Papers by Keyword: Piezoelectric

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Authors: Xue Feng He, Yao Qing Cheng, Jun Gao, You Zhu
Abstract: To harvest ambient vibration energy of different directions, a micromachined vibration energy harvester which can harvest two-dimensional vibration energy was proposed. The harvester is composed of a curled piezoelectric cantilever, a proof mass and the substrate. One end of the cantilever is fixed onto the substrate and the other end is connected with a proof mass. It is the residual stress of micromachining processes that causes the cantilever to curl. A proof-of-concept prototype of the two-dimensional vibration energy harvester was assembled and tested to evaluate the performance. Experimental results show that the vibration direction with the highest energy scavenging efficiency changed with the frequency of the ambient vibration. The vibration energy of any direction in the neutral plane of the curled cantilever can be harvested by using the first two natural vibration modes of the prototype.
Authors: Xin Yue Kan, Li Feng Wen, Hui Ling Zhou, Shu Yun Wang
Abstract: To improve energy harvesting performance, a magnet-coupled piezoelectric vibration energy harvester (MCPEH) for low-level and low-frequency vibration was presented and investigated experimentally. The MCPEH consisted mainly of a piezo-cantilever with a permanent magnet at its free-end and another excitation magnet fixed on vibration structure. The magnets are used to produce magnetic attractive force to enhance energy generation. A MCPEH was fabricated with a piezo-cantilever measured 60x10x0.5mm3 and two magnets sized ø12x3mm3. The testing results show that the magnetic force, denoted by the initial separated distance between the magnetic dipoles (SDMD), exerts great influence on all of the generated voltage, optimal frequency, and effective bandwidth. With the SDMD reducing from 40mm to 15mm, the optimal frequency decrease from 32.75Hz to 30.5Hz, the effective bandwidth for the MCPEH to generated voltage of 15V rises from 2.5Hz to 7.5Hz, and the generated voltage rises from 30.4V to 44.4V.
Authors: Xing Qiang Zhao, Zhi Yu Wen, Li Cheng Deng, Guo Xi Luo, Zheng Guo Shang, Dong Ling Li
Abstract: A micro piezoelectric cantilever beam array is designed for vibration energy harvesting. A single degree of freedom analytical model is developed to predict the properties of the device and is verified by finite element method. The piezoelectric material Aluminum Nitride was chosen for the compatibility with the CMOS process. The devices consisting of 5 piezoelectric cantilever beams and one proof mass were fabricated using micromachining technology. The resonance frequency, voltage and power were tested at excitation acceleration of 5.0 g. The maximum output power of the device is 9.13 μW at the resonance frequency of 1315 Hz when piezoelectric beams are connected in parallel.
Authors: Xing Qiang Zhao, Zhi Yu Wen, Zhi Gang Du
Abstract: A novel miniaturized piezoelectric wind flutter generator is proposed which consisted of a flexible beam and a PZT cantilever. The working principle is based on flexible beam flutter, which can amplify the PZT cantilever vibration. A prototype was tested in a wind tunnel. It is found that there are three behavior states with wind speed increasing, and flutter behavior takes place when wind speed varies between the critical wind speed Uc1 and Uc2, an empirical formula was obtained about the critical speed Uc1. The open circuit voltage and power were measured. The device can generate 794μW output power with 30kΩ resistor in a wind of speed 20m/s, power density is 139μW/cm3.
Authors: Ya Xin Liu, Ming Zhong, Li Guo Chen
Abstract: Micro-dissection technology possesses revolutionary significance in the research field about Cancer Genomics, through which pure population of targeted cells can be procured from tissue sections for subsequent analysis. In this paper, a novel Micro-dissection technology using ultrasonic vibration was proposed and the piezo-powered micro-dissection tool with its control and drive system were also developed. The micro-dissection tool employs the multilayer piezoelectric actuator for generating the ultrasonic vibration with high frequency and low amplitude. To control the piezo-powered Micro-dissection tool, a driving power for piezoelectric actuator was designed using direct digital synthesizer and direct current amplifying principle, thus the micro-dissection tool could vibrate with the frequency scope from 0.5k to50K and the amplitude scope from 0 to 2μm. Finally, experiments about bio-microdissection on liver tissue slice were carried out with the tool and better micro-dissection result was obtained. The experiments show the feasibility of the micro-dissection method with ultrasonic vibration. The new micro-dissection method can be adopted in the bio-micro-manipulation field and it can also significantly promote the development of Cancer Genomics.
Authors: Song Mei Yuan, Lu Tao Yan, Qiang Liu
Abstract: A novel nebulizer used in near dry machining systems for supplying cutting fluids and cooling air is presented. The nebulizer includes double-layer micro-nebulizers, each adopting piezoelectric transducer as the actuator, generating pressure in the chamber and ejecting liquid or air out of it. The mixture of cooling air and micro-partical spraying into cutting area has both the cooling and lubricating action. The design of the piezoelectric actuator and cavity structure, including the selection of the piezoelectric actuator type and materials is studied. The vibration modes are obtained by means of FEM.
Authors: Song Mei Yuan, Qiang Liu, Zhi Tong Chen, Chi Zhuang, Fang Wang
Abstract: A novel piezoelectric actuator used for transporting some living cells in micro fluidic systems is presented. The mechanism of the living cell transportation is studied based on the acoustics principles. The structural resonant model and a solid-liquid coupling analysis are obtained by FEM. The works will be useful for design optimization of some corresponding actuators and their applications.
Authors: Dauda Sh. Ibrahima, Asan G.A. Muthalif, Tanveer Saleh
Abstract: In recent years, utilizing kinetic energy in mechanical vibrations has become an interesting area of research. This is due to ubiquitous sources of vibration energy, coupled with the ever increasing demands to power wireless sensing electronics and Microelectromechanical (MEMs) devices with low energy requirements. Thus, researchers have ventured into developing different system configurations with the aim of harvesting vibration energy to power these devices. Cantilever beam systems with piezoelectric layer have been used as vibration energy scavengers due to their abilities of converting kinetic energy in vibrating bodies into electrical energy, whereas permanent magnets have been used to improve their performance. The only unresolved challenge is to develop energy harvesters that can produce optimum energy at a wider bandwidth. In this study, a mathematical model of a system of cantilever beams with piezoelectric layers having a magnetic coupled tip mass is proposed. The lumped parameter model of the harvester is developed to estimate the power output of the proposed harvester, and to visualise the effect of magnetic coupled tip mass in widening the frequency bandwidth of the energy harvester. Preliminary Simulation results using MATLAB have however shown the effectiveness of the proposed system.
Authors: Bao Wei Wang, Xiang Cheng Chua, Long Tu Li
Abstract: This paper presents a valve-less micropump which is actuated by a piezoelectric ceramic chip. We employ a microelectromechanical system process for the silicon substrate and anodic bonding for assembly of the Pyrex glass and silicon wafer. The reciprocating type micropump contains two nozzle/diffuser elements and a silicon membrane with an embedded piezoelectric ceramic actuator.
Authors: Zhen Yan, Qing He
Abstract: Piezoelectric vibration generator has the advantages of small volume and simple technology and working in various poor environments, so it will inevitably power for wireless sensor network, micro electromechanical system (MEMS) devices, and other electric devices, instead of traditional cell. First of all, the generation power principle as well as the vibration mode of piezoelectric vibration generator is presented. Then, the basic theory and its application of structural behavior and damping influence are analyzed. Finally, the problems and the challenge of piezoelectric vibration generator are discussed.
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