共查询到20条相似文献,搜索用时 187 毫秒
1.
2.
3.
提出了一种基于光纤光栅法布里-珀罗(F-P)腔的低频振动传感方案并进行了理论分析和实验研究。采用单频激光器作为光源,光纤光栅F-P腔通过两点涂胶方式粘接在等强度悬臂梁上,待测振动信号通过支架和悬臂梁将振动作用传至光纤光栅F-P腔,引起腔长周期性变化,从而改变光纤光栅F-P腔的反射光谱特性,通过解调输出光信号的振荡频率和峰值,即可实现对振动信号频率和幅值的测量。利用压电陶瓷模拟的低频振动信号进行了实验验证,测量结果与理论分析相吻合。该传感器测量灵敏度高,特别适用于微弱振动信号的测量。 相似文献
4.
本文设计了一种基于涡激振动的流体动能收集装置。该器件主要包括钝体和PVDF(Polyvinylidene Fluoride)压电悬臂梁,涡街的交替脱落引起梁发生振动,通过压电效应将振动能量转为电能.基于流固耦合计算对该结构压电能量收集特性,以及压电悬臂梁的升阻力系数、振幅和频率等特性进行了数值分析,并着重研究圆柱型钝体与PVDF压电悬臂梁的位置对装置发电效率的影响。结果表明,圆柱与悬臂梁直接相连(即L=0.5D)会得到较高电压输出,在雷诺数Re=6000时,振幅峰值为A=0.97D,输出电压峰值达到0.923V。 相似文献
5.
6.
7.
8.
设计了悬臂梁振动引起的微多普勒频移实验系统.采用10.525GHz的X波段雷达模块发射和接收电磁波,采用AD620放大雷达回波毫伏级信号,采用NI-6009数据采集模块与LabVIEW软件对回波信号采集、滤波、加窗和频谱分析,采用压电传感器验证雷达测频结果.实验结果表明:悬臂梁的有阻尼自由振荡对雷达波产生频率调制作用,其微多普勒频谱图由相邻间距为固有频率的谱线对构成. 相似文献
9.
建立了一套交流放电产生N2等离子体喷束的装置,该装置可对氮气进行高达15 kV连续放电.采用浓度调制光谱技术对放电辉光光谱进行探测,并对实验中放电电流和光谱信号的关系进行了讨论.沿着束流的轴向探测了不同位置N2等离子体的发射光谱,发现其激发态振动温度随着束流的下降先降低继而升高,并根据实验条件分析了其变化规律和产生机理.研究了束流中N2 /N2比例变化过程,发现随着束流向下两者比例逐渐升高,并结合实验装置进行讨论. 相似文献
10.
11.
提出一种基于光纤光栅传感技术的称重系统.用特种粘贴剂将布喇格光纤光栅(FBG)粘贴于悬臂梁的自由端,当悬臂梁自由端受力发生微挠度弯曲时,光纤光栅将沿轴向发生形变,通过监测布喇格光纤光栅传感器反射波长漂移测量悬臂梁的微挠度变化.通过分析悬臂梁结构,建立悬臂梁受力与挠度的数学关系,进而测量出加载在悬臂梁自由端应力的数值.通过对系统结构理论分析和实验验证,该装置称重测量范围达到50千克力,测量灵敏度达到0.05千克力,线性拟合度达到0.9997. 相似文献
12.
研究了利用系统非线性来提高悬臂梁压电振子宽带低频振动能量俘获效率的随机共振机理,通过增加一对矩形永磁铁对传统线性悬臂梁压电振子结构进行了改进,结果揭示:在外部非线性磁力作用以及合适的磁铁间距条件下,这种外加磁力悬臂梁压电振子会构成一个双稳系统,在外部宽带低频随机振动源激励下发生随机共振现象,且发生随机共振时的输出电压明显增大,从而可以扩展悬臂梁压电振子的共振频率范围、提高低频振动能量的转化输出.
关键词:
压电悬臂粱
振动能量俘获
宽带低频
随机共振 相似文献
13.
14.
In this paper the vibrational behaviour of a cracked cantilever beam carrying end mass and rotary inertia is investigated. The transverse and axial vibrations of the beam are coupled through the crack model. The values of the ratio between the cracked and uncracked beam natural frequencies, the frequency ratio, are examined and are shown to follow well-defined trends with respect to the crack parameters and end mass and rotary inertia. However, the coupling between the transverse and axial vibrations is shown to be weak for the first two modes for moderate values of crack depth ratio. High crack depth ratios appear to increase the coupling effects. Low aspect ratios are expected to show strong coupling effects and further investigation is recommended using Timoshenko beam theory. 相似文献
15.
In our consideration, a comparison between four different types of controllers for suppression the vibrations of the cantilever beam excited by an external force is carried out. Those four types are the linear velocity feedback control, the cubic velocity feedback control, the non-linear saturation controller (NSC) and the positive position feedback (PPF) controller. The suitable type is the PPF controller for suppression the vibrations of the cantilever beam. The approximate solution obtained up to the first approximation by using the multiple scale method. The PPF controller effectiveness is studied on the system. We used frequency-response equations to investigate the stability of a cantilever beam. We notified that, there is a good agreement between the analytical solution and the numerical solution. 相似文献
16.
An electromagnetic device, acting like a spring with alternating stiffness, has been designed to parametrically excite the cantilever beam. However, only one parametric excitation (induced by one electromagnetic device) was considered in current research, and the effects of the design parameters of the device upon the instability were studied inadequately. Actually, multiple parametric excitations with various phases and amplitudes would bring significant impacts to the system instability. The electromagnetic device with various design parameters could cause the unstable regions to change evidently. Thus, the parametric instability of a cantilever beam subjected to two electromagnetic excitations is studied experimentally and analytically in the paper. The governing equations for the beam system are established utilizing the assumed mode method, and then verified through a DC current test. Based upon these, the instability experiments for the cantilever beam with one or two electromagnetic excitations are conducted in detail. Two design parameters of the device (magnet spacing and device location) are investigated, respectively, for their effects upon the instability regions. When two electromagnetic devices operate together to bring two parametric stiffness excitations with various phases and amplitudes to the cantilever beam, the variations of both simple and combination instability regions with coil current are observed and discussed. The above experimental results are all found to agree well with the analytical ones. 相似文献
17.
Harvesting energy from ambient mechanical vibrations by the piezoelectric effect has been proposed for powering microelectromechanical systems and replacing batteries that have a finite life span. A conventional piezoelectric energy harvester (PEH) is usually designed as a linear resonator, and suffers from a narrow operating bandwidth. To achieve broadband energy harvesting, in this paper we introduce a concept and describe the realization of a novel nonlinear PEH. The proposed PEH consists of a primary piezoelectric cantilever beam coupled to an auxiliary piezoelectric cantilever beam through two movable magnets. For predicting the nonlinear response from the proposed PEH, lumped parameter models are established for the two beams. Both simulation and experiment reveal that for the primary beam, the introduction of magnetic coupling can expand the operating bandwidth as well as improve the output voltage. For the auxiliary beam, the magnitude of the output voltage is slightly reduced, but additional output is observed at off-resonance frequencies. Therefore, broadband energy harvesting can be obtained from both the primary beam and the auxiliary beam. 相似文献
18.
硅微机械谐振器特性与激励光斑位置关系的研究 总被引:6,自引:2,他引:4
阐述了对硅悬臂梁谐振子进行光激励研究的结果,结果表明,谐振子的振幅与激励光斑的位置以及所激励的模态有关,在模态的两节点的中心位置进行激励,可得到最大的振幅,而且振幅随着激励光斑偏离子中心位置而下降基节点处激励时,振幅达到最小。上述结论也适用于其它点热源激励的微机械谐振器,并为点热激激励的微机械谐振器的设计和制作提供了依据。 相似文献
19.
Jae-Sung Bae Jai-Hyuk Hwang Jin-Ho Roh Jong-Hyuk Kim Mi-Seon Yi Jae Hyuk Lim 《Journal of sound and vibration》2012,331(26):5669-5684
Eddy currents are induced by the movement of a conductor through a stationary magnetic field or a time varying magnetic field through a stationary conductor. These currents circulate in the conductive material and are dissipated, causing a repulsive force between the magnet and the conductor. These electromagnetic forces can be used to suppress the vibrations of a flexible structure. A tuned mass damper is a device mounted in structures to reduce the amplitude of mechanical vibrations and is one of the effective vibration suppression methods. In the present study, an improved concept of this tuned mass damper for the vibration suppression of structures is introduced. This concept consists of the classical tuned mass damper and an eddy current damping. The important advantages of this magnetically tuned mass damper are that it is relatively simple to apply, it does not require any electronic devices and external power, and it is effective on the vibration suppression. The proposed concept is designed for a cantilever beam and the analytical studies on the eddy current damping and its effects on the vibration suppression. To show the effectiveness of the proposed concept and verify the eddy current damping model, experiments on a cantilever beam are performed. It is found that the proposed concept could significantly increase the damping effect of the tuned mass damper even if not adequately tuned. 相似文献
20.
采用微硅 锆钛酸铅(Si-PZT)悬臂梁结构并在悬臂梁末端附加镍质量块,构成可以工作于低频环境(小于1 000 Hz)的微压电能量采集器,一种利用压电效应将环境振动能转换为电能的器件。利用金薄膜作为中间层的共晶键合技术和PZT研磨减薄技术制备了微压电悬臂梁结构,PZT减薄实验最好结果为减薄至8 m。镍质量块(2 mm2 mm0.6 mm)采用微电铸工艺制备。通过对硅片与块材PZT的共晶键合工艺与PZT减薄技术的研究,制备出总厚度约为71 m的Si-PZT悬臂梁结构,其中硅梁厚约为47 m,PZT梁厚约为24 m。制备的微压电振动能量采集器样品的测试结果表明:在谐振频率为950 Hz,1.0g加速度激励条件下,其交流输出峰值电压可达958 mV。 相似文献