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: In this article, the linear, three-dimensional, piezoelectric equations for a body in equilibrium are reduced to approximate, two-dimensional ones, treating the flexure of thin bimorphs, partly coated by electrodes (incomplete bimomorphs).
Abstract: In this paper the linear, three-dimensional, piezoelectric equations for a body in equilibrium are reduced to approximate, two-dimensional ones, treating the flexure of thin bimorphs, partly coated by electrodes (incomplete bimorphs). For that purpose two-dimensional equations are derived for piezoelectric plates and for bimorphs with completely coated faces. An assumption about the charge distribution on the inner electrode is given, stating that the charge vanishes on those parts where the outer faces are free of electrodes. This assumption allows the application of the mentioned, approximate equations for plates and bimorphs to the parts of incomplete bimorphs. By stating edge and continuity conditions, the approximate theory ls completed. The solution for a circular, incomplete, piezoceramic bimorph, loaded by a singular force in the centre, is given and compared with experimental results.
12 citations
TL;DR: In this article, a new cantilever design was developed, which decreases the cantilevers sensitivity to in situ stresses and thermal bimorph effects by using polycrystalline silicon and silicon oxide.
Abstract: This note reports on cantilever-based sensor elements coated with a hydrogel. The hydrogel responds with a volume change on varying the pH value of surrounding liquids. The change in volume leads to a static deflection of the cantilevers, which is detected using integrated piezoresistors. To increase deflection sensitivity of the sensor elements, sub-micron, multilayered cantilevers consisting of polycrystalline silicon and silicon oxide are used. A new cantilever design is developed, which decreases the cantilever sensitivity to in situ stresses and thermal bimorph effects. A theoretical model for the sensor elements is introduced providing the output signal of multiple cantilevers connected in a full Wheatstone bridge. Measurements of deflection sensitivity prove the theoretical model. Finally, the cantilevers are coated with a 2-hydroxyethyl methacrylate and 2-(dimethylamino) ethyl methacrylate copolymer-based hydrogel, and changes in the pH value from pH 4 to pH 10 are measured.
12 citations
TL;DR: In this article, bimorph piezoelectric fiber actuators are used to enable tip and tilt control in fiber collimators, as well as their integration into a fiber-array based beam-projection system.
Abstract: We describe bimorph piezoelectric fiber actuators, which enable tip and tilt control in fiber collimators, as well as their
integration into a fiber-array based beam-projection system. A mechanism for alignment of individual fiber actuators
within the array was developed. It provides six degrees of freedom and allows for high subaperture density. The
alignment procedures for a seven-subaperture prototype system as well as first results from evaluation experiments are
presented.
12 citations
TL;DR: In this paper, an accurate and efficient approach to laminated piezoelectric plates based on a refinement of elastic displacement and electric potential through the plate thickness is proposed, which accounts for a shearing function and a layerwise approximation for the electric potential.
Abstract: We propose an accurate and efficient approach to laminated piezoelectric plates based on a refinement of elastic displacement and electric potential through the plate thickness. More precisely, the model accounts for a shearing function and a layerwise approximation for the electric potential. The layerwise approach becomes a necessity in order to accommodate electric potential at the electrode interfaces. The equations of motion for the piezoelectric composite are deduced from a variational formulation incorporating the continuity conditions at the layer interfaces by using Lagrange multipliers. Different situations are investigated among them (i) bimorph and (ii) sandwich structures for two kinds of electro-mechanical loads applied (density of force and electric potential) and are compared to the finite element computations performed on the 3D model. The vibration problem is also presented and the frequencies for the axial and flexural modes are obtained. At last performance and effectiveness of the model are also discussed and applications to control of the structure shape and vibration are proposed.
12 citations
01 Jan 2004
TL;DR: A small piezoelectric bimorph actuator is developed that possesses flat frequency characteristics in the vibratory frequency of tactilely perceivable bandwidth and the experimental results showed that the frequency-displacement relationships were almost the same as the estimation obtained from the mechanical simulation model.
Abstract: In order to investigate tactile perception characteristics of the human fingerpad for the optimal design of a sensory substitution system, we have developed a small piezoelectric bimorph actuator that possesses flat frequency characteristics in the vibratory frequency of tactilely perceivable bandwidth. The parameters for the design of the bimorph were determined by using a mechanical simulation model of a piezoelectric bimorph and a fingerpad skin. To evaluate the performance of the bimorph, we measured frequency-displacement relationships when the skin of a fingerpad was vibrated by the piezoelectric bimorph. The experimental results showed that the frequency-displacement relationships were almost the same as the estimation obtained from the mechanical simulation model.
12 citations