Osseointegrated transfemoral implants have been introduced as an alternative to conventional, socket-based prostheses for above knee amputees. This method is showing great promise; however, the frequency of device failure is of concern. As a means to understand some of these failures, this study investigates the mechanical behaviour of three osseointegrated transfemoral implant systems; an in-house prototype design and two assemblies comprised of implant-grade parts provided by Integrum AB, Sweden. A series of mechanical tests were administered to evaluate the effects of tightening specifications and connection geometry on the material response, and mechanical behaviour of the assemblies. The tests included torque-elongation measurements, torque to failure tests, and strain analyses during loading. This research was carried out in an attempt to better understand the behaviour of components under loading, in order to optimize the assembly specifications and improve the useful life of the system. The results obtained confirm that the Integrum assemblies exhibit improved performance when tightened to a level beyond the current specified tightening torque of 12 Nm. Increased tightening torque provides an improved connection between components, leading to increased torque retention, decreased peak tensile strain values and a more gradual, primarily compressive distribution of strains throughout the assembly. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-09-29 12:14:18.438

Tightening systems are used in several industries, including assembly in the auto- motive industry and installation of computer hardware. Both the company mak- ing the tools and the customers need to know the performance of the tightening system to ensure that the screw joints tighten as desired. This can be done using a test joint system. High demands on safety as well as fast assembly speeds, puts high demands on the test equipment. The problem with the existing test joints is that they are hard to do repeatable tests on. The most common test joints are constructed us- ing mechanic or hydraulic systems. The mechanical systems have problems with wear of screws, changes in lubrication etc., while the hydraulic systems some- times are too slow. This master’s thesis is a study of whether it would be possible to construct a test joint using an electric motor. The electric motor together with a controller should simulate a screw joint so that the tool would perceive it as a real one. All investigation has been performed by system modeling and simulations in MATLAB. Four different control structures have been evaluated: a PID controller, one combined controller which uses feedforward from reference as well as distur- bance, one which is based on the same structure as the second but with an added inner current loop and the last one is an LQ controller. The conclusion is that it is possible to make a test joint using an electric motor and that the LQ controller seems to be the best choice. To prove the result, a few more aspects could be investigated more closely. One is to add a dynamic model of the tool, now only the reference to the tool is used. Another is to implement it on hardware.

O meio corporativo, principalmente quando se trata de montadoras automotivas, é carente de conhecimento dos fatores que podem influenciar o processo de união entre pares tribológicos. Quando há um fim específico, como o tema deste trabalho: assegurar níveis de controle capazes de eliminar os riscos de uma vedação deficiente na câmara de combustão com custo mínimo, tal carência é ainda maior. O estudo da tribologia inerente à união entre cabeçote e bloco do motor diesel é fundamental para se compreender a que ponto é possível garantir a melhor estanqueidade possível, especialmente no que esteja relacionado ao processo rotineiro de aperto na linha de produção. Nesse sentido, a investigação proposta neste trabalho tem o claro objetivo de propor melhores condições técnicas de vedação ao caso particular da união entre cabeçote e bloco do motor de forma a eliminar / minimizar qualquer influência externa durante o aparafusamento do par supracitado. Adicionalmente, o conhecimento aqui exposto poderá ser difundido a muitas outras aplicações similares nas quais a fixação aparafusada está atrelada a funções que não apenas de fixação, podendo estas estarem inclusive em outros universos do produto, tais como motores, cabinas, eixos e transmissão. / The automobile corporate field has a lack of knowledge when the subject is related to tightening specific issues, especially regarding tribological studies. When there is a specific goal as this thesis theme: ensure all the control levels to eliminate sealing deficiency risks inside combustion chamber in a low investment cost, the needs are even higher. The tribological study between diesel engine block and its cylinder heads assembly is essential to comprehend what is necessary to have the best possible sealing, mostly when it\'s related to the routine on the assembly tightening process. Thinking on that, this work has the goal to propose the best condition on fastening technique that guarantees the sealing to any superficial topography roughness. Additionally, the acquired knowledge will be spread to other similar applications that are not unequally associated to bolted joints, but also in other vehicle universes, such as engines, cabs, axles and transmissions.

Double-nut anchor bolt systems are used in the erection of traffic signal poles, high-mast luminaries, and other highway appurtenances. An absence of a tightening standard for such systems decreases the confidence in their performance under fatigue loading. Past research has shown that a tightening standard should include the development of preload in the anchor bolt sufficient to provide adequate resistance to fatigue failure. Preload should be measured by a turn-of-the-nut method. Laboratory progressive tightening tests were performed in order to monitor the stress ranges occurring in the bolt at various locations of interest at various degrees of turn-of-the-nut tightness. Tests were performed on six diameters of anchor bolt ranging from 1 to 2-1/4 inches in diameter and two different categories of thread pitch: UNC and 8UN. Plots of stress range versus degree of tightness were developed for each test and evaluated to find the minimum degree of turn-of-the-nut at which stress range inside the nuts dropped below that outside the nuts. This shift was considered to be the principle theoretical indication of adequate performance. A fatigue test which saw failure outside the double-nut connection was set down as the practical indicator of adequate fatigue performance. The 2 inch 8UN bolt was chosen as the critical specimen due to its overall low generation of preload during tightening tests. Theoretical testing showed that 1/24 turn-of-the-nut would guarantee sufficient fatigue performance. Two practical fatigue tests of the bolt at that tightness saw one positive and one negative failure. After actual lab tests, finite element modeling was used to investigate the behavior of the bolt. It was found that performance did not see improvement until 1/12 turn-of-the-nut. After all results were considered, a standard of 1/6 turn-of-the-nut or refusal of tightening by specified methods was recommended, provided a minimum of 1/12 turn-of-the-nut was achieved. This value allows for ease of measurement, sufficient tightness, degree of safety, and has been shown in past testing not to cause failure through over-tightening. However, tightening to only 1/12 turn-of-the-nut still provided adequate performance.

O meio corporativo, principalmente quando se trata de montadoras automotivas, é carente de conhecimento dos fatores que podem influenciar o processo de união entre pares tribológicos. Quando há um fim específico, como o tema deste trabalho: assegurar níveis de controle capazes de eliminar os riscos de uma vedação deficiente na câmara de combustão com custo mínimo, tal carência é ainda maior. O estudo da tribologia inerente à união entre cabeçote e bloco do motor diesel é fundamental para se compreender a que ponto é possível garantir a melhor estanqueidade possível, especialmente no que esteja relacionado ao processo rotineiro de aperto na linha de produção. Nesse sentido, a investigação proposta neste trabalho tem o claro objetivo de propor melhores condições técnicas de vedação ao caso particular da união entre cabeçote e bloco do motor de forma a eliminar / minimizar qualquer influência externa durante o aparafusamento do par supracitado. Adicionalmente, o conhecimento aqui exposto poderá ser difundido a muitas outras aplicações similares nas quais a fixação aparafusada está atrelada a funções que não apenas de fixação, podendo estas estarem inclusive em outros universos do produto, tais como motores, cabinas, eixos e transmissão. / The automobile corporate field has a lack of knowledge when the subject is related to tightening specific issues, especially regarding tribological studies. When there is a specific goal as this thesis theme: ensure all the control levels to eliminate sealing deficiency risks inside combustion chamber in a low investment cost, the needs are even higher. The tribological study between diesel engine block and its cylinder heads assembly is essential to comprehend what is necessary to have the best possible sealing, mostly when it\'s related to the routine on the assembly tightening process. Thinking on that, this work has the goal to propose the best condition on fastening technique that guarantees the sealing to any superficial topography roughness. Additionally, the acquired knowledge will be spread to other similar applications that are not unequally associated to bolted joints, but also in other vehicle universes, such as engines, cabs, axles and transmissions.

This diploma thesis is focused on the concept of threaded connection of the turbine wheel and shaft. At the beginning are described current welding methods of the turbine wheel and shaft connections as well as methods of the compressor wheel and shaft connections. Four possible concepts were designed and evaluated, and the best concept was chosen. For this concept was calculated tightening torque and concept was evaluated in terms of turbocharger operating conditions.

Atlas Copco Industrial Technique AB is a global supplier of systems, software, services, and tools for the global assembly industry with keywords such as ergonomics, productivity, and traceability central to Atlas Copco’s products. The objective of the thesis was to construct a prototype tool based on the result of a previous course held at Luleå University of technology. The course provided the development of a conceptual tool that utilized a chain driveline to transmit high dynamic torque to a bolt and an experimental setup with torque measurements. The scope of the thesis, as for the course, was to design a tool able to tighten joints up to 150Nm utilizing a pulsating tightening technique with the goal of no increase of defined dimension and vibrations lower than1m/s2. The thesis was initiated with a state-of-art benchmark where potential drivelines and competing solutions were acquired and were followed by the establishment of the framework for the prototype, a decided driveline, dimensioning of the components, the modeling and order of the prototype and a stiffness study. When the prototype was assembled and three competing solutions were obtained, vibrational, torsional and stiffness experiments were conducted.The experimental measurements concluded that the tool could tighten the sought 150Nm joints but with a declared vibrational value of ahd = 8.6m/s2. The extension tool also increased the vital centre-to-side distance by 5.5mm compared to the STR61-150 tool. The thesis examined the association between chain tension and torque transmission but could not determine this relationship. However, the experiment conducted suggests that an increasing chain tension would overall increase the magnitude of the pulse.

The diploma thesis addresses the topic of optical measurements of flange joints during tightening and thermal loading. Commercially available optical systems with decreasing invasiveness were compared in opportunity which offer to an industrial environment. Various conditions are evaluated in 3D (scanning, DIC) as well as in 2D (DIC). The data for evaluation of sensitivity and system accuracy together with the evaluation of the data range were obtained by the measurement. Data evaluation showed the same accuracy for 2D and 3D system and the possibility of quality inspection of the joint by assessing the inspection dimensions in operation.

This diploma thesis deals with the problem of designing an automatic robotic workstation for automatic tightening screws connections seatback – seat and belt buckle. The research part of this thesis deals with current trends in the automotive industry, especially with the problem of assembling seats part, with focus on screwing. The design part of this thesis maps the process of designing two variants of an automatic robotic workstation. Special attention was given to the process of choosing the right industrial robot for the task, as well as to the construction of the end-effector and of the resulting 3D data. The right version of the workstation for the consecutive implementation was then chosen based on multi-criteria evaluation. The finishing touch of this thesis is a risk analysis for the implemented workstation.

In recent years, there is an increased focus on integrating digital technologies in industrial processes, also termed ”Industry 4.0”. Out of the many challenges for the transition, one is to understand how to find useful insights from data collected over large periods of time, predominantly in industrial IT systems. Automotive assembly plant X is currently undergoing a digital transformation to leverage such technologies. There is an emphasis to understand the implications of data analytics and visualization and how it could be leveraged for process optimization. The torque tightening assembly process at plant X was chosen to carry out the study as there were opportunities to access the process data from the tool management system database. The purpose of this master thesis was thus to find the implications of data analytics on the torque tightening operations in assembly plant X. In addition, the thesis also aimed to understand how visualization of key performance indicators (KPIs) can improve traceability of operational deviations. In other words, the study aims to validate how data analytics and visualization of KPIs facilitate data-driven decision making, improve traceability of operational deviations. The research is based on an inductive, exploratory case study approach. The study was carried out by understanding the current state through a series of interviews and then followed by the development of the framework and dashboard for visualization of operational deviations. Further, a discussion on how data analytics and visualization could help in decision-making for continuous improvement efforts is presented. / På senare år har det funnits ett ökat fokus på att integrera digital teknik i industriella processer, även kallad ”Industry 4.0”. Av de många utmaningarna för övergången är en att förstå hur man kan hitta användbara insikter från data som samlats in under långa tidsperioder, främst i industriella IT-system. Fordonsmonteringsfabrik X genomgår för närvarande en digital transformation för att dra nytta av sådan teknik. Det finns en betoning på att förstå implikationerna av dataanalys och visualisering och hur det kan utnyttjas för processoptimering. Vridmoment åtdragning monteringsprocessen vid anläggning X valdes för att genomföra studien eftersom det fanns möjligheter att komma åt processdata från verktygshanteringssystemdatabasen. Syftet med detta examensarbete var alltså att hitta implikationerna av dataanalys på momentåtdragningsoperationerna i monteringsanläggning X. Dessutom syftade examensarbetet också till att förstå hur visualisering av nyckeltalsindikatorer (KPI) kan förbättra spårbarheten av driftsavvikelser. Med andra ord syftar studien till att validera hur dataanalys och visualisering av KPI:er underlättar datadrivet beslutsfattande, förbättrar spårbarheten av operativa avvikelser. Forskningen bygger på en induktiv utforskande fallstudiemetod. Studien genomfördes genom att förstå nuläget genom en serie intervjuer och sedan följdes av utvecklingen av ramverket och digital informationstavla för visualisering av operativa avvikelser. Vidare presenteras en diskussion om hur dataanalys och visualisering kan hjälpa till vid beslutsfattande för ständiga förbättringsarbeten.