Bimorph

About: Bimorph is a research topic. Over the lifetime, 3339 publications have been published within this topic receiving 51880 citations.

Optimal design of Al/Si bimorph electro-thermal microactuator by integrating finite-element code with optimization method

Abstract: The present study is aimed to develop an optimization approach which is employed to design an electro-thermal microactuator based on numerical simulation of the device performance. The microactuator basically adopts a bimorph structure which consists of a P-type silicon layer and an aluminum layer. A finite-element multi-physics code (ANSYS 10.0) is used to develop the direct problem solver for predicting the stress/stain, electric, and thermal fields associated with the varying material layers thicknesses during the iterative optimization process. The simplified conjugate-gradient method (SCGM) is used as the optimization method. Regarded as a test case, the modifications of a conventional design, which suffered from high temperature, excessive power consumption, and oxidization of aluminum layer, are attempted. In this study, firstly the direct problem solver is used to predict the performance of various design models so as to select the best one with highest performance. Parametric study of the best design model is then performed, and based on the solutions yielded from the parametric study, the subtle influence of thicknesses of the P-type silicon and the aluminum layers ( t S and t AL ) on the performance of the microactuator is observed. Finally, the developed optimization approach is applied to predict the optimal combination of the geometrical parameters. The optimal thicknesses of the material layers used in the microactuator are successfully determined, and the optimization process leads to a great improvement in the performance of the microactuator. Results also show that the approach is robust and the obtained optimal combination of the geometrical parameters is independent of the initial guess for the particular case.

Tracking control devices for video tape recorders

Abstract: A tracking control device for a video tape recorder comprises a bimorph leaf on which a rotary playback head is mounted so as to be deflectable in a direction perpendicular to tracks to be scanned. A triangular wave signal generating circuit comprising cascaded flip-flops generates a substantially triangular wave signal which is supplied to the bimorph leaf to cause the playback head to wobble relative to the tracks. A detecting circuit detects an envelope signal in the signal reproduced by the playback head, and a phase comparing circuit which includes an exclusive-OR circuit compares the phase of this envelope signal with the phase of the triangular wave signal. The output of the phase comparing circuit is fed back to the bimorph leaf to effect tracking correction.

Resonant frequency of bimorph triangular V-shaped piezoelectric cantilever energy harvester

Abstract: The concept of “energy harvesting” is to design smart systems to capture the ambient energy and to convert it to usable electrical power for supplying small electronics devices and sensors. The goal is to develop autonomous and self-powered devices that do not need any replacement of traditional electrochemical batteries. Now piezoelectric cantilever structures are being used to harvest vibration energy for self-powered devices. However, the geometry of a piezoelectric cantilever beam will greatly affect its vibration energy harvesting ability. This paper deduces a remarkably precise analytical formula for calculating the fundamental resonant frequency of bimorph V-shaped cantilevers using Rayleigh method. This analytical formula, which is convenient for mechanical energy harvester design based on Piezoelectric effect, is then validated by ABAQUS simulation. This formula raises a new perspective that, among all the bimorph V-shaped cantilevers and in comparison with rectangular one, the simplest tapered cantilever beam can lead to maximum resonant frequency and highest sensitivity. The derived formula can be commonly used as a relatively precise rule of thumb in such systems.

Heat Resistant Piezo Bimorph Synthetic Jet Apparatus

Abstract: A heat resistant piezo bimorph synthetic jet apparatus comprises a working fluid chamber partially defined by a plate, a working fluid port that provides fluid flow communication between the working fluid chamber and a working fluid mass, and a bimorph piezoelectric structure included in the plate. The bimorph piezoelectric structure alternately increases and decreases chamber volume by alternately expanding convexly and concavely in response to application of voltage of alternating polarity to alternately draw working fluid into and expel working fluid from the working fluid chamber through the working fluid port. A thermal insulating layer is disposed between the working fluid chamber and the bimorph piezoelectric structure to protect a ceramic layer within the first bimorph piezoelectric structure from high temperature working fluid.

Bimorph spirals for uncooled photothermal spectroscopy

Abstract: A bimorph spiral which exhibits a shape-altering response to thermal radiation and is dimensioned to have a focussing effect on light, such as a visible light, by acting as a quasi-Fresnel element. The focussing effect varies as the shape of the bimorph spiral changes due to absorption of thermal radiation. An array of such bimorph spirals can be used for efficient, high-resolution and rapid uncooled photothermal spectroscopy.