Indiana University-Purdue University Indianapolis (IUPUI) / Belt-drives are used in many applications such as industrial machines, washing ‎machines, and accessory drives for automobiles and other vehicles. Multibody dynamics/finite ‎element numerical models have become an effective way to predict the dynamic response of ‎belt-drives. In this thesis, a high fidelity numerical model was built using a multibody ‎dynamics/finite element code to simulate a belt-drive. The belt-drive transmits power from a ‎turbine of a Rankin cycle (that uses the exhaust waste heat of the internal combustion engine as ‎heat source) to the crank shaft of the engine. The code uses a time-accurate explicit numerical ‎integration technique to solve the multibody dynamics differential equations. The belt was ‎modeled using three-node beam elements to account for the belt axial and bending ‎stiffness/damping, while the pulleys, shafts and tensioner body were modeled as rigid bodies. ‎The penalty technique was used to model normal contact between the belt and the pulleys. An ‎asperity-based friction model was used to approximate Coulomb friction between the belt and ‎the pulleys. The dynamic response predicted using the model was validated by comparing it to ‎experimental results supplied by Cummins Inc. A parameter sensitivity study was performed to ‎evaluate the change in response due to change in various belt-drive parameters. A fatigue ‎model was developed to predict the belt fatigue life using output from the explicit finite ‎element code including normal and tangential forces between the belt and the pulleys and belt ‎tension. The belt fatigue life was evaluated for alternative belt-drive configurations in order to ‎find the configuration with the longest life.‎

駆動プーリ上の回転変動が金属Vベルトを介して従動プーリへと伝達される際には，摩擦力が飽和状態に近づくにつれ，従動プーリへ伝達される回転変動は減衰する．この回転変動の変化に着目して滑り状態を指標化した． / When fluctuations in the speed of rotation of the drive pulley are transmitted to the driven pulley via the metal V-belt, the transmitted fluctuations become attenuated as friction force approaches a state of saturation. The research discussed in this paper focused on these fluctuations in the speed of rotation and developed an index for the slip state between the belt and the pulleys. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

No description available.

The selection of the bulk power transmission technology in offshore wind farms is strongly related to the wind farm size and its distance to shore. Several alternatives can be evaluated depending on the rated power of the offshore wind farm, the transmission losses and the investment cost for constructing the transmission system. However, when is necessary to connect larger and more distant offshore wind farms; the best technological solution tends to the transmission system based on highvoltage and direct-current with line commutated converters (LCC-HVdc). This dissertation proposes the use of diode-based rectifers as a technical alternative to replace the thyristor-based rectifers in an LCC-HVdc link with unidirectional power flow. This alternative shows advantages with regard to lower conduction losses, lower installation costs and higher reliability. Nonetheless, as a counterpart the offshore ac-grid control performed by the thyristor-based HVdc rectifer is no longer available. This lack of control is compensated by using new control strategies over an offshore wind farm composed by wind turbines with permanent-magnet generators and fully-rated converters. The control strategies have been based mainly on the ability of the wind turbine grid-side converter to perform the control of the offshore ac-grid voltage and frequency. The performance has been evaluated by using PSCAD. Wherein, the most common grid disturbances have been used to demonstrate the fault-ride-through capability as well as the adequate steady state and transient response. / Rodríguez D'derlée, JJ. (2013). Control strategies for offshore wind farms based on PMSG wind turbines and HVdc connection with uncontrolled rectifier [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34510

The forecasting of Eskom transmission electrical network demands is a complex task. The lack of historical data on some of the network components complicates this task even further. In this dissertation a model is suggested which will address all the requirements of the transmission system expansion engineers in terms of future loads and market trends. Suggestions are made with respect to ways of overcoming the lack of historical data, especially on the point loads, which is a key factor in modelling the electrical networks. A brief overview of the transmission electrical network layout is included to provide a better understanding of what is required from such a forecast. Lastly, some theory on multiple regression, neural networks and qualitative forecasting techniques is included, which will be of value for further model developments. / Computing / M. Sc. (Operations Research)

Water distribution systems, electrical power transmission systems, and other civil infrastructure systems are essential to the smooth and stable operation of regional economies. Since the functions of such infrastructure systems often are inter-dependent, the systems sometimes suffer unforeseen functional disruptions. For example, the widespread power outage due to the malfunction of an electric power substation, which occurred in the northeastern United States and parts of Canada in August 2003, interrupted the supply of water to several communities, leading to inconvenience and economic losses. The sequence of such failures leading to widespread outages is referred to as a cascading failure. Assessing the vulnerability of communities to natural and man-made hazards should take the possibility of such failures into account. In seismic risk assessment, the risk to a facility or a building is generally specified by one of two basic approaches: through a probabilistic seismic hazard analysis (PSHA) and a stipulated scenario earthquake (SE). A PSHA has been widely accepted as a basis for design and evaluation of individual buildings, bridges and other facilities. However, the vulnerability assessment of distributed infrastructure facilities requires a model of spatial intensity of earthquake ground motion. Since the ground motions from a PSHA represent an aggregation of earthquakes, they cannot model the spatial variation in intensity. On the other hand, when a SE-based analysis is used, the spatial correlation of seismic intensities must be properly evaluated. This study presents a new methodology for evaluating the functionality of an infrastructure system situated in a region of moderate seismicity considering functional interactions among the systems in the network, cascading failure, and spatial correlation of ground motion. The functional interactions among facilities in the systems are modeled by fault trees, and the impact of cascading failures on serviceability of a networked system is computed by a procedure from the field of operations research known as a shortest path algorithm. The upper and lower bound solutions to spatial correlation of seismic intensities over a region are obtained.

Die Arbeit befasst sich mit einem neuen textilverstärkten Zugmittel mit formschlüssiger Krafteinleitung. Im Grundlagenteil werden Aufbau, Eigenschaften und Dimensionierungsgrundlagen von Rollenketten und Zahnriemenantrieben erörtert, sowie textile und elastomere Werkstoffe betrachtet. Aus den Betrachtungen zum Stand der Technik, der Maschenware mit hochfesten Filamentgarnen und deren polymeren Beschichtungen wird der Entwicklungsansatz abgeleitet. Mit Hilfe eines Spezialkettenwirkverfahrens werden die textilen Zugträger als Recht/Links-Maschenware hergestellt. Das besondere daran ist die teilungsgenaue Einbindung der Bolzen in die Maschenstruktur bei der Fertigung. Eine anschließende elastomere Beschichtung verbessert die mechanischen Eigenschaften erheblich und fixiert die Bolzen axial. Dabei werden reaktive Polyurethane im Gießverfahren und thermoplastische Elastomere im Spritzgießverfahren eingesetzt. Drei ausgewählte textile Bindungen mit verschiedenen Beschichtungen wurden statisch und dynamisch, anhand von Proben und endlos verbundenen Zugmitteln, ausführlich untersucht. Die daraus abgeleiteten Bauteil-Wöhlerlinien und Leistungsdiagramme bilden die Grundlage zur Auslegung der textilverstärkten Zugmittel für Anwendungen im Maschinenbau. / The dissertation deals with a new textile reinforced with form-closed force application. The basis of structure, properties and sizing basics of roller chain drives and belt drives are discussed and considered textile and elastomeric materials. From consideration of the prior art, the knitted fabric with high tenacity filament of polymeric coatings and their development approach is derived. Using a special knitting process, the textile chain tension members are produced as a right / left-knit fabric. The special thing about it is the exact distribution of involvement of the pins in the mesh structure during manufacturing. Subsequent elastomeric coating significantly improves the mechanical properties and fixes the bolt axially. These reactive polyurethanes by casting and thermoplastic elastomers are used in injection molding. Three selected textile bonds with different coatings were statically and dynamically examine in detail the basis of samples and associated endless traction means. The derived component S/N curves and performance charts are the basis for the design of textile-reinforced tension means for applications in mechanical engineering.

Στην παρούσα διπλωματική εργασία αναζητείται ένας αυτόματος τρόπος ελέγχου, του επιπέδου της εκπεμπόμενης ισχύος προς το εσωτερικό του ανθρωπίνου σώματος. Εκεί μέσα βρίσκεται κάποιο ενεργό ιατροτεχνολογικό εμφύτευμα. Αυτό το εμφύτευμα στην περίπτωση της εργασίας αυτής, ήταν μία κάψουλα που καταγράφει με φωτογραφίες το γαστρεντερικό σύστημα καθώς οι περισταλτικές κινήσεις του εντέρου προωθούν την κάψουλα προς την έξοδο. Οι φωτογραφίες μεταδίδονται προς καταγραφικό που βρίσκεται έξω από το σώμα με ασύρματο τρόπο. Όπως καταλαβαίνουμε η κάψουλα αυτή αλλά και οποιοδήποτε άλλο ενεργό ιατροτεχνολογικό εμφύτευμα έχει ενεργειακές ανάγκες για την απρόσκοπτη λειτουργία του. Αυτές οι ανάγκες καλύπτονται με ασύρματη μετάδοση ενέργειας. Οι καινοτομίες που υπάρχουν σ’ αυτήν την εργασία είναι οι εξής: 1. Όσον αφορά το εξωτερικό τροφοδοτικό χρησιμοποιήθηκε ένας αντιστροφέας συντονισμού κλάσης D 2. Το πιο καινοτόμο στοιχείο είναι η δημιουργία κλειστού βρόχου ελέγχου μεταξύ του εξωτερικού τροφοδοτικού και του εμφυτεύματος ώστε αυτό να λαμβάνει την ποσότητα της ενέργειας που χρειάζεται κάθε στιγμή. 3. Επίσης σημαντικό είναι ότι η μετάδοση πληροφορίας από το εμφύτευμα προς τα έξω δεν γίνεται με μία ξεχωριστή συχνότητα αλλά χρησιμοποιώντας αρχές παθητικής τηλεμετρίας. Η εργασία αυτή πέρα από την θεωρητική προσέγγιση υλοποιήθηκε και πρακτικά σε εργαστήρια του πανεπιστημίου KUL (ESAT MICAS) στο Βέλγιο. Ο Βρόγχος ελέγχου λειτούργησε και πολλά συμπεράσματα εξάχθηκαν για περεταίρω βελτιώσεις. Η δομή του παρόντος πονήματος είναι ως εξής: Μετά την αρχική εισαγωγή το δεύτερο κεφάλαιο μας δίνει ένα θεωρητικό υπόβαθρο για την ασύρματη μετάδοση ενέργειας. Στη συνέχεια τα διάφορα μέρη των ηλεκτρονικών κυκλωμάτων που αναπτύχθηκαν αναλύονται διεξοδικά στα επόμενα κεφάλαια. Τέλος καταγράφονται τα συμπεράσματα και προτείνονται πιθανές βελτιώσεις για το μέλλον. / In this diploma thesis a way to have an automated control of the transmitted power level into the human body is sought. Inside the body there is an active medical implant. This implant in the case of this project is a swallowable capsule-camera that captures images along the GI tract as the peristaltic propulusion of the bowel push the capsule towards the exit. The photos are transmitted wirelessly to a special recording device that is located out of the body. It is obvious that not only this capsule but any other active medical implant needs energy to operate uninterrupted. This necessary energy is given through inductive power transmission. Innovations in this project are these: 1. The power supply outside the body is realized with Class-D resonant inverter topology. 2. The most innovative is the effectuation of closed control loop between the outer power supply and the implant in order to be received from the implant the exact amount of power that is needed every instant. 3. Also significant is that the transmission of data from the implant to the controlled power supply is not be done with a different carrier but using passive telemetry principles. Beyond the theoretic approximation that was made for this project, it was also realized in KUL university laboratories (ESAT MICAS) in Belgium. The closed control loop functioned properly and conclusions for further development are inferred. The structure of this diploma thesis is as follows: After the starting introduction the theoretic background for wireless inductive power transmission is given in chapter 2. Following, the different parts of the electronic circuits that were developed are analyzed comprehensively in next chapters. Finally conclusions are registered and future improvements are proposed.

Devido à alta demanda energética e a grande complexidade dos atuais Sistemas Elétricos de Potência (SEPs), altamente interligados, torna-se cada vez mais importante para o operador do sistema, conhecer o estado atual do SEP. Além disso, dispor de ferramentas que permitam prever situações que venham a comprometer o bom funcionamento do sistema. Como um bom funcionamento, enquadra-se a continuidade do suprimento e perfis adequados de tensão elétrica, mesmo após a ocorrência de perturbações, o que pode ser afetado pelo fenômeno de instabilidade de tensão (ou colapso de tensão). Por isso, o objetivo deste trabalho é desenvolver uma metodologia de análise do colapso de tensão em tempo real considerando limites de potência ativa e reativa de geradores, a qual visa auxiliar o operador do sistema. Esta metodologia é dividida em cinco etapas. A primeira delas consiste em uma análise do caso base dos SEPs considerados, utilizando um algoritmo que permite estimar a margem de estabilidade de tensão do sistema, considerando os limites de potência ativa e reativa dos geradores. Esta primeira etapa utiliza a metodologia de fluxo de potência continuado, utilizando a carga e a tensão como parâmetros de continuação. A segunda etapa apresenta uma análise de contingências rápida considerando contingências simples de linhas de transmissão, seguindo o critério N-1. Nesta segunda etapa, foi utilizado o método de Look Ahead Modificado. A terceira etapa é uma análise apurada das contingências mais críticas, identificadas na etapa dois, a fim de verificar a presença de bifurcações induzidas por limites. Nesta terceira etapa, também se utilizou a metodologia de fluxo de potência continuado. Na quarta etapa, são aplicados todos os controle disponíveis no sistema, como inserção de banco de capacitores e ajuste do TAP dos transformadores, a fim de verificar qual seria o impacto dessas ações de controle no limite de operação segura do sistema, utilizando o método de Look Ahead Modificado. Essas quatro etapas possibilitam uma análise da estabilidade de tensão do sistema em tempo real. Por fim, é proposta uma quinta etapa de análise de contingências Offline, sendo uma análise mais precisa de todas as contingências, utilizando a metodologia de fluxo de potência continuado. Os SEPs analisados nesta dissertação foram o sistema de cinco barras Stagg, o sistema de quatorze barras padrão do Institute of Electrical and Electronics Engineers (IEEE) e o sistema de trinta barras padrão IEEE. / Due to the high energy demand and the high complexity of today's interconnected Electrical Power Systems (SEPs), it is becoming increasingly important for the system operator to know the current state of the SEP. In addition, have the tools to predict situations that may compromise the smooth operation of the system. As a good operation, the continuity of the supply and adequate voltage profiles are correct, even after the occurrence of disturbances, which can be affected by the phenomenon of voltage instability (or voltage collapse). Therefore, the objective of this work is to develop a methodology for the analysis of voltage collapse in real time considering the limits of active and reactive power of generators, which aims to assist the system operator. This methodology is divided into five steps. The first one consists of an analysis of the base case of the considered SEPs, using an algorithm that allows estimating the voltage stability margin of the system considering the limits of active and reactive power of the generators. This first step uses the continuous power flow methodology, using load and voltage as continuation parameters. The second stage presents a fast contingency analysis considering simple contingencies of transmission lines, following the criterion N-1. In this second step, the Modified Look Ahead method was used. The third step is an accurate analysis of the most critical contingencies, identified in step two, in order to verify the presence of limits-induced bifurcations. In this third step, we also used the continuous power flow methodology. In the fourth step, all available system controls, such as capacitor bank insertion and TAP adjustment of the transformers, are applied in order to verify the impact of these control actions on the safe operation limit of the system, using the Look Ahead Modified. These four steps enable a real-time analysis of the voltage stability of the system. Finally, a fifth stage of analysis of Offline contingencies is proposed, and a more precise analysis of all the contingencies using the methodology of continuous power flow is proposed. The SEPs analyzed in this dissertation were the Stagg five-bar system, the Institute of Electrical and Electronics Engineers (IEEE) standard fourteen bar system and the IEEE standard thirty-bar system.

The forecasting of Eskom transmission electrical network demands is a complex task. The lack of historical data on some of the network components complicates this task even further. In this dissertation a model is suggested which will address all the requirements of the transmission system expansion engineers in terms of future loads and market trends. Suggestions are made with respect to ways of overcoming the lack of historical data, especially on the point loads, which is a key factor in modelling the electrical networks. A brief overview of the transmission electrical network layout is included to provide a better understanding of what is required from such a forecast. Lastly, some theory on multiple regression, neural networks and qualitative forecasting techniques is included, which will be of value for further model developments. / Computing / M. Sc. (Operations Research)