Bimorph

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

A low power, tight seal, polyimide electrostatic microvalve

Abstract: An electrostatically-actuated polyimide microvalve is developed with sub-micron gaps between the electrodes to provide high force with low power consumption (< 1 mW) Built-in residual stress results in a curled bimorph cantilever which allows for a n-Licroactuator with large displacement This microactuator is used to open and close a fluid path hole etched in silicon for a microvalve The microactuator can be actuated with 25V for a displacement of 200 {mu}m The cantilever actuator is mainly composed of polyimide, which is flexible enough to conform over the flow hole, thereby eliminating the need for the design of a valve seat

Optimized Design of Piezoelectric Flap Actuators for Active Flow Control

Abstract: Piezoelectric flap actuators are often used in active flow-control applications. However, effective design tools are lacking in the flow-control community. This paper discusses theoretical modeling, experimental validation, and optimal design of piezoelectric unimorph and bimorph flap actuators. First, two different finite element models are described. One is a simple beam model that assumes a perfect bond exists between the piezoelectric patch and the shim,whereasthesecondincorporatesalinearelasticshearelementforthebondlayer.Thesemodelsarethenusedto predict the magnitude of the dc response (tip displacement per unit applied voltage) and the natural frequency (a measureofthebandwidth)oftheseactuators.Next,anapproximateanalyticalmodelisdevelopedtofacilitatedesign optimization. The models are compared with experimental data obtained from a parametric study in which 10 otherwise identical unimorph piezoelectric actuators with varying piezoelectric patches are fabricated and characterizedusingalaserdisplacementsensor.Allmodelsproduceestimatesthatareaccuratetowithin15%and 10% for the dc response and natural frequency, respectively. The analytical model is also extended to bimorph actuators. Finally, a general design optimization procedure is presented, and representative results are provided.

Parameter identification for resonant piezoelectric energy harvesters in the low- and high-coupling regimes

Abstract: We demonstrate a method for identifying the parameters of piezoelectric harvesters by simple electrical measurements. The basic equations are derived from a simplified yet accurate model. The accuracy of the model is proven by comparison with the full model. Two beam harvesters, one with a unimorph beam and one with a bimorph beam, have been fabricated and characterized. The results coincide well with proposed theory and demonstrate the differences between harvesters with low and high coupling constants. It turns out that four parameters are sufficient to completely describe the electrical behavior of a harvester with a low coupling constant. For harvesters with high coupling constants, five parameters are needed.

Image shifting mechanism and imaging device

Abstract: The disclose is intended to miniaturize the actuator of an image shifting mechanism, to operate the actuator at high speed, and to reduce the effect of image shifting on image resolution. In an image shifting mechanism, a pair of bimorph type piezoelectric elements are disposed on both sides of a refraction plate. The bimorph type piezoelectric elements have a cantilever structure. The base end sides of the bimorph type piezoelectric elements are bonded and secured to a stage, and the free end sides are sandwiched between an upper holding plate and a lower holding plate so as to support one end of the refraction plate. When the bimorph type piezoelectric elements are displaced, the refraction plate can be inclined around its rotation center O. In the case of this structure, the specifications of the refraction plate and the bimorph type piezoelectric elements are determined so that the relationship between the moment of inertia Ic around the rotation center of the moving portions of the image shifting mechanism and the moment of inertia Ig around the center of gravity of the image shifting mechanism is Ic/Ig≦1.6.

Capacitive vibration energy harvesting with resonance tuning

Abstract: Electromechanical conversion of mechanical vibration into electrical energy looks very attractive for industrial applications recently proposed and involving wireless sensors networks. A preliminary analysis of the energy scavenger configuration is proposed by investigating the performance of microsystems based on the electrostatic coupling and testing the power scavenged by a capacitive microscavenger, with out-of-plane gap closing layout. This study includes some key features of the mechatronic design of the energy scavenger. Some strategies for tuning the MEMS resonance frequency on the exciting vibration are investigated. An original procedure based on the static electro-mechanical coupling is introduced. A parametric modeling of the microscavenger is performed and experimentally validated. This investigation allows comparing the performance of the energy harvesting strategy to the configuration with in-plane motion of electrostatic benders and to the performance of bimorph piezoelectric transducers.