After decades of routine operation, the hydropower industry faces new challenges. Large-scale integration of other renewable sources of generation in the power system accentuates the role of hydropower as a regulating resource. At the same time, an extensive reinvestment programme has commenced where many old components and apparatus are being refurbished or replaced. Introduction of new technical solutions in existing power plants requires good systems knowledge and careful consideration. Important tools for research, development and analysis are suitable mathematical models, numerical simulation methods and laboratory equipment. This doctoral thesis is devoted to studies of the electromechanical interaction between hydropower units and the power system. The work encompasses development of mathematical models, empirical methods for system identification, as well as numerical and experimental studies of hydropower generator and power system interaction. Two generator modelling approaches are explored: one based on electromagnetic field theory and the finite element method, and one based on equivalent electric circuits. The finite element model is adapted for single-machine infinite-bus simulations by the addition of a network equivalent, a mechanical equation and a voltage regulator. Transient simulations using both finite element and equivalent circuit models indicate that the finite element model typically overestimates the synchronising and damping properties of the machine. Identification of model parameters is performed both numerically and experimentally. A complete set of equivalent circuit parameters is identified through finite element simulation of standard empirical test methods. Another machine model is identified experimentally through frequency response analysis. An extension to the well-known standstill frequency response (SSFR) test is explored, which involves measurement and analysis of damper winding quantities. The test is found to produce models that are suitable for transient power system analysis. Both experimental and numerical studies show that low resistance of the damper winding interpole connections are vital to achieve high attenuation of rotor angle oscillations. Hydropower generator and power system interaction is also studied experimentally during a full-scale startup test of the Nordic power system, where multiple synchronised data acquisition devices are used for measurement of both electrical and mechanical quantities. Observation of a subsynchronous power oscillation leads to an investigation of the torsional stability of hydropower units. In accordance with previous studies, hydropower units are found to be mechanically resilient to subsynchronous power oscillations. However, like any other generating unit, they are dependent on sufficient electrical and mechanical damping. Two experimentally obtained hydraulic damping coefficients for a large Francis turbine runner are presented in the thesis.

The goal of this project was to evaluate the viability of a mass-spring-damper based model for modeling of biological tissue. A method for automatically generating such a model from data taken from 3D medical imaging equipment including both the generation of point masses and an algorithm for generating the spring-damper links between these points is presented. Furthermore, an implementation of a simulation of this model running in real-time by utilizing the parallel computational power of modern GPU hardware through OpenCL is described. This implementation uses the fourth order Runge-Kutta method to improve stability over similar implementations. The difficulty of maintaining stability while still providing rigidness to the simulated tissue is thoroughly discussed. Several observations on the influence of the structure of the model on the consistency of the simulated tissue are also presented. This implementation also includes two manipulation tools, a move tool and a cut tool for interaction with the simulation. From the results, it is clear that the mass-springdamper model is a viable model that is possible to simulate in real-time on modern but commoditized hardware. With further development, this can be of great benefit to areas such as medical visualization and surgical simulation. / Målet med detta projekt var att utvärdera huruvida en modell baserad på massa-fjäderdämpare är meningsfull för att modellera biologisk vävnad. En metod för att automatiskt generera en sådan modell utifrån data tagen från medicinsk 3D-skanningsutrustning presenteras. Denna metod inkluderar både generering av punktmassor samt en algoritm för generering av länkar mellan dessa. Vidare beskrivs en implementation av en simulering av denna modell som körs i realtid genom att utnyttja den parallella beräkningskraften hos modern GPU-hårdvara via OpenCL. Denna implementation använder sig av fjärde ordningens Runge-Kutta-metod för förbättrad stabilitet jämfört med liknande implementationer. Svårigheten att bibehålla stabiliteten samtidigt som den simulerade vävnaden ges tillräcklig styvhet diskuteras genomgående. Flera observationer om modellstrukturens inverkan på den simulerade vävnadens konsistens presenteras också. Denna implementation inkluderar två manipuleringsverktyg, ett flytta-verktyg och ett skärverktyg för att interagera med simuleringen. Resultaten visar tydligt att en modell baserad på massa-fjäder-dämpare är en rimlig modell som är möjlig att simulera i realtid på modern men lättillgänglig hårdvara. Med vidareutveckling kan detta bli betydelsefullt för områden så som medicinsk bildvetenskap och kirurgisk simulering.

Abstract: Highway bridges have great values in a country because in case of any natural disaster they may serve as lines to save people’s lives. Being vulnerable under significant seismic loads, different methods can be considered to design resistant highway bridges and rehabilitate the existing ones. In this study, base isolation has been considered as one efficient method in this regards which in some cases reduces significantly the seismic load effects on the structure. By reducing the ductility demand on the structure without a notable increase of strength, the structure is designed to remain elastic under seismic loads. The problem associated with the isolated bridges, especially with elastomeric bearings, can be their excessive displacements under service and seismic loads. This can defy the purpose of using elastomeric bearings for small to medium span typical bridges where expansion joints and clearances may result in significant increase of initial and maintenance cost. Thus, supplementing the structure with dampers with some stiffness can serve as a solution which in turn, however, may increase the structure base shear. The main objective of this thesis is to provide a simplified method for the evaluation of optimal parameters for dampers in isolated bridges. Firstly, performing a parametric study, some directions are given for the use of simple isolation devices such as elastomeric bearings to rehabilitate existing bridges with high importance. Parameters like geometry of the bridge, code provisions and the type of soil on which the structure is constructed have been introduced to a typical two span bridge. It is concluded that the stiffness of the substructure, soil type and special provisions in the code can determine the employment of base isolation for retrofitting of bridges. Secondly, based on the elastic response coefficient of isolated bridges, a simplified design method of dampers for seismically isolated regular highway bridges has been presented in this study. By setting objectives for reduction of displacement and base shear variation, the required stiffness and damping of a hysteretic damper can be determined. By modelling a typical two span bridge, numerical analyses have followed to verify the effectiveness of the method. The method has been used to identify equivalent linear parameters and subsequently, nonlinear parameters of hysteretic damper for various designated scenarios of displacement and base shear requirements. Comparison of the results of the nonlinear numerical model without damper and with damper has shown that the method is sufficiently accurate. Finally, an innovative and simple hysteretic steel damper was designed. Five specimens were fabricated from two steel grades and were tested accompanying a real scale elastomeric isolator in the structural laboratory of the Université de Sherbrooke. The test procedure was to characterize the specimens by cyclic displacement controlled tests and subsequently to test them by real-time dynamic substructuring (RTDS) method. The test results were then used to establish a numerical model of the system which went through nonlinear time history analyses under several earthquakes. The outcome of the experimental and numerical showed an acceptable conformity with the simplified method. / Résumé: Les ponts routiers ont une grande valeur dans un pays parce qu’en cas de catastrophe naturelle, ils peuvent servir comme des lignes pour sauver des vies. Étant vulnérable sous des charges sismiques importantes, on peut considérer différentes méthodes pour concevoir des ponts routiers résistants et également pour réhabiliter des ponts existants. Dans cette étude, l'isolation de la base a été considérée comme une méthode efficace qui peut réduire significativement les effets des charges sismiques sur la structure. En réduisant la demande en ductilité sur la structure sans une augmentation notable de force, la structure est conçue pour rester élastique sous des charges sismiques. Le problème associé aux ponts isolés, particulièrement avec des appuis en élastomère, peut être leurs déplacements excessifs sous les charges de service et de séisme. Ceci peut défier l’objectif d'utiliser des appuis en élastomère pour les ponts typiques de petite portée où les joints de dilatation et les dégagements peuvent aboutir à une augmentation significative des frais d'exploitation et de maintenance. Ainsi, supplémenter la structure avec des amortisseurs d’une certaine rigidité peut servir de solution, ce qui peut cependant augmenter l’effort tranchant transmis à la sous-structure. Cette étude a pour but de fournir une méthode simplifiée afin d’évaluer les paramètres optimaux des amortisseurs dans les ponts isolés. Dans cette thèse, premièrement, basé sur une étude paramétrique, quelques directions sont données pour l'utilisation de dispositifs d'isolation simples, dont les appuis en élastomère, afin de réhabiliter des ponts existant avec une haute importance. Les paramètres comme la géométrie du pont, les clauses des normes et le type de sol sur lequel la structure est construite ont été appliqués sur un pont typique de deux portées. Il est conclu que les paramètres mentionnés peuvent déterminer l'emploi d'isolement de la base des ponts routiers. À la deuxième phase, basé sur le coefficient de réponse élastique des ponts isolés, une méthode de conception simplifiée d’amortisseur pour des ponts routiers réguliers isolés à la base a été présentée dans cette étude. En sélectionnant des objectifs pour la réduction du déplacement et la variation de l’effort tranchant, la rigidité et l'amortissement exigés d'un amortisseur hystérétique peuvent être déterminés. L’étude s’est poursuivie par une modélisation numérique d’un pont à deux portées pour vérifier l'efficacité de la méthode. Pour un modèle numérique d'un pont isolé typique, la méthode a été utilisée pour identifier des paramètres linéaires équivalents pour un certain déplacement et effort tranchant désigné. Par la suite, assumant un amortisseur de type hystérétique, les paramètres non linéaires de l’amortisseur ont été calculés et utilisés. La comparaison des résultats du modèle numérique sans amortisseur et avec l'amortisseur a démontré que la méthode proposée est suffisamment précise. Par la suite, un nouvel amortisseur hystérétique simple en acier a été conçu. Cinq spécimens ont été fabriqués de deux différents grades d’acier et ont été testés en combinaison avec un isolateur à l’échelle réelle dans le laboratoire de structures de l'Université de Sherbrooke. La procédure comprenait la caractérisation des spécimens par des tests cycliques en contrôle de déplacement et par la suite la réalisation d’essais par la méthode de sous-structuration dynamique en temps réel. Les résultats des essais ont été utilisés pour établir un modèle numérique du système qui a subi des analyses temporelles non linéaires sous plusieurs séismes. Le résultat des essais expérimentaux et numériques montrent une conformité acceptable avec la méthode simplifiée.

This master thesis deals with the dynamic analysis of a footbridge. Computational model of the footbridge was created using ANSYS software. The model was subjected to dynamic wind load in longitudal and lateral direction. Furthermore pedestrian load in lateral direction was analyzed. Afterwards, due to unsatisfactory response to the pedestrian laod, a tuned mass damper was introduced to reduce the vibration. This lead to decrease in the vibration to a satisfactory levels, as is shown in the analyses of the model.

Tato diplomová práce byla psána při studentské zahraniční stáži, pod záštitou Evropské Unie – program „ERASMUS Student Mobility for Placement“. Stáž byla absolvována mezi prosincem 2010 a květnem 2011 ve společnosti a.d.Tramontana, mající sídlo v Palau de Santa Eulália, Španělsko. Pro kompletní návrh podvozku a odpružení jakéhokoli vozidla je nezbytná znalost mnoha technických disciplín. Tato diplomová práce se zabývá dvěma z nich – odpružení a řízení. Nejprve je rozebrána teorie, na kterou se může navázat v praktické části práce. Velká pozornost byla věnována srozumitelnosti textu a názornosti obrázků, bez zbytečných detailů, avšak bez vynechání důležitého. Tuto práci je tedy možné užít jako prvního kroku před návrhem podvozku. V další části je popsáno, jak byla probraná teorie využita při návrhu řízení u skutečného vozu, přičemž největší pozornost je věnována Ackermannově teorii řízení a geometrii zabraňující samořízení při propružení. V závěrečných částech je pozornost věnována ukázce některých z každodenních činností v malosériové výrobě automobilů – jde o zjištění maximálně možného pohybu kola při propružení a proces výroby příčných trojúhelníkových ramen včetně návrhu jejich připevnění k šasi.

In zunehmendem Maße werden Kraftfahrzeuge mit Sensoren zur Erfassung des Fahrzeugniveaus, also der Lage des Fahrzeugs relativ zur Straßenoberfläche in Richtung der Fahrzeughochachse, ausgestattet. Informationen zum Fahrzeugniveau werden beispielsweise für die automatische Leuchtweitenregulierung für Gasentladungsscheinwerfer und Fahrwerkregelsysteme benötigt. Mit dem Ziel der Vermeidung wesentlicher Nachteile üblicher Seriensensoren mit Kugelgelenken wurde von der ZF Lemförder Fahrwerktechnik GmbH & Co. KG in Zusammenarbeit mit der Volkswagen AG und der Technischen Universität Dresden ein Fahrzeugniveausensor prototypisch in ein Gummi-Metall-Lager eines Fahrwerklenkers integriert. In diesem mechatronischen System wird mit anisotropen magnetoresistiven (AMR) Sensoren, welche in den Lagerkern integriert sind, die Richtung des Magnetfeldes eines auf der Innenseite der äußeren Lagerhülse angeordneten Perma¬nentmagnetrings gemessen. Ein spezielles Design von Mechanik und Magnetfeld erlaubt die Messung der Lagertorsion als Maß für den vertikalen Radweg des entsprechenden Rades weitgehend unabhängig von kardanischen und translatorischen Lagerverformungen. Diese Dissertation stellt eine Zusammenfassung wesentlicher Inhalte dieses Projektes dar. Einleitend wird die Eignung von Messgröße und Sensorprinzip für die Messung des Fahrzeugniveaus anhand der Anforderungen an Fahrzeugniveausensoren diskutiert und ein optimierter mechanischer Aufbau des Sensorlagers vorgestellt. Den wissenschaftlichen Schwerpunkt dieser Dissertation bildet das Design des Magnetfeldes des erforderlichen Permanentmagneten. Auf der Basis geeigneter Ansätze erfolgt unter Anwendung der Theorie magnetischer Felder die Herleitung eines Feldverlaufs, der ein Optimum hinsichtlich der Unempfindlichkeit gegenüber der sensorischen Erfassung störender Lagerverformungen, der erreichbaren Feldstärke am Sensor, der Signallinearität und der Herstellbarkeit des Permanentmagnetrings darstellt. Zu den weiteren Themen dieser Arbeit zählen die Erörterung der verwendeten Sensorelektronik einschließlich der wesentlichen Software¬algorithmen sowie die Diskussion der experimentell ermittelten Eigenschaften eines Prototyps des Sensorlagers und dessen Komponenten. / In motor vehicles, information on the position of the vehicle in direction of the vehicle height axis in relation to the road surface is increasingly provided by sensors. This positional information is required for the automatic headlight range control of gaseous discharge headlights and chassis control systems. In cooperation with Volkswagen AG and University of Technology Dresden, ZF Lemförder Fahrwerktechnik GmbH & Co. KG integrated a vehicle height sensor as a prototype in a rubber mount of an axle link with the aim of avoiding the disadvantages of standard sensors using ball joints. In this mechatronic system, the direction of the magnetic field of a permanent magnetic ring placed on the inside of the outer bearing case is measured by anisotropic magnetoresistive (AMR) sensors integrated in the centre of the bearing. The vertical movement of the relevant wheel is measured via the torsion of the rubber mount. The mechanics and the magnetic field were designed in order to get measurements that are not affected by rotational and linear rubber mount distortions. This thesis works summarizes the key points of this project. The reader will be first introduced to advantages and disadvantages of the measuring quantity and the sensor principle used for measuring the positioning of the vehicle concerning the requirements of vehicle height sensors. In addition, an optimized construction of the sensor rubber mount will be described. The main focus of this work is the design of the magnetic field of the required permanent magnet. While considering adequate approaches, the magnetic field of this magnet is formulated from the theory of magnetic fields. The presented magnetic field is an optimisation in terms of the insensitivity of sensoric measurements towards interferic rubber mount distortions, the field force that can be accomplished at the sensor, the linearity of the signal and the producibility of the permanent magnet ring. Further topics that are addressed in this thesis are the discussion of the used sensor electronic including essential software algorithms and the discussion of the experimentally derived characteristics of the prototype of the sensor rubber mount and its components.

The presented work is concerned with the development and application of an ultrasonic detection scheme suitable for the monitoring of muscle dynamics with high temporal - down to 5 µs - and spatial resolution - down to 0.78 µm. A differential detection scheme has been developed to monitor the variations of the velocity of longitudinal polarized ultrasound waves travelling in contracting and relaxing muscle, compensating for variations of the path length by referencing to a frame. The observed time dependent variations of the time-of-flight of the ultrasonic waves caused by variations in the muscle and in addition by minor deformations of the enclosure are detected each separately and synchronously and are evaluated differentially. Beside of the detected increase of the speed of sound observed for contracted muscle with respect to the relaxed state of about 0.6%, the recovery time from maximum isometric contraction is quantified and relaxation processes are observed for the recovery phase following the isometric contraction. The developed ultrasonic calliper was employed to monitor both, the brain controlled and externally excited muscle dynamics with sampling intervals down to 10 ms synchronously with signals relating to the excitation. Monitored are the activation, hold, and relaxation phase for maximum voluntary isometric contraction of the gastrocnemius muscle. A so far not reported post tetanus overshoot and subsequent exponential recovery are observed. Both are attributed to the muscle as suggested by combined monitoring with EMG and are modelled with a lumped mechanical circuit containing an idealized bidirectional linear motor unit, ratchet, damper, and springs. Both, the rapid contraction and relaxation phases require a high order filter or alternatively a kernel filter, attributed to the nerve system as suggested by external electric stimulation. The respective response function is modelled by an electrical lumped circuit. Together with a reaction time and occasionally observed droops in the hold phase, both adjusted empirically, the monitored response is represented in close approximation by the combined electrical and mechanical lumped circuits. The respectively determined model parameters provide a refined evaluation scheme for the performance of monitored athletes. Valuable parameters relate to the latent period, the muscle response time, the activation and deactivation dynamics, a possible droop and other instabilities of the hold phase, and parameters characterizing the relaxation phase including the observed post tetanus overshoot and subsequent contraction. Monitored and modelled are also the different processes involved in active muscle dynamics including isotonic, isometric, and eccentric contraction or stretching. The developed technology provides time sequential observation of these processes and registration of their path in the extension and force parameter space. Under suitable conditions the closed-loop cycles of mind controlled human muscle movements proceed along characteristic lines coinciding with well identifiable elementary processes. The presentation of the monitored processes in the extension and force parameter space allows the determination of the mechanical energy expenditure for the observed different muscle actions. An elementary macroscopic mechanical model has been developed, suitable to express the basic features of the monitored muscle dynamics.:Table of Contents Chapter 1 1. Introduction 1 1.1 Monitoring of muscle biomechanics 1 1.2 Detection methods in biomechanics 2 1.3 Ultrasound in biomechanical application 5 1.4 Skeletal muscle 6 1.5 Activation of skeletal muscle 8 1.6 Catatonus effect 10 Chapter 2 2. Concepts and methods in ultrasonic motion monitoring 12 2.1 Ultrasound 12 2.2 Specific concepts of the developed ultrasonic detection scheme 16 2.2.1 Time-of-flight 17 2.2.2 Cross correlation 18 2.2.3 Concepts of cross correlation 19 2.2.4 Chirp technique 19 Chapter 3 3. Ultrasonic monitoring of the muscle extension 21 3.1 Data analysis 21 3.2 Application of the developed monitoring scheme 23 3.2.1 Fast signal and data acquisition mode 23 3.2.2 Monitoring with off-line evaluation 24 3.2.3 Method 26 3.2.4 Data evaluation 27 3.3 Quasi-continuous monitoring scheme 28 3.3.1 Slow with on-line data processing and display 29 3.3.2 Fast with data storage only 30 3.4 Monitoring with on-line evaluation 34 3.4.1 Application involving monitoring of athletic performance 36 3.4.2 Data evaluation 37 3.4.3 Summary 42 3.5 Comparative study of pre and post physical loading session 43 3.5.1 Method 43 3.5.2 Results 44 3.5.3 Summary 45 Chapter 4 4. High resolution monitoring of the velocity of ultrasound in contracting and relaxing muscle 47 4.1 Methods 49 4.2 Results and evaluation 51 4.2.1 Poission’s ratio for isometrically contracted muscle 52 4.3 Summary 53 Chapter 5 5. Monitoring of muscle dynamics, muscle force, and EMG 56 5.1 Synchronous monitoring of muscle dynamics with muscle force 56 5.1.1 Force-length dynamics under all-out isometric contraction 56 5.1.1.1 Method 56 5.1.1.2 Result and evaluation 58 5.1.2 Force-length dynamics of equal holding monitoring 62 5.1.2.1 Method 62 5.1.2.2 Results and evaluation 63 5.1.3 Summary 67 5.2 Synchronous monitoring of muscle movement with EMG 69 5.2.1 Method 69 5.2.2 Results and evaluation 70 5.3 Synchronous monitoring of muscle movement, EMG and muscle force 73 5.3.1 Method 73 5.3.2 Results and evaluation 74 5.3.3 Summary 77 Chapter 6 6. Monitoring of skeletal muscle dynamics under isometric contraction and modelling of the non-linear response including post tetanus effects 80 6.1 Method 82 6.2 Data analysis 82 6.3 Results and evaluation 82 6.3.1 Mechanical model 83 6.3.2 Equations relating to modelling 85 6.3.3 Comparison of experimental results and modelling 91 6.3.4 Electrical lumped circuit 93 6.4 Summary 100 Chapter 7 7. Lumped Circuit Model and Energy Transfer for quasi-static approximation 101 7.1 Basic muscle model and biomechanical processes 102 7.1.1 Muscle model 102 7.1.2 Force in the muscular motoric processes 104 7.2 Method 104 7.3 Results of experimental observations of muscle action 106 7.3.1 Muscle force and closed-loop contraction dynamics 106 7.3.2 Muscle work considerations 109 7.4 Summary 110 Chapter 8 8.1 Ultrasonic calliper 112 8.2 Interpretation of sound velocity variation in muscle 114 8.3 Monitored muscle dynamics 118 8.4 Isometric muscle action and tetanus effect 121 8.5 Quasi-static muscle action 125 8.6 Summarizing statement with a moderate outlook 126 References 128 Acknowledgements 140 Selbständigkeitserklärung 141

This master thesis aims to develop a test methodology for electromechanical linear actuators. A linear actuator acts as a linear motor, converting a power source to linear motion. The electromechanical linear actuator in this project has an electric motor as its power source and uses a rack and pinion system to transfer that power to linear motion.  The test methodology is to impose a force onto the rack of the actuator, to ensure that operation under a load scenario is within specification. To accomplish this, the design of a test rig implementation is analyzed. The test rig consists of the test unit, which is to be tested, the load unit, which is to provide the load force, and a control system for the load unit. The load unit is another linear actuator and is controlled via a load cell. The load cell gives out the load force being applied, and the controller gives out the corresponding appropriate motor command to the load unit to ensure the load force is as desired. This analysis is done through simulation of the setup. Viable options for the setup were first analyzed in order to implement the deemed promising options for a setup into a simulation environment. The simulation environment in this project was Simscape, an extension of MATLAB’s Simulink. In simulation the parameters for the test rig were rigorously analyzed, in order to determine acceptable thresholds. The primary load unit tested was another electromechanical linear actuator from Cascade Drives, the model A-100-8P. Two secondary setups, one using the same model as being tested, and another setup using two of the models being tested. Simulation found that the suggested options’ applied load force have a poor rise time, large overshoot and substantial oscillation errors. The primary source for this was determined to be the latency between load cell input, and motor command output in the controller. The poor metrics from the result could lead to problems when emergency braking, and with a long honing period, which would render most test data unusable.

Thesis deals with the modeling of pedestrian excitation of structures and obtaining the corresponding dynamic response of the structure. The trend of modern slender structures places more emphasis on the accuracy of modeling pedestrian dynamic excitation, which is difficult because of the intelligent behavior of pedestrians and the biological nature of the modeled pedestrian. First part of the thesis deals with traditional models of pedestrian excitation, based on application of pedestrian ground force to the model of construction. Models are explored on a model of slender footbridge for many different excitation variants in order to explore the specifics of the force excitation application and the structure response calculation. In second part of the thesis biomechanical pedestrian models are developed, including inertial forces, to calculate the pedestrian interaction with the structure. Parametric studies carried out on simplified structural models research the influence of design parameters of biomechanical models on dynamic response. The aim is to obtain a more accurate model of the pedestrian-construction system for refinement of the design of structures. The design of a tuned mass dampers for the reduction of pedestrian induced vibrations is also explored. Tuned mass dampers are devoted to parametric studies that deal with the influence of design parameters of the damper on the efficiency and design requirements of the device. The aim is to explore the design parameters and their influence on the efficient and economical design of the device. In the thesis were developed two biomechanical models, a simple biomechanical model with one vertical degree of freedom and a bipedal model of a human walking. Models have proven a certain degree of interaction when exciting light footbridges by one pedestrian. Bipedal model then also brought a partial insight into the mechanics of walking and the causes of pedestrian contact forces.

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