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Among the MEMS field, the design and simulation of piezoelectric micro-actuators are difficult as compared to thermal micro-actuators and electrostatic micro-actuators. The main reason of the piezo-electric material coupling effect is difficult to calculate. However the piezo-electric material has several advantages and characteristics for designing micro-actuators. Moreover, the design is usually done by the experimental or try-and-error method which is not so effective. It should be noted that there is not a simple method already developed for the design and simulation of the piezo-electric micro-actuators. In this research we proposed to use the software of ANSYS for the simulation of piezo-electric micro-pump. Simulation of force output of piezo-micro-pump can use ANSYS software to establish the simulation system of piezo-micro-pump. The micro-pump will have different resonance frequency, back-pressure and fluid due to piezo-electric characteristic. In this study, the author used a square, rectangle and circle geometric shape to simulate the result, each geometric shape has four different kinds of size. As a result, there are twelve groups of different simulation results. We are able to using the chart to present and explain the relation between resonance frequency and displacement.

Increasing demand for precision components made of hard and brittle materials such as glasses, steel alloys and advanced ceramics, is such that conventional grinding and polishing techniques can no longer meet the requirements of today's precision manufacturing engineering. Particularly, in order to undertake micro-milling of optical glasses or other hard-machining materials, vibration assisted machining techniques have been adopted. However, it is essential and much needed to undertake such processes based on a scientific approach, i.e. the process to be quantitatively controlled and optimized rather than carried out with a trial-and-error manner. In this research, theoretical modelling and instrumental implementation issues for vibration assisted micro-milling are presented and explored in depth. The modelling is focused on establishing the scientific relationship between the process variables such as vibration frequency, vibration amplitude, feedrate and spindle speed while taking into account machine dynamics effect and the outcomes such as surface roughness generated, tool wear and material removal rate in the process. The machine dynamics has been investigated including a static analysis, machine tool-loop stiffness, modal analysis, frequency response function, etc, carried out for both the machine structure and the piezo-actuator device. The instrumentation implementation mainly includes the design of the desktop vibration assisted machining system and its control system. The machining system consists of a piezo-driven XY stage, air bearing spindle, jig, workpiece holder, PI slideway, manual slideway and solid metal table to improve the system stability. The control system is developed using LabVIEW 7.1 programming. The control algorithms are developed based on theoretical models developed by the author. The process optimisation of vibration assisted micro-milling has been studied by using design and analysis of experiment (DOE) approach. Regression analysis, analysis of variance (ANOVA), Taguchi method and Response Surface Methodology (RSM) have been chosen to perform this study. The effects of cutting parameters are evaluated and the optimal cutting conditions are determined. The interaction of cutting parameters is established to illustrate the intrinsic relationship between cutting parameters and surface roughness, tool wear and material removal rate. The predicted results are confirmed by validation experimental cutting trials. This research project has led to the following contribution to knowledge: (1) Development of a prototype desktop vibration assisted micro-milling machine. (2) Development of theoretical models that can predict the surface finish, tool wear and material removal rate quantitatively. (3) Establishing in depth knowledge on the use of vibration assisted machining principles. (4) Optimisation of cutting process parameters and conditions through simulations and machining trials for through investigation of vibration assisted machining.

Les matériaux magnéto-électro-élastiques (MEE) sont l'association des matériaux piézo-électrique et piézo-magnétique qui présentent un couplage "magnéto-électrique". L'objectif de cette thèse est d'étudier d'une part, le comportement effectif de ces composites et d'autre part, la propagation des ondes planes dans le milieu homogène équivalent. Dans la première partie de la thèse, nous avons modélisé le comportement effectif des composites MEE à partir de la méthode de la moyenne. Nous avons d'abord établi les équations générales, ensuite nous avons traité le cas où chaque phase est supposée isotrope transverse suivant un axe et polarisée suivant la même direction. La loi de comportement obtenue, ainsi que les tenseurs effectifs du milieu homogène équivalent ont été établis. Les propriétés élastiques effectives sont influencées par les propriétés électriques et magnétiques et réciproquement. Nous nous sommes intéressés en particulier à deux types de composites : les stratifiés et les fibres longues. L'influence de la géométrie des constituants ainsi que la proportion des phases sur le comportement effectif ont été étudiées. La deuxième partie du travail a porté sur l'étude de la propagation d'ondes planes dans les stratifiés. En utilisant la méthode d'homogénéisation périodique, nous avons obtenu les équations de la dynamique dans le milieu homogène équivalent. La longueur d'onde considérée est supposée grande devant la périodicité spatiale. Une méthode de résolution numérique a été développée afin d'obtenir les courbes de dispersion. Nous avons obtenu ces courbes en fonction des proportions des phases constitutives. Bien que les trois propriétés: élastique, électrique, magnétique, contribuent au comportement oscillatoire global, l'onde conserve essentiellement une nature élastique. / The objective of this thesis is estimating fundamental properties and studying the propagation of waves in the equivalent homogeneous medium based on the periodic magneto-electro-elastic (MEE) composite. These artificial MEE media are realized by means of combining piezo-electric and piezo-magnetic materials, and featurea direct "magneto-electric" coupling. In the first part, we modeled the effective behavior of these composites applying the averaging method. First, we derived the general equations, then we treated a particular case a uni axial medium comprised of alternating layers of piezo-electric and piezo-magnetic phases and polarized in the direction normal to the surfaces of these layers. The law of behavior was obtained as well as the effective tensors of the equivalent homogeneous medium. The effective elastic properties are influenced by the magnetic and electrical properties and inversely. We were particularly interested in two types of materials: multi-layers (planar symmetry) and long fibers (cylindrical symmetry). The influence of the geometry of these components on the effective behavior was revealed. The second part of the study focuses on the propagation of plane waves in the case of periodic multilayer structures. Using the periodic homogenization method, we obtained the effective tensors and the equations of propagation of elasto-electro-magnetic plane waves. The wavelength is supposed much larger than the spatial period of the investigated structure, hence the quasi-static approximation for the equations of electromagnetic could be used. The chosen method has allowed estimation of the wave frequency as a function of the wave number, the corresponding dispersion curves were plotted for a wide range of proportions of the constituent materials. Although all the three properties, mechanical, electrical and magnetic contribute to the global oscillatory behavior, the wave is essentially elastic.

Nagrinėjama pjezoelektrinės pavaros pozicionavimo tikslumas ir pjezoelemento suveikimo laikas. Aprašomas tiriamas objektas, jo valdymo įrenginiai ir bandymams naudojama aparatūra. Aptariami atliktų bandymų rezultatai. Pateikiamos išvados ir rekomendacijos. / The piezoelectric drive positioning accuracy and the piezo element play time are analyzed in the paper. The investigated object, its control and equipment for testing are described. Experimentation results are analyzed. Conclusion and recommendations are given.

Researchers have offered a variety of solutions for overcoming the old and challenging problem of undesired vibrations. The optimum vibration-control solution that can be a passive, semi-active or active solution, is chosen based on the desired level of vibration-control, the budget and the nature of the vibration source. Mechanical vibration-control systems, which work based on variable stiffness control, are categorized as semi-active solutions. They are advantageous for applications with multiple excitation frequencies, such as seismic applications. The available mechanical variable stiffness systems that are used for vibration-control, however, are slow and usually big, and their slowness and size have limited their application. A new semi-active variable stiffness solution is introduced and developed in this thesis to address these challenges by providing a faster vibration-control system with a feasible size. The new solution proposed in this thesis is a semi-active variable stiffness mount/isolator called the antagonistic Variable Stiffness Mount (VSM), which uses a variable stiffness spring called the Antagonistic Variable stiffness Spring (AVS). The AVS is a kinematically singular prestressable mechanism. Its stiffness can be changed by controlling the prestress of the mechanisms links. The AVS provides additional stiffness for a VSM when such stiffness is needed and remains inactive when it is not needed. The damping of the VSM is constant and an additional constant stiffness in the VSM supports the deadweight. Two cable-mechanisms - kinematically singular cable-driven mechanisms and Prism Tensegrities - are developed as AVSs in this thesis. Their optimal configurations are identified and a general formulation for their prestress stiffness is provided by using the notion of infinitesimal mechanism. The feasibility and practicality of the AVS and VSM are demonstrated through a case study of a typical engine mount by simulation of the mathematical models and by extensive experimental analysis. A VSM with an adjustable design, a piezo-actuation mechanism and a simple on-off controller is fabricated and tested for performance evaluation. The performance is measured based on four criteria: (1) how much the VSM controls the displacement near the resonance, (2) how well the VSM isolates the vibration at high frequencies, (3) how well the VSM controls the motion caused by shock, and (4) how fast the VSM reacts to control the vibration. For this evaluation, first the stiffness of the VSM was characterized through static and dynamic tests. Then performance of the VSM was evaluated and compared with an equivalent passive mount in two main areas of transmissibility and shock absorption. The response time of the VSM is also measured in a realistic scenario.

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Ferroelectric materials are very promising for a variety of applications such as high-permittivity capacitors, ferroelectric memories, pyroelctric sensors, piezoelectric and electrostrictive transducers and electro-optic devices, etc. In the area of ferroelectric ceramics, lead-based compounds, which include lead zirconatetitanate (PZT) solid solutions, occupy an important place because of their superior physical properties. However, due to the toxicity of lead, there is an increasing concern over recycling and disposing of the devices made out of these compounds, which has compelled the researchers around the globe to search for lead-free compounds with promising piezo and ferroelectric properties. Ferroelectric materials that belong to Aurivillius family of oxides have become increasingly important from the perspective of industrial applications because of their high Curie-temperatures, high resistivity, superior polarization fatigue resistanceand stable piezoelectric properties at high temperatures. These bismuth layer-structured ferroelectrics (BLSF) comprise an intergrowth of [Bi2O2]2+ layers and [An+1Bn O3n+1]2- pseudo-perovskite units, where ‘n’ represents the number of perovskite-like layers stacked along the c-axis. ‘A’ stands for a mono-, di- or trivalent ions or a combination of them, ‘B’ represents a small ion with high valencysuch as Ti4+, Nb5+, Ta5+or a combination of them.Ferroelectricity in the orthorhombic phase of these compounds was generally attributed to the cationic displacement along the polar a-axis and the tilting of octahedra around the a- and c-axes. Sr2Bi4Ti5O18(SBT) is ann = 5 member of the Aurivillius family and possess promising ferroelectric and piezoelectric properties that could be exploited for a wide range of applications, including ferroelectric random access memories (FeRAM), piezoelectric actuators, transducers and transformers. Reports in the literaturereveal that the ferroelectricand piezoelectric properties of these oxides can be tuned depending on synthesis routes vis-a-vis micro-structural aspects (texture, grain size) and site specific dopant substitutions.In the present study, textured SBT ceramics were fabricated using pre-reacted precursors and their anisotropic dielectric, piezoelectric and ferroelectric properties were demonstrated. Grain size tunability with regard to their physical properties was accomplished in the ceramics, fabricated using fine powders obtained from citrate assisted sol-gel synthesis. The grain size dependent second harmonic generation activity of SBT ceramics was investigated. Enhancement in the piezoelectric and ferroelectric properties of SBT ceramics was achieved by substituting A site ions (Sr2+) with a combination of Na+ and Bi3+. From the perspective of non-linear optical device applications, physical properties associated with the SBT crystallized in a transparent lithium borate glass matrix were studied. The results obtained in the present investigations are organized as follows, Chapter 1 gives a brief exposure to the field of ferroelectrics. The emphasis has been on the ferroelectric oxides belonging to the Aurivillius family. Structural aspects and the underlying phenomena associated with ferroelectricity in these compounds are discussed. A brief introduction to the glasses, thermodynamic aspects of glass formation and fabrication of glass- ceramics are included. Basic principles involved in the non-linear optical activities are highlighted. Chapter 2 describes the various experimental techniques that were employed to synthesize and characterize the materials under investigation. The experimental details pertaining to the measurement of various physical properties are included. Chapter 3 deals with the fabrication of Sr2Bi4Ti5O18 ceramics using the pre-reacted Bi4Ti3O12 and SrTiO3 powders viasolid-state reaction route. These in stoichiometric ratio were uniaxially pressed and sintered at 1130oC for 3 h resulting in textured Sr2Bi4Ti5O18 ceramics. The obtained dense ceramics exhibited crystallographic anisotropy with prominent c-axis oriented grains (Lotgering factor of 0.62) parallel to the uniaxially pressed direction. The resultant anisotropy in the ceramics was attributed to the reactive template-like behavior of Bi4Ti3O12 that was used as a precursor to fabricate Sr2Bi4Ti5O18 ceramics. Dielectric, ferro and piezoelectric properties measured on the ceramics in the direction perpendicular to the uniaxially pressed axis were found to be superior to that measured in the parallel direction. Chapter 4 reports the details pertaining to the synthesis of strontium bismuth titanate (Sr2Bi4Ti5O18) powders comprising crystallites of average sizes in the range of 94–1400 nm via citrate-assisted sol-gel route. X-ray powder diffraction, Transmission Electron Microscopy (TEM) and Raman spectroscopy were employed for the structural studies. A crystallite size-dependent variation in the lattice parameters and the shift in the Raman vibration modes were observed. Second harmonic signal (532 nm) intensity of the Sr2Bi4Ti5O18 powders increased with the increase in the average crystallite size and the maximum intensity obtained in the reflection mode was 1.4 times as high as that of the powdered KH2PO4. Piezo force microscopic analyses carried out on an isolated crystallite of size 74 nm, established its single domain nature with the coercive field as high as 347 kV/cm. There was a systematic increase in the d33 value with an increase in the size of the crystallite and a high piezoelectric coefficient of ~27 pm/V was obtained from an isolated crystallite of size 480 nm. Chapter 5 illustrates the details concerning the fabrication of Sr2Bi4Ti5O18(SBT) ceramics with different grain sizes (93 nm–1.42 μm) using nano-crystalline powders synthesized via citrate assisted sol-gel method. The grain growth in these powder compacts was found to be controlled via the grain boundary curvature mechanism, associated with anactivation energy of 181.9 kJ/mol. Interestingly with a decrease in grain size there was an increase in the structural distortion which resulted in a shift of Curie-temperature (phase transition) towards higher temperatures than that of conventional bulk ceramics. Extended Landau phenomenological theory for the ferroelectric particles was invoked to explain experimentally observed size dependent phase transition temperature and the critical size for SBT is predicted to be 11.3 nm. Grain size dependent dielectric, ferroelectric and piezoelectric properties of the SBT ceramics were studied and the samples comprising average grain size of 645 nm exhibited superior physical properties that include remnant polarization (2Pr) = 16.4 μC cm-2, coercive field (Ec) = 38 kV cm-1, piezoelectric coefficient (d33) = 22 pC N-1 and planar electromechanical coupling coefficient (kp) = 14.8 %. In Chapter 6, the studies pertaining to the fabrication of Sr(2-x)(Na0.5Bi0.5)xBi4Ti5O18 (SNBT) ceramics for various x values (0, 0.1, 0.25, 0.3, 0.4 and 0.5), using fine powders synthesized via sol-gel route are dealt with. X-ray powder diffraction, transmission electron microscopy and Raman spectroscopic studies were carried out to confirm composition dependent structural changes taking place in the SNBT ceramics. Scanning electron microscopic studies carried out on ceramics revealed that dopants played an important role in inhibiting the grain growth. Dielectric constants of the ceramics were found to decrease with an increase in ‘x’. The increase in Curie temperature with increase in ‘x’ is attributed to the decrease in the tolerance factor. Particularly,x = 0.3 composition of the SNBT ceramics exhibited better piezo and ferroelectric properties with a higher Curie-temperature (569 K). The piezoelectric coefficient (d33) and the planar electromechanical coupling coefficient (kp) of SNBT(x = 0.3) were enhanced by 25% and 42% respectively as compared to that of the undoped ceramics. Chapter 7 deals with the glasses in the system (100 –x) {Li2O + 2B2O3} ─x {2SrO + 2Bi2O3 +5TiO2} (where, x = 10, 25 and 35) fabricated via conventional melt-quenching technique. The amorphous and glassy characteristics of the samples were confirmed respectively using X-ray diffraction (XRD) and differential scanning calorimetric (DSC) methods. All the compositions under investigation exhibited two distinct crystallization peaks (exothermic peaks in the DSC traces): the first peak at ~ 545 °C and the second at ~610 °C that were found to be associated with the crystallization of the phases (as confirmed from the XRD studies) Sr2Bi4Ti5O18 (SBT)and Li2B4O7 (LBO) respectively. Non-isothermal crystallization kinetics (using modified Ozawa-type plots) for SBT crystallization in the LBO glass matrix for the compositions x = 10 and 35, indicated three dimensional growth of the crystallites from pre-existing nuclei present in the as-quenched samples and their effective activation energies for crystallization were found to be around 686 ± 85 kJ/mol and 365 ± 53 kJ/mol, respectively. The optical band gap of the as-quenched glasses for the composition x = 35 was 2.52 eV, is less than that of the composition x = 10 (2.91 eV). The Urbach energies for the as-quenched glasses of compositions x = 10, 25 and 35 were found to be 118 ± 2 meV, 119 ± 2 meV and 192 ± 1 meV respectively.The glasses associated with the composition x = 35, on controlled heat-treatment at 515 °C for various durations (1―20 h), yielded glass-ceramics comprising SBT nano-crystals (18―28 nm) embedded in the LBO glass matrix. Compressive strain in the nano-crystallites of SBT, analyzed using Williamson-Hall method was found to decrease with an increase in the crystallite size. The second harmonic generation signal (532 nm) intensity emanating from glass-nanocrystal composites comprising 22.1 nm SBT crystallites was nearly 0.3 times that of a KDP single crystal. Although each chapter is provided with conclusions and a list of references, thesis ends with a separate summary and conclusions.

Im ESF geförderten Projekt E-PISA sind verschiedene, hoch innovative, von der globalen Forschungslandschaft ausgezeichnete und gleichzeitig industrierelevante technische Entwicklungen im Bereich der Mikrosystemtechnik, Medizintechnik und Industrie 4.0 vorangetrieben worden. Fokus der technischen Entwicklung waren zum einen Grundlagenforschung und zum anderen Applikationen von Mikrosystemen auf Basis piezoelektrischer Dünnschichten mit Aluminiumnitrid und Elektronik mit Carbon-Nano-Tubes.:Liebe LeserInnen, 5 E-PISA Team 6 Innovative Applikationen 11 Innovative Technologien 13 Regionaler Bezug 15 Wissenstransfer in Zahlen 17 Piezoelektrisches Dünnschicht-Aluminiumnitrid für Mikrosysteme 19 Mikro-opto-elektro-mechanische Systeme 23 Acoustic Emission Sensoren 29 Drucksensoren für medizinische Katheter 33 Kristallwachstum 37 Innovationssysteme, Märkte und Forschungsnetzwerke 45 Zuverlässigkeit piezoelektrischer Schichtsysteme der Mikrotechnologie 51 Veröffentlichungen und Auszeichnungen 53 Zukunftsfähigkeit 61 Danksagung 63