Coupled extensional and flexural cylindrical vibrations of a corrugated cylindrical piezoelectric shell consisting of multiple pieces of circular cylindrical surfaces smoothly connected along their generatrix are studied. To validate the results for the case of relatively thick shells or equivalently high-frequency modes with short wavelengths, existing analysis is extended by considering shear deformation and rotatory inertia. An analytical solution is obtained. Based on the solution, resonant frequencies and mode shapes are calculated.
Hualong DuLimei XuHongping HuYuantai HuXuedong ChenHui FanJiashi Yang
<正>We study the coupled extensional and flexural vibrations of axially-symmetrical annular corrugated shell pi...
Limei Xu~1,Feng Yang~2,Hualong Du~1,Hongping Hu~2, Xuedong Chen~3,Yuantai Hu~(2,*) 1 Institute of Astronautics and Aeronautics,University of Electronic Science and Technology,Chengdu,China 2 Department of Mechanics,Huazhong University of Science and Technology,Wuhan 430074,China 3 National NC System Engineering Research Center,Huazhong University of Science and Technology, Wuhan 430074,China
The coupled extensional and flexural vibrations of an annular corrugated shell piezoelectric transducer consisting of multiple circularly-annular surfaces smoothly connected along the interfaces were investigated in the paper. Only a time-harmonic voltage is applied across two electrodes of the piezoelectric shell as the external loading. A theoretical solution was obtained using the classical shell theory. Based on the solution, basic vibration characteristics of resonant frequencies, mode shapes were calculated and examined.
Hui LiFeng YangHualong DuHongping HuWei JiangXuedong ChenYuantai Hu
介绍了一种新的切实可行的能量俘获方法,即通过压电结构的力/电转换功能从环境振动中提取能量,实现微电子器件的无线供能.这种由压电结构制作的能从环境振动中提取能量的声波器件称为压电俘能器,可分为两类:一类是压电结构在环境振动激励下所输出的功率直接供给微电子器件工作,不进行能量储存,这类俘能器称为第一类压电俘能器(piezoelectric power harvester);另一类是环境振动较弱,压电结构的输出功率低于器件的瞬时耗能,考虑到某些器件大部分时间处于休眠状态,而俘能器却随时可以从环境振动中提取能量,因此经过一段时间的能量累积后,由俘能器所储存的能量仍能满足器件的短期工作耗能.显然,这类俘能器需要具备能量储存功能,称为第二类压电俘能器(piezoelectric energy harvester).本文详细介绍了压电俘能器结构以及两类俘能器的不同分析方法,阐述了提高俘能效率的有效措施并揭示了相关的改进机理,对压电俘能器的设计和应用具有重要意义.
An improved harvester available in scavenging energy from the operating environment with either weaker or stronger vibration levels is studied. To ensure the optimal harvester performance, a Cuk dc-dc converter is employed into the modulating circuit. This paper reports how this harvester scav- enges maximal energy from varying-level vibrations and store energy into an electrochemical battery. Dependence of the duty cycle upon the external vibration level is calculated, and it is found that: 1) for weaker vibrations, the charging current into the battery is smaller than the allowable current, and thus all the optimal output power of the harvesting structure can be absorbed by the battery. In this case, the duty cycle should be fixed at 1.86%; 2) for stronger external forcing, the allowable charging current of the battery is smaller than the optimal harvested current. This indicates that just a portion of the sca- venged energy can be accepted by the battery. Thus, the duty cycle should be decreased gradually with the increase of the vibration level. Finally the energy transmission process and the roles of each elec- tronic element are analyzed. It is shown that a Cuk converter can greatly raise the efficiency of such a harvester, particularly when subjected to a weaker ambient vibration.
