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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Entropy Analysis of an Economic Activity: A Case Study of Simple Brickmaking in China

Coulter, John Edward, n/a January 1993 (has links)
1. There is a crisis in economics. The discipline evolved in nineteenth century Europe and is difficult to adapt to modern conditions, even in the West, and particularly in alien cultures. Application of conventional economic analysis to economic activity in a culture as alien as traditional China highlights the biases in assumptions of the paradigm. 2. The concepts, models and vocabulary evolved over one hundred years ago predate important developments in the natural sciences. It is now necessary for economists to concede no goods can ever be 'produced', and they are not 'consumed' either. In clear terms matter is transformed, but is not created or destroyed (First Law of Thermodynamics). 3. When people transform matter, in lay language we say energy is 'used'. In a simple cottage industry, 'raw material' is transformed into a commodity in front of our eyes by the use of human energy and the release of energy from a 'fuel'. In modem complex economic activity, it is difficult or impossible to keep track of the processes from raw matter to transformed 'product' although the principle is the same. 4. The Second Law of Thermodynamics states that in any transformation, energy is not created or destroyed, but becomes 'less available'. In short, entropy increases. This appears to work well for pure physics and chemistry, but its application to analysis of economic activity has only been notional. 5. There is a reason why economists borrowing terms from hard science experience difficulty. It is because physicists and chemists have addressed specific laboratory and engineering problems, but not the broader economic issues. The hypothesis gradually evolved in this research program that not only economic concepts and terms needed reworking, but those in physics as well. The definitions of energy as 'ability to do works and of entropy as 'unavailable energy' jar the logic of our commonsense. 6. The notion of 'available energy' was traced back to the phenomenon in physical chemistry known as exothermicity, or the release of energy during a chemical reaction. It was reasoned that while scientists had focussed on this phenomenon and measured it carefully they saw no need to ask where the energy came from, or to measure its transformation. From the perspective of analysing economic activity, the question was important. 7. It was hypothesised that the energy released from a fuel as electromagnetic radiation (mainly heat) was the residual of the set of coulombic forces within atoms that maintain the structure of shells of electrons around the protons. This idea in turn came from the presumption that molecular bonding is a residual of vectors of the set of coulombic forces within atoms, and the likelihood that in an exothermic reaction, after the reactants are said (by scientists) to 'seek equilibrium', product molecules have a portion of the coulombic forces 'left over' and not required to maintain their structures. An estimate was made of the coulombic forces extant in various fuels, and compared with the known data for their release of energy. 8. The idea was developed in detail. The concept we call in economics, 'production', and should call 'transformation' can only occur when forces locked within atoms are released as electromagnetic forces. (Gravitational forces exist because matter has been put 'there' by electromagnetic radiation). When 100 grams of dry grass fuel is burnt, about 2 megajoules of electromagnetic radiation are released. It was estimated that the coulombic forces between each electron and proton in that amount dry grass total 150 gigajoules (or giganewtons, since the reference is to forces). 9. Within the boundary of a simple economic activity, the ratio of aggregated coulombic forces locked up within atoms to the electromagnetic forces radiated out was estimated at the beginning of the activity, and then after a duration. The ratio of forces always tends towards 'evening out'. This measurement captures the entropy phenomenon which has been said by Georgescu-Roegen to be the basis of all economic activity. 10. At the roots of the economic paradigm founded by Adam Smith is the premise that the material world, as a set of substances, is a stage on which economic actors 'add value', bid prices up and down, and by their rational perception manage their livelihoods and surroundings well. From the findings of this research program it is contended that the surroundings of economic actors can be classed into two categories: locked up (coulombic) electromagnetic forces, and radiated electromagnetic forces. The former has a tendency to convert to the latter. All action, including all economic activity, and all life can be traced to a point in space and time where this conversion is (naturally) occurring. The phenomenon is analogous to a slope where water cascades, and gravitational potential energy converts to other (either useless or useful) forms of energy. To appreciate the nature of this phenomena, and to attempt to fathom its dimensions, sets our perceptions of ourselves as economic actors in a quite different and very humbling context.
2

Theoretical and experimental investigations on radial electromagnetic forces in relation to vibration problems of induction machines

Balan, Anil 01 January 1997 (has links)
Accurate assessment of the electromagnetic excitation forces and the vibration behaviour of stators is essential to arrive at a suitable design for quiet operation of an electrical machine. These electromagnetic forces are produced on the surfaces of the stator and rotor along the air-gap periphery. The physical mechanisms underlying the production of the electromagnetic forces, and the characteristics of the ensuing vibrations are described in this thesis. <p>In this thesis, comprehensive analytical methods are developed for the determination of the radial electromagnetic forces in squirrel-cage and wound-rotor induction machines. Various magnetic fields are generated due to the distribution of the windings in slots, the slotting of the stator and rotor surfaces, and the magnetic saturation of the iron. The air-gap fields are determined using the permeance method by expressing the MMF and the air-gap permeance as waves. <p>In the analyses, the mutual interactions between the stator and rotor are incorporated. Asthe load increases, these interactions become prominent and influence significantly the nature of the air-gap field. Their effects on the electromagnetic forces are discussed from the perspective of the production of vibrations. Extensive investigations were conducted on a 7.5 kW squirrel-cage induction motor and a 70 kW wound-rotor induction motor to verify the validity of the analyses. The comparisons made between the experimental and the analytical results prove the general validity of the analytical methods. <p>Conclusions are drawn with a view to determine the actual role played by the harmonic air-gap fields on the production of the electromagnetic forces and the ensuing vibrations. In the course of these investigations, an experimental set-up which is particularly suited for the measurement of magnetic fields, magnetic forces, resonant frequencies, vibrations and noise was developed. A fundamental study on the vibration behaviour of electrical machine stators using an experimental modal-analysis is presented in the thesis. Modal-analysis is a process of forcing a structure to vibrate predominantly at a selected resonance. In order to achieve this, distributed electromagnetic forces are used.<p>Detailed investigations were conducted on the stator models of a 120 hp induction motor to study their vibration behaviour, and to critically examine the damping present in them. The physical interpretations of the results given in the thesis would help in acquiring a better understanding of the vibration behaviour of stators in relation to the problem of electromagnetic acoustic noise in electrical machines. This work was supported by the National Sciences and Engineering Research Council of Canada through grant no. OGP0004324.
3

Estudo do efeito magnetohidrodinâmico em um eletrólito a partir do uso de um dispositivo ejetor eletromagnético / Study of MHD effect on an electrolyte solution, using an electromagnetic ejector device

Aoki, Luciano Pires 18 July 2011 (has links)
A magnetohidrodinâmica, ou simplesmente MHD, é um campo da ciência que estuda os movimentos de fluidos condutores submetidos a forças eletromagnéticas e une conceitos da fluidodinâmica e eletromagnetismo. Nos últimos anos, a MHD vem sendo aplicada em diversas áreas tecnológicas, desde a propulsão eletromagnética até dispositivos biológicos. Neste trabalho, são mostradas a construção e a operação de um dispositivo MHD, um canal retangular preenchido com um fluido eletrolítico conhecido como macrobomba, isento de partes mecânicas móveis. Os imãs geram um campo magnético externo e os eletrodos criam um campo elétrico, perpendicular ao escoamento, que move o fluido. O modelo MHD é calculado a partir das equações de Navier Stokes acopladas às equações de Maxwell para um fluido incompressível newtoniano. As forças eletromagnéticas que surgem resultam do produto vetorial da densidade de corrente e da densidade de fluxo magnético - essa é a força de Lorentz. Os resultados são apresentados em simulações 3D numéricas, assim como em dados experimentais. O objetivo é relacionar o campo magnético com o elétrico e com a quantidade de movimento produzida, e calcular a densidade de corrente e o perfil de pressão e de velocidade. Um perfil U e M de pressões e velocidades é esperado no experimento. Dados experimentais e computacionais são comparados para validação e posterior uso para futuros trabalhos. / Magnetohydrodynamics or simply (MHD) is a field of science that studies the movement of conductive fluids subjected to electromagnetic forces. Such a phenomenon brings together concepts of fluid dynamics and electromagnetism. Over the years, MHD has been encountered in a wide area of technological applications electromagnetic propulsion to biological devices. The present work didactically shows the construction (materials and equipment) and operation of an MHD device; a rectangular closed circuit filled with an electrolyte fluid, known as macro pumps, where a permanent magnet generates a magnetic field and electrodes generate the electric field, perpendicular to the flow, moving the fluid. The MHD model has been derived from the Navier-Stokes equation and coupled with the Maxwell equations for Newtonian incompressible fluid. Electric and magnetic components engaged in the test chamber assist in creating the propulsion of the electrolyte fluid. The electromagnetic forces that arise are due to the cross product between the vector density of current and the vector density of magnetic field applied. This is the Lorentz force. Results are present of 3D numerical MHD simulation for Newtonian fluid as well as experimental data. The goal is to relate the magnetic field with the electric field and the amounts of movement produced, and calculate de current density and fluid´s pressure and velocity. An u-shaped and m-shaped velocity and pressure profiles are expected in the experiment. Computational and experimental data are compared for validation and future analysis.
4

Estudo do efeito magnetohidrodinâmico em um eletrólito a partir do uso de um dispositivo ejetor eletromagnético / Study of MHD effect on an electrolyte solution, using an electromagnetic ejector device

Luciano Pires Aoki 18 July 2011 (has links)
A magnetohidrodinâmica, ou simplesmente MHD, é um campo da ciência que estuda os movimentos de fluidos condutores submetidos a forças eletromagnéticas e une conceitos da fluidodinâmica e eletromagnetismo. Nos últimos anos, a MHD vem sendo aplicada em diversas áreas tecnológicas, desde a propulsão eletromagnética até dispositivos biológicos. Neste trabalho, são mostradas a construção e a operação de um dispositivo MHD, um canal retangular preenchido com um fluido eletrolítico conhecido como macrobomba, isento de partes mecânicas móveis. Os imãs geram um campo magnético externo e os eletrodos criam um campo elétrico, perpendicular ao escoamento, que move o fluido. O modelo MHD é calculado a partir das equações de Navier Stokes acopladas às equações de Maxwell para um fluido incompressível newtoniano. As forças eletromagnéticas que surgem resultam do produto vetorial da densidade de corrente e da densidade de fluxo magnético - essa é a força de Lorentz. Os resultados são apresentados em simulações 3D numéricas, assim como em dados experimentais. O objetivo é relacionar o campo magnético com o elétrico e com a quantidade de movimento produzida, e calcular a densidade de corrente e o perfil de pressão e de velocidade. Um perfil U e M de pressões e velocidades é esperado no experimento. Dados experimentais e computacionais são comparados para validação e posterior uso para futuros trabalhos. / Magnetohydrodynamics or simply (MHD) is a field of science that studies the movement of conductive fluids subjected to electromagnetic forces. Such a phenomenon brings together concepts of fluid dynamics and electromagnetism. Over the years, MHD has been encountered in a wide area of technological applications electromagnetic propulsion to biological devices. The present work didactically shows the construction (materials and equipment) and operation of an MHD device; a rectangular closed circuit filled with an electrolyte fluid, known as macro pumps, where a permanent magnet generates a magnetic field and electrodes generate the electric field, perpendicular to the flow, moving the fluid. The MHD model has been derived from the Navier-Stokes equation and coupled with the Maxwell equations for Newtonian incompressible fluid. Electric and magnetic components engaged in the test chamber assist in creating the propulsion of the electrolyte fluid. The electromagnetic forces that arise are due to the cross product between the vector density of current and the vector density of magnetic field applied. This is the Lorentz force. Results are present of 3D numerical MHD simulation for Newtonian fluid as well as experimental data. The goal is to relate the magnetic field with the electric field and the amounts of movement produced, and calculate de current density and fluid´s pressure and velocity. An u-shaped and m-shaped velocity and pressure profiles are expected in the experiment. Computational and experimental data are compared for validation and future analysis.
5

Estudo e desenvolvimento de um atuador planar de armadura sem núcleo ferromagnético

Susin, Marcos José January 2016 (has links)
Este trabalho apresenta a proposta de topologia para um atuador planar sem núcleo ferromagnético na armadura, sua análise teórica em termos de forças de tração que nele atuam, seu desenvolvimento e resultados teóricos e experimentais obtidos como base em um protótipo construído. O atuador planar tem características inovadoras: uma armadura estacionária sem ferro com enrolamentos ortogonais e dois carros acoplados magneticamente um ao outro com quatro ímãs permanentes de NdFeB de alto produto energético. A armadura desse estator é composta por enrolamentos planares multifases colocados de tal maneira que dois enrolamentos ortogonais independentes são produzidos e assim definem duas forças de propulsão ortogonais. Cada carro possui uma culatra de aço que suporta os ímãs permanentes e que está ligada a uma estrutura de suspensão mecânica para permitir o movimento bidirecional sobre a área definida pela armadura. Esse tipo de atuador pode ser usado em aplicações que requerem o movimento em qualquer direção ao longo de um plano. O protótipo desenvolvido neste trabalho foi testado com a finalidade de validar suas características estáticas de operação com relação à análise numérica e o modelo analítico. Os valores de densidade de fluxo magnético no entreferro e de força planar de propulsão, obtidos através de ensaios, apresentaram uma boa aproximação em relação aos valores obtidos através da simulação numérica e do modelo analítico. Para os ensaios de força normal este trabalho preocupou-se em analisar numérica e experimentalmente os resultados, que também apresentaram valores convergentes e satisfatórios para os itens propostos. Para os ensaios do atuador planar com regulagem de entreferro de 12 mm e 24 mm foram encontradas sensibilidades médias da força planar de propulsão de 7,19 N/A e 4,13 N/A respectivamente. / This work presents a proposal of topology of a planar actuator with an ironless armature core, its theoretical analysis in terms of the driving forces that acting on the actuator, its development, the theoretical and experimental results obtained for an implemented prototype. Such planar actuator has innovative features: a stationary and ironless armature core with orthogonal planar windings and two cars magnetically coupled to each other by means of four high energy-product NdFeB permanent magnets. The stator of the actuator comprehends an ironless core with two sets of multiphase windings placed in such a way that two independent orthogonal windings form the armature in a way that allows the yielding of two orthogonal propulsion forces. Each car has a back iron which supports two permanent magnets and is supported by a suspension structure to allow bidirectional movement of the coupled cars. This type of actuator can be used in applications that require the movement in any direction over a plane. The prototype of this study was tested in order to validate their static characteristics of operation with respect to the numerical analysis and the analytical model. The values of magnetic flux density in the air gap and the planar propulsion force obtained through testing, showed a good agreement with the values obtained by numerical simulation and analytical model. The normal force tests showed good agreement with the results of the numerical analysis. The tests of planar actuator with air gaps of 12 mm and 24 mm were found to produce an average sensitivity of the planar propulsion force of 7.19 N/A and 4.13 N/A respectively.
6

Estudo e desenvolvimento de um atuador planar de armadura sem núcleo ferromagnético

Susin, Marcos José January 2016 (has links)
Este trabalho apresenta a proposta de topologia para um atuador planar sem núcleo ferromagnético na armadura, sua análise teórica em termos de forças de tração que nele atuam, seu desenvolvimento e resultados teóricos e experimentais obtidos como base em um protótipo construído. O atuador planar tem características inovadoras: uma armadura estacionária sem ferro com enrolamentos ortogonais e dois carros acoplados magneticamente um ao outro com quatro ímãs permanentes de NdFeB de alto produto energético. A armadura desse estator é composta por enrolamentos planares multifases colocados de tal maneira que dois enrolamentos ortogonais independentes são produzidos e assim definem duas forças de propulsão ortogonais. Cada carro possui uma culatra de aço que suporta os ímãs permanentes e que está ligada a uma estrutura de suspensão mecânica para permitir o movimento bidirecional sobre a área definida pela armadura. Esse tipo de atuador pode ser usado em aplicações que requerem o movimento em qualquer direção ao longo de um plano. O protótipo desenvolvido neste trabalho foi testado com a finalidade de validar suas características estáticas de operação com relação à análise numérica e o modelo analítico. Os valores de densidade de fluxo magnético no entreferro e de força planar de propulsão, obtidos através de ensaios, apresentaram uma boa aproximação em relação aos valores obtidos através da simulação numérica e do modelo analítico. Para os ensaios de força normal este trabalho preocupou-se em analisar numérica e experimentalmente os resultados, que também apresentaram valores convergentes e satisfatórios para os itens propostos. Para os ensaios do atuador planar com regulagem de entreferro de 12 mm e 24 mm foram encontradas sensibilidades médias da força planar de propulsão de 7,19 N/A e 4,13 N/A respectivamente. / This work presents a proposal of topology of a planar actuator with an ironless armature core, its theoretical analysis in terms of the driving forces that acting on the actuator, its development, the theoretical and experimental results obtained for an implemented prototype. Such planar actuator has innovative features: a stationary and ironless armature core with orthogonal planar windings and two cars magnetically coupled to each other by means of four high energy-product NdFeB permanent magnets. The stator of the actuator comprehends an ironless core with two sets of multiphase windings placed in such a way that two independent orthogonal windings form the armature in a way that allows the yielding of two orthogonal propulsion forces. Each car has a back iron which supports two permanent magnets and is supported by a suspension structure to allow bidirectional movement of the coupled cars. This type of actuator can be used in applications that require the movement in any direction over a plane. The prototype of this study was tested in order to validate their static characteristics of operation with respect to the numerical analysis and the analytical model. The values of magnetic flux density in the air gap and the planar propulsion force obtained through testing, showed a good agreement with the values obtained by numerical simulation and analytical model. The normal force tests showed good agreement with the results of the numerical analysis. The tests of planar actuator with air gaps of 12 mm and 24 mm were found to produce an average sensitivity of the planar propulsion force of 7.19 N/A and 4.13 N/A respectively.
7

Estudo e desenvolvimento de um atuador planar de armadura sem núcleo ferromagnético

Susin, Marcos José January 2016 (has links)
Este trabalho apresenta a proposta de topologia para um atuador planar sem núcleo ferromagnético na armadura, sua análise teórica em termos de forças de tração que nele atuam, seu desenvolvimento e resultados teóricos e experimentais obtidos como base em um protótipo construído. O atuador planar tem características inovadoras: uma armadura estacionária sem ferro com enrolamentos ortogonais e dois carros acoplados magneticamente um ao outro com quatro ímãs permanentes de NdFeB de alto produto energético. A armadura desse estator é composta por enrolamentos planares multifases colocados de tal maneira que dois enrolamentos ortogonais independentes são produzidos e assim definem duas forças de propulsão ortogonais. Cada carro possui uma culatra de aço que suporta os ímãs permanentes e que está ligada a uma estrutura de suspensão mecânica para permitir o movimento bidirecional sobre a área definida pela armadura. Esse tipo de atuador pode ser usado em aplicações que requerem o movimento em qualquer direção ao longo de um plano. O protótipo desenvolvido neste trabalho foi testado com a finalidade de validar suas características estáticas de operação com relação à análise numérica e o modelo analítico. Os valores de densidade de fluxo magnético no entreferro e de força planar de propulsão, obtidos através de ensaios, apresentaram uma boa aproximação em relação aos valores obtidos através da simulação numérica e do modelo analítico. Para os ensaios de força normal este trabalho preocupou-se em analisar numérica e experimentalmente os resultados, que também apresentaram valores convergentes e satisfatórios para os itens propostos. Para os ensaios do atuador planar com regulagem de entreferro de 12 mm e 24 mm foram encontradas sensibilidades médias da força planar de propulsão de 7,19 N/A e 4,13 N/A respectivamente. / This work presents a proposal of topology of a planar actuator with an ironless armature core, its theoretical analysis in terms of the driving forces that acting on the actuator, its development, the theoretical and experimental results obtained for an implemented prototype. Such planar actuator has innovative features: a stationary and ironless armature core with orthogonal planar windings and two cars magnetically coupled to each other by means of four high energy-product NdFeB permanent magnets. The stator of the actuator comprehends an ironless core with two sets of multiphase windings placed in such a way that two independent orthogonal windings form the armature in a way that allows the yielding of two orthogonal propulsion forces. Each car has a back iron which supports two permanent magnets and is supported by a suspension structure to allow bidirectional movement of the coupled cars. This type of actuator can be used in applications that require the movement in any direction over a plane. The prototype of this study was tested in order to validate their static characteristics of operation with respect to the numerical analysis and the analytical model. The values of magnetic flux density in the air gap and the planar propulsion force obtained through testing, showed a good agreement with the values obtained by numerical simulation and analytical model. The normal force tests showed good agreement with the results of the numerical analysis. The tests of planar actuator with air gaps of 12 mm and 24 mm were found to produce an average sensitivity of the planar propulsion force of 7.19 N/A and 4.13 N/A respectively.
8

Near-field Optical Interactions And Applications

Haefner, David 01 January 2010 (has links)
The propagation symmetry of electromagnetic fields is affected by encounters with material systems. The effects of such interactions, for example, modifications of intensity, phase, polarization, angular spectrum, frequency, etc. can be used to obtain information about the material system. However, the propagation of electromagnetic waves imposes a fundamental limit to the length scales over which the material properties can be observed. In the realm of near-field optics, this limitation is overcome only through a secondary interaction that couples the high-spatial-frequency (but non-propagating) field components to propagating waves that can be detected. The available information depends intrinsically on this secondary interaction, which constitutes the topic of this study. Quantitative measurements of material properties can be performed only by controlling the subtle characteristics of these processes. This dissertation discusses situations where the effects of near-field interactions can be (i) neglected in certain passive testing techniques, (ii) exploited for active probing of static or dynamic systems, or (iii) statistically isolated when considering optically inhomogeneous materials. This dissertation presents novel theoretical developments, experimental measurements, and numerical results that elucidate the vectorial aspects of the interaction between light and nano-structured material for use in sensing applications.
9

Modelagem eletromagnética e mecânica de máquinas síncronas para estudo de vibrações no núcleo do estator. / Electromagnetic and mechanical modelling of synchronous machines for study of stator core vibration.

Barros, Allan de 25 June 2019 (has links)
O campo magnético estabelecido no entreferro das máquinas síncronas é responsável pela transmissão do torque e potência desejados, porém é também precursor de forças radiais inerentes. Tais forças combinadas à resposta dinâmica do sistema mecânico podem resultar em vibração excessiva do núcleo do estator, o que em geral é indesejável devido a eventuais danos e redução de vida útil decorrentes. Este trabalho tem como objetivo principal desenvolver modelos e simulações focados nas forças eletromagnéticas atuantes no núcleo do estator de tal forma que estes possam contribuir para compreensão global dos fenômenos envolvidos bem como para refinamento de resultados já conhecidos. De forma complementar, modelos mecânicos analíticos do núcleo do estator existentes na literatura serão explorados com a finalidade de, em conjunto com as forças eletromagnéticas encontradas, se obter o comportamento vibracional global da estrutura do núcleo do estator. Validação experimental dos resultados também é discutida com base em ensaios em duas máquinas reais. / The magnetic field established in the airgap of a synchronous machine is responsible for the desired torque and power transmission; however it is also precursor of inherent radial forces. Such forces combined to the dynamic response of the mechanical system can result in excessive stator core vibration, what is in general undesirable due to eventual damages and life span reduction. This work has the main objective of developing models and simulations focused on the electromagnetic forces acting on the stator core in such a way that they can contribute for the global comprehension of involved phenomena as well as for the refinement of already known results. Complementarily, analytical mechanical models of the stator core available in the literature will be explored with the goal of, in conjunction with the obtained electromagnetic forces, deriving the global vibrational behavior of the stator core structure. Experimental validation of results is also discussed based on tests performed in two real machines.
10

Electromagnetic damping for control of vibration in civil structures

Ao, Wai Kei January 2017 (has links)
This thesis investigates an alternative solution to deal with the civil structure vibration. Non-contact electromagnetic or Eddy current damping is selected as a score of vibration suppression. Electromagnetic damping relies on the interaction between a permanent magnet and conductor. An electromagnetic damper (EMD) is applied both to a laboratory footbridge structure and 6-storey model-scale aluminium moment resisting frame (AMRF). In this first study the EMD is connected in series with an electronic shunt circuit to construct an electromagnetic shunt damper (EMSD). A robust optimisation method is applied to develop the corresponding optimal design formula of the EMSD. The principle of an EMSD is to convert mechanical energy to electrical energy. Hence, the induced electromotive force (emf) is generated by electromagnetic induction. This emf induces an amount of shunt damping, which is fedback to the structure to achieve vibration suppression. It was found that when the impedance was applied, the shunt damping feature was of a similar nature to viscous dampers. In contrast, when an RLC (resistance-inductance-capacitance) circuit is connected, the shunt damping is analogous to a tuned mass damper. A second form of EMD is Eddy current damper (ECD), which relies on a geometrical arrangement of permanent magnets and conductors to produce damping forces. The vertical and horizontal orientation of the magnet, unidirectional and alternative pole projection and moving different direction of the conductor are investigated. A theoretical study involving the infinite boundary and finite boundary (the method of images current) is carried out to obtain an analytical calculation of the damping force. On the basis of this analysis, one type of ECD prototype was physically built. A performance test was carried out to determine the damping characteristics of the ECD, which agreed with the results of the numerical analysis. In addition, the ECD was applied to control the dynamics of the 6-storey AMRF. It was found that, the ECD can effectively increase system damping and have a satisfactory control effect.

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