This master’s thesis deals with design of spindle for small three axis milling machine. The first part of this thesis includes research in milling spindles and overview of several spindles from different manufacturers. The second part deals with calculation of necessary parameters, design of spindle and subsequent simulation verification. This thesis also includes a 3D model of spindle, assembly drawing and four manufacturing drawings.

This diploma thesis deals with projection and general design of rotary indexing table for dedicated machine tools. The major attention is given to substitution of hydraulic drive table by table driven by servomotor, namely double axis its positions in vertical and horizontal directions. The total configuration of rotary table is solved as a construction kit, user can used any servomotor and additive gearbox. The work is concentrated to the optimization of table construction for this new designed conception. The positioning and fixing of table plate is solved by couple of Hirth couplings with central hydraulic motor. The computational part of work includes calculations of dynamic of rotary motion of the table and hydraulic system. All important screw connection, gear wheels and Hirth couplings were verified by calculations. Also working lifetime of bearings and strength deformation of major constructional sections of rotary table verification were controlled. Inherent part of work is security analysis, economics analysis, patent search and analysis of construction identity. Presented work contains three-dimensional model, drawing documentation of both variants of configurations and production drawing of major section parts of rotary table.

In standard pneumatics, the available signals for data analytics are very limited. As a rule, no continuous status information is available. Usually only the reaching of the end position is indicated - by means of a digital signal of a proximity sensor. This paper examines whether these limited data can be used to derive usable and useful information for predictive maintenance. Pneumatic clamps in bodyin- white construction were chosen as application example. The paper describes a continuous run to investigate the basic feasibility of predictibility. In the following chapters, possibilities for error classification are discussed. Finally, the implementation of the findings in a field test is described.

Threaded fasteners tend to break and loosen when exposed to cyclic loads or potent temperature variations. Additionally, if the joint is held tightly to the structure, distortion will occur under thermal expansion issues. These complications can be prevented by identifying and regulating the clamping force to an appropriate degree – adapted to the properties of the joint. Torque-controlled tightening is a way of monitoring the clamping force, but it assumes constant friction and therefore has low accuracy, with an error of around 17% - 43%.This thesis investigates if the friction and clamping force can be estimated using the Extended and Unscented Kalman filters to increase the precision of the torque-controlled methodology. Before the investigation, data were collected for two widely used tightening strategies. The first tightening strategy is called Continuous Drive, where the angular velocity is kept at a constant speed while torque is increased. The second strategy is TurboTight, where the angular velocity starts at a very high speed and decreases with increased torque. The collected data were noisy and had to be filtered. A hybrid between a Butterworth lowpass filter and a Sliding Window was developed and exploited for noise cancellation.The investigations revealed that it was possible to use both the Extended and Unscented Kalman filers to estimate friction and clamping force in threaded fasteners. In Continuous Drive tightening, both the EKF and UKF performed well - with an averagequality factor of 81.87% and 88.38%, and with an average error (at max torque) of 3.54% and 4.09%, respectively. However, the TurboTight strategy was much more complex and had a higher order of statistical moments to account for. Thus, the UKF outperformed the EKF with an average quality factor of 93.02% relative to 24.49%, and with an average error (at max torque) of 3.50% compared to 4.19%

Last years, lead time, flexibility, cost, and quality have become significant factors for the manufacturing industry. This also applies to gears, which could be manufactured using hobbing and grinding. Fixing systems are used to precisely center and fully fix gears to reach high quality. These are expensive and not flexible which requires a new one for each gear dimension. This limits the production of prototypes and so new product for the market. Developing a 3D concept for affordable and flexible fixing is the purpose. Through literature research, analyzing the current process, discussions with the company, desk research, and benchmarking, requirements are made for the new concept. Then brainstorming sessions are done to come up with new concepts. The concepts are analyzed, discussed with the company, and combined into two better concepts. Even though the higher flexibility of the other concept, the robustness of the winning concept “CoNut”. The principle is that only a few parts have to be changed instead of the whole system. The concept is further developed in 3D, where design for cost and manufacturing are applied. Finally, test procedures are drafted to validate the concept against therequirements. While some require a prototype, others are already validated by using the 3D model. Ultimately, an affordable and more flexible fixing system is developed as a 3D concept, by using a structural design process, which is likely to meet all the requirements. Since the model is cheaper and easier to change within meeting the other requirements, the purpose is reached.

No description available.

It is common to use different construction materials in combination such as concrete, steel, wood and glass in order to optimize buildings. The purpose of this is to reduce weight and increase load capacity, but it also facilitates assembly and reduces construction time. Steel column bases anchored in concrete foundations are an example of a combination of interaction nodes between steel and concrete elements. This report studies the friction between the lower edge of the base plate and the grout, which is a function of the normal force of the column. The friction that occurs between the square washer and the foot plate has also been examined as a result of the tightening moment. The work has placed great focus on discussing the advantages and disadvantages of the different methods for transverse force absorption in column bases. Delimitations have been made, the attachment of the column to the base plate has not been taken into account in this report, as this depends on which column cross section is selected and must be checked for the specific case. To arrive at the results, an in-depth literature study was conducted to gather information on the various issues and a calculation model in Excel was created. The calculation model was used to check how large the design load-bearing capacity is for transverse force absorption in a column base, but the checks were only made for non-prestressed joints. This is because prestressed joints also have other factors that affect the transverse resistance, outside the purpose and issue of the work. The Excel model is based on producing the results from calculation with nominal clamping force and comparing it with clamping force calculated with tightening torque. The results will be reported in the form of graphs and tables, where it will be possible to read the difference in the dimensioning load-bearing capacity for transverse force absorption in non-prestressed joints at nominal clamping force and clamping force calculated with tightening torque. The report shows a clear difference in results, where the nominal clamping force became significantly larger and this is supported by handbook on screw joints, as it is mentioned that “it is not possible to give an exact value of the coefficient of friction due to the large number of factors that affect ”, this means that the impact on the clamping force will be large. / Det är vanligt förekommande att man använder sig av olika konstruktionsmaterial i kombination med varandra såsom betong, stål, trä och glas för att på så sätt kunna optimera byggnader. Syftet med detta är att minska vikt och öka belastningskapacitet, men det underlättar även montaget och minskar byggtiden. Pelarfötter av stål förankrade i betongfundament är ett exempel på en kombination av samverkansknutpunkter mellan stål och betongelement. I denna rapport studeras friktionen mellan underkant fotplatta och undergjutning, som är en funktion av pelarens normalkraft. Även friktionen som uppstår mellan fyrkantsbrickan och fotplattan kommer att undersökas som ett resultat av åtdragningsmomentet. Arbetet har lagt stor fokus på att diskutera för- och nackdelar med de olika metoderna för tvärkraftsupptagning i pelarfötter. Avgränsningar har gjorts, pelarens infästning till fotplåten har inte beaktats i denna rapport, eftersom detta är beroende av vilket pelartvärsnitt som är valt och måste kontrolleras för det specifika fallet. För att komma fram till resultaten utfördes en fördjupad litteraturstudie för att samla ihop information om de olika frågeställningarna och en beräkningsmodell i Excel skapades. Beräkningsmodellen användes för att kontrollera hur stor den dimensionerande bärförmågan är för tvärkraftsupptagning i en pelarfot, men kontrollerna görs endast för icke förspända förband. Detta eftersom förspända förband även har andra faktorer som påverkar tvärkraftskapaciteten, utanför arbetets syfte och frågeställning. Excel-modellen går ut på att ta fram resultaten ur beräkning med nominell spännkraft och jämföra den med spännkraft beräknad med åtdragningsmoment. Resultaten redovisas i form av grafer och tabeller, där man kan läsa av skillnaden i den dimensionerande bärförmågan för tvärkraftupptagning i icke förspända förband vid nominell spännkraft och spännkraft beräknad med åtdragningsmoment. Rapporten visar en tydlig skillnad i resultat, där den nominella spännkraften blev betydligt större och detta stöds av handbok om skruvförband, då det nämns att “det är inte möjligt att ge ett exakt värde på friktionskoefficienten på grund av det stora antalet faktorer som påverkar”, detta medför att inverkan på klämkraften blir stor.

Introdução: Modelos experimentais em suíno são essenciais para pesquisa e treinamento em transplante de fígado. No entanto, este animal apresenta instabilidade hemodinâmica grave durante a fase anepática, exigindo um curto período anepático (não apropriado para fins de treinamento) ou o uso de circulação extracorpórea (que está associado a significativas complicações intra-operatórias). Além disso, a maioria dos modelos em suíno é alogênico, o que não é nem eticamente nem economicamente adequado para treinamento cirúrgico. Objetivo: Desenvolver e testar um modelo de autotransplante hepático em suínos sem o uso de circulação extracorpórea. Métodos: Onze porcos da raça Sus domesticus foram submetidos a cirurgia simulada (SHAM; n = 3) ou autotransplante de fígado (grupo experimental (GE); n = 8) sem o uso de circulação extracorpórea. Após a realização de uma incisão em \"J\", o hilo hepático foi inteiramente dissecado abaixo do nível da artéria gastroduodenal e o fígado completamente mobilizado. A aorta supracelíaca foi então dissecada através do pilar esquerdo do diafragma. Nenhuma outra etapa foi realizada no grupo SHAM. No GE, a partir de então, procedeu-se o autotransplante ortotópico de fígado empregando-se a técnica convencional com duas anastomoses de veia cava, semelhante à técnica clássica utilizada na prática clínica. Durante a fase anepática, foi utilizando o clampeamento da aorta supracelíaca a fim de manter a estabilidade hemodinâmica e evitar o uso do by-pass. Os animais foram submetidos a eutanásia 1h após o término do procedimento cirúrgico. Parâmetros hemodinâmicos e exames laboratoriais foram sistematicamente coletados em 4 tempos distintos: basal, pré-reperfusão, 5min após reperfusão e ao término do experimento. Foi realizada a análise histopatológica do enxerto após a reperfusão. A análise estatística foi feita comparando amostras relacionadas, no GE, e duas amostras independentes, entre os grupos. Resultados: Empregando a técnica por nós padronizada, obteve-se 100% de sobrevida dos animais, todos estáveis hemodinamicamente. Os tempos médios de observação pós-reperfusão e anepático foram de 136±12,50min e 47,88±8,03min, respectivamente. Não houve diferença estatística na pressão arterial média (PAM) entre o início e término do experimento no GE, nem entre os grupos durante a fase anepática. Ao término do experimento, a PAM foi significantemente maior no grupo SHAM quando comparado ao GE. A análise comparativa dos exames laboratoriais entre os grupos demonstrou que o pH, o bicarbonato e o base excess foram significantemente inferiores no GE 5min após a reperfusão e ao término do experimento. O lactato mostrou-se ser significantemente inferior ao término do experimento no grupo SHAM. Conclusão: De acordo com os métodos utilizados no presente estudo, desenvolveu-se um modelo de autotransplante de fígado em suínos sem a utilização de mecanismo de circulação extracorpórea. Para tanto, utilizou-se o clampeamento da aorta supracelíaca durante o período anepático. O modelo proposto é factível por cirurgiões em treinamento e com baixa mortalidade / Background: Experimental swine models have been essential for liver transplantation research and training. However, it experiences severe hemodynamic instability during the anhepatic phase, requiring either a short anhepatic phase (not appropriate for training purposes) or an extracorporeal circulation (which is linked to significant intraoperative complications). Furthermore, most of swine models are allograft ones, which is neither ethically nor financially suitable for surgical training. Objective: To develop and test a liver autotransplantation model in pig without venovenous bypass. Methods: Eleven Sus domesticus pigs underwent either sham surgery (SHAM group; n=3) or liver autotransplantation without venovenous bypass (experimental group (GE); n=8) by resident or fellow from Digestive Organs Transplant Division. After performing a rightsided J-shaped incision, hepatic hilum was entirely dissected under the level of the gastroduodenal artery and liver completely mobilized. Supraceliac aorta was then dissected through the diaphragm\'s left crus. No further step was performed in SHAM group. In the GE, thereafter, a liver autotransplantation was performed applying conventional bicaval anastomosis technique, similar to the classic technique used in clinical setting. During anhepatic phase, supraceliac aorta cross-clamping maneuver was carried out to sustain hemodynamic stability and avoid venovenous bypass. Animals underwent euthanasia one hour after the end of surgical procedure. Hemodynamic variables and blood samples were systematically collected at 4 different times: baseline, pre-reperfusion, 5min after reperfusion and at the end of experiment. Histological analysis of the graft was performed after reperfusion. Statistical analysis was accomplished comparing related samples in the GE and two independent samples between groups. Results: Applying the technique standardized by us, 100% survival was accomplished, all the animals hemodynamically stable. The mean post-reperfusion observation and anhepatic phase times were 136 ± 12.50 min and 48.38 ± 7.80 min, respectively. There was no statistical difference in mean arterial pressure (MAP) between baseline and the end of the experiment time in the GE, nor between the groups during the anhepatic phase. At the end of the experiment, MAP was significantly higher in the SHAM group compared to the experiment group. Blood samples statistical analysis between groups showed that pH, bicarbonate and base excess were significantly lower at 5 min post-reperfusion time and at the end of the experiment in the GE. The lactate was shown to be significantly lower in the SHAM group at the end of the experiment. Conclusion: According to the methods applied in the present study, a model of liver autotransplantation in swine was developed without the use of an extracorporeal circulation mechanism. For this purpose, supraceliac aortic cross-clamping maneuver was carried out during the anhepatic phase. The advocated model is feasible for training purpose with low mortality

Cette thèse présente une nouvelle extension d’onduleur multiniveaux, appelé ‘Multi Neutral Point’ (MNP). Cet onduleur est déduit des topologies des structures multiniveaux ‘Neutral Point Clamped’ (NPC) et ‘Multi Point Clamped’ (MPC). Les intérêts de cette extension sont: l’absence de diodes de bouclage, la possibilité de disposer de tous les nombres de niveaux, pairs et impairs et possibilité de fonctionner en mode dégradé. Nous avons élaboré une commande rapprochée simple des transistors de puissance, d’abord pour un MNP à 3 niveaux, ensuite pour les nombres de niveaux supérieurs. Nous avons comparé les pertes de puissance d’un onduleur MNP et d’un onduleur NPC. Les pertes de l’onduleur MNP sont largement inférieures à celles de l’onduleur NPC. Dans l’optique de contrôler en courant l’onduleur MNP, une stratégie nouvelle par régulateur PID d’ordre fractionnaire est également développée. Ce contrôle permet de diminuer nettement les erreurs d’amplitude et de phase entre le courant de référence et le courant de charge. La méthode nécessite le réglage des différents paramètres de contrôle en utilisant le principe d'optimisation ‘’multi-objectif’’. Le fonctionnement de l’ensemble convertisseur-contrôle-commande est enfin largement validé par simulation et par expérimentation / This thesis presents a new extension of multilevel inverters, called 'Multi Neutral Point' (MNP). This topology is deduced from Neutral Point Clamped (NPC) and Multi Point Clamped (MPC) structures. The advantage of this extension is twofold: the absence of clamping diodes and the possibility of operating on all the numbers of levels (even and odd). We have developed a simple command; we first present the command strategy for a three levels MNP, then for a five level MNP. We have compared the power losses in the power switches of an MNP and an NPC. The power losses for an MNP are far below those of the NPC inverter. For this inverter model, we have chosen a robust current control by a fractional PID controller. This control strategy can sharply reduce the amplitude and the phase errors between the reference current and the load one. This method requires the setting of various control parameters thanks to the principle of ‘’multiobjective optimization.'' In the end the set of converter-control command is validated by simulation and experimentation; the simulated and experimental results match very well

Two failure mechanisms in a double lap joint are investigated. Analytical models of net-section and gross-section failure modes are proposed to describe these mechanisms. The effects of lamping force, interference fit, maximum axial load and WDCP on fatigue performance of the joint are included in the models. The effect of WDCP is assumed to give a reduction in friction coefficient. Three types of stress reduction factors are proposed in the net-section failure model to account for these parameters. The stress reduction factors modify stress range that is used in crack growth calculation. If there are no effects of these parameters, the stress reduction factors are equal to one. Two types of fretting stress are introduced in gross-section failure model to describe either sliding contact or incipient sliding contact on faying surface. The fretting stress is combined with body stress to modify stress range. The net-section failure model predicts that fatigue life is increasing as interference fit, clamping force and friction coefficient increase. The gross-section failure model predicts that fatigue life is decreasing as clamping force and friction coefficient increase. Both models predict that fatigue life is decreasing as maximum axial load increases. Transition of the failure mode occurs earlier as friction coefficient and interference fit increase, while it is delayed as maximum axial load increases. A transition parameter is proposed to establish a relationship between the four main parameters. The transition parameter is expressed in a polynomial equation. It gives an optimum combination of the four main parameters in order to achieve relatively higher fatigue life by having gross-section failure mode. Finite element analysis and fatigue testing are performed to validate the models. The finite element and the analytical models show that stress concentration factor at the edge of the hole is decreasing as clamping force increases. The rate of decrease of stress concentration factor is increasing as friction coefficient increases. While stress concentration factor on the faying surface is increasing as clamping force and friction coefficient increase. Fatigue testing reveals that the fatigue life of the joint is in good agreement with the predicted fatigue life of the proposed models.