On the elliptical inhomogeneity problem in piezoelectric materials under antiplane shear and inplane electric field

1998 ◽  
Vol 36 (3) ◽  
pp. 329-344 ◽  
Author(s):  
S.A. Meguid ◽  
Z. Zhong
Keyword(s):  
Electric Field ◽  
Piezoelectric Materials ◽  
Antiplane Shear ◽  
Elliptical Inhomogeneity ◽  
Inhomogeneity Problem

scholarly journals Charging of Piezoelectric Cellular Polypropylene Film by Means of a Series Dielectric Layer

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 333
Author(s):  
Pedro Llovera-Segovia ◽  
Gustavo Ortega-Braña ◽  
Vicente Fuster-Roig ◽  
Alfredo Quijano-López
Keyword(s):  
Electric Field ◽  
Corona Discharge ◽  
Dielectric Layer ◽  
Dielectric Breakdown ◽  
Piezoelectric Materials ◽  
High Resistivity ◽  
Internal Electric Field ◽  
Dielectric Polarization ◽  
Surface Flashover ◽  
In Series

Piezoelectric polymer cellular films have been developed and improved in the past decades. These piezoelectric materials are based on the polarization of the internal cells by means of induced discharges in the gas inside the cells. Internal discharges are driven by an external applied electric field. With this polarization method, cellular polypropylene (PP) polymers exhibit a high piezoelectric coefficient d33 and have been investigated because of their low dielectric polarization, high resistivity, and flexibility. Charging polymers foams is normally obtained by applying a corona discharge to the surface with a single tip electrode-plane arrangement or a triode electrode, which consists of a tip electrode-plane structure with a controlled potential intermediate mesh. Corona charging allows the surface potential of the sample to rise without breakdown or surface flashover. A charging method has been developed without corona discharge, and this has provided good results. In our work, a method has been developed to polarize polypropylene foams by applying an insulated high-voltage electrode on the surface of the sample. The dielectric layer in series with the sample allows for a high internal electric field to be reached in the sample but avoids dielectric breakdown of the sample. The distribution of the electric field between the sample and the dielectric barrier has been calculated. Experimental results with three different electrodes present good outcome in agreement with the calculations. High d33 constants of about 880 pC/N have been obtained. Mapping of the d33 constant on the surface has also been carried out showing good homogeneity on the area under the electrode.

Low electric field-driven giant strain response in 〈001〉 textured BNT-based lead-free piezoelectric materials

2016 ◽  
Vol 52 (6) ◽  
pp. 3169-3178 ◽  
Author(s):  
Wangfeng Bai ◽  
Daqin Chen ◽  
Peng Zheng ◽  
Jingji Zhang ◽  
Bo Shen ◽  
...  
Keyword(s):  
Electric Field ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Strain Response

Uniform stress state inside a non-elliptical inhomogeneity near an irregularly shaped hole in antiplane shear

2019 ◽  
Vol 25 (2) ◽  
pp. 362-373 ◽  
Author(s):  
Xu Wang ◽  
Peter Schiavone
Keyword(s):  
Antiplane Shear ◽  
Shear Stresses ◽  
Uniform Stress ◽  
Elliptical Inhomogeneity ◽  
Surrounding Matrix ◽  
The Matrix ◽  
Shaped Hole ◽  
Mapping Techniques ◽  
Hole Boundary ◽  
High Level

Analytic continuation and conformal mapping techniques are applied to establish that the state of stress inside a non-elliptical elastic inhomogeneity can remain uniform despite the presence of a nearby irregularly shaped hole when the surrounding matrix is subjected to uniform remote antiplane shear stresses. The hole boundary is assumed to be either traction-free or subjected to antiplane line forces. Detailed numerical results are presented to demonstrate the resulting analytical solutions. Our results indicate that in maintaining a uniform stress distribution inside the inhomogeneity, it is permissible for the stresses in the matrix to exhibit either a square root singularity at sharp corners of a hole boundary or a high level of stress concentration at rounded corners of a hole.

scholarly journals Recent Progress on Electromagnetic Field Measurement Based on Optical Sensors

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2860 ◽  
Author(s):  
Jun Peng ◽  
Shuhai Jia ◽  
Jiaming Bian ◽  
Shuo Zhang ◽  
Jianben Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Electric Field ◽  
Magnetic Fluid ◽  
Optical Sensors ◽  
Field Measurement ◽  
Faraday Effect ◽  
Optical Sensing ◽  
Piezoelectric Materials ◽  
Electrostatic Attraction

Electromagnetic field sensors are widely used in various areas. In recent years, great progress has been made in the optical sensing technique for electromagnetic field measurement, and varieties of corresponding sensors have been proposed. Types of magnetic field optical sensors were presented, including probes-based Faraday effect, magnetostrictive materials, and magnetic fluid. The sensing system-based Faraday effect is complex, and the sensors are mostly used in intensive magnetic field measurement. Magnetic field optical sensors based on magnetic fluid have high sensitivity compared to that based on magnetostrictive materials. Three types of electric field optical sensors are presented, including the sensor probes based on electric-optic crystal, piezoelectric materials, and electrostatic attraction. The majority of sensors are developed using the sensing scheme of combining the LiNbO3 crystal and optical fiber interferometer due to the good electro-optic properties of the crystal. The piezoelectric materials-based electric field sensors have simple structure and easy fabrication, but it is not suitable for weak electric field measurement. The sensing principle based on electrostatic attraction is less commonly-used sensing methods. This review aims at presenting the advances in optical sensing technology for electromagnetic field measurement, analyzing the principles of different types of sensors and discussing each advantage and disadvantage, as well as the future outlook on the performance improvement of sensors.

Development of a Material Constitutive Model and Simulation Technique to Predict Nonlinearities in Piezoelectric Materials under Weak Electric Fields

2017 ◽  
pp. 271-303
Author(s):  
M. K. Samal
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Lead Zirconate Titanate ◽  
Domain Walls ◽  
Piezoelectric Materials ◽  
Experimental Results ◽  
Ferroelectric Ceramics ◽  
Rayleigh Law ◽  
Model And Simulation ◽  
Near Resonance

Piezoceramic materials exhibit different types of nonlinearities depending upon the magnitude of the mechanical and electric field strength in the continuum. Some of the nonlinearities observed under weak electric fields are: presence of superharmonics in the response spectra and jump phenomena etc. especially if the system is excited near resonance. It has also been observed by many researchers that, at weak alternating stress fields, the relationship between the piezoelectrically induced charge and applied stress in ferroelectric ceramics, has the same form as the Rayleigh law (for magnetization versus magnetic field) in ferromagnetic materials. Applicability of the Rayleigh law to the piezoelectric effect has been demonstrated for Lead Zirconate Titanate ceramics by many researchers and their experimental results indicate that the dominant mechanism responsible for piezoelectric hysteresis and the dependence of the piezoelectric coefficient on the applied alternating stress is the pinning of non-180° domain walls. In this chapter, the Rayleigh law for ferromagnetic hysteresis has been modified and incorporated in a nonlinear electric enthalpy function and then applied in the analysis of hysteresis behavior of piezoelectric continua. Analytical solutions have been derived for a cantilever beam actuated by two piezo-patches attached to the top and bottom of the beam and excited by opposite electric fields. Analysis has been carried out at different electric field excitations of varying amplitude and frequencies and the results have been compared with the available experimental results from literature.

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