Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 70 for “"piezoelectric material"”.
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High temperature ultrasonic gas flow sensor based on lead free piezoelectric material
… over alternatives. Weakness of current piezoelectric based transducers are identified as the inability to operate at temperatures above 400 °C due to limitation of piezoelectric materials used, and a case for development of an alternative high temperature material is put forward. A novel …
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Optimization of a Plate Beam System for Energy Harvesting Using a Piezoelectric Material
… of the potential of energy harvesting with smart materials technology and its practical applications. The energy harvesting system considered here works on generating energy through vibrations of a piezoelectric material beam which will undergo sustained vibrations due to flow of air over its …
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Theory of piezoelectric materials and their applications in civil engineering
… mechanical energy into electrical energy using piezoelectric materials is studied. Applications of piezoelectric materials as actuators are also explored, with particular interest in the question: what is the maximum moment that an actuator, whose energy comes from piezoelectricity, can develop …
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An evaluation of critical issues for microhydraulic transducers : silicon wafer bonding, strength of silicon on insulator membranes and gold-tin solder bonding
… which combine microfabrication technology and piezoelectric materials, requires the use of variety of materials and fabrication technologies that are not fully developed. Three materials and structures issues, which are essential to the development of MHT devices, are silicon wafer bonding, …
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Shape Optimization of Microfiber Composite Energy Harvesters
<p>A model of energy harvesting beam with a piezoelectric material, microfiber composite (MFC), in a unimorph configuration was setup in Matlab using the governing equations of motions of a coupled electromechanical system. The equations of motion were derived using Hamilton’s variational …
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Deformation and Force Characteristics of Laminated Piezoelectric Actuators
… the mechanical characteristics of laminated piezoelectric actuators that are manufactured at an elevated temperature, to cure the adhesive bonding the layers together, or to cure the layers made of polymeric composite material, and then cooled to a service temperature. Mainly discussed are …
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Application of smart materials for vibration reduction in ships
Smart Materials have been investigated for decades and widely used in the automotive and aeronautics industries to measure and control noise and vibration. This study covered ship structure vibration and Smart Materials were employed for the purpose of ship vibration attenuation. One specific Smart …
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Characterization of Laminated Magnetoelectric Vector Magnetometers to Assess Feasibility for Multi-Axis Gradiometer Configurations
… exists to a limited degree in single phase materials, it is more easily achieved by laminating a magnetostrictive material, which deforms when exposed to a magnetic field, to a piezoelectric material. The transfer of strain from the magnetostrictive material to the piezoelectric material …
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Determination of Frequency-Based Switch Triggers for Optimal Vibration Reduction via Resonance Frequency Detuning
Resonance frequency detuning (RFD) is a piezoelectric-based vibration reduction approach that applies to systems experiencing transient excitation through the system*s resonance—for example, turbomachinery experiencing changes in rotation speed, such as on spool-up and spool-down. This technique …
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Modeling and Validation of S-Drive: A Nestable Piezoelectric Actuator
This dissertation introduces a novel, nestable piezoelectric actuator, called the s-drive. In the s-drive actuator, the piezoelectric material is sandwiched between two conductors, and the electrodes are configured such that an application of a voltage causes an extension on two beams and …
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An electromechanical system for characterization of piezoelectric materials
Piezoelectric materials have been used in medical applications for a long time due to their unique characteristics, which is to respond to mechanical stimulation by producing an electrical current and vice versa. They perform a pivotal role in medical applications both for diagnostic and …
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Equilibrium of a shallow arch subjected to PZT actuators and a deadweight load
… is presented. The panel is a laminate of piezoelectric material perfectly bonded to the convex and concave surfaces of a core of passive material. Since the curved edges are free and the straight edges are pinned a fixed distance apart, the response of the panel is independent of the axial …
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Multi Array, Conformable Ultrasound Patch for Soft Tissue Imaging
… transducer is dictated by the properties of the piezoelectric material being used. One current drawback to ultrasound is that it is heavily operator dependent. This has motivated research into developing ultrasound systems that are conformable to the body and capable of obtaining relevant …
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Design of test bench apparatus for piezoelectric energy harvesters
… test bench for the characterization of piezoelectric microelectromechanical system (MEMS) energy harvester being developed by the Micro & Nano Systems Laboratory research group at MIT. Piezoelectric MEMS energy harvesters are micro-devices that are able to harvest energy from their …
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The utilization of piezoelectric materials and optical fiber sensors for electric field detection
… sensor, and the actuation produced by a piezoelectric material when placed in an electric field. Classical electromagnetic theory is used to mathematically model the performance of the sensor within a given electric field. Experimental and theoretical results are presented which …
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Materials and device design for MEMS piezoelectric mechanical vibration energy harvesters
Piezoelectric vibration energy harvesters (PVEHs) for microelectromechanical systems (MEMS) have received considerable attention as an enabling technology for self-powered wireless sensor networks. MEMS-PVEHs are particularly attractive because of the potential to deliver power indefinitely and …
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Design, fabrication, and characterization of a lithium niobate optomechanical photodetector based on released whispering-gallery-mode microdisk resonators
Lithium Niobate (LiNbO3) is a piezoelectric material that also exhibits promising optical characteristics such as low optical loss and high electro-optic coefficient, making it an interesting choice for Radio Frequency (RF) micro-opto-electro-mechanical systems (MOEMS) and devices, electro-optical …
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A Multi-functional Touch Panel for Multi-Dimensional Sensing in Interactive Displays
… while force sensing in the z-direction is by a piezoelectric PVDF/graphene sandwich. By employing different frequency bands for the capacitive- and force-induced electrical signals, the two stimuli are detected simultaneously, achieving three-dimensional touch sensing. Static force sensing and …
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Low resonant frequency beam design for a piezoelectric energy harvesting device
… batteries. Using MEMS technology, a thin film Piezoelectric Micropower Generator device could be constructed. The PMPG is simply a cantilever structure tuned to resonate at environmental frequencies. At resonance, sizable strain is induced in a layer of the beam made from the piezoelectric …
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Modeling a piezoelectric flag as a membrane for energy harvesting
The goal of this research is to model a piezoelectric flag as a membrane for the sake of energy harvesting. Typically, a flag is modeled as a beam, but it is modeled as a membrane in this study with the hopes of more accurately describing the dynamics of the system. Following this is an overview of …
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