This project studies how tactile feedback can be implemented in existing CrossControl products,in this case the V1200-display computer. The main purpose of this function is to minimizedistraction for the user by implementing tactile feedback which creates the possibility for theuser to use the device without looking at the display. A key variable to achieve this function is tocreate a haptic button, by using a force detector where the vibration strength will be related tohow much force users have applied on the screen. This technology can be applied with a piezoelectric sensor and actuator which can be integratedinto the V1200-display device. When a user touches the screen, feedback will be initiated, andusers can feel the feedback in the form of vibration which will represent a button press. Threedifferent design ideas on how piezoelectric sensors will be implemented under the V1200device’s display has been studied to determine which is the most optimal design to create thebest vibration and consequently best feedback to the users. The final implementation of the new function does not have a force detection and has onlytactile feedback with a piezoelectric actuator which will receive a PWM signal from the V1200device touch display. The glass panel on the screen is not flexible because of its thickness,which will cause a non-readable display touch that is not reachable by the sensor. In conclusion, the demo product could be mounted with either two or three sensors, dependingon whether the economical- or the efficiency aspect is the target for the producer. Since bothaspects will still provide 2 g acceleration force in the z-axis along the screen resulting in asatisfactory feeling / Detta projekt studerar hur haptisk feedback kan implementeras i befintliga CrossControl produkter, mer specifikt för V1200-skärmdatorn. Denna nya funktionen har i huvudsyfte att minimera distraktioner för användaren genom implementering av haptisk återkoppling som ger föraren möjligheten att använda skärmenheten utan att titta på skärmen. En nyckel variabel för att åstadkomma denna funktion är att tillverka känsel övertygande knappar genom kraftigenkänning, där vibrationens styrka kommer att relatera till hur mycket kraft som användaren tillämpat.  Denna teknik kan tillämpas med en piezoelektrisk sensor och aktuator som kan integreras under V1200-skärmenhet. När användaren klickar på skärmen ska en återkoppling sättas igång ,där användaren kan känna denna återkoppling i form av en vibration som representerar exempelvis en knapptryckning. Tre olika designidéer på hur piezoelektriska sensorerna skulle implementeras under V1200 enhetens skärm studerades för att sedan besluta om vilken som är den mest optimala designen som ger bäst vibration och därmed bäst återkoppling till användaren. Den slutgiltiga implementeringen resulterade i att den nya funktionen blir utan kraftigenkänning och enbart får haptisk återkoppling med piezoelektriska aktuatorer som får en PWM signal från V1200 enhetens touchdisplay. Orsaken till att funktionen ej har kraftigenkänning är på grund av att den tjocka glasskärmen inte är tillräckligt flexibel för att tryckningen på skärmen ska vara läsbar av sensorn.  Avslutningsvis blev den färdigställda produkten med implementering av haptisk återkoppling med två stycken piezoelektriska aktuatorer inom den ekonomiska aspekten medan den mest effektiva återkopplingen blev med tre styckna sensorer. Båda dessa design gav en accelerationskraft på 2g i z-riktningen längs skärmen och gav ett tillfredsställande resultat.

The objective of this work is to demonstrate the feasibility of on-chip sensing of bistable mechanism state using the piezoresistive properties of polysilicon, thus eliminating the need for electrical contacts. Changes in position are detected by observing changes in resistance across the mechanism. Sensing the state of bistable mechanisms is critical in their various applications. The research in this thesis advances the modeling techniques of MEMS devices which use piezoresistivity for position sensing. A fully compliant bistable micro mechanism was designed, fabricated, and tested to demonstrate the feasibility of this sensing technique. Testing results from two fabrication processes, Fairchild's SUMMiT IV and MUMPs, are compared. The Fairchild mechanism was then integrated into various Wheatstone bridge configurations to show the advantages of bridges and to demonstrate various design layouts. Repeatable and detectable results were found with independent mechanisms and with those integrated into Wheatstone bridges. Finite element models were constructed for the different Wheatstone bridges which were used to predict piezoresistive trends. A bistable mechanism for high-acceleration sensing was designed using uncertainty analysis optimization. The piezoresistive effects for this mechanism were also modeled. Discussion concerning nonvolatile memory applications is also presented.

In this thesis we use a new numerical code, based upon a mixed FEM-Runge-Kutta method, for the analysis and the design of plane 2-dimensional smart structures. We applied the developed code to the study of arbitrarily shaped piezo-electromechanical (PEM) plates. This code is based on a weak formulation of their governing equations as found in [18]. The optimal parameters needed to synthesize the appropriate electric networks are computed, and the overall performances of such plates are investigated. In particular, two examples are studied: firstly, a simple case is used to test the main features of the code; secondly, a more complex PEM plate is designed and analyzed by means of the proposed numerical approach. / Master of Science

No description available.

<p dir="ltr">Plants are capable of perceiving and responding to biotic and abiotic stress. They have evolved a variety of mechanisms to help them recognize and trigger rapid responses to both chemical and mechanical stimuli. These signals coordinate plant growth, development, and innate immune responses. However, we have limited knowledge about how mechanical signals are perceived and transduced during the plant immune response. In this study, we investigated the potential role of PIEZO, a mechanosensitive ion channel that is responsible for cellular mechanotransduction in both the plant and animal kingdoms, during the plant immune responses. Publicly- available RNAseq data revealed that <i>PIEZO</i> expression remained constant and unaltered in response to a variety of phytopathogens or elicitors. We, then, conducted infectious growth assays on <i>piezo</i> mutants in <i>Arabidopsis thaliana</i> plants. Our results indicated that <i>piezo</i> mutants, <i>pzo1-1 </i>and<i> pzo1-5,</i> were more susceptible to <i>Pseudomonas syringae </i>pv. tomato<i> </i>(Pst) DC3000 and to the <i>P. syringae hrcC</i>^<em>-</em> mutant confirming PIEZO’s role in plant defense and PTI. We further explored disease progression with necrotrophic fungi, <i>Alternaria brassisicola</i> and <i>Botrytis cinerea, </i>on <i>piezo</i> mutant plants and found enhanced fungal growth compared to the wild type (Col-0) with <i>Botrytis</i>. Building upon these findings, we probed the role of PIEZO in the growth-defense tradeoff using a root growth inhibition assay with flg22 as the MAMP elicitor. <i>pzo1-1</i> was less sensitive to flg22 treatment with less reduction in root growth compared to wild type whereas <i>pzo1-5</i> shows no difference in reduction compared to Col-0. In addition, we investigated whether PIEZO operates upstream of the main NADPH-oxidase, RBOHD, and the associated oxidative burst that occurs in early defense. There was no significant difference in Reactive Oxygen Species (ROS) production between <i>piezo</i> mutants and the wild type in an apoplastic ROS assay with a MAMP elicitor (flg22) and also with Ca²⁺ flux leaf disk assay. In conclusion, we demonstrated a potential role for PIEZO in plant immune defense responses and the growth-defense tradeoff.</p>

No description available.

A mechanical wave is generated as a result of an external force interacting with the well-defined medium and it propagates through that medium transferring energy from one location to another. The ability to generate and control the motion of the mechanical waves through the finite medium opens up the opportunities for creating novel actuation mechanisms not possible before. However, any impedance to the path of these waves, especially in the form of finite boundaries, disperses this energy in the form of reflections. Therefore, it is impractical to achieve steady state traveling waves in finite structures without any reflections. In-spite of all these conditions, is it possible to generate waveforms that travel despite reflections at the boundaries? The work presented in this thesis develops a framework to answer this question by leveraging the dynamics of the finite structures without any active control. Therefore, this work investigates how mechanical waves are developed in finite structures and identifies the factors that influence steady state wave characteristics. Theoretical and experimental analysis is conducted on 1D and 2D structures to realize different type of traveling waves. Owing to the robust characteristics of the piezo-ceramics (PZTs) in vibrational studies, we developed piezo-coupled structures to develop traveling waves through experiments.The results from this study provided the fundamental physics behind the generation of mechanical waves and their propagation through finite mediums. This research will consolidate the outcomes and develop a structural framework that will aid with the design of adaptable structural systems built for the purpose. The present work aims to generate and harness structural traveling waves for various applications. / Ph. D.

This last decade experienced a sudden increase of interest in the control of thermo-acoustic instabilities, in particular through the use of fuel modulation techniques. The primary goal of this research was to design, construct and characterize a high bandwidth proportional fuel injection system, which could be used to study the effect of specific levels of fuel modulation on the combustion process and the reduction of thermo-acoustic instabilities. A fuel injection system, incorporating the use of a closed loop piston and check valve, was designed to modulate the primary fuel supply of an atmospheric liquid-fueled swirl stabilized combustor operating at a mean volumetric fuel flow rate of 0.4 GPH. The ability of the fuel injection system to modulate the fuel was examined by measuring the fuel line pressure and the flow rate produced during operation. The authority of this modulation over the combustion process was investigated by examining the effect of fuel modulation on the combustor pressure and the heat release of the flame. Sinusoidal operation of the fuel injection system demonstrated: a bandwidth greater that 800 Hz, significant open loop authority (averaging 12 dB) with regards to the combustor pressure, significant open loop authority (averaging 33 dB) with regards to the unsteady heat release rate and an approximate 8 dB reduction of the combustor pressure oscillation present at 100 Hz, using a phase shift controller. It is possible to scale the closed loop piston and check valve configuration used to create the fuel injection system discussed in this work to realistic combustor operating conditions for further active combustion control studies. / Master of Science

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

Les matériaux actifs, tout d'abord piézoélectriques et piézo-électromagnétiques, sont souvent utilisés comme parties fonctionnelles de différents dispositifs électroniques, y compris les capteurs, les transducteurs et les actionneurs, car ces matériaux ont la possibilité de changer de forme sous le champ électrique ou magnétique. Dans de nombreux cas, la taille des appareils mentionnés est extrêmement petite, mais ils peuvent néanmoins être soumis à de très grands champs mécaniques, électriques et magnétiques. En outre, ces dispositifs sont habituellement construits en éléments pouvant être fabriqués avec différents matériaux (éléments piézoélectriques ou piézoélectro-magnétiques, électrodes, etc.).En raison d'une adhérence imparfaite des éléments mentionnés, différents défauts, comme le décollement et la délamination, peuvent se produire entre différents éléments. Ces situations peuvent avoir lieu lors de la fabrication et de l'exploitation des structures intelligentes actives. Les défauts mentionnés entre différents éléments constitutifs sont appelés fissures d'interface. Ces fissures sont généralement la cause principale de l'échec des constructions. Par conséquent, leur enquête est très importante pour éviter une telle défaillance et fournir la fiabilité des appareils électroniques. Différentes méthodes d'étude des problèmes de mécanique des fractures pour les corps piézoélectriques et piézoélectromagnétiques avec des fissures d'interface ont été développées jusqu'à présent. Les méthodes d'analyse des fissures d'interface dépendent essentiellement de la modélisation des conditions électriques sur les faces des fissures. Parce que les fissures sont habituellement remplies d'un milieu (air, huile de silicium, eau, etc.), il est souhaitable de tenir compte des propriétés de ce support. Pour cette raison, les modèles de fissuration perméables à l'électricité, imperméables et à perméabilité limitée sont développés et utilisés activement à l'heure actuelle. En outre, les faces des fissures peuvent parfois être recouvertes d'électrodes ou la fissure peut être remplie par un fluide conducteur. Dans les deux cas, le modèle de fissure électriquement conducteur doit être appliqué. De nombreux problèmes pour les fissures d'interface dans le cadre des modèles de fissure électriques mentionnés sont déjà résolus, mais certains problèmes importants restent résolus jusqu'à nos jours. La solution de ces problèmes définit les tâches de la présente enquête. Tout d'abord, il convient de mentionner que l'étude analytique des fissures d'interface avec des conditions électriques mixtes sur les faces des fissures est inconnue pour l'auteur de cette thèse. Par conséquent, la première tâche du travail est liée à l'étude d'une fissure d'interface dans un matériau thermique piézoélectrique sous l'action de charges mécaniques anti-avion mécaniques et planes, à condition qu'une partie des faces de fissure soit électriquement conductrice tandis qu'une autre soit électriquement perméable. En raison de la présentation des quantités électromécaniques via des fonctions analytiques en section, le problème est réduit au problème combiné de la valeur limite Dirichlet-Riemann et résolu exactement. Toutes les caractéristiques électromécaniques le long de l'interface, y compris les facteurs d'intensité de contrainte, se trouvent sous une forme analytique simple. La deuxième tâche est consacrée à la prise en compte d'une fissure d'interface électriquement conductrice avec une partie restante partiellement électrodéputée de l'interface matérielle sous le même système de chargement externe. Une attention particulière est accordée à la prise en compte du nouveau modèle de fissure d'interface, qui est exempt de l'oscillation dans le cas d'une interface complètement perméable (pas d'électrode) en dehors de la fissure. L'approche analytique basée sur la méthode des potentiels complexes est utilisée. (...) / Active materials, first of all piezoelectric and piezo-electro-magnetic ones, are often used as functional parts of different electronic devices including sensors, transducers and actuators because these materials have the ability to change their shape under electric or magnetic field. In many cases the size of the mentioned devices is relatively small, but nevertheless they can undergo to very large mechanical, electric and magnetic fields. Moreover, these devices are usually constructed of elements which can be manufactured of different materials (piezoelectric or piezoelectromagnetic elements, electrodes etc.). Because of an imperfect adhesion of the mentioned elements different defects, like debonding and delamination, can occur between different elements. These situations may take place during the manufacture and exploitation of the active smart structures. The mentioned defects between different constitutive elements are called interface cracks. These cracks are usually the main reason of constructions failure, therefore, their investigation is very important for avoidance of such failure and providing the reliability of electronic devices. Various methods of the investigation of fracture mechanics problems for piezoelectric and piezoelectromagnetic bodies with interface cracks have been developed up to now. The methods of interface crack investigations essentially depend on the modeling of the electrical conditions at the crack faces. Because cracks are usually filled with some medium (air, silicon oil, water and so on), it is desirable to take the properties of this medium into consideration. On this reason the so called electrically permeable, impermeable and limited permeable crack models are developed and actively used at present. Moreover, the crack faces can be sometimes covered with electrodes or the crack can be filled by conducting fluid. In both cases the so called electrically conducting crack model should be applied. Many problems for interface cracks in the framework of the mentioned electric crack models are already solved, however some important problems remains unresolved till nowadays. The solution of these problems defines the tasks of the present investigation. First of all it should be mentioned that the analytical investigation of interface cracks with mixed electrical conditions at the crack faces are unknown for the author of this thesis. Therefore the first task of the work is related to the investigation of an interface crack in a piezoelectric bimaterial under the action of antiplane mechanical and in-plane electric loadings provided that one part of the crack faces is electrically conducting whilst another one is electrically permeable. Due to the presentation of electromechanical quantities via sectionally-analytic functions the problem is reduced to the combined Dirichlet-Riemann boundary value problem and solved exactly. All electromechanical characteristics along the interface, including the stress intensity factors, are found in a simple analytical form. The second task is devoted to the consideration of a conductive crack and an electrode interaction at a piezoelectric bi-material interface under the action of anti-plane mechanical loading and in-plane electrical field parallel to the crack faces. Special attention is devoted to the consideration of new interface crack model, which is free from the oscillation in case of completely permeable interface (no electrode) outside of the crack. The analytical approach based upon complex potentials method is used. The third task is associated with the first one, but for piezoelectromagnetic material and an additional in-plane magnetic loading. The presentations of mechanical, electric and magnetic quantities via sectionally-analytic functions are found and the problems of linear relationship are formulated and solved exactly for any lengths of electro-magneto conducting and electro-magneto permeable parts of the crack. (...)