In this thesis a piezo-electro-mechanical system, constituted of an aluminum beam with five piezoelectric patches glued on it, each of them shunted with an RL electrical circuit, has been numerically and experimentally investigated, in order to determine the optimal electric tuning parameters for vibration damping. A numerical code based upon Galerkin weighted-residual method is developed and the complete piezo-electro-mechanical system is designed, realized and finally tested by a standard modal testing technique. Comparisons between different shunting configurations of the system are given and finally the experimental data are compared with ones obtained by the developed numerical code in order to verify the accuracy of the latter. / Master of Science

Dans cette thèse nous proposons de développer un système d’imagerie ultrasonore innovante de micro- défauts basé sur l’utilisation conjointe de techniques d’acoustique non linéaire et du concept de "transducteur à cavité chaotique". Ce transducteur correspond à la combinaison d’une céramique piézoélectrique collée sur une cavité de forme chaotique et du principe de retournement temporel. La faisabilité et les performances de ce nouveau système sont explorées par des simulations numériques. Des paramètres optimaux d’utilisation pour une implémentation expérimentale sont proposés. Une grande partie des travaux menés dans le cadre de cette thèse se concentre sur le développement d’outils numériques permettant l’amélioration de telles techniques d’imagerie. Un schéma d’éléments finis de type Galerkin Discontinu (GD) est étendu à l’élastodynamique non linéaire. Un type de zone absorbante parfaitement adaptée, appelée "Nearly Perfectly Matched Layer" (NPML) a aussi été développé. Dans le cas de matériaux orthotropes, comme des problèmes de stabilité apparaissent, un mélange de NPML et de zone atténuante, dont on contrôle la proportion respective, est introduit afin de stabiliser les NPML. Une validation expérimentale du concept de "transducteur à cavité chaotique" pour la focalisation dans un milieu solide, réverbérant ou non, en utilisant une seule source est réalisée. Les méthodes de retournement temporel et de filtre inverse sont présentées et comparées. La démonstration expérimentale qu’un "transducteur à cavité chaotique" peut être utilisé conjointement avec les méthodes d’inversion d’impulsion afin de réaliser une image de non linéarités localisées est présentée / In this thesis we propose the development of an innovative micro-damage imaging system based on a combination of Nonlinear Elastic Wave Spectroscopy techniques and “chaotic cavity transducer” concept. It consists of a combination of a PZT ceramic glued to a cavity of chaotic shape with the time reversal principle. The feasibility and capabilities of these new ideas is explored by numerical simulations, and optimal operational parameters for experimental implementation are suggested based on the modelling support. A large part of the research work conducted in this thesis is concentrated on the development of numerical simulation tools to help the improvement of such nonlinear imaging methods. A nodal Discontinuous Galerkin Finite Element Method (DG-FEM) scheme is extended to nonlinear elasto-dynamic including source terms. A Perfectly Matched Layer absorbing boundary condition well adapted to the DG-FEM scheme, called Nearly Perfectly Matched Layer (NPML), is also developed. In the case of orthotropic material as stability problems appear, a mixture of NPML and sponge layer, with a controllable ratio of these two kinds of absorbing layers, is introduced. The experimental validation of “chaotic cavity transducer” to focalize in reverberant and non-reverberant solid media with only one source is made. Classical time reversal, inverse filter and 1 Bit time reversal process are discussed and compared. The experimental demonstration of the use of a “chaotic cavity transducer”, in combination with the pulse inversion and 1-bit methods, to obtain an image of localized nonlinearity is made. This opens the possibility for high resolution imaging of nonlinear defects

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This student paper was produced as part of the team design competition in the University of Arizona course ECE 485, Radiowaves and Telemetry. It describes the design of a telemetering system for race cars. Auto Racing is an exciting sport where the winners are the ones able to optimize the balance between the driver’s skill and the racing teams technology. One of the main reasons for this excitement is that the main component, the race car, is traveling at extremely high speeds and constantly making quick maneuvers. To be able to do this continually, the car itself must be constantly monitored and possibly adjusted to insure proper maintenance and prevent damage. To allow for better monitoring of the car’s performance by the pit crew and other team members, a telemetering system has been designed, which facilitates the constant monitoring and evaluation of various aspects of the car. This telemetering system will provide a way for the speed, engine RPM, engine and engine compartment temperature, oil pressure, tire pressure, fuel level, and tire wear of the car to be measured, transmitted back to the pit, and presented in a way which it can be evaluated and utilized to increase the car’s performance and better its chances of winning the race. Furthermore, this system allows for the storing of the data for later reference and analysis.

Cette recherche vise à étudier l’intégration contemporaine, dans la composition et la performance, des outils technologiques et artistiques correspondant à l’état de l’art en matière d’interaction temps-réel entre production instrumentale, production numérique du son et production de formes spatio-temporelles dans le lieu d’écoute. On souhaite notamment étudier comment cette intégration pourra constituer en retour une nouvelle modalité de l’écriture où fusionnent en cohérence une écriture du son, une écriture du temps et une écriture de l’espace informées par la technologie.Les paradigmes informatiques pour la gestion du temps et de l'interaction, les outils de synchronisation de processus, l'analyse de flux sonores et gestuels, le contrôle des paramètres à partir du son instrumental, la recherche sur la question du timbre instrumental et de ses descripteurs numériques et l’interaction interprète-ordinateur forment les éléments clefs de cette recherche.L’idée principale de ce travail est centrée sur l’interaction en temps réel avec des dispositifs informatiques avancés, dans le cadre d’une écriture particulièrement virtuose, avec des aspects spécifiques de construction temporelle et spatiale, cette situation hybride influençant en retour la nature de l’écriture elle-même. Les différents thèmes relatifs à cette exploration, tels que l’écriture du son, du temps et de l’espace, sont le point de départ pour décliner et développer, selon la nature des diverses productions envisagées, les liens possibles avec d’autres disciplines artistiques. / This research project aims to study the contemporary integration, in the composition and performance, of technological and artistic tools corresponding to the state of the art in terms of real-time interaction between instrumental production, digital sound production and production of spatio-temporal forms in the listening space. In particular, we study how this integration can in turn constitute a new modality of writing in which a coherent writing of sound, a writing of time and a writing of space informed by technology do merge together in a coherent way.Computer paradigms for time and interaction management, synchronization tools, sound and gestural flow analysis, parameter control from instrumental sound, research on the issue of instrumental timbre and its digital descriptors, and interpreter-computer interaction are key elements of this research and creation work.We focus on real-time interaction with smart computer devices in a particularly virtuoso writing with specific aspects of temporal and spatial construction, this hybrid situation in turn influencing the nature of the writing itself. The various themes relating to this exploration, such as the writing of sound, time and space, are the starting point for declining and developing, according to the nature of the various productions envisaged, the possible links with other artistic disciplines.

Les systèmes SHM (Structural Health Monitoring) basés sur la propagation d’ondes ultrasonores guidées sont utilisés pour des structures de grandes dimensions, par exemple dans les secteurs de l’aéronautique ou du génie civil. Les ondes de Lamb ou SH sont généralement employées car elles se propagent sur de longues distances dans des structures planes tout en sondant l’épaisseur des pièces. Cependant, des modes moins conventionnels se propagent dans les guides d’ondes de section droite finie, tels que les barreaux, les rails ou les tuyaux. Le nombre de modes peut être très élevé dans ce type de guide, et il est important de bien sélectionner un mode particulier.Les méthodes actuelles de sélectivité modale, basées sur l’emploi de plusieurs émetteurs,considèrent habituellement des éléments PZT identiques (même sensibilité, même réponse en fréquence...) et ne prennent pas en compte les conditions réelles de montage et leurs éventuelles imperfections (couplage variable entre traducteurs, mauvais alignement, différence de réponse de l’électronique...). Ce travail présente une méthodologie générale pour la sélectivité modale dans des guides à section droite finie, à l’aide de plusieurs éléments piézoélectriques disposés à leur surface. Cette sélectivité est basée sur la mesure expérimentale préalable, à l’aide d’un vibromètre laser 3D, des amplitudes des modes générés par chaque élément excité individuellement.Une procédure d’optimisation permet d’inverser le problème afin de maximiser l’amplitude du mode désiré, alors obtenue en excitant simultanément tous les émetteurs. Le problème à inverser requiert la connaissance des courbes de dispersion ainsi que des déformées modales des modes,obtenues en utilisant la méthode SAFE 2D. La méthodologie est testée à travers des simulations numériques et des mesures expérimentales sur un barreau d’aluminium de section rectangulaire instrumenté avec huit éléments PZT à sa surface. L’efficacité de la méthode pour générer différents modes purs, mais aussi pour détecter et localiser des défauts calibrés, est démontrée sur le barreau d’aluminium. Son fort potentiel pour des applications de SHM de structures plus complexes est étudié, tels qu’un rail ou un assemblage collé de matériaux composites. / SHM systems (Structural Health Monitoring) based on ultrasonic guided waves propagation are used for large structures, e.g. in Aerospace or Civil Engineering. Lamb or SH waves are usually employed as they propagate over long distances in plate-like structures while probing the entire thickness. However less conventional modes propagate in wave guides with finite crosssection,such as bars, rails or pipes. The number of modes can be very high even at low frequencyin this type of guide, and it is important to carefully select a specific mode. Current methods for modal selectivity, based on the use of several emitters, usually consider identical PZT elements(same sensitivity, same frequency response, etc.) and do not account for real experimental conditions and possible differences (variable coupling between transducers, flawed alignment,variable electronic response, etc.). This work presents a global methodology for modal selectivity in waveguides with finite cross-section, using several piezoelectric elements attached to their surface. This selectivity is based on experimental measurements, with a 3D laser vibrometer,of the amplitudes of the modes generated by each emitter. An optimization process allows to inverse the problem in order to maximize the amplitude of the desired mode, then generated by exciting all the emitters at once. This process requires knowing dispersion curves as well as the displacements of the various modes, calculated with SAFE 2D method. The methodology is tested through numerical simulations and experiments on an aluminium rectangular bar instrumented with 8 PZT elements on top. The method efficiency to generate different pure modes,and to detect and locate calibrated defects, is demonstrated for the aluminium bar. Its potential for SHM application of more complex structures is studied, like a rail or an adhesively bonded composite structure.

A busca constante por soluções mais eficientes, tanto no âmbito técnico como econômico, tem levado à crescente adoção de sistemas de automação baseados em redes de controle e transdutores inteligentes. A fragmentação desse mercado, no entanto, decorrente da proliferação de inúmeros protocolos e especificações para as redes de controle, impõe restrições e entraves ao desenvolvimento dos transdutores e dos sistemas de automação. A família de normas IEEE 1451 procura atenuar esse problema propondo interfaces padronizadas entre os transdutores e as redes, permitindo separar o projeto do transdutor da escolha da rede de controle. Neste trabalho foi desenvolvido um transdutor inteligente baseado na norma IEEE 1451.2 (STIM) e sua interface para a rede de controle LonWorks (NCAP). Através do desenvolvimento e avaliação dos protótipos foi verificada a aplicabilidade da norma e dos conceitos gerais da IEEE 1451, comprovando ainda seu uso em uma rede para a qual, no presente momento, não se tem conhecimento de solução similar. Constatou-se também que um transdutor inteligente baseado na IEEE 1451.2 pode ser desenvolvido com ferramentas e componentes comerciais de fácil acesso e baixo custo, e que é possível agregar os benefícios da IEEE 1451 às qualidades presentes nas redes LonWorks. Verificou-se ainda que a aceitação da IEEE 1451 no mercado é ainda incipiente, sendo imprescindível a publicação das demais normas que compõe a família para facilitar e incentivar sua adoção e disseminação. / The need for more efficient and cost-effective solutions in the control and automation market drives the increasing demand for systems based on control networks and smart transducers. However, the fragmented nature of the control network market hinders the development of solutions based on such technologies. The IEEE 1451 family of standards tries to solve this problem by specifying a common set of interfaces between the transducers and the control networks, isolating the transducer\'s project from the choice of networks. In this work, a smart transducer based on the IEEE 1451.2 standard (STIM) and its interface module to a LonWorks network (NCAP) were developed. Through the development and evaluation of the prototypes, the applicability of the standard and the concepts involved in the IEEE 1451 were verified. It was confirmed that a smart transducer based on the IEEE 1451.2 standard can be developed with low-cost, off-the-shelf components and software tools, and that it is possible to combine the benefits of the IEEE 1451 with the qualities of the LonWorks system. It was also perceived that the acceptance of the IEEE 1451 in the market is quite low, and that the release of the remaining standards that make up the IEEE 1451 family is essential for its success.

La miniaturisation est l’objectif actuel de tous les fabricants de composants radio-fréquence depuis plusieursdécennies. Si les composants actifs pour la microélectronique sont fondés sur la structuration de plaquesde silicium, les composants passifs reposent sur l’utilisation de cristaux tels que le quartz ou le niobate delithium. Ce dernier est particulièrement utilisé quand il s’agit de générer et exploiter des ondes élastiques, ainsique pour le guidage de faisceaux lumineux afin de réaliser des filtres ou des capteurs sensibles à différentsparamètres environnementaux. L’amélioration du guidage de ces ondes permet un gain en consommation et encompacité des dispositifs mais nécessite une structuration de la matière souvent tridimensionnelle. Cette étapetechnologique clé est industriellement mature pour la mise en forme du silicium, mais s’avère di_cilementtransposable à des matériaux tels que le quartz ou le niobate de lithium. Les travaux présentés dans cemanuscrit visent à réaliser des structures tridimensionnelles à hauts facteurs de forme dans des matériauxmonocristallins à l’aide d’une scie circulaire de précision. Des structures utilisant l’inversion périodique dedomaine ferroélectrique seront réalisées afin de les utiliser pour y guider des ondes élastiques possédant descouplages électromécaniques particulièrement élevées. Le guidage d’ondes optiques par le biais de ces mêmesstructures permet une amélioration du confinement par rapport aux systèmes de guidage massifs classiquescouramment utilisés pour la réalisation de filtre ou de modulateur électro-optiques. En utilisant conjointementle guidage d’ondes optiques et les domaines ferroélectriques alternés, les structures ainsi découpées permettentl’apparition de phénomènes optiques non-linéaires exaltés par l’amélioration du confinement. Ces structuresont ainsi montré leur intérêt dans plusieurs domaines de la physique avec un champ applicatif particulièrementvaste / Over the past decades, minutiarization and compacity have become a focus subject for companies specialisedin the manufacturing of radio-frequency components. Active components are typically manuafctured onsilicon wafers with well-known structuring methods. Passive ones are often manufactured on single cristalsuch as Quartz or Lithium Niobate, especially for acoustic wave generation or lightwave guiding. Theguiding of optical or acoustical waves leads to the manufacturing of sensors or filters which can be usedfor telecommunications or for the industry. Improvement in waveguiding allows for less power-consuming andmore compact devices but a 3D-structuring is usually required. This technology readness is high leveled forsilicon structuring but not for single crystals such as Lithium Niobate. This work presents the development andthe manufacturing of high aspect ratio three-dimensionnal structures in single-crystals using precise sawing.These structures show an optical waveguiding capability which allow the improvements of electro-opticmodulators or filters. Combined with a periodic reversing of Lithium Niobate polarization, these structuresallows for bulk acoustic wave generation leading to high electromechanical coupling and equivalent phasevelocity resonant modes. In non-linear optic field, this kind of structures lead to the improvement of secondharmonic generation e_ciency by reducing the cross section of waveguide. The manufactured devices in theframework of this project can actuelly be used in several domains of physic.

A busca constante por soluções mais eficientes, tanto no âmbito técnico como econômico, tem levado à crescente adoção de sistemas de automação baseados em redes de controle e transdutores inteligentes. A fragmentação desse mercado, no entanto, decorrente da proliferação de inúmeros protocolos e especificações para as redes de controle, impõe restrições e entraves ao desenvolvimento dos transdutores e dos sistemas de automação. A família de normas IEEE 1451 procura atenuar esse problema propondo interfaces padronizadas entre os transdutores e as redes, permitindo separar o projeto do transdutor da escolha da rede de controle. Neste trabalho foi desenvolvido um transdutor inteligente baseado na norma IEEE 1451.2 (STIM) e sua interface para a rede de controle LonWorks (NCAP). Através do desenvolvimento e avaliação dos protótipos foi verificada a aplicabilidade da norma e dos conceitos gerais da IEEE 1451, comprovando ainda seu uso em uma rede para a qual, no presente momento, não se tem conhecimento de solução similar. Constatou-se também que um transdutor inteligente baseado na IEEE 1451.2 pode ser desenvolvido com ferramentas e componentes comerciais de fácil acesso e baixo custo, e que é possível agregar os benefícios da IEEE 1451 às qualidades presentes nas redes LonWorks. Verificou-se ainda que a aceitação da IEEE 1451 no mercado é ainda incipiente, sendo imprescindível a publicação das demais normas que compõe a família para facilitar e incentivar sua adoção e disseminação. / The need for more efficient and cost-effective solutions in the control and automation market drives the increasing demand for systems based on control networks and smart transducers. However, the fragmented nature of the control network market hinders the development of solutions based on such technologies. The IEEE 1451 family of standards tries to solve this problem by specifying a common set of interfaces between the transducers and the control networks, isolating the transducer\'s project from the choice of networks. In this work, a smart transducer based on the IEEE 1451.2 standard (STIM) and its interface module to a LonWorks network (NCAP) were developed. Through the development and evaluation of the prototypes, the applicability of the standard and the concepts involved in the IEEE 1451 were verified. It was confirmed that a smart transducer based on the IEEE 1451.2 standard can be developed with low-cost, off-the-shelf components and software tools, and that it is possible to combine the benefits of the IEEE 1451 with the qualities of the LonWorks system. It was also perceived that the acceptance of the IEEE 1451 in the market is quite low, and that the release of the remaining standards that make up the IEEE 1451 family is essential for its success.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Systems Science and Industrial Engineering Department, 2006. / Includes bibliographical references.

The ability to reduce flexural vibrations of lightweight structures has been a goal for many researchers. A type of transducer-controller system that accomplishes this is a piezoelectric patch connected to an electrical impedance, or shunt. The piezoelectric patch converts the vibrational strain energy of the structure to which it is bonded into electrical energy. This converted electrical energy is then modified by the shunt to influence to mechanical response. There are many types of shunt circuits which have demonstrated effective control of flexural systems. Of interest in this work is the negative capacitance shunt, which has been shown to produce significant reduction in vibration over a broad frequency range. A negative capacitance circuit produces a current that is 180̊ out of phase from a traditional, passive capacitor. In other words, the voltage of the capacitor decreases as charge is added. The negative capacitance shunt consists of a resistor and an active negative capacitance element. By adding a resistor and negative capacitor to the electrical domain, the shunt acts as a damper and negative spring in the mechanical domain. The performance of the negative capacitance shunt can be increased through proper selection of the shunt's electrical components. Three aspects of component selection are investigated: shunt efficiency, maximum suppression, and stability. First, through electrical modeling of the shunt-patch system, the components can be chosen to increase the efficiency of the shunt for a given impedance. Second, a method is developed that could be utilized to adaptively tune the magnitude of resistance and negative capacitance for maximum control at a given frequency. Third, with regard to stability, as the control gain of the circuit is increased, by adjusting the circuit parameters, there is a point when the shunt will become unstable. A method to predict the stability of the shunt is developed to aid in suppression prediction. The negative capacitance shunt is also combined with a periodic piezoelectric patch array to modify the propagating wave behavior of a vibrating structure. A finite element method is utilized to create models to predict both the propagation constant, which characterizes the reduction in propagating waves, and the velocity frequency response of a full system. Analytical predictions are verified with experimental results for both a 1- and 2-D periodic array. Results show significant attenuation can be achieved with a negative capacitance shunt applied to a piezoelectric patch array. Three electromechanical aspects are developed: design for maximum suppression, more accurate stability prediction, and increased power-output efficiency. First, a method is developed that may be used to adaptively tune the magnitude of resistance and negative capacitance for maximum suppression. Second, with regard to stability, a method is developed to predict the circuit components at which the circuit will obtain a stable output. Third, through electrical modeling of the shunt-patch system, the components are chosen to increase the power output efficiency of the shunt circuit for a given impedance. The negative capacitance shunt is also combined with a periodic piezoelectric patch array to modify the propagating wave behavior of a vibrating structure. Analytical predictions are verified with experimental results for both a 1- and 2-D periodic array. Results show significant attenuation can be achieved with a negative capacitance shunt applied to a piezoelectric patch array.