Bimorph

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

A Broadband Vibration-Based Energy Harvester Using an Array of Piezoelectric Beams Connected by Springs

Abstract: Piezoelectric cantilevered beams have been widely used as vibration-based energy harvesters. Nevertheless, these devices have a narrow frequency band and if the excitation is slightly different there is a significant drop in the level of power generated. To handle this problem, the present investigation proposes the use of an array of piezoelectric cantilevered beams connected by springs as a broadband vibration-based energy harvester. The equations for the voltage and power output of the system are derived based on the analytical solution of the piezoelectric cantilevered energy harvester with Euler-Bernoulli beam assumptions. To study the advantages and disadvantages of the proposed system, the results are compared with those of an array of disconnected beams (with no springs). The analytical model is validated with experimental measurements of three bimorph beams with and without springs. The results show that connecting the array of beams with springs allows increasing the frequency band of operation and increasing the amount of power generated.

Piezoelectric Cantilever Beams Actuated By PZT Sol-gel Thin Film

Abstract: Micromachined silicon cantilever beams actuated by the converse piezoelectric effect are of great interest for actuator applications [1], and for the characterization of piezoelectric thin films [2]. In this work a study of the mechanical response of piezoelectrically operated heterogeneous bimorph structures is given and compared with finite elements simulations. Determination of the piezoelectric parameter d/sub 31/ using interferometric displacement measurements, electrical impedance measurements, and finite element calculation will be discussed.

Piezoelectric and piezooptic effects in porous silicon

Abstract: Although silicon is a simple cubic crystal, it can be induced to have a piezoelectric response, by making pores in it and thus spoiling its symmetry. By etching a silicon wafer into porous material, we found that it responds to voltage applied to it, as well as to light. A porous shallow layer on the surface of the wafer induced bimorph bending roughly proportional to the voltage squared. Illuminating the porous patch caused a similar bending.

An improved small-deflection electromechanical model for piezoelectric bending beam actuators and energy harvesters

Abstract: The analytical model presented in this paper describes the energy conversion mechanism of a piezoelectric beam (bimorph) under small-deflection static and vibrating conditions. The model provides an improved approach to design and analyze the performance of piezoelectric actuators and energy harvesters (sensors). Conventional models assume a linear voltage distribution over the piezoelectric beam thickness, which is shown here to be invalid. The proposed modeling method improves accuracy by using a quadratic voltage distribution. The equivalent capacitance of a beam shows a 40% discrepancy between a conventional model and the proposed model for PZT5A material. This inaccuracy level is not negligible, especially when the design of micro-power electrical energy harvesting is concerned. The method solves simultaneously the solid mechanics and Maxwell's equations with the constitutive equations for piezoelectric materials. The paper also proposes a phasor-based procedure for measuring the damping of a piezoelectric beam. An experimental setup is developed to verify the validity of the model. The experimental results confirm the accuracy of the improved model and also reveal limitations in using models for small deflections.

A Low Mass Power Electronics Unit to Drive Piezoelectric Actuators for Flying Microrobots

Abstract: This paper presents a power electronics design for the piezoelectric actuators of an insect-scale flapping-wing robot, the RoboBee The proposed design outputs four high-voltage drive signals tailored for the two bimorph actuators of the RoboBee in an alternating drive configuration It utilizes fully integrated drive stage circuits with a novel highside gate driver to save chip area and meet the strict mass constraint of the RoboBee Compared with previous integrated designs, it also boosts efficiency in delivering energy to the actuators and recovering unused energy by applying three power saving techniques, dynamic common mode adjustment, envelope tracking, and charge sharing Using this design to energize four 15 nF capacitor loads with a 200 V and 100 Hz drive signal and tracking the control commands recorded from an actual flight experiment for the robot, we measure an average power consumption of 290 mW