Active broadband low-frequency smart transducer with negative capacitance

2013 ◽  
Author(s):  
Zhang Wenqun ◽  
Wu Xinyue
Keyword(s):  
Low Frequency ◽  
Negative Capacitance ◽  
Smart Transducer

Low-frequency negative capacitance in La0.8Sr0.2MnO3∕Nb-doped SrTiO3 heterojunction

2008 ◽  
Vol 92 (5) ◽  
pp. 052905 ◽  
Author(s):  
C. C. Wang ◽  
G. Z. Liu ◽  
M. He ◽  
H. B. Lu
Keyword(s):  
Low Frequency ◽  
Negative Capacitance

Band Gap Control in an Active Elastic Metamaterial With Negative Capacitance Piezoelectric Shunting

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Y. Y. Chen ◽  
G. L. Huang ◽  
C. T. Sun
Keyword(s):  
Band Gap ◽  
Elastic Waves ◽  
Low Frequency ◽  
Lattice System ◽  
Band Gaps ◽  
Negative Capacitance ◽  
Bending Waves ◽  
Stiffness Constant ◽  
Elastic Metamaterials ◽  
Gap Control

Elastic metamaterials have been extensively investigated due to their significant effects on controlling propagation of elastic waves. One of the most interesting properties is the generation of band gaps, in which subwavelength elastic waves cannot propagate through. In the study, a new class of active elastic metamaterials with negative capacitance piezoelectric shunting is presented. We first investigated dispersion curves and band gap control of an active mass-in-mass lattice system. The unit cell of the mass-in-mass lattice system consists of the inner masses connected by active linear springs to represent negative capacitance piezoelectric shunting. It was demonstrated that the band gaps can be actively controlled and tuned by varying effective stiffness constant of the linear spring through appropriately selecting the value of negative capacitance. The promising application was then demonstrated in the active elastic metamaterial plate integrated with the negative capacitance shunted piezoelectric patches for band gap control of both the longitudinal and bending waves. It can be found that the location and the extent of the induced band gap of the elastic metamaterial can be effectively tuned by using shunted piezoelectric patch with different values of negative capacitance, especially for extremely low-frequency cases.

scholarly journals Design and Experimental Validation of a Metacomposite Made of an Array of Piezopatches Shunted on Negative Capacitance Circuits for Vibroacoustic Control

2013 ◽  
Author(s):  
F. Tateo ◽  
M. Collet ◽  
M. Ouisse ◽  
M. N. Ichchou ◽  
K. A. Cunefare
Keyword(s):  
New Technologies ◽  
Control Method ◽  
Low Frequency ◽  
Elastic Solid ◽  
Numerical Approach ◽  
Anomalous Behavior ◽  
Phononic Crystals ◽  
Underlying Structure ◽  
Negative Capacitance ◽  
New Class

In the last few decades, researchers have given a lot of attention to new engineered materials with the purpose of developing new technologies and devices such as mechanical filters, low frequency sound and vibration isolators, and acoustic waveguides. For instance, elastic phononic crystals may come to mind. They are materials with elastic or fluid inclusions inside a matrix made of an elastic solid. The anomalous behavior in phononic crystals arises from interference of waves propagating within an inhomogeneous material. The inclusions inside the matrix cause strong modifications of scattering properties. However, the application of phononic crystals is still limited to sonic frequencies. In fact, band gaps can be generated only when the acoustic wavelength is comparable to the distance between the inclusion. In order to overcome this limitation, a new class of metamaterial has been proposed: meta composite. This new class of material can modify the dynamics of the underlying structure using a bidimensional array of electromechanical transducers, which are composed by piezo patches connected to a synthetic negative capacitance. In this study, an application of the Floquet-Bloch theorem for vibroacoustic power flow optimization will be presented. In the context of periodically distributed, damped 2D mechanical systems, this numerical approach allows one to compute the multimodal waves dispersion curves into the entire first Brillouin zone. This approach also permits optimization of the piezoelectric shunting electrical impedance, which controls energy diffusion into the proposed semiactive distributed set of cells. Experiments performed on the examined structure illustrates the effectiveness of the proposed control method. The experiment requires a rectangular metallic plate equipped with seventyfive piezopatches, controlled independently by electronic circuits. More specifically, the out-of-plane displacements and the averaged kinetic energy of the controlled plate are compared in two different cases (control system on/off). The resulting data clearly show how this proposed technique is able to dampen and selectively reflect the incident waves.

Low-frequency negative capacitance effect in systems of metallic nanoparticles embedded in dielectric matrix

2004 ◽  
Vol 85 (2) ◽  
pp. 302-304 ◽  
Author(s):  
G. B. Parravicini ◽  
A. Stella ◽  
M. C. Ungureanu ◽  
R. Kofman
Keyword(s):  
Metallic Nanoparticles ◽  
Low Frequency ◽  
Negative Capacitance ◽  
Dielectric Matrix ◽  
Capacitance Effect
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