mm × 40 mm which were cut in the longitudinal direction of the wood grain. The tensile-shear strength of the welded Scots pine samples were determined using European standard EN 205. Different non-destructive methods such as X-ray Computed Tomography (CT-) scanning to study crack formation and propagation, and magnetic Resolution Imaging (MRI) to characterize water penetration and the distribution mechanism in welded wood were used. Solid state CPMAS 13C NMR spectrometry and X-ray microdensitometry investigations were carried out to study the mechanism of adhesion in Scots pine. These various non-destructive methods offer the advantage of non-invasive analysis and the elimination of any artifacts present due to preparation and sectioning. The most important results are summarized as follows: (1) X-ray Computed Tomography (CT-) scanning and Magnetic Resolution Imaging (MRI) are versatile research methods applicable to investigations of welded woods. (2) Water resistance of welded Scots pine can be increased using heartwood, a welding pressure of 1.3 MPa, and a welding time of 1.5 s. (3) Optimization tests showed that the tensile-shear strength of Scots pine was more sensitive to welding time changes than holding time and could be optimized to more than 9.7 MPa using 1.3 MPa welding pressure, > 3.5 s welding time, and < 60 s holding time. (4) Changing welding parameters and wood properties can increase water resistance of welded wood to some extent, but treating the weldline with certain natural and environmentally-friendly water repellents is still necessary. (5) Welded Scots pine shows unusually high water resistance and tensile-shear strength. This may be explained by there being more extractives compounds in Scots pine. (6) MRI experiments showed that the origin of the joint failure in welded beech is poor water resistance of the weldline, while swelling and shrinkage of wood are the main reasons for joint failure of welded Scots pine. (7) Extractives in Scots pine dramatically improve water resistance of the welded joint, but not to a level to classify the joint as an unprotected exterior grade. However, it can qualify as a joint for protected semi-exterior application
Mjali, Kadephi Vuyolwethu. "Analysing the effect of FSP on MIG-laser hybrid welded 6082-T6 AA joints". Thesis, Nelson Mandela Metropolitan University, 2007. http://hdl.handle.net/10948/563.
Texto completoOyedemi, Kayode. "Increasing the gap tolerance in friction stir welded joints of AA6082-T6". Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1012325.
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