Topic
Bimorph
About: Bimorph is a research topic. Over the lifetime, 3339 publications have been published within this topic receiving 51880 citations.
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TL;DR: The bimorph matrix is diagonalized and eigenvalues and eigens are found for the extremes of nonpiezoelectric and strong piezoeLECTric coupling and a physical interpretation of the eigen Values and Eigenstates is proposed.
Abstract: The networks associated with the bimorph matrix are presented. The bimorph matrix is diagonalized and eigenvalues and eigenstates are found for the extremes of nonpiezoelectric and strong piezoelectric coupling. A physical interpretation of the eigenvalues and eigenstates is proposed. The bimorph matrix is also diagonalized through elementary operation matrices, which give the matrix in equivalent form. The transformation matrices are of upper triangular form. This transformation yields networks of the simplest possible connection schemes. It is shown that when fewer than the maximum number of boundary conditions are applied, the networks are easily simplified. The networks of the admittance and impedance matrix are presented. >
28 citations
TL;DR: A system of two-dimensional, first-order equations for electroded piezoelectric crystal plates with general symmetry and thickness-graded material properties recently was deduced from the three-dimensional equations of linear piezOElectricity, showing that the agreement is close.
Abstract: A system of two-dimensional, first-order equations for electroded piezoelectric crystal plates with general symmetry and thickness-graded material properties recently was deduced from the three-dimensional equations of linear piezoelectricity. These equations are simplified for the two limiting cases of thickness-graded piezoelectric properties, i.e., the homogeneous plate and bimorph of piezoelectric ceramics. Closed-form solutions are obtained from these reduced equations for the flexural and thickness-shear vibrations and static response of bimorph disks as well as for the extensional and thickness-stretch vibrations of homogeneous disks. Frequency spectra and modes are computed and examined. Resonance frequencies for both homogeneous and bimorph disks of PZT-857 are computed and measured. The comparison of the results shows that the agreement is close.
27 citations
TL;DR: In this paper, a laminated general quadrilateral shell finite element with eight nodes and curved edges is developed for turbomachinery applications and the mathematical formulation of the element is described.
Abstract: Piezoelectric materials are becoming increasingly popular in the emerging field of adaptive structures. In particular, active control of wings and helicopter rotors using these materials is being pursued currently. The present work is an effort at modeling piezoelectric actuated blades for turbomachinery applications. A laminated general quadrilateral shell finite element with eight nodes and curved edges is developed for this purpose. the mathematical formulation of the element is described. Experiments have been conducted on a commercially available piezoceramic bimorph. Our finite-element and experimental results are shown to match very well. The laminated element developed is then used to perform a static analysis of typical turbomachinery blades. Effects of the angle of pre-twisting and aspect ratio have been studied. PVDF and PZT piezoelectric materials have been compared.
27 citations
TL;DR: In this article, an exact analytical solution is presented to calculate the power generated from vibration of exponentially tapered unimorph and bimorph with series and parallel connections, and the steady states harmonic solution results are verified both numerically and experimentally.
Abstract: It has been proven that tapering the piezoelectric beam through its length optimizes the power extracted from vibration based energy harvesting. This phenomenon has been investigated by some researchers using semianalytical, finite element and experimental methods. In this paper, an exact analytical solution is presented to calculate the power generated from vibration of exponentially tapered unimorph and bimorph with series and parallel connections. The mass normalized mode shapes of the exponentially tapered piezoelectric beam with tip mass are implemented to transfer the proposed electromechanical coupled equations into modal coordinates. The steady states harmonic solution results are verified both numerically and experimentally. Results show that there exist values for tapering parameter and electric resistance in a way that the output power per mass of the energy harvester will be maximized. Moreover it is concluded that the electric resistance must be higher than a specified value for gaining more power by tapering the beam.
27 citations
TL;DR: In this article, a new theoretical model for photovoltaic effect first, then enhanced performance through sample thickness and surface characteristics, finally its potential future applications are discussed. But, for the fabrication of these devices, higher response speed must be achieved.
Abstract: Photostrictive materials, exhibiting light-induced strains, are of interest for future generation wireless remote control photo-actuators, micro-actuators, and micro-sensors applications. (Pb, La)(Zr, Ti) O3 (PLZT) ceramics doped with WO3 exhibit large photostriction under uniform illumination of near-ultraviolet light. Using a bimorph configuration, a photo-driven relay and a micro walking device have been demonstrated. However, for the fabrication of these devices, higher response speed must be achieved. The present paper reviews a new theoretical model for photovoltaic effect first, then enhanced performance through sample thickness and surface characteristics, finally its potential future applications.
27 citations