Dissertations / Theses on the topic 'Mechanical connection'
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Kiani, Sepehr. "Multi-connection vias for printed circuit boards." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/8665.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1999.Includes bibliographical references (p. 182-184).
As the performance of digital electronic components improves, maintaining the integrity of high-frequency signals through circuit boards becomes increasingly challenging. The dimensions and material parameters of in-plane circuit board features, such as striplines, microstrips and co-planar waveguides are tuned to control signal impedance. Conventional multi-layer vertical interconnects, which connect between board layers, are not impedance matched to the in-plane signal traces. Multi-connection vias, developed in this thesis, provide a method for matching the impedance of vertical and in-plane features by forming co-cylindrical waveguides. Solutions from a high-frequency full-wave solver provide insight into field interactions within multi-connection vias; and results from these simulations and signal integrity experiments indicate impedance "tuneability" by adjusting the multi-connection via dimensions. The results also suggest that features can be impedance-matched independent of via diameter. Multi-connection vias are formed by creating distinct conductor paths within cylindrical plated through-holes. The thesis explores several alternative manufacturing methods for fabricating these features. A specialized broaching machine and carbide-insert broaches were used to manufacture multi-connection vias for signal integrity experiments. Models of the broach tool and cutting force simulations resulted in several iterations of the broach design.
(cont.) Broaching multi-connection vias is challenging due to the small diameters and high aspect ratios of plated through-holes, as well as the unique copper-epoxy/resin material. Since the broaching process prefers larger plated through-holes to permit larger broach tools, a new method was developed to analyze the cumulative connection density of multi-connection via arrays. Multi-connection vias provide fertile ground for the development of corollary electronic products. Simulations for connector launches indicate that via impedance control can extend to board-mounted devices and connectors. Products that may benefit from multi-connection vias include by-pass capatrs, IC packages, test probes and pogo pins. The thesis presents a road map for commercializing multi-connection vias. Elements of the roadmap ... integration of new signal routability constraints in CAD/CAM software, manufacturing processes, machine tool design, board testing, and durability.
by Sepehr Kiani.
Ph.D.
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Li, Xinming. "Piezoelectric-based structural health monitoring of flexible beam connection damage." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26511.
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Structural health monitoring is an emerging technology addressing major concerns in the operation of in-service structures, i.e. the reliability of the structures and the cost associated with maintaining reliability. In this thesis, the motivation of structural health monitoring has been discussed within the framework of non-destructive evaluation. To be a common failure mode, connection damage or lap joint damage is chosen as damage signature in a structure, consisting of a flexible aluminum beam jointed on a frame by bolts. To simulate connection damage, the stress relaxing on the bolt is achieved by the action of bolt looseness quantified by rotation angle. The dynamic response of flexible beam system is monitored with a piezoelectric transducer. To produce exciting signal, an electro-mechanical system processes the voltage signal. Response interpretation is carried out on PC or on an embedded DSP chip in real time. The two analysis methods, frequency response method and wavelet analysis method, were explored to identify early "changes" of beam connection so as to reach the goal of structural health monitoring.
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Ligon, Thomas (Thomas Crumrine). "Automated inter-model parameter connection synthesis for simulation model integration." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39887.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 73-75).
New simulation modeling environments have been developed such that multiple models can be integrated into a single model. This conglomeration of model data allows designers to better understand the physical phenomenon being modeled. Models are integrated together by creating connections between their interface parameters, referred to as parameter mapping, that are either shared by common models or flow from the output of one model to the input of a second model. However, the process of integrating simulation models together is time consuming, and this development time can outweigh the benefit of the increased understanding. This thesis presents two algorithms that are designed to automatically generate and suggest these parameter mappings. The first algorithm attempts to identify previously built integration model templates that have a similar function. Model interfaces and integration models are represented by attributed graphs. Interface graph nodes represent interface parameters and arcs relate the input and output parameters, and integration models graph nodes represent interface graphs and arc represent parametric connections between interface graph nodes.
(cont.) A similarity based pattern matching algorithm initially compares interface graphs in two integration model graphs. If the interface graphs are found to match, the algorithm attempts to apply the template integration model's parameter mappings to the new integration model. The second algorithm compares model interface parameters directly. The algorithm uses similarity measures developed for the pattern matching algorithm to compare model parameters. Parameter pairs that are found to be very similar are processed using a set of model integration rules and logic and those pairs that fit these criteria are mapped together. These algorithms were both implemented in JAVA and integrated into the modeling environment DOME (Distributed Object-based Modeling Environment). A small set of simulation models were used to build both new and template integration models in DOME. Tests were conducted by recording the time required to build these integration models manually and using the two proposed algorithms. Integration times were generally ten times faster but some inconsistencies and mapping errors did occur. In general the results are very promising, but a wider variety of models should be used to test these two algorithms.
by Thomas Ligon.
S.M.
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de, Julien de Zelicourt Diane Alicia. "A Mechanical Fluid Assessment of Anatomical Models of the Total Cavopulmonary Connection (TCPC)." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4882.
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BACKGROUND: Understanding the hemodynamics of the total cavopulmonary connection (TCPC) may lead to further optimization of the connection design and surgical planning, which in turn may lead to improved surgical outcome. While most experimental and numerical investigations have mainly focused on somewhat simplified geometries, the investigation of the flow field of true TCPC configurations is necessary for a true understanding.
METHODS: This study details a manufacturing methodology yielding more accurate in vitro models that would provide a better understanding of the TCPC hemodynamics and adequate data for the validation of anatomical CFD simulations. This approach is illustrated on two different TCPC templates: an intra-atrial TCPC with a single superior vena cava (SVC) and a bilateral SVC with an extra-cardiac conduit. Power loss, flow visualization, digital particle image velocimetry (DPIV) flow measurements as well as computational fluid dynamics simulations are performed to characterize the anatomic flow structure. Additional parametric glass models of the TCPC were manufactured to help understand the fluid dynamics of the anatomical models and support the computational model validation effort.
RESULTS/CONCLUSIONS: Both anatomic configurations revealed very different fluid dynamics underlining once again the need for at least one comprehensive experimental campaign per TCPC template for a good understanding of the flow phenomena. The absence of caval offset in the anatomical intra-atrial model resulted in important flow turbulence, which was enhanced by the large connection area and yielded high pressure drops and power losses. On the other hand, the bilateral SVC, which featured a smooth extra-cardiac conduit and wider vessels, led to power losses that were one order of magnitude lower than those of the anatomic intra-atrial model and a smooth flow field with lower levels of instability. The simplified glass models demonstrated that the diameter of the connecting vessels and of the pulmonary arteries in particular, was a parameter of prime importance.
Finally, this study also reports on a combined experimental and numerical validation methodology, suggesting a cautious approach for the straightforward use of available CFD tools and pointing out the need for developing high resolution CFD techniques specifically tailored to tackle the complexities of cardiovascular flows.
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Magnusson, Emelie. "FE analysis and design of the mechanical connection in an osseointegrated prosthesis system." Thesis, Linköpings universitet, Mekanik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69402.
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In this master thesis the connection between the two major parts of an osseointegrated prosthesis system for lower limb amputees has been investigated by finite element (FE) analysis. The prosthesis system is developed by Integrum and the current design consists of a fixture, which is integrated in the residual bone, an abutment that penetrates the skin and an abutment screw that holds the parts together. The connection between the fixture and the abutment has a hexagonal section and a press-fit section that together form the connection. Due to wear and fracture problems it is desired to improve the connection. A tapered connection could be an alternative and three different taper angles, the effect of the length of the taper and the smoothness of the outer edge of a tapered fixture have been investigated. The results show that the taper has potential to function well and that a longer connection will give lower stresses in the system, but further investigations are needed.
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Brown, Christian R. (Christian Randall). "Effect of hull-to-bulkhead flexible connection on blast resistance of double hulled ships." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33434.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 65).
The use of double hull construction is commonplace within the shipping industry though it is largely unexploited within naval vessels. The Impact and Crashworthiness Lab at MIT has proposed the use of adaptive sandwich structures to improve the blast resistance of naval hulls. This project will address two main areas of investigation through the use of simplified analytical models: the integration of hardening and softening plastic core responses in the crushing of a rigidly supported sandwich panel; and the deformation analysis of a sandwich panel supported by non-rigid connections. The analytical solutions were utilized to perform a series of parametric studies to evaluate both the useable range of the models as well as to investigate the general behavior of a sandwich panel under a uniform load when supported by crushable connections. This initial investigation provides the simplified tools to begin and to validate a more detailed, numerical analysis.
by Christian R. Brown.
S.M.
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Gikonyo, Joan, and Pierre Modig. "Parameterized and Adaptive Modelling of Mechanical Connections in Timber Frame Structures." Thesis, Linnéuniversitetet, Institutionen för byggteknik (BY), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-77189.
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This study investigates the global stiffness of a timer frame structure under wind loading using the finite element method by creating parameterized script files. Of key interest was the accuracy of the global stiffness determined from an adaptive 3D beam model in comparison to a 2D beam model and, the stiffness of a 3D beam model when subjected to different types of bracing in the presence of internal bracing provided by a lift shaft structure. Investigation of contact forces on the surfaces between the fastener and the timber at the connection was carried out and a design check for the specified bolts shear capacity done with respect to Eurocode 5. A 3D adaptive connection was created for a 2D frame model and the stiffness of the structure was studied. A comparison of the maximum displacement of the structure in the x direction, under the same wind loading, spring stiffness and boundary conditions, with a 2D beam structure without the adaptive connection initially showed a difference in the displacement. This implied that the rotational stiffness in the beam model was greater than that of the adaptive connection created. Therefore after altering the rotational stiffness of the beam model to achieve similar displacement as in the adaptive model, the rotational stiffness of the created connection was found to be 33.4 · 106Nm. The study also determined the contact forces generated at the surfaces between the fasteners and the timber using the finite element method to integrate over the surfaces and calculate the forces. The results were generated using the History Output in the step module. The only disadvantage of acquiring the contact forces was that, the contact surface simulation caused larger run times for the model to complete the time step. For the adaptive model it took 18 hours to complete each step. Further investigation into the stiffness of a 3D frame structure was conducted. The model of the 3D structure was created by a parameterized script which makes it easy to change input variables such as number of internal walls, geometry in x-z-plane, number of storeys, cross-sectional dimensions, material properties number of diagonals and location of diagonals. A variety of models with different conditions was analyzed. This showed that stiffness has a major impact on the magnitude of reaction forces and displacements.
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Juchnevičius, Žilvinas. "Deformation and strength of a cyclically bent threaded connection." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120206_165453-81433.
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Industry equipment such as pressure vessels, mining equipment, heat exchang-ers, steam generators and other structures are provided with bolted closures for the purpose of in-service inspection and maintenance of internal components. Threaded connections often experience variable cyclic loads due to temperature, inner pressure and variation in the deformation of connection fittings. Often, studs and screws are not only affected by an axial load, but also by bending moments.
More sophisticated high-cycle and low-cycle durability calculation meth-odologies have been already developed for threaded connections experiencing cyclic axial loads, and in these methodologies the distribution of axial load among turns is assessed quantitatively. The quantitative data of load distribu-tion in the thread enables a more accurate assessment of the influence of the constructional design particularities (connection length, material, nut and turn’s form) and the deformation stages of the connection element.
These durability calculation methodologies are not applied for threaded connections that are cyclically bent, as the analytical models that are suitable for practical application in the load distribution of the turns have not been cre-ated for bent threaded connections. In this field, no models have been created to be calculated by the BE method.
As the threaded connection is a complex node consisting of deformed el-ements, the load distribution among turns is influenced by the... [to full text]Srieginės jungtys dažnai patiria ciklinių lenkimo apkrovų dėl temperatū-ros, vidaus slėgio ir jungiamųjų detalių deformacijų kitimo. Srieginėms jung-tims, kurios patiria ašinių ciklinių apkrovų jau yra sukurtos modernesnės daugiaciklio ir mažaciklio ilgaamžiškumo skaičiavimo metodikos, kuriomis detaliai kiekybiškai įvertinamas ašinės apkrovos pasiskirstymas tarp vijų. Ap-krovos pasiskirstymo sriegyje kiekybiniai duomenys leidžia detaliau ir tiksliau įvertinti konstrukcijos ypatumų (jungties ilgio, medžiagos, veržlės ir vijų for-mos) ir jungties elementų deformavimo stadijų įtaką. Tokios ilgaamžiškumo skaičiavimo metodikos cikliškai lenkiamoms srieginėms jungtims netaikomos, nes lenkiamoms srieginėms jungtims nėra sukurtų apkrovos pasiskirstymo vijose analitinių modelių, tinkamų praktiniam naudojimui. Šioje srityje taip pat nėra sukurtų ir modelių, kurie skaičiuojami baigtinių elementų metodu. Kadangi srieginė jungtis yra kompleksinis mazgas, kurį sudaro deformuo-jami elementai, tai apkrovos pasiskirstymą tarp vijų lemia jungties elementų deformacijų ir poslinkių suderinamumas. Matematiškai aprašant jungties de-formuotą būvį, reikalingi teoriniai ir eksperimentiniai duomenys, kurie atspin-dėtų jungties elementų deformavimo specifinius ypatumus, pasireiškiančius veikiant lenkimui. Disertacijoje siekiama sukurti cikliškai lenkiamų srieginių jungčių apkro-vos pasiskirstymo sriegyje skaičiavimo metodą ir pritaikyti jį mažacikliam ilga-amžiškumui skaičiuoti.
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Spratley, Jon Peter Frederick. "mechanical design of an injectable microsensor for neural connection within the motor cortex of the human brain." Thesis, University of Birmingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.532287.
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Platt, Robert Terry. "Development of A Ready-To-Assemble Construction System." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/29315.
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To accommodate an expanding global population, a renewable raw material resource base, in conjunction with new building technologies, must be applied to the residential housing sector. Desirable characteristics of housing systems are economy, safety, environmental sustainability, durability, design flexibility and a long service life. The system should be acceptable to the end-user, consist of renewable, indigenous resources, and require a minimum investment in labor and equipment for both production and erection.
The objective of this research was to develop a ready-to-assemble (RTA) framing system. Integral to the framing system is a nail plate connector, developed in this project, that laminates wood or wood composite elements into larger building components. The laminated components can be bolted together to form various structural configurations. Decisions on the development of the RTA system were structured according to an Innovation Development Decision Model (IDDP) that was constructed from previous adoption and diffusion research. The IDDP model elucidates and illustrates the innovation process from conceptual idea to product adoption. The critical issues for product acceptance include system performance in terms of safety, cost, and building code approval. The objective of the experimental portion of the research was to test the performance of the RTA connection system in specific modes and to develop a theoretical method to predict the strength of the connection. A series of experiments to quantify the shear strength and stiffness of six joint configurations assembled with the RTA connector were designed and conducted. The joints were fabricated from solid sawn lumber and three different wood-base composites.
The experimental results indicated that the strength of the RTA connector in perpendicular-to-grain and parallel-to-grain orientations can be predicted from a theoretical dowel yield model. The material properties used in the yield model were adjusted for duration of load and safety. Empirical test values were within ±6.3 % of the predicted values from the theoretical model. Joint stiffness was evaluated, modeled and quantified in the linear and non-linear ranges. A structural analysis program was used to design and model a simple RTA building for realistic gravity and wind loads. The structural model was used to predict joint forces that the RTA connector must resist in-service. The computer model predictions were compared to the empirical joint test data. The results indicate that the RTA system can be designed to meet safety and serviceability criteria. A comparison between the estimated costs of a RTA building and the costs of traditional on site construction of a building of equal dimensions indicated that the RTA system is economically competitive.Ph. D.
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Pocius, Mindaugas. "Detalių sujungimo tyrimai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2006. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2006~D_20060613_133703-79555.
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„Researches of part joints“ Process of peg and hole connection for automatic assembly is analyzed in the work. Mathematical model of the parts connection was formed. Programs for simulation of the connection process were written using MatLab software. Characteristics of connecting forces variation and movement of the peg were determined. Parameters influencing lower loading of the assembly equipment and values of these parameters were determined. It was determined that probability of the connection process can be increased by selecting particular values of correspondent parameters of the connection process. Results of the analysis can be used for designing of new, economic, high performance and reliable assembly equipment.
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Ghodrati, Ashkan, and Ahmed Rashid. "Modelling and Simulation of a Power Take-off in Connection with Multiple Wave Energy Converters." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3396.
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The objective of this thesis is to develop a model that will integrate multiple buoys to a power take-off hub. The model will be derived using a time domain analysis and will consider the hydraulic coupling of the buoys and the power take-off. The derived model is reproduced in MATLAB in order to run simulations. This will give possibility to conduct a parameter study and evaluate the performance of the system. The buoy simulation model is provided by Wave4Power (W4P). It consists of a floater that is rigidly connected to a fully submerged vertical (acceleration) tube open at both ends. The tube contains a piston whose motion relative to the floater-tube system drives a power take-off mechanism. The power take-off model is provided by Ocean Harvesting Technologies AB (OHT). It comprises a mechanical gearbox and a gravity accumulator. The system is utilized to transform the irregular wave energy into a smooth electrical power output. OHT's simulation model needs to be extended with a hydraulic motor at the input shaft. There are control features in both systems, that need to be connected and synchronized with each other. Another major goal within the thesis is to test different online control techniques. A simple control strategy to optimize power capture is called sea-state tuning and it can be achieved by using a mechanical gearbox with several discrete gear ratios or with a variable displacement pump. The gear ratio of the gear box can be regulated according to a 2D look up table based on the average wave amplitude and frequency over a defined time frame. The OHT power take-off utilizes a control strategy, called spill function, to limit the excess power capture and keep the weight accumulator within a span by disengaging the input shaft from the power take-off. This is to be modified to implement power limitation with regulation of the gear ratio of the gearbox.+46736290781
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Erdem, Melek Esra. "Failure Analysis Of Thick Composites." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615605/index.pdf.
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A three-dimensional finite element model is constructed to predict the failure of a hybrid and thick laminate containing bolted joints. The results of the simulation are compared with test results. The simulation comprises two main challenging steps. Firstly, for a realistic model, a 3D model is established with geometric nonlinearities and contact is takeninto account. The laminated composite model is constructed by 3D layered elements. The effect of different
number of elements through the thickness is investigated. The failure prediction is the second part of the simulation study. Solutions with and without progressive failure approach are obtained and the effect of progressive failure analysis for an optimum simulation of failure is discussed. The most appropriate failure criteria to predict the failure of a thick composite structure is also investigated by considering various failure criteria. By comparing
the test results with the ones found from the finite element analyses, the validity of the developed model and the chosen failure criteria are discussed.
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Karlsson, Louise, and Alexander Sjöberg. "Framtagning av snabbkoppling i polymera material för vätskekylda datacentraler." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-15320.
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Examensarbetets mål är att ta fram ett konceptförslag på en snabbkoppling på uppdrag av CEJN. Rapporten redovisar de metoder som använts för att nå slutligt resultat. Utvecklad snabbkoppling syftar till en marknad för vätskekylning i datacenter. CEJN önskar ligga i framkant på den expansiva marknaden, vilket kräver att tillverkningskostnaderna för befintlig aluminiumkoppling reduceras, bland annat genom materialbyte till plast. Företaget har idag ingen plasttillverkning i huset. Genereringsarbetet baseras på förstudie i form av litteraturstudier, konkurrensanalyser delvis genom demontering av befintliga produkter på marknaden, samt användartester. Prototyper har använts för test och utvärdering i flera stadier i processen. Snabbkopplingens yttre komponenter, som även visades vara de största kostnadsbärarna, utvecklades som separata delproblem så som låsmekanism, utformning av inre o-ringsspår och sammanfogning för att tillåta montering och säkerställa spillsäkerhet. Beslutsunderlag för slutliga konceptval baserades på kostnader, användande utifrån tillverkade prototyper samt utlåtanden från externa experter inom plasttillverkning, varpå konceptval kunde utföras tillsammans med uppdragsgivande företag. Dellösningarna anpassades i ett slutligt koncept som reducerar kostnader och samtidigt uppfyller krav gällande prestanda, utseende och användbarhet. Projektet med slutligt konceptförslag föreslås ligga till grund för vidareutveckling och tester för att säkerställa den högkvalitativa produkt CEJN eftersträvar.The objective of the Bachelor thesis is to create a concept proposal in collaboration with CEJN. This report is presenting activities involved in the development process used to obtain the final result. Referring to the expansive market for liquid cooled data centres, CEJN aims to be in the leading edge with a new quick connection coupling. This demands reduction of production costs relative their existing aluminium coupling, partly by change of material to plastics. Outsourcing is relevant as the company does not produce plastic components at set. The idea generation phase has been based on a pre-study consisting of literature studies, analyses of competing products through demolition, and user tests. Prototypes have been used for testing and evaluation throughout the process. The outer components of the quick connection coupling proved to be among the costliest details. Locking mechanism, the formation of an inner slot for seals and the junction between nipple- or coupling body and back part to allow assembly and to ensure a non-drip application, have been developed separately. Decisions for final concept selection were made with the company of commission, with data regarding costs, usage interpreted from prototypes and verdicts from external experts within plastics production. Sub solutions mentioned, were combined into a final concept which reduces costs and fulfils demands regarding performance, appearance and usability. The material from the project is propositioned to form the basis for further development and testing to ensure high product quality representing CEJN.
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Shariatmadar, Hashem. "Seismic response of connections in precast concrete double-tees." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30386.pdf.
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Rama, Glauber Macedo. "Próteses parciais fixas apoiadas sobre conexão dente-implante rígida: análise do comportamento biomecânico antes e após ciclagem mecânica." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/58/58131/tde-12122014-103741/.
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A associação entre dente e implante em uma prótese parcial fixa (PPF) vêm sido questionada há muitos anos devido a suas implicações clínicas, incluindo a seleção do melhor tipo de união dos elementos protéticos (conexão rígida ou semi-rígida). Este estudo avaliou próteses dento-implanto-suportadas de conexão rígida do tipo cimentada sobre 3 tipos de conexão protética (hexágono externo - HE, hexágono interno - HI e cone morse - CM) e sua relação com o desajuste vertical e falhas na prótese antes e após ciclagem mecânica, além da análise fotoelástica destas situações. Foram confeccionados 21 corpos de prova (7 HE, 7 HI e 7 CM) sobre um modelo mestre que simulou a perda dentária dos elementos 46 e 47, sendo um implante posicionado na área do 47 e um dente preparado com ligamento periodontal simulado em poliéter na área do 45. Sobre este modelo foram confeccionadas PPFs metalocerâmicas de 3 elementos rígidas cimentadas sobre dente e implante (munhão universal). Os corpos de prova foram preparados e submetidos ao ensaio de ciclagem mecânica com uma carga de 120N por 1.000.000 de ciclos, simulando o uso clínico da prótese por 2 anos. Análises do desajuste vertical foram realizadas por meio de microscopia óptica (40x) em todos os períodos de confecção das PPFs (antes da solda, após solda, após aplicação da cerâmica e após ciclagem). O percentual de falhas nas próteses após ciclagem também foi avaliado (trincas/fraturas/decimentações), além da execução do ensaio fotoelástico (carga pontual dental, bipontual nos pilares e oclusal simultânea). Os resultados obtidos para o desajuste vertical indicaram um aumento significante dos níveis de desajuste para todas as etapas de confecção tanto para dente quanto implante (p<0,0001), porém não significante entre os grupos (p>0,059). Para o percentual de falhas na prótese, encontrou-se um índice decrescente na ordem CM>HI>HE. Para análise fotoelástica, encontrou-se um índice de concentração de tensões crescente na ordem CM<HI<HE. Baseado nos resultados encontrados, dentro das limitações do estudo foi possível concluir que: os níveis de desajuste vertical tendem a aumentar nas etapas de confecção da prótese para todas as conexões protéticas; a fadiga mecânica tende a interferir no grau de desajuste vertical a longo prazo pela deformação da estrutura a depender de sua espessura; o aumento no percentual de falhas da prótese tende a ser proporcional ao aumento da rigidez da conexão protética; apesar da redução da rigidez da conexão protética favorecer a longevidade da PPF, esta também tende a aumentar as tensões nos elementos pilares e stress no osso circundante; a utilização da conexão Morse subcrestal para união dente-implante rígida tende a ser preferível pela preservação dos elementos pilares devido a menor concentração de tensões em detrimento da longevidade da PPF, entretanto esta pode ser substituída caso a falha seja irreversível.The association between tooth and implant in fixed partial dentures (FPD′s) have been questioned for many years due to its clinical implications, including selecting the best kind of connection design (rigid or semi-rigid connection). This study assessed cemented toothimplant supported rigid connected FPD′s on 3 types of implant connections (external hexagon - EH, internal hexagon - IH and morse taper - MT) and its relationship to the vertical misfit and FPD failure before and after mechanical cycling plus the photoelastic analysis of those situations. 21 specimens (7 EH, 7 IH and 7 MT) were fabricated on a master model that simulated tooth loss of elements 46 and 47, with an implant placed on the 47 area and a prepared tooth with simulated periodontal ligament in polyether on the 45 area. On this model, three-element metalloceramic rigid FPD′s were made, cemented to tooth and implant (universal post). The specimens were prepared and subjected to mechanical cycling with a 120N load under 1,000,000 cycles, simulating a 2-year clinical use of the prosthesis. Analyses of vertical misfit were performed by optical microscopy (40x) in all periods of FPD′s fabrication (before welding, after welding, after application of ceramic and after cycling). The FPD failure percentage after cycling was also evaluated (cracks/fractures/loss of cementation), and photoelastic test was performed (dental load only, simultaneous abutment load and occlusal load). The results for vertical misfit indicated a significant increase in the levels of misfit for all stages of fabrication for both tooth and implant (p<0.0001) but not significant between groups (p>0.059). For the FPD failure percentage, we found a decreasing rate in the order MT>IH>EH. The photoelastic test indicated a major amount of tension increase in the order MT<IH<EH. Based on these results, within the limitations of the study it was concluded that: the levels of vertical misfit tend to increase in the prosthesis fabrication steps for all implant connections; mechanical fatigue tends to interfere on vertical misfit in long term due to deformation of the framework depending on its thickness; the FPD failure percentage tends to be proportional to the rigidity increase of the implant connection; despite the decrease of rigidity of the implant connection favors the longevity of the FPD, this also tends to increase tensions on the abutments and stress on the surrounding bone; the use of subcrestal morse taper connection on rigid tooth-implant FPD′s tends to be preferable for the preservation of the abutments due to the lower abutment stress concentration at the expense of longevity of FPD, though this can be replaced if the failure is irreversible.
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Dike, Nnadozie N. F. "Performance of Mechanical and Non-mechanical Connections to GFRP Components." Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5187.
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There are presently many solutions to dealing with aging or deteriorated structures. Depending on the state of the structure, it may need to be completely over-hauled, demolished and replaced, or only specific components may need rehabilitation. In the case of bridges, rehabilitation and maintenance of the decks are critical needs for infrastructure management. Viable rehabilitation options include replacement of decks with aluminum extrusions, hybrid composite and sandwich systems, precast reinforced concrete systems, or the use of pultruded fiber-reinforced polymer (FRP) shapes. Previous research using pultruded glass fiber-reinforced polymer (GFRP) decks, focused on behaviour under various strength and serviceability loading conditions. Failure modes observed were specific to delamination of the flexural cross sections, local crushing under loading pads, web buckling and lip separation. However certain failure mechanisms observed from in-situ installations differ from these laboratory results, including behaviour of the connectors or system of connection, as well as the effect of cyclic and torsional loads on the connection. This thesis investigates the role of mechanical and non-mechanical connectors in the composite action and failure mechanisms in a pultruded GFRP deck system. There are many interfaces including top panel to I-beam, deck panel to girder, and panel to panel, but this work focuses on investigating the top panel connection. This is achieved through comparative component level shear, uplift, and flexure testing to characterize failure and determine connector capacity. Additionally, a connection of this GFRP deck system to a concrete girder is investigated during the system-level test. Results show that an epoxy non-mechanical connection may be better than mechanical options in ensuring composite behaviour of the system.ID: 031001297; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Title from PDF title page (viewed March 7, 2013).; Thesis (M.S.)--University of Central Florida, 2012.; Includes bibliographical references (p. 80-82).
M.S.
Masters
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Civil Engineering; Structural and Geotechnical Engineering
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Schleifenbaum, Stefan, Michael Schmidt, Robert Möbius, Thomas Wolfskämpf, Christian Schröder, Ronny Grunert, Niels Hammer, and Torsten Prietzel. "Load and failure behavior of human muscle samples in the context of proximal femur replacement." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-204698.
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Background: To ensure adequate function after orthopedic tumor reconstruction, it is important to reattach the remaining soft tissue to the implant. This study aimed at obtaining mechanical properties of textile muscle-implant and muscle-bone connections in a preliminary test. Methods: Two groups of soft-tissue attachment were mechanically tested and compared: Native bone-muscle samples obtained from human femora and muscles attached to a prosthetic implant by means of Trevira® attachment tubes. Additionally, muscle samples were tested with muscle fibers aligned parallel and perpendicular to the tension load. A uniaxial load was exerted upon all samples. Results: Failure loads of 26.7 ± 8.8 N were observed for the native bone-muscle group and of 18.1 ± 9.9 N for the Trevira® group. Elongations of 94.8 ± 36.2 % were observed for the native bone-muscle group and 79.3 ± 51.8 % for the Trevira® group. The location of failure was mainly observed in the central area of the muscle fibers. Muscle fibers with parallel fiber orientation (47.6 ± 11.5 N) yielded higher tensile strength than those with perpendicular fiber orientation (14.8 ± 4.1 N). Conclusions: Our experiments showed that higher forces were transmitted in the origin and insertion areas than in areas of flat soft tissue reconstruction using attachment tubes. The data indicate that the tested material allows reattaching muscles, but without reinforcing the insertion site. Therefore, attachment tubes with region-dependent
and potentially anisotropic material behavior might be advantageous to optimize muscle-bone load transmission after surgery, which may allow lower complication rates and shorter physical recovery.
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Shokrieh, Mahmood M. (Mahmood Mehrdad). "Failure of laminated composite pinned connections." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60608.
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In this investigation the behavior of pin-loaded composite plates is studied analytically. A progressive damage model is presented which is capable of predicting the three different mechanisms of failure: bearing, shearout, and net tension. The model consists of three major parts: stress analysis, and material property degradation rules.Based on the model a computer code is developed. The computer code is capable of assessing damage, evaluating residual strength, and predicting ultimate strength of pin-loaded composite plates. Predicted results are compared with available experimental data. Excellent agreement between the predicted and the experimental data was found.
The computer code is used to study geometric parameters that influence joint strength. Such studies are useful in designing mechanical fastened joints using advanced composites.
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Turetta, Maxime. "Development of an innovative U-shaped steel-concrete composite beam solution : experimental and numerical studies on the mechanical behaviour." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0203.
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Une solution innovante de poutre mixte acier-béton a été développée en tenant compte des problématiques de résistance au feu et de montage sur chantier. La poutre est composée d'une partie métallique en U connectée à une partie en béton armé. En phase de construction, la poutre métallique supporte la dalle et constitue un coffrage pour la retombée en béton armé. La poutre en U résiste aux charges de construction sans système d’étaiement temporaire. Lors du coulage du béton, la poutre en acier est remplie en même temps que la dalle, ce qui permet un gain de temps considérable sur chantier. En phase d'exploitation, la poutre est mixte acier-béton. La connexion entre les deux matériaux est réalisée par des goujons à tête soudée en partie inférieure de la poutre en U. En situation d'incendie, la poutre mixte répond aux durées de stabilité au feu conventionnelles grâce aux armatures longitudinales à l'intérieur de la retombée avec des enrobages suffisants. Un état de l'art sur les solutions existantes répondant aux critères de la thèse est réalisé afin de proposer une solution innovante et optimisée. En phase de construction, sans présence de maintien, la poutre métallique en U est sujette à l’instabilité globale de déversement. Afin de caractériser la stabilité de la poutre, un test à échelle réelle est effectué au Laboratoire de l'Université du Luxembourg. Les résultats de l’essai sont comparés à des simulations numériques et à des études analytiques. Une étude paramétrique portant sur 200 configurations géométriques de la poutre en U est réalisée afin de valider l'utilisation de la courbe « b » pour le dimensionnement au déversement selon l’Eurocode 3. En phase d'exploitation, une fois le béton durci, la poutre présente un comportement mixte acier-béton assuré par la connexion. Pour des raisons de fabrication, la connexion est située dans une zone où le béton est soumis à des efforts de traction induits par la flexion de la poutre. Le béton dans cette zone est potentiellement fissuré, l’efficacité de la connexion et par conséquent le comportement mixte acier-béton sont étudiés. Un autre test, à échelle réelle, est effectué dans le Laboratoire de l'Université du Luxembourg. La ruine de la poutre mixte, par effort tranchant, se produit à très grands déplacements. Cependant, l’échantillon présente un réel comportement mixte avec une ductilité élevée, la connexion est donc très efficace. Les résultats de l’essai sont comparés à des simulations numériques afin de valider le modèle par éléments finis développé. A partir des résultats numériques et des résultats d’essais, une méthode de conception pour déterminer la résistance à la flexion de cette poutre, basée sur l’Eurocode 4, est proposée en tenant compte de la plastification partielle des parois de la section en U. Une méthode de conception analytique globale est proposée pour la solution développée basée sur les Eurocodes, avec des considérations supplémentaires et des conseils de mise en œuvreAn innovative solution of steel-concrete composite beam was developed taking into consideration the fire situation and the construction stage. The beam is composed of a U-shaped steel part connected to a reinforced concrete part. In the construction phase, the beam is supporting the slab and constitutes a formwork for the reinforced concrete part. The U-shaped beam withstands the construction loads without any temporary propping system. When casting concrete, the steel beam is filled at the same time as the slab, this allows considerable time-saving on site. In exploitation stage, the beam behaves as a steel-concrete composite beam. The connection between the two materials is made by welded headed studs on the lower part of the U-shaped beam. In fire situations, the composite beam satisfies conventional fire stability durations due to the longitudinal reinforcements inside the concrete downstand part with sufficient covers. A literature review focuses on modern solutions that fulfils the criteria of the thesis is performed in order to develop an innovative solution optimised. In construction stage, the U-shaped steel beam without restraints is prone to lateral torsional buckling instability. In order to characterise the stability of the beam, a full-scale test is carried out at the Laboratory of the University of Luxembourg. The test clearly showed the lateral torsional buckling of the steel beam. The test results are compared to numerical simulations and analytical studies. A parametrical study, covering 200 geometrical configurations of the U-shaped beam, is carried out to validate the use of the curve "b" for the design of the steel beam for lateral torsional buckling according to Eurocodes 3. In the exploitation phase, once the concrete hardens, the beam has a steel-concrete composite behaviour provided by the shear connection between the two materials. For manufacturing reasons, the connection is located in a zone where the concrete is subjected to tension forces induced by the bending of the beam. The concrete in this zone is potentially cracked, thus the efficiency of the connection and therefore the mechanical steel-concrete composite behaviour is investigated. Another test is therefore carried out in the Laboratory of the University of Luxembourg, this time the specimen tested is made of concrete and steel. The failure mode is a shear mechanism of the composite beam at very large displacements. However, the beam specimen exhibited a real steel-concrete composite behaviour with high ductility, the connection is therefore very efficient. The test results are compared to numerical simulations in order to validate the finite element model developed. From numerical results and test results, an analytical method, based on EN 1994-1-1, is proposed to find the bending resistant of this composite beam by taking into account the partial yield of the side plates of the U-shaped steel section. A global analytical design method is proposed for the developed solution based on the Eurocodes with additional considerations and constructional guidelines
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Vallance, Robert Ryan. "Precision connector assembly automation." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/38433.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1999.Includes bibliographical references (p. 209-214).
Telecommunication systems, network servers, mainframes, and high-performance computers contain several printed circuit boards (PCBs) that are mounted in card-cage assemblies. Level-3 connectors, often called board-to-board connectors, transmit signals between the primary backplane PCB and the daughter card PCBs. These connectors are customized for each PCB by configuring modules along the length of the connector. Hence, the connector's assembly system must flexibly accommodate the connector configurations. Prior to this research, the assembly of daughter card connectors was a manual process. This thesis presents the conceptual design of an assembly cell, and thoroughly presents the selected concept, a flexible assembly system. In the flexible assembly system, the connector is fixtured on a pallet and transferred to assembly stations on a conveyor. The pallet must be precisely located at each station, to minimize the relative errors between the new component and the connector on the pallet. Kinematic couplings deterministically locate one rigid body with respect to another. Therefore, a pallet system was developed that uses split-groove kinematic couplings between the pallets and machines. Experiments demonstrated that the split-groove kinematic pallet was approximately O1X more repeatable than conventional pallet location methods. The design is evident in the fabrication and operation of the first automated machines for the connector assembly system. In automated machinery, kinematically coupled bodies are often subjected to ranges of disturbance forces. This thesis presents new methods for analyzing the static equilibrium, errors due to contact deformation, and contact stresses that result from disturbance forces. In addition, the manufacturing errors within individual pallets and machines combine to cause system-wide, variability in pallet location. Two methods are presented for estimating the system-wide variability in the position and orientation of the pallets.
by Robert Ryan Vallance.
Ph.D.
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Ensley, Ann Elizabeth. "A fluid mechanic assessment of the total cavopulmonary connection." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/15724.
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Hagg, Lobland Haley E. "Definition of Brittleness: Connections Between Mechanical and Tribological Properties of Polymers." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9097/.
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The increasing use of polymer-based materials (PBMs) across all types of industry has not been matched by sufficient improvements in understanding of polymer tribology: friction, wear, and lubrication. Further, viscoelasticity of PBMs complicates characterization of their behavior. Using data from micro-scratch testing, it was determined that viscoelastic recovery (healing) in sliding wear is independent of the indenter force within a defined range of load values. Strain hardening in sliding wear was observed for all materials-including polymers and composites with a wide variety of chemical structures-with the exception of polystyrene (PS). The healing in sliding wear was connected to free volume in polymers by using pressure-volume-temperature (P-V-T) results and the Hartmann equation of state. A linear relationship was found for all polymers studied with again the exception of PS. The exceptional behavior of PS has been attributed qualitatively to brittleness. In pursuit of a precise description of such, a quantitative definition of brittleness has been defined in terms of the elongation at break and storage modulus-a combination of parameters derived from both static and dynamic mechanical testing. Furthermore, a relationship between sliding wear recovery and brittleness for all PBMs including PS is demonstrated. The definition of brittleness may be used as a design criterion in selecting PBMs for specific applications, while the connection to free volume improves also predictability of wear behavior.
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Fang, Demi L. "Timber joinery in modern construction: Mechanical behavior of wood-wood connections." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127868.
Full textAbstract:
Thesis: S.M. in Building Technology, Massachusetts Institute of Technology, Department of Architecture, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references (pages [107]-112).
Timber joinery is a method of geometrically interlocking timber elements prevalent in historic cultures around the world, including North America, Europe, and East Asia. The use of joinery as structural connections faded with the development of metallic screws and nails. Two recent developments offer the opportunity to revive this historic timber connection type: 1) the increasing desire to reduce embodied carbon in buildings by replacing more components with timber as a low-carbon structural material, and 2) recent digital fabrication capabilities which enable the precise milling of complex geometries as an alternative to the time- and labor-intensive handiwork required previously. How can joinery connections be designed in modern structural joints? Can we quantify the sustainability advantage of using these all-timber joints in lieu of the modern convention of metallic fasteners? This thesis addresses both questions as applied to the Japanese Nuki joinery type, though the workflows may be applied to any joinery geometry. First, the rotational stiffness of the Nuki joint is characterized and cross-verified using multiple methods. Second, the embodied carbon of a gravity frame using Nuki joints is compared to that of a gravity frame using conventional metallic fasteners. The use of Nuki joints not only eliminates the use of steel and aluminum but also provides rotational stiffnesses that enable smaller beam sections to be used. It is shown that gravity frames designed with Nuki joints could reduce embodied carbon by over 70% compared to gravity frames designed using conventional beam hanger connections. The findings make a case for all-timber joinery connections to be implemented as a sustainable alternative to conventional metallic connections used in modern timber construction.
by Demi L. Fang.
S.M. in Building Technology
S.M.inBuildingTechnology Massachusetts Institute of Technology, Department of Architecture
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Hagg, Lobland Haley E. Brostow Witold. "Definition of brittleness connections between mechanical and tribological properties of polymers /." [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-9097.
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Brennan, Feargal Peter. "Fatigue and fracture mechanics analysis of threaded connections." Thesis, University College London (University of London), 1992. http://discovery.ucl.ac.uk/1317863/.
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This thesis aims to develop a comprehensive usable engineering design approach to the fatigue analysis of threaded connections. Although primarily concerned with the fatigue-fracture mechanics behaviour of screw threads, a broad review of stress analysis investigations in such connections is reported. Connection types, their functions and standardisation authorities are presented with the purpose of familiarising the reader with the subject and the options available to the design of threaded fasteners. Fatigue crack initiation is discussed with reference to the specific setting of a critical thread root. A crack initiation model is adapted for employment in thread root design. A novel weight function approach is developed for use in the determination of stress intensity factors for threaded connections. A generic solution is proposed valid for the fatigue crack growth from any thread root under any symmetrical stress system. Its development and discussion is examined in detail, remaining close to its proposed application. Two engineering situations where the chief structural components are comprised of threaded members are taken as case studies. The background to each situation is elaborated in detail and full-scale fatigue tests were conducted on the critical components. In all, fourteen full-scale tests under constant and variable amplitude loading are reported. The results of these are analysed and used to validate the fatigue crack initiation and propagation models. Useful observations which are helpful to understanding the fracture mechanisms operating during the fatigue of threaded connections are reported. Material and environmental considerations are examined and a survey of relevant materials and their behaviour in environments associated with threaded fasteners is presented. The merits or otherwise of some common engineering practices are discussed with regard to fatigue. A method has been developed for predicting fatigue life in large threaded connections under random loading. Experimental results have been gathered on two types of components used on certain oil rigs, tether joints and drill strings. The agreement found between prediction and experiment is appreciably better than by previous methods of analysis and also points to aspects open to further improvement.
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Topp, David Anthony. "Fatigue/fracture mechanics analysis of threaded tether connections." Thesis, University College London (University of London), 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428985.
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Kharouf, Nourhene. "Post-elastic behavior of bolted connections in wood." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36970.
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A nonlinear finite element model is developed to study the behavior of single- and double-bolted timber connections with relatively low member thickness-to-fastener diameter ratios. These structural joints tend to fail in a brittle fashion. The established model is capable of predicting the post-elastic deformations of the connections locally and globally, and the unequal load fractions transferred by each bolt in a two-fastener connection.The ADINA software package is used to generate the model. The problem presents two types of non-linearity. The first is due to geometric effects caused by increased sliding contact between the bolts and the oversized holes in the wood member. Contact is simulated using the Lagrange Multiplier algorithm available in ADINA. This algorithm enforces the compatibility of surface displacements at the wood member which is the contactor surface, and Coulomb frictional conditions over the contact segments, with a coefficient of friction of 0.7. The second non-linearity results from the material post-elastic behavior adjacent to the contact points. A plasticity-based compressive constitutive material model is developed to represent wood as elasto-plastic orthotropic according to the Hill yield criterion in regions of bi-axial compression. Linear elastic orthotropic response is applied otherwise. The model is incorporated as a user-supplied material model of ADINA to carry out the analysis.
The performance of the program and the effectiveness of the elasto-plastic material model are first verified with examples from the literature. Thereafter, numerical simulations of the post-elastic deformations of one- and two-bolt connections are compared to experimental results from tensile tests undertaken on glued-laminated timber connections with stocky bolts and subject to monotonic loading. Characterization tests are undertaken to obtain stiffness and strength for compression and tension parallel and perpendicular to grain, and shear, required as input in the new material model. Five configurations of single-bolt connections and four configurations of double-bolt connections have been tested with different combinations of end distance, edge distance, and spacing between bolts. Reasonable agreement is found between numerical and experimental load vs. strains obtained using single axis strain gages and strain rosettes mounted in regions of stress concentrations. The model is capable of tracing the post-elastic global deformation as obtained from experimental load vs. displacements of LVDT's mounted on specimens. The non-linearity of these load-slip curves is primarily caused by the inelastic wood deformation beneath the bolts at low load levels. This behavior explains the redistribution of load proportions among the bolts in a double-bolt connection. Under test configurations forces are unequally shared between the bolts even at the ultimate load. As a consequence, joint capacity as estimated with the proposed elasto-plastic material model is bounded by the so-called European Yield Model, which assumes equal load distribution among the bolts at ultimate, and the linear elastic model. Observed shear-out brittle failures of wood bolted connections are believed to be caused by excessive combined shear and tension perpendicular to grain along the sides of the contact zone.
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Mahjoub, Musaab. "FE modeling of glulam beams with mechanical slotted-in steel plate connections." Thesis, Linnéuniversitetet, Institutionen för byggteknik (BY), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-105430.
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The mechanical behavior of timber beams with a slotted-in steel plate is studied by creating anumerical model that can simulate the global bending behavior and the load carrying capacity aswell as the nonlinear plastic fastener force distribution. Experimental results from Material TestingInstitute (MPA), University of Stuttgart were compared with simulation results done at LinnaeusUniversity. The modeling of the timber beams and the mechanical connections is performed withshell, beam, and nonlinear connector elements. Three models were created, where the first modelwas a single-dowel double shear joint model to study the ability to use structural elements in themodeling of the test beams. It was used to simulate some of the basic failure modes in Eurocode5 (EC5). The second model was a beam model used to simulate the bending of a jointed timberbeam with a slotted-in steel plate, where only two connector elements are used to model the jointbehavior of each dowel group. It can be used to study the global deflection and the load carryingcapacity of the timber beams. The third model was a combined beam-shell model where the beamelements are used for the timber parts outside the connection area and the fasteners, while the shellelements are used for the slotted-in steel plate and the timber parts within the connection area.It uses two nonlinear connectors to connect each dowel to the wood and pure coupling to connectthe dowels to the slotted-in steel plate. This model can simulate same things as model two andalso the development of the elasto-plastic shear force distribution in all the dowels. All the modelswere created using parameterized Python scripts, which makes it possible to easily change differentinput parameters.Most of the modeling results show good agreement with both experimental results and with calculated load carrying capacity results for individual dowels according to EC5. The use of thesestructural elements (beam, shell, and connector elements) was found to result in much less computational time compared to the use of solid elements.
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Pritchard, Robyn. "Investigations into the mechanics of connective tissue." Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/247921.
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This thesis presents work on investigations into the mechanical properties of connective tissue. A model system of hydrogels was used to investigate how volume change through water flow is coupled to relaxation. This was done using digital image correlation (DIC) and a custom built setup. It was found, in hydrogels, that water loss is directly coupled to an increase in tension and water intake is directly coupled to tension relaxation. The experimental setup was tested by investigating the mechanical properties of the well known material polydimethylsiloxane (PDMS) and the novel materials of carbon nanotube (CNT) elastomers, cholesteric liquid crystal elastomers (CLCEs), and 3D polydomain liquid crystal elastomers (3DLCEs). The setup accurately demonstrated the incompressibility of PDMS, even at short time scales, and demonstrated how DIC can map the inhomogeneity of material by locating clusters of CNTs in CNT elastomers by how they deform. Novel results for 3DLCEs were also found, where it was discovered that there is a softening of the bulk modulus at small time scales resulting in a volume increase following deformation, the bulk modulus then recovers and there is over all no volume change. This is in stark contrast to the typical case, where it is the shear modulus that becomes comparable to the bulk modulus, resulting in increased volume. A theoretical investigation was carried out into critical damping in viscoelastic oscillators, where the aim was to apply to the findings to connective tissue. The fractional Maxwell model and zener model where both solved for, where it was found that damping decreases as the material becomes more solid and the peak of critical damping becomes broader. Finally, investigations into how strain relates to the viscoelastic properties of connective tissue were carried out on horse tendon and rat fascia. How relaxation changes was determined through the relaxation constant, where a large constant means it takes the sample longer to relax and it is more solid like. It was found, that in general, the relaxation constant increases quickly with an imposed strain and then either stabilises or increases more slowly. This growth of relaxation constant also occurs during the initial stages of tissue injury, where irreversible deformation occurs.
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Rohrbach, Thomas Juhl. "Investigation of Design, Manufacture, Analysis, and Test of a Composite Connecting Rod Under Compression." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/1996.
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Composite materials hold great potential for the replacement of traditional materials in machines utilized on a daily basis. One such example is within an engine block assembly where massive components inherently reduce the efficiency of the system they constitute. By replacing metal elements such as connecting rods, cylinder caps, or a crank shaft with composite alternatives, a significant increase in performance may be achieved with respect to mechanical strength, thermal stability, and durability, while also reducing mass. Exploration of this technology applied to a connecting rod geometry was investigated through a combination of process development, manufacturing, numerical analysis and testing. Process development explored composite material options based on experimental characterization, fabrication, and machining methods. Finite element analysis provided insight into model and data accuracy, as well as a basis for study on a unidirectional composite I-beam geometry. Destructive testing of the composite connecting rods provided data for a strength to weight ratio comparison with the original steel component. The composite connecting rods exhibited weight savings of 15%-17% that of the steel component. The rod made of woven composite material exhibited an elastic modulus of 68.1 Msi in its linear behavior before failure, thereby exhibiting a higher stiffness than the steel rod tested. Although the failure strengths were 25% below the required design load, the calculated strength to weight ratios showed favor for the composite alternatives.
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Heitritter, Kenneth I. J. "Mechanics of the diffeomorphism field." Thesis, University of Iowa, 2019. https://ir.uiowa.edu/etd/6761.
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Coadjoint orbits of Lie algebras come naturally imbued with a symplectic two-form allowing for the construction of dynamical actions. Consideration of the coadjoint orbit action for the Kac-Moody algebra leads to the Wess-Zumino-Witten model with a gauge-field coupling. Likewise, the same type of coadjoint orbit construction for the Virasoro algebra gives Polyakov’s 2D quantum gravity action with a coupling to a coadjoint element, D, interpreted as a component of a field named the diffeomorphism field. Gauge fields are commonly given dynamics through the Yang-Mills action and, since the diffeomorphism field appears analogously through the coadjoint orbit construction, it is interesting to pursue a dynamical action for D.
This thesis reviews the motivation for the diffeomorphism field as a dynamical field and presents results on its dynamics obtained through projective connections. Through the use of the projective connection of Thomas and Whitehead, it will be shown that the diffeomorphism field naturally gains dynamics. Results on the analysis of this dynamical theory in two-dimensional Minkowski background will be presented.
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Macdonald, Kenneth Alasdair. "Fatigue of drillstring threaded connections." Thesis, University of Aberdeen, 1996. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU090407.
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Analytical, experimental and numerical work is reported on failure and fatigue crack growth in rotary shouldered drillstring threaded connections, where fatigue failure occurs at critical (last engaged) threads. A comprehensive review is made of drillstring failure data in the period 1989 to 1994, where connection failure accounted for 58% of the total, confirming it as the principal cause of drillstring equipment failure over the period. Approximately equal proportions of pin and box failures occurred. An extensive programme of 2-D elastostatic finite element analyses was undertaken on drilling motor and drillcollar connections investigating peak stress response at the critical threads to preload (from connection make-up) and applied loads. A pronounced effect of preload on these peak notch stresses was found, particularly at the pin, revealing the stress concentration factor (based upon remote nominal pipe stress) to be inconstant and a strong function of applied load, its value reducing with increasing load. Fracture mechanics data in the form of finite element derived stress intensity factor solutions were produced. New K solutions in the form of Y functions were derived for tension loaded connections containing cracks: in a drilling motor box at its last engaged thread (without preload): and in an API NC-61 nonmagnetic drillcollar pin and box at their last engaged thread sites, both with preload. These solutions are all conveniently referenced to nominal stresses in the uniform pipe making their use in crack growth studies straightforward. A new solution is also given for a fully circumferential internal surface crack in a tube under axial tension. The growing fatigue crack is also shown to cause load to be shed from the last engaged thread onto adjacement threads. The dominance of the thread root notch singularity at short crack lengths (a/T<0.1) means that equations fitted to the majority of the Y function data using linear regression analysis are done so for two separate regions of a/ T.
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Zamani, Zavieh Shahram. "Punching shear strength of edge column connections of rectangular flat plates." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26550.
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Edge column slab connections of continuous flat plate structures, under combined shear and moment transfer, can be susceptible to failure by punching shear. A 2 bay by 2 bay, rectangular flat plate, panel aspect ratio 2:1, was fabricated and loaded to failure under a simulated uniformly distributed load. The edge and corner columns were supported so that the reactions and reactive moments could be measured. The interior column, no moment transfer, punching shear strength was less than inferred from previous research. Based upon the strain gauge results neither the long or short direction flexural reinforcements yielded. The fact that the interior column was rectangular in section was a complication.
Comparison of the measured reactions to those calculated by finite element analysis, FEM, and a modified direct design method, RDDM shows that both methods predict the reactions with acceptable accuracy. (Abstract shortened by UMI.)
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LeBlanc, David N. "Beam shear connections to HSS composite columns." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63273.
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Douglas, Neil. "Self-rotating life-forms, mechanical connections and simulation of deformable bodies in inviscid flow." Thesis, University of Surrey, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531369.
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Tinl, Nicholas E. "An Investigation of the Bearing Strength of Bolted Connections in Aluminum and Titanium Alloys." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1322506214.
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Bergstedt, Joel. "Connecting casting simulations with strength analysis." Thesis, KTH, Hållfasthetslära (Avd.), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223951.
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The finite element method and casting simulations have reached higher popularity and accuracy partly due to increase in computer power over the last couple of years. The increase in computer power has led to better simulations and hence a better reflection of reality. The development in simulations has made it possible to connect different kinds of physics and simulation tools, a type of multiphysics. In this work the connection between casting simulations and strength analysis (with finite element method) has been evaluated with focus on improving the computation accuracy at Scania.This work indicates that by implementing data from casting simulation into a strength analysis the result changes. These changes are local and often located in areas where the stress levels are large. This emphasise the importance of using casting simulation data in strength analyses. Furthermore there are a large room for improvement and some calibration should be executed before usage.A method has been developed on how to implement casting simulations into a strength analysis. This method requires a interdisciplinary connection between different groups at Scania. The result of this connection is not only a better simulation but also an exchange of knowledge regarding the product that is of interest for all involving groups.Finita element metoden och gjutsimuleringar har utvecklats och blivit väldigt populära i och med den utveckling som har skett på dator sidan. Kraftfullare datorer har lett till att simuleringar idag mer och mer speglar verkligheten. Detta har lett till att kopplingar mellan olika simuleringsverktyg har börjat utvecklats, så kallade multifysik verktyg. I detta arbete har kopplingen mellan gjutsimuleringar och hållfasthetssimuleringar utvärderats i avseende att förbättra Scanias beräkningsprocess.Arbetet visar att genom att implementera data från gjutsimuleringar i en hållfasthetsanalys så kan beräknaren förvänta sig en förändring i resultat. Förändringen är lokal och till stor del lokaliserad i områden med höga påfrestningar. Detta visar på betydelsen av att i framtiden använda sig av gjutsimuleringsdata i hållfasthetssynpunkt. Vidare så finns det stora utvecklingsmöjligheter inom ämnet och viss kalibrering bör genomföras innan användning.Under arbetets gång har en metod utvecklats som beskriver hur kopplingen mellan gjutsimuleringar och hållfasthet bör genomföras. Metoden kräver ett tvärfunktionellt samarbete mellan olika grupper på Scania men resultatet är givande för alla inblandade. Detta då förståelse för hur komponenten beter sig är av betydelse för både gjutsimuleraren liksom hållfasthets-beräknaren.
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Chernozatonskii, L. A., and V. A. Demin. "Nanotube Connections in Bilayer Graphene with Elongated Holes." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35460.
Full textAbstract:
Structures, stability and electronic properties of AA-stacking bigraphene with holes are studied using molecular mechanic and DFT method calculations. It has been shown the zig-zag edges of considered elon-gated holes lead to armchair sp2-nanotube-type connection between these two edges forming all sp2-structure. We consider similar periodic structures with (n,n) nanotubes formed among elongated holes and connected with bigraphene fragments, which edges are also closed edges. The stability and electronic prop-erties of these structures are investigated. Band structures of considered materials have energy gaps 0.20-0.27 eV in the direction of tube axes through jumpers on the connections, and Dirac-like point views in the opposite direction.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35460
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Abiose, Kabir. "Improving the concentrated solar power plant through connecting the modular parabolic solar trough." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105718.
Full textAbstract:
Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.
Concentrating solar power (CSP) stands as a promising renewable energy technology with the ability to contribute towards global reduction of carbon emissions. A major obstacle to increased adoption of CSP plants has to do with their high initial investment cost; consequently, there is a powerful desire to find improvements that decrease the initial capital investment for a CSP plant. One such improvement involves connecting modularized parabolic trough segments, each with the same dimensions, decreasing the overall amount of actuators required along with greatly simplifying system control architecture. This thesis is concerned with the extent to which parabolic solar trough modules can be connected together while still being able to operate to desired accuracy under expected load. Accuracy requirements are calculated, along with expected loads resulting in frictional torque on the trough. These expected loads are combined with a model for the effect of connecting multiple trough modules to generate a relationship between number of chained modules and required torsional stiffness. To verify said model, an experimental setup was designed and constructed to simulate loads due to both trough weight and wind loads.
by Kabir Abiose.
S.B.
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Yahya, Najeeb Ali. "Failure analysis of bonded steel/CFRP laminate connections." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6659/.
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Adhesive-bonded applications are widely used in industry, because of significant advantages such as uniform stress distribution, design flexibility and suitability to bond similar and dissimilar structural materials. This study focuses the adhesive-bonded long overlap of steel/carbon fibre reinforced polymer (CFRP) composite double lap shear (DLS) joints. The purpose of the work is to predict and assess the structural failure and behaviour of the DLS joint, including delamination of the composite, and to determine the effects of the design parameters of adherend thickness, overlap length and fabric orientation on the joint’s failure. There are different ways for such a joint to fail, which makes predicting failure very difficult. Another important difference is the failure mode of composites, where the relatively low interlaminar shear or tensile strength of the resin system causes failure of the composite before failure of the adhesive bondline occurs. Both experimental and numerical methods were used for the analysis. The experimental programme includes fabrication, mechanical testing and failure examinations of various joints. The numerical methods are based on 2D models, using strength of materials and cohesive zone modelling (CZM) approaches. In order to model adhesive joints accurately and efficiently, fracture tests were implemented to determine the fracture criteria. Mode-I and mode-II fracture energies were obtained by double cantilever beam (DCB) and end notched flexure (ENF) tests. An inverse method was used to define the cohesive parameters of the bilinear relation, fitting the numerical and experimental load-displacement curves. The DLS model has been created in Abaqus software, and results for each approach have been presented. Critical locations of stress concentrations in the DLS joint were identified, and the CZM successfully predicted the delamination initiation and propagation region observed in the experiment. As a result, it was concluded that the data obtained from the analysis showed good agreement with the experimental results, and in addition to the fibre orientation angles of the CFRP laminate markedly affecting the failure load of joints, the failure mode and stress distributions appeared in adhesive and composite. Furthermore, the study shows that the cohesive elements enable the numerical results to be obtained in shorter simulation times than the strength of materials approach, which should encourage use of CZM to analyse large structural applications.
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Roberts, Wayne S. "An alternative shear connection for steel concrete composite bridges." Thesis, Queensland University of Technology, 1999.
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Gustafsson, Johan, and Jakob Myhrberg. "Expansion Joints in timber bridges : Mechanical behavior under external loading." Thesis, Linnéuniversitetet, Institutionen för byggteknik (BY), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-105321.
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To design a bridge, different typologies of construction materials can be used. All materials have in common that deformations occur due to different events, such as externalloading, temperature- and moisture variations. To allow these kinds of deformations,Expansion Joints (EJs) are used in the structure. In timber bridges, these joints haveturned out to be a complex construction detail, due to problems related to their strengthand moisture capacity. The purpose of this thesis is to overview design codes and tostudy the mechanical behavior of Nosing EJs in a roadway timber bridge under externalloading. The aim is to identify critical actions and provide an alternative design of thestudied EJ. The aim is also to create a Finite Element (FE) model of the EJs and carryout calculations according to the design codes. To achieve this, literature studies, designcalculations and FE-simulations were performed. It turned out that there were lack ofearlier studies within this field. Therefore, studies which treats EJs in bridges with othermaterial than timber were considered. The results from the simulations indicated thatthe steel components in EJs are the most exposed parts in the detail. It also turned outthat an eventual failure can transferred away from the screws to the parts consideredmore favorable in the EJ.
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Salihu, B. M. "Stress analysis of drillstring threaded connections." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/7752.
Full textAbstract:
The demand for energy from developed and developing economies of the world is
driving the search for energy resources to more challenging environments. The
exploration and exploitation of hydrocarbons now requires the drillbit to hit pay zones
from drillships or platforms that are located on water surfaces below which is, possibly,
in excess of ten thousand feet of water above the sea bed. From Brazil, to the Gulf of
Mexico and the Gulf of Guinea on the western coast of Africa, hitherto unfamiliar, but
now common, concepts in the drilling parlance such as ultra-deep drilling (UDD), ultraextended-
reach drilling (uERD) and slimhole drilling, are employed to reach and
produce reservoirs which a few decades ago would seem technologically impossible to
produce.
This is expected to exert tremendous demands on the physical and mechanical
properties of the drillstring components. Limiting factors for reaching and producing oil
and gas resources hidden very deep in the subsurface are both the capacity of the
drilling rig to support the weight of the drillstring, which in some instances can be
several kilometres long, and the bending, tensile and impact stresses the string has to
withstand in well trajectories that are getting both longer and more tortuous.
Associated with this increased well depths and complex well trajectories is the
prohibitive cost penalty of a failed drillstring. The in-service failure of drillstrings has
always been an issue in the industry long before the wells become this deep and
complex. The global oil and gas industry estimates the cost of string failure to be in
excess of quarter of a billion dollars annually.
Researchers are continuously looking for ways to design against string failure and
improve the level of confidence in drillstrings. Defect-tolerant design, tooljoint geometry
modification and surface coldworking are just a few of the ideas that have gained
mileage in this effort. Others that are now in consideration are the use of nonconventional
materials such as aluminium and titanium alloys for drillstring
components. More novel, still, is the use of a combination of two materials - one ‘softer’
than the other to form a hybrid string of two materials of unequal moduli of elasticity.
This is done to make the string lighter, reduce stress concentration factor at the
connections and place fatigue resistant materials in areas of high well bore curvature.In this work a computational technique in the form of two-dimensional finite element
analysis is used to develop a robust model of a drillstring connection and to analyse the
stresses on the model of a threaded connection of standard drillstring tooljoint made
from alloy steel. Further comparative analyses were undertaken on models of
drillstrings made from a newly developed drillstring material for ultra-deep drilling, the
UD-165, aluminium and titanium alloys and, finally, on hybrid drillstrings made from two
different materials of unequal moduli of elasticity.
The aim is not only to develop and validate a better method of computational drillstring
analysis but also to use the model to investigate and suggest areas of optimisation that
will benefit industry especially in the areas hybrid strings.
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Nandy, Ananya. "Fabrication process and electromechanical characterization of a sliding connector system for modular stretchable electronics." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123275.
Full textAbstract:
Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 48-49).
The development of stretchable electronics has opened the potential for novel types of wearable electronic devices that can conform to curvilinear surfaces. In the traditional wearable space, modularity has been explored as a way to make devices customizable and multi-functional. Extending modularity and customizability to stretchable electronics could allow improved data collection in contexts where traditional sensor deployment is more challenging, such as on the human body. However, the use of soft materials for creating the stretchable electronic circuits necessitates a solution to modular connections for which traditional rigid electrical connectors are not adequately suited. To address the electrical connection problem, a process was developed for fabricating a new custom connector that was intended to be integrated more easily into the stretchable electronic circuit. The sliding custom connector was evaluated against integrating off-the-shelf electrical connectors into the stretchable substrate. It was found that the custom connector had several desirable traits in comparison to the existing connectors, including a low profile, good form factor at the band interface, and easier integration into a stretchable substrate. In addition, the connector was able to achieve an average of 12.1% strain before failure, higher than the maximum 8.7% strain achieved by the snap-button, a tested off-the-shelf connector. However, the custom connector resistance was much higher, on the order of 10 [Omega] in comparison to between 0.2 and 2 [Omega] in the tested off-the-shelf connector systems. It will be necessary to pursue further iterations to reach the electrical properties afforded by the tested off-the-shelf connectors and to increase the strain before failure.
by Ananya Nandy.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Au, Eu Ving. "The Mechanics and Design of a Non-tearing Floor Connection using Slotted Reinforced Concrete Beams." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2010. http://hdl.handle.net/10092/4949.
Full textAbstract:
Ductile plastic hinge zones in beams of reinforced concrete frames are known to incur extensive damage and elongate. This ‘beam elongation’ can inflict serious damage to adjacent floor diaphragms, raising concerns of life safety. In light of this, the slotted reinforced concrete beam was investigated as a promising non-tearing floor substitute for conventional design. It consists of a conventional reinforced concrete beam, modified with a narrow vertical slot adjacent to the column face, running approximately three-quarters of the beam depth. Seismic rotations occur about the remaining concrete “top-hinge”, such that deformations are concentrated in the bottom bars of the beam, away from the floor slab, and beam elongation is minimised.
The inclusion of the slot raised several design issues which needed to be addressed. These were the shear transfer across the top-hinge, buckling of bottom longitudinal reinforcement, low cycle fatigue, bond anchorage of reinforcement in interior joints, interior joint design, detailing with floor units and beam torsion resulting from eccentric floor gravity loads. These issues were conceptually investigated in this project. It was found that most issues could be resolved by providing additional reinforcement and/or specifying alternative detailing.
As part of the experimental investigation, quasi-static cyclic tests were performed on in-plane beam-column joint subassemblies. Specimens tested included exterior and interior joint subassemblies with slotted-beams and a conventional exterior joint as a benchmark. This was followed by a test on a slotted-beam interior joint subassembly with precast floor units and imposed gravity load. Experimental tests revealed significant reductions in damage to both the beam and floor when compared to conventional beams. Issues of bar buckling, bond-slip and altered joint behaviour were also highlighted, but were resolved in the final test.
A simple analytical procedure to predict the moment-rotation response of slotted-beams was developed and verified with experimental results. This was used to perform sensitivity studies to determine appropriate limits for the concrete top-hinge depth, top-to-bottom reinforcement ratio and depth of diagonal shear reinforcement.
For the numerical investigation, a multi-spring model was developed to represent the flexural response of slotted-beams. This was verified with experimental tests and implemented into a five-storey, three-bay frame for earthquake time history analyses. To provide a benchmark, a conventional frame was also setup using the plastic hinge element developed by Peng (2009). Time history analyses showed that the slotted-beam frame response was very similar to the response of a conventional frame. Due to greater hysteretic damping, there was a slight reduction in the average interstorey drift and lateral displacement envelopes. The slotted-beam frame also exhibited 40% smaller residual drifts than the conventional frame.
The research carried out in this thesis showed slotted reinforced concrete beams to be an effective non-tearing floor solution, which could provide a simple and practical substitute for conventional reinforced concrete design.
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Miller, Crispin Mount. "So can you build one? : learning through designing--connecting theory with hardware in engineering education." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11548.
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Whitenack, Russell D. "Design and analysis of solder connections using accelerated approximate procedure with disturbed state concept." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280662.
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The accelerated approximate procedure developed and used herein for analysis, design and parametric optimization in electronic packaging is based on the disturbed state concept (DSC) and the hierarchical single surface (HISS) constitutive models. Over the past many years the benefits of the DSC/HISS model, compared to those of available plasticity models, have been demonstrated and validated for a wide range of materials and solder connections. When the DSC/HISS model is implemented in a two-dimensional finite element code, it is well suited for failure analyses of lead/tin solder connections under cyclic thermal and mechanical loading that are typically occur in electronic packages. Unfortunately, an analysis of a single solder connection, for approximately 4000 or more cycles, can require much effort and computer time, which may be too long to be of practical use. The accelerated approximate procedure significantly reduces the effort and the analysis time to approximately 10 to 15 minutes on a Pentium 4, 3.2 GHz personal computer. The main emphasis of this dissertation is the use of the unified DSC model with the finite element procedure to predict the behavior of chip-substrate solder connections. The DSC code is used to validate the performance of a number of packages (144 BPGA, 313 PBGA) tested in the laboratory under thermomechanical loading. Using the accelerated approximate procedure, the effect of the variable thickness solder connection in a plane stress idealization is compared with that of the constant thickness assumption, and a three-dimensional analysis. It shows that the analysis with variable thickness (in plane stress idealization) yields improved results. The accelerated approximate procedure is then used to perform parametric design analyses of a solder connection by varying a number of important factors such as connection size, shape and misalignment. The effects of varying the DSC/HISS parameters on cycle life are also analyzed. The results of this research can be used for design, analysis and failure life prediction of solder connections in electronic packages. The accelerated approximate procedure is considered to yield improved results compared to other available modeling methods.
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Kim, Jueseok. "Linear Finite Element Modeling of Joined Structures with Riveted Connections." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563273473791073.
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Chandrappa, Kori Vinay Kumar, and Ganesan Gowtham Prasath Radhakrishnan. "Design optimization and testing of electrical connector for low voltage transmission cabinets : In collaboration with ABB AB Kabeldon." Thesis, Högskolan i Halmstad, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40761.
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Abstract: This thesis work was a part of Halmstad University’s Mechanical Masterprogramme curriculum done in favour of ABB Alingsås. Our industrial partnerproduces and manufactures low voltage electrical distribution cabinets, connectorsand switch gears. This project is focused on specific electrical connector used inABB’s trademark cabinets. These electrical connectors serve as both the input and output points for thedistribution cabinets. The product under scope is an extension connector calledADI3M which is used in conjunction with the large sized cable connectors(AD300). This is a sequential design optimization activity performed after theredesigning of the AD300 to ensure interface compatibility and also aimed atopportunistic cost reduction. The ADI3M should provide design compatibility withboth old and new AD300 connector designs along with the comfortable interfacinginside the CDC and SDC cabinets. With the design process and concepting knowledge gained from the course work inHalmstad university along with the ABB’s industrial exposure towards the powersupply networks we proposed four different design concepts. These design conceptswere then evaluated against interface compatibility, cost aspects, manufacturingreadiness, mechanical strength, heat generation and electricity conductionproperties. Among the product development techniques, we applied QFD processto generate the concepts, waterfall method to frame the engineering design processflow and morphological matrix to select the generated concepts. We then changedthe raw material from brass to aluminium and extrusion process due to its beneficialproperties compared to brass and copper with various other reasons explainedclearly in the thesis content. For the plastic cover we preferred poly-carbonate dueto requirements such as transparency, stiffness, etc. Two of the best feasibleconcepts were selected and the design proposals were prototyped using 3D printingtechnology. The 3D printing method used was fused deposition modelling (FDM).Later machined aluminium prototypes were then produced for the metalsubcomponents to do real time strength analysis and interface checks. Weperformed a theoretical product strength analysis using ANSYS19.2. Then resultswere then evaluated, and the final concept was chosen according to the factors suchas cost impact, easy installation and comfortable inter-component clearance.Finally, the prototypes were tested for IP rating fulfilment and compatible interfaceswith adjacent components. The consecutive activities to be done out of thesis scope is to conduct mechanicaland tests and record the performance. The future scope of this project is to developa hybrid design combining the AD300 and ADI3M connectors which would enableeasy product handling, simplified functionality and further reduce cost.