Hydraulic systems represent a crucial part of the drivetrain of mobile machines. The most important drivers of current developments, increasing energy efficiency and productivity, are leading to certain trends in technology. On a subsystem level, working hydraulics are utilizing effects by improving control functions and by maximum usage of energy recovery potential. Independent metering and displacement control, partly in combination with hybrid concepts, are the dominating approaches. Traction drives gain advantage from optimized power split transmissions, which consequently are being used in a growing number of applications. On the level of components, increase of efficiency and dynamics as well as power density are important trends. Altogether, design of systems and components is more and more based on modular concepts. In this sense, among others, sensors and control elements are being integrated to actuators; electric and hydraulic technology is being merged. In order to achieve maximum efficiency and performance of the entire machine, control of hydraulics has to include the whole drivetrain and the entire mobile machine in its application. In modern words, mobile hydraulic systems are a part of cyber physical systems.

Thesis (PhD)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: Control of beta-type free-piston Stirling engines has been the topic of research and development for many years. In this dissertation, an alternative approach to free-piston Stirling engine control, namely direct piston displacement control, is proposed. Direct piston displacement control entails the instantaneous and direct control of the piston displacement to control the engine according to preferred criteria, e.g. maximum power conversion or efficiency. To control free-piston engines in this manner, it is necessary to independently control both the displacement of the displacer and the power piston in real time. The primary arrangement by which to achieve this is through external control of the instantaneous forces exerted by the linear electrical machines fixed to the pistons. The challenge of displacement control is whether suitable linear machine technology exists or whether technology could be established that would adhere to the requirements of real time direct control. To answer the question whether direct piston displacement control is at all possible, a process was followed to set specifications that linear machines should adhere to and to set design guidelines for linear machines and free-piston Stirling engines. The first step was to establish the ability to simulate free-piston Stirling engine dynamics accurately. This was done by adapting a second order formulation and to verify and improve the accuracy thereof by comparing simulated results with experimental results of one of the best documented Stirling engines, namely the GPU-3 engine. It was found that this second order formulation could simulate the GPU-3 engine to a fair degree of accuracy. Key indicators were defined and later refined with the view of setting specifications. A case study of the influence of a range of variations, including operational, dimensional and other variations, on the dynamics of the GPU-3 was then undertaken. From the findings of this case study, specifications of the key indicators and design guidelines were established. A design optimisation approach was proposed to evaluate linear machine topologies. This approach makes specific provision for the specifications that linear machines need to adhere to, as well as for representative dynamic responses of the forces exerted on the linear machine by the displacer or the power piston. These representative responses and the associated piston displacement were determined for the displacer, the power piston and the combination of the two from the study conducted to set specifications. An air-core, longitudinal flux linear machine with surface mounted permanent magnets (LFPM) was then evaluated to determine its suitability for direct piston displacement control. This linear machine topology was optimised for the traditional approach to establish a benchmark with which to compare subsequent optimisations. The LFPM linear machine not only compared well with other topologies for the traditional application in resonant free-piston Stirling engines, but it was found also to be able to perform displacement control for both the displacer and the power piston. For both pistons, displacement should however be limited to sinusoidal displacement, and in the case of the displacer, an important qualification is that the linear machine should be assisted by spring forces to reach practical design optimisations. Direct piston displacement control is shown to be possible. Future work should concentrate on the practical implementation thereof in free-piston Stirling engines. / AFRIKAANSE OPSOMMING: Die beheer van beta-tipe vrysuier Stirling enjins is al vir baie jare die onderwerp van navorsing en ontwikkeling. In hierdie proefskrif word ’n alternatiewe benadering tot vrysuier Stirlingenjins voorgestel, naamlik direkte suierverplasingsbeheer. Direkte suierverplasingsbeheer behels die oombliklike en direkte beheer van die suierverplasing om die enjin volgens voorkeur kriteria, soos maksimum drywingsomsetting of benuttingsgraad, te beheer. Om vrysuier enjins op hierdie wyse te beheer, is dit noodsaaklik om intyds die verplasing van beide die verplaser en die werksuier onafhanklik te beheer. Die primêre wyse om dit te bereik is deur eksterne beheer van die oomblikskragte wat uitgevoer word deur die lineêre masjiene wat vas is aan die suiers. Die uitdaging van verplasingsbeheer is of toepaslike lineêre masjien tegnologie bestaan en of tegnologie gevestig kan word wat sal voldoen aan die vereistes van intydse direkte beheer. Om die vraag te beantwoord of direkte suierverplasingsbeheer hoegenaamd moontlik is, is ’n proses gevolg om spesifikasies daar te stel waaraan lineêre masjiene moet voldoen en om ontwerpsriglyne vir lineêre masjiene en vrysuier Stirling enjins te stel. Die eerste stap was om die vermoë daar te stel om vrysuier Stirling enjin dinamika akkuraat te simuleer. Dit is gedoen deur ’n tweede orde formulering aan te pas en om die akkuraatheid daarvan te kontroleer en te verbeter deur gesimuleerde resultate met eksperimentele resultate van een van die bes gedokumenteerde Stirling enjins, naamlik die GPU-3 enjin, te vergelyk. Daar is bevind dat die tweede orde formulering die GPU-3 tot ’n redelike mate akkuraat kon simuleer. Sleutel aanwysers is gedefinieer en later verfyn met die oog op die daarstelling van spesifikasies. ’n Gevallestudie van die invloed van ’n reeks variasies, insluitende operasionele, dimensionele en ander variasies, op die dinamika van die GPU-3 is onderneem. Gegrond op die bevindinge van hierdie gevallestudie kon spesifikasies en ontwerpsriglyne vasgestel word. ’n Ontwerpsoptimeringsbenadering is voorgestel om lineêre masjiene te evalueer. Hierdie benadering maak spesifiek voorsiening vir die spesifikasies waaraan lineêre masjiene moet voldoen, sowel as verteenwoordigende dinamiese response van die kragte wat op die lineêre masjien van die verplaser en die werksuier uitgeoefen word. Vanaf die bevindinge van die studie wat uitgevoer is om spesifikasies daar te stel, is verteenwoordigende response en gepaardgaande suierverplasing bepaal vir die verplaser, die werksuier en die kombinasie van die twee. ’n Lugkern, longitudinale vloed lineêre masjien met oppervlak-gemonteerde permanente magnete (LVPM) is toe geëvalueer om die geskiktheid daarvan te bepaal vir direkte suierverplasingsbeheer. Hierdie lineêre masjien topologie is geoptimeer vir die tradisionele benadering om ’n maatstaf te vestig waarteen daaropvolgende optimerings vergelyk kan word. Die LVPM lineêre masjien vergelyk nie net goed met ander topologieë vir die tradisionele toepassing in resonante vrysuier Stirling enjins nie, maar daar is ook bevind dat dit in staat is om verplasingsbeheer te doen vir beide die verplaser en die werksuier. Vir beide suiers moet die verplasing egter tot sinusvormige verplasing beperk word en in die geval van die verplaser, is ’n belangrike kwalifikasie dat die lineêre masjien ondersteun moet word deur veerkragte om praktiese ontwerpsoptimerings te bereik. Daar is aangetoon dat direkte suierverplasingsbeheer moontlik is. Toekomstige werk moet konsentreer op die praktiese implementering daarvan in vrysuier Stirling enjins.

O emprego de fibras para reforço de concreto é uma técnica bastante conhecida e estudada mundialmente. As mais conhecidas e estudadas são as fibras de aço, embora utilização das macrofibras poliméricas esteja amplamente difundida no mercado brasileiro. Entretanto, a caracterização do comportamento mecânico de concretos reforçados com essas macrofibras ainda deve ser mais bem avaliada. Dentre os diversos métodos utilizados para essa finalidade, os ensaios realizados com sistema fechado de controle de velocidade de deslocamento fornecem resultados mais confiáveis. A principal vantagem conferida por esse sistema está na avaliação desses compósitos em baixo nível de fissuração com maior acurácia. O desempenho desses compósitos foi estudado segundo as normas ASTM C1609 (2010), ASTM C1399 (2010) e EN 14651 (2007) e o método JSE-SF4 (1984). Os quatro procedimentos prescrevem ensaios de flexão de corpos-de-prova prismáticos para determinação da resistência residual pós-fissuração e da tenacidade. Os procedimentos americanos e o método japonês prescrevem configuração de aplicação de carga por dois cutelos superiores, posicionados sobre o terço médio do corpo-de-prova. Já a configuração do método europeu é de aplicação de carga por apenas um cutelo superior, centralizado em relação ao vão de ensaio, com corpos-de-prova com entalhe na face inferior. Foram estudadas uma macrofibra de polipropileno, nas dosagens de 0,22, 0,33, 0,50, 0,66, 0,82 e 1,0% em volume em três matrizes de concreto, com resistências médias à compressão de 30, 35 e 40MPa, e uma fibra de aço, nas dosagens de 0,19, 0,32 e 0,45% em volume em uma matriz de resistência média à compressão de 35MPa. Foi observado que a utilização da velocidade de deslocamento do corpo-de-prova como parâmetro de controle do ensaio forneceu boas condições de avaliação do compósito, devido à redução da instabilidade pós-pico. Com isso, a determinação da resistência residual do compósito nos níveis iniciais de deslocamento e fissuração da matriz foi mais bem caracterizada. Pela análise e comparação dos resultados, foram formuladas equações para estabelecer correlações entre os diferentes métodos de ensaio. Com o modelo de regressão utilizado na análise estatística foi possível verificar que a resistência à compressão da matriz, o tipo e o teor de fibra são as variáveis independentes que mais influenciam os resultados de resistência residual. Foi necessário estabelecer correlações para cada tipo de fibra separadamente, pois o comportamento de slip-softening ou de slip-hardening influencia as funções obtidas. / The use of fibers for concrete reinforcing is a very common practice, used all over the world. Steel fibers are the most common and studied, although synthetic macrofibers are in very common use in the Brazilian market. However, the evaluation of the mechanical behavior of concrete reinforced with this type of fiber must be evaluated. A broad range of tests is available for this purpose. Tests performed under closed-loop displacement control provide more reliable results. The main advantage of that system is in the evaluation of the composite at low levels of crack opening with higher accuracy. In this study, the performance of these composites was examined according to the standard test methods ASTM C1609 (2010), ASTM C1399 (2010), EN 14651 (2007) and JSCE-SF4 (1984). These four methods prescribe flexural tests in prismatic specimens for the determination of post-crack residual strength and toughness. The American and the Japanese test methods prescribe four-point bending tests, while the European test method prescribes three-point bending tests and specimens with a notch in the bottom face. Two fibers were analyzed: a polypropylene macrofiber, used in the dosages of 0.22, 0.33, 0.50, 0.66, 0.82 and 1.0 in volume percentage, in three concrete matrices with average compressive strengths of 30, 35 and 40MPa, and a steel fiber, in the dosages of 0.19, 0.32 and 0.45 in volume percentage, in one concrete matrix of average compressive strength of 35MPa. It was observed that the use of the net displacement of the specimen as the parameter to control the load application provided good conditions for the evaluation of the mechanical behavior of the composite, due to the reduction of post-peak instability. Therefore, the determination of the residual strength of the composite in the initial levels of displacement and cracking of the matrix was better achieved. From the comparative analysis of the results, equations were developed to establish a correlation among the test methods. Based on the model used in the statistical analysis, the main independent variables that influence the results of residual strength are the compressive strength of the concrete matrix, the type and the content of the fiber. The equations were obtained separately according to the fiber type, because the behavior of slip-hardening or slip-softening influence the correlations.

No description available.

Made available in DSpace on 2016-12-12T17:38:37Z (GMT). No. of bitstreams: 1 Paulo Sergio Dainez - resumo.pdf: 31972 bytes, checksum: 94a24928564b90b196513e814cfe09a3 (MD5) Previous issue date: 2010-06-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the resonant linear compressor the piston is drive by a linear actuator and a resonant mechanical spring directly in the reciprocating motion, this is a mass spring resonant system, eliminating bearing and crank of the conventional reciprocating compressors, and the friction loss has a significant reduction. The maximum displacement of the piston is regulating by the equilibration between the power supply by the actuator and the power transfer to the gas compression process. This type of the compressor is design to work at the resonant frequency of the mass spring system, in this condition the efficiency is maximum. Then the control must drive the linear actuator in the maximum displacement of the piston and adjust the drive frequency at the system resonant frequency. For enable of this process is necessary that piston position is known with precision, however the installation of a sensor have same difficulty, since the refrigeration compressor is hermetic system, and it have high pressure and temperature, with wide range of variation. This work develop the implementation of a full order linear observer to estimate the displacement and the velocity of the piston of the resonant linear compressor, and a control system able to drive the compressor in the maximum piston displacement and in the resonant frequency, and only measured a current of the linear actuator, without sensor inside de compressor. For this a nonlinear model of the compressor and a linear model with variable coefficients for the observer are develop, also a simulator of the system is develop, where the compressor model is controlled by the displacement and the velocity signals calculate by observer, demonstrated the feasibility of the proposed technique in the present work. / Nos compressores lineares ressonantes o pistão é acionado por um atuador linear e molas diretamente no sentido do seu movimento alternativo, formando um sistema massa-mola ressonante, eliminando assim os mancais mecânicos e o sistema biela e manivela dos compressores convencionais, reduzindo de forma significativa as perdas por atrito. A amplitude do deslocamento do pistão é regulada pelo equilíbrio da potência fornecida pelo atuador e a potência transferida para o processo de compressão do gás. Estes compressores são projetados para funcionar na frequência de ressonância do sistema massa-mola, nesta condição a eficiência do sistema é máxima. Assim, o controle deve acionar o atuador linear na máxima amplitude de deslocamento do pistão e ajustar a frequência de acionamento na frequência de ressonância do sistema. Para viabilizar este processo é necessário que o curso do pistão seja conhecido com precisão, porém a instalação de um sensor apresenta dificuldades, pois os compressores de refrigeração são herméticos e estão sujeitos a pressões e temperaturas elevadas e com grande faixa de variação. Este trabalho propõe a implementação de um observador de estados de ordem plena, para estimar o deslocamento e a velocidade do pistão do compressor linear ressonante, e um sistema de controle capaz de acionar o compressor no deslocamento máximo e na frequência de ressonância, medindo somente a corrente no atuador linear, sem a necessidade de sensores instalados dentro do compressor. Para isto desenvolve-se um modelo não linear do compressor e um modelo linear equivalente de coeficientes variáveis para o projeto do observador, também é desenvolvido um simulador do sistema, onde o modelo do compressor é controlado pelos sinais de deslocamento e velocidade calculados pelo observador, demonstrando a viabilidade da técnica proposta no presente trabalho.

O emprego de fibras para reforço de concreto é uma técnica bastante conhecida e estudada mundialmente. As mais conhecidas e estudadas são as fibras de aço, embora utilização das macrofibras poliméricas esteja amplamente difundida no mercado brasileiro. Entretanto, a caracterização do comportamento mecânico de concretos reforçados com essas macrofibras ainda deve ser mais bem avaliada. Dentre os diversos métodos utilizados para essa finalidade, os ensaios realizados com sistema fechado de controle de velocidade de deslocamento fornecem resultados mais confiáveis. A principal vantagem conferida por esse sistema está na avaliação desses compósitos em baixo nível de fissuração com maior acurácia. O desempenho desses compósitos foi estudado segundo as normas ASTM C1609 (2010), ASTM C1399 (2010) e EN 14651 (2007) e o método JSE-SF4 (1984). Os quatro procedimentos prescrevem ensaios de flexão de corpos-de-prova prismáticos para determinação da resistência residual pós-fissuração e da tenacidade. Os procedimentos americanos e o método japonês prescrevem configuração de aplicação de carga por dois cutelos superiores, posicionados sobre o terço médio do corpo-de-prova. Já a configuração do método europeu é de aplicação de carga por apenas um cutelo superior, centralizado em relação ao vão de ensaio, com corpos-de-prova com entalhe na face inferior. Foram estudadas uma macrofibra de polipropileno, nas dosagens de 0,22, 0,33, 0,50, 0,66, 0,82 e 1,0% em volume em três matrizes de concreto, com resistências médias à compressão de 30, 35 e 40MPa, e uma fibra de aço, nas dosagens de 0,19, 0,32 e 0,45% em volume em uma matriz de resistência média à compressão de 35MPa. Foi observado que a utilização da velocidade de deslocamento do corpo-de-prova como parâmetro de controle do ensaio forneceu boas condições de avaliação do compósito, devido à redução da instabilidade pós-pico. Com isso, a determinação da resistência residual do compósito nos níveis iniciais de deslocamento e fissuração da matriz foi mais bem caracterizada. Pela análise e comparação dos resultados, foram formuladas equações para estabelecer correlações entre os diferentes métodos de ensaio. Com o modelo de regressão utilizado na análise estatística foi possível verificar que a resistência à compressão da matriz, o tipo e o teor de fibra são as variáveis independentes que mais influenciam os resultados de resistência residual. Foi necessário estabelecer correlações para cada tipo de fibra separadamente, pois o comportamento de slip-softening ou de slip-hardening influencia as funções obtidas. / The use of fibers for concrete reinforcing is a very common practice, used all over the world. Steel fibers are the most common and studied, although synthetic macrofibers are in very common use in the Brazilian market. However, the evaluation of the mechanical behavior of concrete reinforced with this type of fiber must be evaluated. A broad range of tests is available for this purpose. Tests performed under closed-loop displacement control provide more reliable results. The main advantage of that system is in the evaluation of the composite at low levels of crack opening with higher accuracy. In this study, the performance of these composites was examined according to the standard test methods ASTM C1609 (2010), ASTM C1399 (2010), EN 14651 (2007) and JSCE-SF4 (1984). These four methods prescribe flexural tests in prismatic specimens for the determination of post-crack residual strength and toughness. The American and the Japanese test methods prescribe four-point bending tests, while the European test method prescribes three-point bending tests and specimens with a notch in the bottom face. Two fibers were analyzed: a polypropylene macrofiber, used in the dosages of 0.22, 0.33, 0.50, 0.66, 0.82 and 1.0 in volume percentage, in three concrete matrices with average compressive strengths of 30, 35 and 40MPa, and a steel fiber, in the dosages of 0.19, 0.32 and 0.45 in volume percentage, in one concrete matrix of average compressive strength of 35MPa. It was observed that the use of the net displacement of the specimen as the parameter to control the load application provided good conditions for the evaluation of the mechanical behavior of the composite, due to the reduction of post-peak instability. Therefore, the determination of the residual strength of the composite in the initial levels of displacement and cracking of the matrix was better achieved. From the comparative analysis of the results, equations were developed to establish a correlation among the test methods. Based on the model used in the statistical analysis, the main independent variables that influence the results of residual strength are the compressive strength of the concrete matrix, the type and the content of the fiber. The equations were obtained separately according to the fiber type, because the behavior of slip-hardening or slip-softening influence the correlations.

La plupart des bâtiments de moyenne et grande hauteur en béton armé sont munis de murs de refend ductiles afin résister aux charges latérales dues au vent et aux séismes. Les murs de refend ductiles sont conçus selon des règles conception stricts. Ces murs sont généralement conçus de façon à forcer la formation d’une rotule plastique à leur base dans l’éventualité d’un séismemajeur. Lors de la conception d’un mur, l’enveloppe des moments fléchissants ainsi que l’enveloppe des efforts tranchants dans la portion du mur situé au-dessus de la rotule plastique sont basés sur la résistance probable en flexion du mur dans la région de la rotule plastique. Plusieurs études sur les murs de refend conçus selon cette philosophie de conception on fait le constat que l’effort tranchant maximum dans un mur peut être sous-estimé lors d’un séisme, et que des rotules plastiques peuvent également se former à d’autres endroits qu’à la base du mur, ce qui constitue un mécanisme de ruine indésirable. Ces effets sont principalement attribuables à la contribution des modes supérieures à la réponse dynamique globale des bâtiments lors d’un séisme. L’effet des modes supérieurs est particulièrement important dans les bâtiments élancés de grande hauteur ayant une période propre de vibration longue. L’essai pseudo-dynamique avec sous-structure est uneméthode efficace et économique d’évaluer expérimentalement l’effet des modes supérieurs sur le comportement sismique des murs de refend dans les bâtiments. Lors de tels essais, comme la masse du bâtiment est modélisée numériquement, ceci permet de tester des structures à de relativement grandes échelles sans avoir à combattremécaniquement les forces d’inerties générées lors d’un séisme. Dans le cadre de la présente étude, la portion constituant la base d’un mur de refend correspondant à la zone de rotule plastique faisant partie d’un bâtiment de huit étages à l’échelle 1/2,75 a été testé. Les dimensions générales de la portion de mur testée étaient de 1800 mm de longueur, par 2200 mm de hauteur par 160 mm d’épaisseur. Le mur étudié a été conçu selon l’édition 2015 du Code National du Bâtiment du Canada (CNBC 2015) ainsi que selon la norme CSA A23.3-14 (Calcul des ouvrages en béton), où le facteur d’amplification de l’effort tranchant causé par l’effet des modes supérieurs n’a pas été pris en compte. Lors des essais pseudo-dynamiques avec sous-structure, une nouvelle méthode de contrôle à trois degrés de liberté convenant à des spécimens d’essai très rigides axialement a été développée et validée. Une procédure novatrice de redémarrage d’un essai interrompu en cours de route a également été développée et validée. Lors des essais, le bâtiment de huit étages incluant la portion de mur dans le laboratoire a été soumis à trois séismes. Le premier séisme était de très faible intensité, l’intensité du deuxième séisme correspondait au séisme de conception, et le troisième séisme correspondait au séisme de conception dont l’intensité a été doublé. Durant les deux séismes de forte intensité, le mur testé s’est comporté de manière ductile et des fissures de cisaillement et de flexion importantes ont été observées. Même si l’effort tranchant maximum mesuré durant le séisme de conception a atteint 2,16 fois la valeur de conception du mur, et 3,01 fois la valeur de conception du mur dans le cas du séisme amplifié, aucun mécanisme de ruine n’a été observé. Suite aux essais pseudo-dynamiques avec sous-structure, un essai par poussée progressive a également été effectué. Les résultats des essais pseudo-dynamiques avec sous-structure portent à croire que la valeur de l’effort tranchant de conception d’un mur selon la norme CSA A23.3-14 est sous-estimé. De plus, l’essai poussée progressive a permis de démontrer que lemur était beaucoup plus résistant qu’anticipé, puisque l’effort tranchant avait été sous-estimé lors de la conception. L’essai par poussée progressive a également permis de démontrer que le mur peut atteindre des niveaux de ductilité en déplacement supérieur à celui prévu par la norme CSA A23.3-14. / Abstract: Most mid- and high-rise reinforced concrete (RC) buildings rely on RC structural walls as their seismic force resisting system. Ductile RC structural walls (commonly called shear walls) designed according to modern building codes are typically detailed to undergo plastic hinging at their base. Both the design moment envelope for the remaining portion of the wall and the design shear forces are evaluated based on the probable flexural resistance of the wall in the plastic hinge region. Several analytical studies have shown that so-designed structural walls can be subjected to shear forces in excess of the design values. Plastic hinging can also develop in the upper portion of the walls. These effects are mainly attributed to higher mode response and, hence, are more severe in taller or slender walls with long fundamental periods. Considering the literature, there is a significant uncertainty regarding the behavior of the structural walls under the higher mode of vibrations excited under earthquake excitations. Hybrid testing is an effective experimentalmethod to study the natural behaviour of structures such as shear walls. The hybrid testing method enables the simulation of the seismic response of large structural elements like RC shear walls without the need to include large masses typically encountered in multi-storey buildings. In this study a barbell shaped RC shear wall specimen of 1800mm in length including a 300mm × 300mm boundary element at each end that is 2200mm in height, and 160mm thick was investigated. A test specimen corresponding to the base plastic hinge zone of an 8-storey shear wall was tested in a laboratory evolvement whilst the reminder of the building structure was modeled numerically. The reference wall was scaled down by a factor of 1/2.75 to obtain dimensions of the test specimen. The RC wall was designed in accordance with the 2015 edition of the National Building Code of Canada (NBCC 2015) and the Canadian Standard Association A23.3-14 code. The amplification of the base design shear force accounting for the inelastic effects of higher modes specified by the CSAA23.3-14 standard was not taken into account in order to evaluate the amplification experimentally. In order to investigate the response of ductile RC walls under earthquake ground motions and track the effect of the higher vibration modes on the shear force demand, three earthquakes with different intensities were applied on the hybrid model successively. The RC wall exhibited a ductile behaviour under the ground motions and flexural and shear cracks developed all over the height of the wall. In spite of amplifying the shear force demand by a factor of 2.16 under the design level earthquake and 3.01 under a high intensity earthquake, no shear failure was observed. The test results indicated that the amplification of the design shear forces at the base of ductile RC shear walls are underestimated by the CSAA23.3-14 standard. A new method for controlling three degrees of freedomin hybrid simulation of the earthquake response of stiff specimens was developed and verified in this study. Also, an innovative procedure to restore an interrupted hybrid test was programmed and verified. The hybrid tests were followed by a push-over test under a lateral force distribution equal to the square root of sum of the squares of the first five modes in order to evaluate the displacement ductility of the RC wall. Findings of the final push-over test showed that the tested ductile RC wall can withstand higher displacement ductilities than the presented levels in the NBCC 2015.

Elektrisch-hydrostatische Kompaktantriebe (EKA) stellen ein innovatives, neuar-tiges Antriebskonzept dar, welches – ausgeführt als funktionsfertige Baugruppe – die Anwenderfreundlichkeit bei der Maschinenintegration, Inbetriebnahme und Wartung signifikant steigert. Elektrisch-hydrostatische Kompaktantriebe verbinden die inhärenten Vorteile hydraulischer Antriebstechnik wie beispiels-weise Robustheit, hohe Leistungsdichte und Überlastschutz mit Energieeffizi-enz, Ressourceneffizienz, Anwenderfreundlichkeit und geringem Bauraum. Auf-grund seines kompakten und kostengünstigen Aufbaus ist der Differentialzylin-der der mit Abstand am häufigsten eingesetzte Aktor bei hydraulischen Anwen-dungen. Die Herausforderung beim Einsatz eines Differentialzylinders im hyd-rostatischen Getriebe ist die Steuerung der asymmetrischen Volumenströme, die durch die einseitige Kolbenstange hervorgerufen werden. Die vorliegende Arbeit widmet sich der systematischen Entwicklung und Unter-suchung von Schaltungskonzepten, die sich für elektrisch-hydrostatische Kom-paktantriebe mit Differentialzylinder für die industrielle Anwendung eignen. Vor dem Hintergrund eines ressourcenschonenden und wirtschaftlichen Einsatzes der Antriebe werden Vorzugsvarianten ermittelt, die sowohl energie- als auch kosteneffizient sind. Das statische und dynamische Übertragungsverhalten so-wie die Energieeffizienz der ausgewählten Schaltungen werden auf der Grund-lage von praxisnahen Demonstratoren bestimmt. Die analytische und experi-mentelle Untersuchung der Vorzugsvarianten zeigt das Potential und die Gren-zen der Schaltungskonzepte für den industriellen Einsatz auf. Darüber hinaus wird der Vergleich mit elektromechanischen Kompaktantrieben im gleichen Leistungsbereich geführt, um die erzielten Ergebnisse in der Gegenüberstellung einordnen zu können. Um die Notwendigkeit einer aktiven Kühlung für potentielle Einsatzgebiete ohne aufwendige Experimente abschätzen zu können, werden zudem die Methoden der thermo-energetischen Netzwerksimulation auf elektrisch-hydrostatische Kompaktantriebe angewendet. Anhand eines Beispielantriebs wird ermittelt, mit welcher Genauigkeit das thermo-energetische Verhalten und die sich einstel-lende Beharrungstemperatur berechnet werden können.:1 Einleitung 1 2 Zielstellung der Arbeit 6 3 Stand der Forschung 8 3.1 Grundlagen 8 3.2 Hydrostatische Getriebe mit Gleichgangzylinder 10 3.2.1 Elektrisch-hydrostatische Aktuatoren (EHA) 11 3.3 Hydrostatische Getriebe mit Differentialzylinder 13 3.4 Thermo-energetische Analyse und Modellierung 24 4 Systematisierung der Schaltungsmöglichkeiten 27 4.1 Analyse typischer Anwendungen für EKA 27 4.2 Systematisierung der Lastfälle 27 4.3 Schaltungssystematik 29 4.4 Auswahl von Vorzugsvarianten 35 5 Einpumpenkonzept mit Ausgleichsventil 40 5.1 Aufbau und Funktionsweise 40 5.2 Demonstrator 43 5.3 Statisches Betriebsverhalten 46 5.4 Dynamisches Übertragungsverhalten 47 5.4.1 Dynamische Streckenkennwerte 47 5.4.2 Lastfallspezifisches dynamisches Verhalten 57 5.4.3 Dynamisches Verhalten bei dominanten Massekräften 60 5.5 Energieeffizienz 89 5.5.1 Elektrischer Antrieb 91 5.5.2 Hydrostatisches Getriebe 93 5.5.3 Gesamtantrieb 96 5.6 Fazit und Einsatzempfehlungen 97 6 Tandempumpenkonzept im offenen Kreis 99 6.1 Aufbau und Funktionsweise 99 6.2 Demonstrator 101 6.3 Statisches Übertragungsverhalten 102 6.4 Dynamisches Übertragungsverhalten 103 6.4.1 Dynamische Streckenkennwerte 103 6.4.2 Lastfallspezifisches dynamisches Verhalten 106 6.5 Energieeffizienz 109 6.5.1 Hydrostatisches Getriebe 109 6.5.2 Gesamtantrieb 111 6.6 Fazit und Einsatzempfehlungen 112 7 Untersuchung eines elektromechanischen Referenzantriebs 114 7.1 Bauarten, Eigenschaften und Einsatzgebiete elektromechanischer Linearantriebe 114 7.1.1 Übersetzung 117 7.1.2 Maximale Hubgeschwindigkeit 117 7.1.3 Maximale Hubkraft 117 7.1.4 Lebensdauer und Verschleiß 118 7.1.5 Wirkungsgrad 120 7.1.6 Steifigkeit 120 7.1.7 Fail-safe 121 7.2 Referenzantrieb 121 7.3 Statisches Übertragungsverhalten 122 7.4 Dynamisches Übertragungsverhalten 122 7.5 Energieeffizienz 123 7.5.1 Kugelgewindetrieb 123 7.5.2 Gesamtantrieb 124 8 Vergleich und Bewertung der Antriebssysteme 126 8.1 Statisches Übertragungsverhalten 126 8.2 Dynamisches Übertragungsverhalten 127 8.3 Energieeffizienz 128 8.4 Weiterführender Vergleich und Bewertung 129 9 Thermo-hydraulische Netzwerksimulation 134 9.1 Methodik 134 9.2 Grundlagen der Thermodynamik und Wärmeübertragung 135 9.2.1 Wärmeleitung 136 9.2.2 Konvektion 136 9.2.3 Wärmestrahlung 138 9.2.4 Wärmeübergang an Fugen zwischen Bauteilen 139 9.3 Analyse der Verlustleistungen 142 9.4 Analyse der Wärmeströme und thermischen Widerstände 145 9.4.1 Erzwungene Konvektion zwischen Öl und Innenfläche 146 9.4.2 Wärmeleitung in Festkörpern (Gehäuse) 147 9.4.3 Wärmeübergang an Fugen zwischen Bauteilen 147 9.4.4 Freie Konvektion an den Außenflächen 148 9.4.5 Wärmestrahlung an den Außenflächen 150 9.4.6 Zusammenfassung 151 9.5 Zulässige Öltemperatur des Antriebs 152 9.6 Thermo-hydraulisches Simulationsmodell des Demonstrators 152 9.7 Validierung 155 9.7.1 Vorbetrachtungen an einer Modellgeometrie 155 9.7.2 Prüfstandsaufbau und Versuchsparameter 157 9.7.3 Gegenüberstellung von Simulation und Messung 159 9.8 Sensitivitätsanalyse 162 9.8.1 Variation der Verlustleistung 163 9.8.2 Variation der Umgebungstemperatur 164 9.8.3 Variation des Korrekturfaktors für Umgebungsströmungen 165 9.9 Simulationsstudie zur Verbesserung des Wärmeabgabevermögens 166 9.10 Zusammenfassung 166 10 Zusammenfassung und Ausblick 168 11 Literaturverzeichnis 172 12 Anhang 194

Hydraulic systems represent a crucial part of the drivetrain of mobile machines. The most important drivers of current developments, increasing energy efficiency and productivity, are leading to certain trends in technology. On a subsystem level, working hydraulics are utilizing effects by improving control functions and by maximum usage of energy recovery potential. Independent metering and displacement control, partly in combination with hybrid concepts, are the dominating approaches. Traction drives gain advantage from optimized power split transmissions, which consequently are being used in a growing number of applications. On the level of components, increase of efficiency and dynamics as well as power density are important trends. Altogether, design of systems and components is more and more based on modular concepts. In this sense, among others, sensors and control elements are being integrated to actuators; electric and hydraulic technology is being merged. In order to achieve maximum efficiency and performance of the entire machine, control of hydraulics has to include the whole drivetrain and the entire mobile machine in its application. In modern words, mobile hydraulic systems are a part of cyber physical systems.

Hydrostatische Zylinderantriebe mit drehzahlvariablem Pumpenantrieb stellen modulare translatorische Antriebssysteme dar, die die Vorteile der elektrome-chanischen und hydraulischen Domänen verbinden. Zusätzlich bieten diese sog. elektrohydrostatischen Kompaktantriebe den Vorteil einer einfach umsetzbaren, diskret variablen Übersetzung. Diese erlaubt es, bei Arbeitsspielen mit dedizierten Eil- und Kraftphasen den elektrischen Antriebsmotor kleiner auszulegen als bei einer Referenz mit fester Übersetzung. Dadurch kann Downsizing-Potential in Bezug auf Größe und Masse des elektrischen Antriebsmotors und der Leistungselektronik erschlossen werden. In der vorliegenden Arbeit werden zunächst die möglichen Ersparnisse durch diese Technologie beleuchtet und die prinzipiellen Möglichkeiten einer schaltbaren Übersetzung dargestellt. Es wird eine Methodik erarbeitet, die es erlaubt, den gesamten Lösungsraum diskret umschaltbarer elektrohydrostatischer Kompaktantriebe systematisch zu erfassen und zu bewerten. Schließlich werden anhand von zwei Demonstratoren die Grenzen und Potentiale der Technologie experimentell untersucht und unterschiedliche, im Rahmen der Arbeit erarbeitete Strategien für den Umschaltvorgang zwischen zwei Übersetzungsstufen validiert. / Hydrostatic cylinder drives with variable speed pumps pose a modern form of modular translational drive systems, which merge the benefits of both electro-mechanic and hydraulic domains. Beyond that, these so called electrohydrostatic compact drives feature a possibility of implementing a discrete variable trans-ission ratio in a cost-effective manner. In the case of work cycles with dedicated rapid and force strokes, this allows the electric drive motor to be designed smaller than in the case of a reference with a fixed transmission ratio. In this way, downsizing potential can be exploited in terms of the size and mass of the electric drive motor and power electronics. In this thesis, the possible gains through this technology are first examined and the fundamental possibilities of a variable transmission are presented. A methodology is developed that allows the entire solution space of discretely switchable electrohydrostatic compact drives to be systematically mapped and evaluated. Finally, the limits and potentials of the technology are investigated experimentally by means of two demonstrators, and different strategies for the switching process between two transmission stages developed in the course of the thesis are validated.