Piezoelectric polymer composites for sensors and actuators

As a result of the Internet of Things (IoT) and Industry 4.0 paradigms, based on increasing interconnectivity, the development of advanced high-performance materials for sensor and actuator applications are increasingly required. In particular, piezoelectric composites are of large scientific and technological interest from fundamental and applied point of views. Piezoelectric composites are applied in a wide range of applications as they combine the excellent properties of polymers and ceramics. The definition and properties of piezoelectric materials and composites are presented as well as the recent applications in areas such as electronics, energy harvesting, environmental sensors and biomedical applications. The outlook and future trends for piezoelectric composites are also provided.FCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of Strategic Funding grants UID/FIS/04650/2020, UID/EEA/04436/2020 and UID/QUI/0686/2020; and project no. PTDC/FISMAC/28157/2017, PTDC/BTM-MAT/28237/2017 and PTDC/EMDEMD/28159/2017. The authors also thank the FCT for financial support under grants SFRH/BD/145455/2019 (E.C.), SFRH/BD/145345/2019 (L.F.) and SFRH/BPD/112547/2015 (C.M.C.). Financial support from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06

NASA Tech Briefs, February 2005

Topics discussed include: Instrumentation for Sensitive Gas Measurements; Apparatus for Testing Flat Specimens of Thermal Insulation; Quadrupole Ion Mass Spectrometer for Masses of 2 to 50 Da; Miniature Laser Doppler Velocimeter for Measuring Wall Shear; Coherent Laser Instrument Would Measure Range and Velocity; Printed Microinductors for Flexible Substrates; Digital Receiver for Microwave Radiometry; Printed Antennas Made Reconfigurable by Use of MEMS Switches; Traffic-Light-Preemption Vehicle-Transponder Software Module; Intersection-Controller Software Module; Central-Monitor Software Module; Estimating Effects of Multipath Propagation on GPS Signals; Parallel Adaptive Mesh Refinement Library; Predicting Noise From Aircraft Turbine-Engine Combustors; Generating Animated Displays of Spacecraft Orbits; Diagnosis and Prognosis of Weapon Systems; Training Software in Artificial-Intelligence Computing Techniques; APGEN Version 5.0; Single-Command Approach and Instrument Placement by a Robot on a Target; Three-Dimensional Audio Client Library; Isogrid Membranes for Precise, Singly Curved Reflectors; Nickel-Tin Electrode Materials for Nonaqueous Li-Ion Cells; Photocatalytic Coats in Glass Drinking-Water Bottles; Fast Laser Shutters With Low Vibratory Disturbances; Series-Connected Buck Boost Regulators; Space Physics Data Facility Web Services; Split-Resonator, Integrated-Post Vibratory Microgyroscope; Blended Buffet-Load-Alleviation System for Fighter Airplane; Gifford-McMahon/Joule-Thomson Refrigerator Cools to 2.5 K; High-Temperature, High-Load-Capacity Radial Magnetic Bearing; Fabrication of Spherical Reflectors in Outer Space; Automated Rapid Prototyping of 3D Ceramic Parts; Tissue Engineering Using Transfected Growth-Factor Genes; Automation of Vapor-Diffusion Growth of Protein Crystals; Atom Skimmers and Atom Lasers Utilizing Them; Gears Based on Carbon Nanotubes; Patched Off-Axis Bending/Twisting Actuators for Thin Mirrors; and Improving Control in a Joule-Thomson Refrigerator

Integrated Actuation And Energy Harvesting In Prestressed Piezoelectric Synthetic Jets

With the looming energy crisis compounded by the global economic downturn there is an urgent need to increase energy efficiency and to discover new energy sources. An approach to solve this problem is to improve the efficiency of aerodynamic vehicles by using active flow control tools such as synthetic jet actuators. These devices are able to reduce fuel consumption and streamlined vehicle design by reducing drag and weight, and increasing maneuverability. Hence, the main goal of this dissertation is to study factors that affect the efficiency of synthetic jets by incorporating energy harvesting into actuator design using prestressed piezoelectric composites. Four state-of-the-art piezoelectric composites were chosen as active diaphragms in synthetic jet actuators. These composites not only overcome the inherent brittle and fragile nature of piezoelectric materials but also enhance domain movement which in turn enhances intrinsic contributions. With these varying characteristics among different types of composites, the intricacies of the synthetic jet design and its implementation increases. In addition the electrical power requirements of piezoelectric materials make the new SJA system a coupled multiphysics problem involving electro–mechanical and structural–fluid interactions. Due to the nature of this system, a design of experiments approach, a method of combining experiments and statistics, is utilized. Geometric and electro-mechanical factors are investigated using a fractional factorial design with peak synthetic jet velocity as a response variable. Furthermore, energy generated by the system oscillations is harvested with a prestressed composite and a piezo-polymer. Using response surface methodology the process is optimized under different temperatures and pressures to simulate harsh environmental conditions. Results of the fractional factorial experimental design showed that cavity dimensions and type of signal used to drive the synthetic jet actuator were statistically significant factors when studying peak jet velocity. The Bimorph (~50m/s) and the prestressed metal composite (~45m/s) generated similar peak jet velocities but the later is the most robust of all tested actuators. In addition, an alternate input signal to the composite, a sawtooth waveform, leads to jets formed with larger peak velocities at frequencies above 15Hz. The optimized factor levels for the energy harvesting process were identified as 237.6kPa, 3.7Hz, 1MΩ and 12°C and the power density measured at these conditions was 24.27µW/mm3. Finally, the SJA is integrated with an energy harvesting system and the power generated is stored into a large capacitor and a rechargeable battery. After approximately six hours of operation 5V of generated voltage is stored in a 330µF capacitor with the prestressed metal composite as the harvester. It is then demonstrated that energy harvested from the inherent vibrations of a SJA can be stored for later use. Then, the system proposed in this dissertation not only improves on the efficiency of aerodynamic bodies, but also harvests energy that is otherwise wasted

NASA Tech Briefs, December 2005

Topics covered include: Video Mosaicking for Inspection of Gas Pipelines; Shuttle-Data-Tape XML Translator; Highly Reliable, High-Speed, Unidirectional Serial Data Links; Data-Analysis System for Entry, Descent, and Landing; Hybrid UV Imager Containing Face-Up AlGaN/GaN Photodiodes; Multiple Embedded Processors for Fault-Tolerant Computing; Hybrid Power Management; Magnetometer Based on Optoelectronic Microwave Oscillator; Program Predicts Time Courses of Human/ Computer Interactions; Chimera Grid Tools; Astronomer's Proposal Tool; Conservative Patch Algorithm and Mesh Sequencing for PAB3D; Fitting Nonlinear Curves by Use of Optimization Techniques; Tool for Viewing Faults Under Terrain; Automated Synthesis of Long Communication Delays for Testing; Solving Nonlinear Euler Equations With Arbitrary Accuracy; Self-Organizing-Map Program for Analyzing Multivariate Data; Tool for Sizing Analysis of the Advanced Life Support System; Control Software for a High-Performance Telerobot; Java Radar Analysis Tool; Architecture for Verifiable Software; Tool for Ranking Research Options; Enhanced, Partially Redundant Emergency Notification System; Close-Call Action Log Form; Task Description Language; Improved Small-Particle Powders for Plasma Spraying; Bonding-Compatible Corrosion Inhibitor for Rinsing Metals; Wipes, Coatings, and Patches for Detecting Hydrazines; Rotating Vessels for Growing Protein Crystals; Oscillating-Linear-Drive Vacuum Compressor for CO2; Mechanically Biased, Hinged Pairs of Piezoelectric Benders; Apparatus for Precise Indium-Bump Bonding of Microchips; Radiation Dosimetry via Automated Fluorescence Microscopy; Multistage Magnetic Separator of Cells and Proteins; Elastic-Tether Suits for Artificial Gravity and Exercise; Multichannel Brain-Signal-Amplifying and Digitizing System; Ester-Based Electrolytes for Low-Temperature Li-Ion Cells; Hygrometer for Detecting Water in Partially Enclosed Volumes; Radio-Frequency Plasma Cleaning of a Penning Malmberg Trap; Reduction of Flap Side Edge Noise - the Blowing Flap; and Preventing Accidental Ignition of Upper-Stage Rocket Motors

A state-of-the-art assessment of active structures

A state-of-the-art assessment of active structures with emphasis towards the applications in aeronautics and space is presented. It is felt that since this technology area is growing at such a rapid pace in many different disciplines, it is not feasible to cover all of the current research but only the relevant work as relates to aeronautics and space. Research in smart actuation materials, smart sensors, and control of smart/intelligent structures is covered. In smart actuation materials, piezoelectric, magnetostrictive, shape memory, electrorheological, and electrostrictive materials are covered. For sensory materials, fiber optics, dielectric loss, and piezoelectric sensors are examined. Applications of embedded sensors and smart sensors are discussed

A Hybrid Technique of Energy Harvesting from Mechanical Vibration and Ambient Illumination

Hybrid energy harvesting is a concept applied for improving the performance of the conventional stand-alone energy harvesters. The thesis presents the analytical formulations and characterization of a hybrid energy harvester that incorporates photovoltaic, piezoelectric, electromagnetic, and electrostatic mechanisms. The initial voltage required for electrostatic mechanism is obtained by the photovoltaic technique. Other mechanisms are embedded into a bimorph piezoelectric cantilever beam having a tip magnet and two sets of comb electrodes on two sides of its substructure. All the segments are interconnected by an electric circuit to generate combined output when subjected to vibration and solar illumination. Results for power output have been obtained at resonance frequency using an optimum load resistance. As the power transduced by each of the mechanisms is combined, more power is generated than those obtained by stand-alone mechanisms. The synergistic feature of this research is further promoted by adding fatigue analysis using finite element method

วัสดุทรานสดิวเซอร์ผลิตจากสารไพอิโซอิเล็กตริกซ้อนหลายชั้น

Thesis (M.Sc., Physics)--Prince of songkla University, 200

Effect of piezoelectric actuation on curved beams and single lap joints

Piezoelectric materials have seen a significant usage increase over the past decade. They have been found to be effective as either sensors or actuators in smart structure applications, which allows them to act more as an adaptive system rather than a passive system. Piezoelectric materials are very effective transducers which convert mechanical energy into electrical energy, known as the direct piezoelectric effect or they have the ability to convert electrical energy to mechanical energy, known as the converse piezoelectric effect. The absence of additional mechanical parts, its lightweight and high strength to weight ratio is what make piezoelectric materials so attractive for many applications. Many existing studies have focused on surface bonding or embedding piezoelectric actuators to straight structures but in recent years, piezoelectric actuator performance has been investigated for curved bream applications. The aim of this thesis is twofold; first, the performance of piezoelectric actuators and their capability to reduce strain and counter balance an external load for both a tensile configuration and a bending configuration is investigated. Secondly, the performance of the piezoelectric actuator on a curved beam structure when system parameters are varied will be investigated. An analytical model, FEM and experimental results are obtained and compared for the curved beam. It was shown that when the piezoelectric actuator is placed at the joint location, it is more effective for the tensile configuration rather than the bending configuration. For the bending actuation, it was experimentally shown that the most effective actuator placement on the composite beam was region 1 in order to recover the most strain due to the external load. Preload actuation deemed more effective compared to post load actuation for both the single lap joint and curved beam. It was also shown that the deflection of the curved beam increased as the length of the piezoelectric actuator was increased. An actuator with a length of 15 mm positioned near the beam’s free end, proved to be the best choice for the beam configuration selected. The analytical model provided the total deflection, including the x and y component, which can be calculated by knowing Fp, â1, â2 and â3 respectively. The location of the actuator, as well as its size can be changed with â1 and â2. By altering the system parameters, parametric studies can be conducted to find the optimal location and size of the actuator that will provide the greatest deflection and find the minimal voltage required by the actuator. Therefore by performing the parametric studies, optimization can be obtained by using the piezoelectric actuator to counterbalance the external force and return the free end to its initial position. If multiple actuators are available, this study will not only be able to return the free end to its initial position but multiple actuators can be placed along the beam in order to bring multiple points back to its initial position

Thermo-mechanical design, realization and testing of screen-printed deformable mirrors

Die primäre Zielstellung dieser Dissertation ist die Entwicklung ungekühlter, unimorph deformierbarer Spiegel (DM) zum Ausgleich thermischer Linsen in Hochleistungslasersystemen. Die sekundäre Zielstellung ist die Entwicklung eines Herstellungsprozesses für DM, der hauptsächlich auf Waferleveltechnologien beruht und somit manuelle Prozesse reduziert.Der DM besteht aus einem Spiegelsubstrat auf dessen Rückseite eine piezoelektrische Schicht zwischen zwei Elektroden aufgebracht ist. Diese Art von Spiegeln wurde bereits erfolgreich in Hochleistungslasersystemen eingesetzt. Eine weitere Erhöhung der Laserleistungsdichte erfordert jedoch neue thermische Kompensationstechniken, bei der die Spiegelperformance nicht durch Temperaturschwankungen in der Spiegelbaugruppe vermindert wird.Ein hierfür entwickeltes Mehrlagendesign integriert mehrere Schichten in den Spiegelaufbau, dessen thermo-mechanische Parameter sich vom Substrat und der piezoelektrischen Schicht unterscheiden. Mittels analytischen Methoden und der Methode der finiten Elemente wurde eine Optimierung im Hinblick auf großen piezoelektrischen Hub und optimierte thermisch-induzierte Deformation durchgeführt. Diese wird entweder durch eine homogene Temperaturveränderung in der Spiegelmembran oder durch Absorption von Laserstrahlung generiert. Die dabei hervorgerufenen Veränderungen werden abhängig von Diskontinuitäten der piezoelektrischen Schicht, den mechanischen Randbedingungen, der spiegelnden Kupferschichtdicke und der Spiegelfassungsmaterialen simuliert.Ein aus sechs Arbeitsschritten bestehende Herstellungsprozess für DM mit siebgedruckter piezoelektrischer Aktorstruktur wurde entwickelt. Fünf Schritte sind davon auf Waferlevel prozessierbar. Einzig die Bearbeitung der Spiegelfläche mittels eines ultrapräzisen Drehprozesses ist keine Serienfertigung. Im Gegensatz zum Stand der Technik für DM ist die elektrische Verdrahtung der strukturierten Elektroden auch auf Waferlevel prozessierbar und das Spiegelsetup ist monolithisch.Thermisch induzierte Deformationen durch homogene Temperaturveränderung kann durch eine sog. zero deflection Konfiguration ausgeglichen werden. Laserinduzierte Deformationen werden mit gegenläufigen, thermisch homogen induzierten Deformationen kompensiert. Dieser Ansatz wird als Compound loading bezeichnet und in einem praktischen Spiegelaufbau umgesetzt. Im realisierten DM wird eine Deformation, induziert durch 1.3 W absorbierte Laserleistung, über eine homogene Temperaturerhöhung um 34 K kompensiert. Damit wird gezeigt, dass die entwickelten und vorwiegend mit parallelen Fertigungstechnologien hergestellten Spiegel für Hochleistungslaseranwendungen geeignet sind.Abstract: The primary objective of this thesis is the development of non-cooled deformable unimorph mirrors (DM) for thermal lensing compensation in high-power laser systems. The secondary objective is the development of a manufacturing regime that consists mainly of batch-fabrication and reduced manual processes. The DM consists of a mirror substrate with a piezoelectric layer sandwiched between two electrodes, bonded on the mirror’s rear surface. These types of mirror have been successfully integrated into high-power laser systems; however, further increase in laser power requires new thermal compensation techniques in which the DMs performance is not affected by temperature changes in the mirror assembly.To achieve this objective, a multi-layer design was studied. The multi-layer design integrates several layers with thermo-mechanical parameters that differ from the substrate and the active layer into the mirror set-up. Beginning with this set-up, an optimization is performed with regard to the required large piezoelectric stroke and low thermally-induced deflection by analytical and finite element modelling. The thermally-induced deflection of the multi-layer is distinguished by their source into homogeneous thermal loading and inhomogeneous laser loading. The mirror response upon piezoelectric activation and both thermal loadings was simulated with respect to piezoelectric layer discontinuity, different mechanical boundary conditions, reflective copper-layer thickness, and mirror mount materials.The manufacturing regime of screen-printed piezoelectric DM is developed. The manufacturing process comprises six steps out of which five are batch-fabrication techniques. The mirror surface finishing by means of an ultraprecise turning process alone does not involve batch fabrication. In contrast to state-of-the-art deformable mirror technologies, the electric wiring of the addressing electrodes of the deformable mirror is also batch-fabricated and the mirror set-up is monolithic.The thesis presents possible concepts to compensate for thermally-induced mirror deformation. Thermally-induced deformation by homogeneous loading is balanced by the zero deflection configuration of the multi-layer. The compensation for laser-induced deformation can be achieved by homogeneous thermal loading that can compensate as the deformation caused by the loading opposes the laser-induced deformation. This approach is referred to as compound loading, and it is investigated in a practical mirror set-up. Here, a 1.3-W absorbed laser power is compensated by a 34-K homogeneous loading. It is concluded that the developed and mainly batch-fabricated DM are suitable for high-power laser applications