Effect of Molecular Mass of B-site Ions on Electromechanical Coupling Factors of Lead-Based Perovskite Piezoelectric Materials

2000 ◽  
Vol 39 (Part 1, No. 9B) ◽  
pp. 5593-5596 ◽  
Author(s):  
Yohachi Yamashita ◽  
Yasuharu Hosono ◽  
Kouichi Harada ◽  
Noboru Ichinose
Keyword(s):  
Molecular Mass ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Coupling Factors

scholarly journals Anisotropy Factors and Electromechanical Coupling in Lead-Free 1–3-Type Composites

2019 ◽  
Author(s):  
Chris Bowen
Keyword(s):  
Single Crystal ◽  
Polymer Matrix ◽  
Electromechanical Coupling ◽  
Volume Fraction ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Aspect Ratios ◽  
Polymer Component ◽  
Coupling Factors

The effective electromechanical properties andanisotropy factors of novel lead-free 1–3-type compositesare studied to demonstrate their large piezoelectricanisotropy and considerable level of electromechanicalcoupling. The composites studied contain two single-crystal components and a polymer component. The firstpiezo-active component is a domain-engineered [001]-poled single crystal based on ferroelectric alkali niobates-tantalates, and this component is in the form of a system oflong rods that are parallel to the poling axis OX3. Thesecond single-crystal component is a system of spheroidalpiezoelectric Li2B4O7 inclusions aligned in a continuousand relatively large polymer matrix. The single-crystalrods are surrounded by a single crystal / polymer matrix,and the connectivity of the composite is 1–0–3. It is shownthat the conditions d * /| d * | 3 5, which indicates a large 33 31degree of anisotropy of the piezoelectric coefficients, and k* /|k* |35and k*/|k*|35,whichindicatealargeanisotropyof the electromechanical coupling factors, can be achievedsimultaneously in specific ranges of the component volumefractions and inclusion aspect ratios. Moreover, in thesame volume-fraction and aspect-ratio ranges, largeelectromechanical coupling factors (k* » k* » 0.8–0.9) are 33 talso achieved. In this context, the important role of the elastic properties of the continuous anisotropic matrix is discussed. The properties and anisotropy factors of the lead-free 1–3-type composites are compared to similar parameters of conventional lead-containing piezoelectric materials, and the advantages of the composite system studied are described.

scholarly journals FEM Analysis of Various Multilayer Structures for CMOS Compatible Wearable Acousto-Optic Devices

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7863
Author(s):  
Mehwish Hanif ◽  
Varun Jeoti ◽  
Mohamad Radzi Ahmad ◽  
Muhammad Zubair Aslam ◽  
Saima Qureshi ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Figure Of Merit ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Fem Analysis ◽  
Film Structure ◽  
Multilayer Structures ◽  
Electromechanical Coupling Coefficient ◽  
Materials Used ◽  
The Individual

Lately, wearable applications featuring photonic on-chip sensors are on the rise. Among many ways of controlling and/or modulating, the acousto-optic technique is seen to be a popular technique. This paper undertakes the study of different multilayer structures that can be fabricated for realizing an acousto-optic device, the objective being to obtain a high acousto-optic figure of merit (AOFM). By varying the thicknesses of the layers of these materials, several properties are discussed. The study shows that the multilayer thin film structure-based devices can give a high value of electromechanical coupling coefficient (k2) and a high AOFM as compared to the bulk piezoelectric/optical materials. The study is conducted to find the optimal normalised thickness of the multilayer structures with a material possessing the best optical and piezoelectric properties for fabricating acousto-optic devices. Based on simulations and studies of SAW propagation characteristics such as the electromechanical coupling coefficient (k2) and phase velocity (v), the acousto-optic figure of merit is calculated. The maximum value of the acousto-optic figure of merit achieved is higher than the AOFM of all the individual materials used in these layer structures. The suggested SAW device has potential application in wearable and small footprint acousto-optic devices and gives better results than those made with bulk piezoelectric materials.

Optimisation of a Hybrid Energy Scavenger with Piezoelectric/Magnetic Coupling for Sensor-Bearing Units

2013 ◽  
Vol 745 ◽  
pp. 41-56 ◽  
Author(s):  
Eugenio Brusa
Keyword(s):  
Energy Conversion ◽  
Rolling Mill ◽  
Structural Damage ◽  
Electromechanical Coupling ◽  
Permanent Magnets ◽  
Piezoelectric Materials ◽  
Vibration Monitoring ◽  
Vibration Energy Harvesting ◽  
Distributed Sensors ◽  
Energy Scavenger

Vibration monitoring based on wireless distributed sensors is currently used in steelmaking plants to early detect structural damage occurring in the rolling mill components. This approach allows overcoming some severe limitations of access to those industrial equipments, but sensors need a local power supply. Vibration energy harvesting based on piezoelectric materials is therefore proposed for this purpose. Nevertheless, very often it happens that dimensions of the energy scavenger are incompatible with the size of the system, thus not allowing a perfect tuning of its resonance upon the frequency of the dynamic excitation. Moreover, sometimes the amplitude of vibration is too low to induce a sufficient amount of energy conversion. Those problems motivated a previous work of the author, about the feasibility of plucking the flexible structure through either a relative motion or rotation of the harvested system and the energy scavenger, respectively. To avoid the drawbacks due to the wear in plucking the material, a contactless electromechanical coupling was proposed. The interaction between two permanent magnets, being one applied to the scavenger tip and the other fixed, was used to excite the vibration and the electromechanical conversion through the piezoelectric layer. The effectiveness of such hybrid system composed by the structure with surface bonded piezoelectric layers and the couple of magnets was investigated and compared to the power requirements of some sensors currently used to measure the dynamic response of the backup roll bearings located at the outer crown of the rolling mill. An optimisation of the whole device to increase the overall performance is proposed by following some approaches assessed in the literature and tested on some specimens of energy scavenger. The optimisation activity was based on a suitable selection of the piezoelectric material aimed at reaching the highest electromechanical coupling with a good mechanical strength and on a suitable shaping of the electrode surface aimed at assuring the largest efficiency in the energy conversion.

Fabrication Methods for Improved Electromechanical Behavior in Piezoelectric Membranes

2005 ◽  
Vol 872 ◽  
Author(s):  
M.C. Robinson ◽  
P.D. Hayenga ◽  
J.H. Cho ◽  
C.D. Richards ◽  
R.F. Richards ◽  
...  
Keyword(s):  
Residual Stress ◽  
Electromechanical Coupling ◽  
Silicon Oxide ◽  
Piezoelectric Materials ◽  
Electrical Energy ◽  
Fabrication Technique ◽  
Simply Supported ◽  
Electromechanical Behavior ◽  
Pzt Films ◽  
Electrode Coverage

AbstractPiezoelectric materials convert mechanical to electrical energy under stretching and bending conditions. Optimizing the coupling conversion is imperative to the electromechanical behavior of a micromachined membrane's performance. This paper discusses analytical calculations that were devised to determine the microscale structure that minimizes residual stress and outlines the implementation of fabrication technique variations including three different electrode configurations, trenching around the membrane, and reducing the total composite residual stress of the support structure using compressive silicon oxide. Lead zirconacte titanate (PZT) films between 1 and 3 μm thick with a ratio of Zr to Ti of 40:60 were deposited onto 3 mm square silicon membranes. The total tensile stress in the composite structure reaches 100 MPa during standard fabrication processing. Utilizing analytical calculations, a structure was determined that lowered the residual stress of the composite to 11 MPa and increased the electromechanical coupling 35 times. Changing the geometry of the electrode coverage decreased the residual stress of the composite by 40%. Trenching around the membrane provided a membrane with boundary conditions that approached simply supported and decreased the composite residual stress by another 16%. A comparison of the electromechanical behavior for these structures will be discussed, showing a route towards increasing electromechanical coupling in PZT MEMS.

A parametric analysis of the nonlinear dynamics of bistable vibration-based piezoelectric energy harvesters

2020 ◽  
pp. 1045389X2096318
Author(s):  
Luã Guedes Costa ◽  
Luciana Loureiro da Silva Monteiro ◽  
Pedro Manuel Calas Lopes Pacheco ◽  
Marcelo Amorim Savi
Keyword(s):  
Nonlinear Dynamics ◽  
Energy Harvesting ◽  
Parametric Analysis ◽  
Electromechanical Coupling ◽  
Performance Enhancement ◽  
Piezoelectric Materials ◽  
Electrical Power ◽  
Harmonic Excitation ◽  
Piezoelectric Energy ◽  
Harvesting Systems

Piezoelectric materials exhibit electromechanical coupling properties and have been gained importance over the last few decades due to their broad range of applications. Vibration-based energy harvesting systems have been proposed using the direct piezoelectric effect by converting mechanical into electrical energy. Although the great relevance of these systems, performance enhancement strategies are essential to improve the applicability of these system and have been studied substantially. This work addresses a numerical investigation of the influence of cubic polynomial nonlinearities in energy harvesting systems considering a bistable structure subjected to harmonic excitation. A deep parametric analysis is carried out employing nonlinear dynamics tools. Results show complex dynamical behaviors associated with the trigger of inter-well motion. Electrical power output and efficiency are monitored in order to evaluate the configurations associated with best system performances.

Flutter instabilities of cantilevered piezoelectric pipe conveying fluid

2019 ◽  
Vol 30 (4) ◽  
pp. 606-617 ◽  
Author(s):  
Gang Wang ◽  
Jinwei Shen
Keyword(s):  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Fluid Velocity ◽  
Pipe Conveying Fluid ◽  
Performance Predictions ◽  
Parametric Studies ◽  
Cycle Oscillation ◽  
And Performance ◽  
The Galerkin Method ◽  
Conveying Fluid

In this article, a nonlinear model was developed for a cantilevered piezoelectric pipe conveying fluid that included geometric nonlinearity and electromechanical coupling. The Galerkin method discretized the system in order to characterize its behavior. Critical flutter velocity and its associated unstable mode can be determined based on linear analysis. Due to the presence of piezoelectric materials, the critical flutter velocity depends on the resistive piezoelectric damping and electromechanical coupling. This added resistive piezoelectric damping tends to decrease the flutter velocity. Comprehensive simulations were also conducted to characterize the post-flutter behaviors. System parameters including amplitude, deformed pipe shape, and collected voltage in piezoelectric materials were calculated. The system will undergo limited cycle oscillation when the fluid velocity passes the flutter velocity. Parametric studies were conducted as well to investigate the system responses under different flow velocities. Physical insights can be collected from these simulation results to conduct piezoelectric pipe design and performance predictions for future pipe vibration control and energy harvesting applications.

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