scholarly journals Electric Displacement by Earthquakes

10.5772/27999 ◽  
2012 ◽  
Author(s):  
Antonio Lira ◽  
Jorge A.
Keyword(s):  
Electric Displacement

The Higher Order Crack Tip Fields for Interfacial Crack between Linear Functionally Graded and Homogeneous Piezoelectric Materials

2014 ◽  
Vol 1015 ◽  
pp. 97-100
Author(s):  
Yao Dai ◽  
Xiao Chong ◽  
Ying Chen
Keyword(s):  
Piezoelectric Materials ◽  
Electric Displacement ◽  
Interfacial Crack ◽  
Crack Tip ◽  
Higher Order ◽  
Functionally Graded ◽  
Linear Functions ◽  
Intensity Factors ◽  
Crack Tip Fields ◽  
Functionally Graded Piezoelectric Materials

The higher order crack-tip fields for an anti-plane crack situated in the interface between functionally graded piezoelectric materials (FGPMs) and homogeneous piezoelectric materials (HPMs) are presented. The mechanical and electrical properties of the FGPMs are assumed to be linear functions of y perpendicular to the crack. The crack surfaces are supposed to be insulated electrically. By using the method of eigen-expansion, the higher order stress and electric displacement crack tip fields for FGPMs and HPMs are obtained. The analytic expressions of the stress intensity factors and the electric displacement intensity factors are derived.

FINITE ELEMENT ANALYSIS OF PIEZOELECTRIC ELASTICITY WITH SINGULAR INPLANE ELECTROELASTIC FIELDS

2006 ◽  
Vol 03 (01) ◽  
pp. 115-135 ◽  
Author(s):  
MENG-CHENG CHEN ◽  
JIAN-JUN ZHU ◽  
K. Y. SZE
Keyword(s):  
Finite Element ◽  
Ad Hoc ◽  
Wedge Angle ◽  
Electric Displacement ◽  
Weak Form ◽  
Efficient Solutions ◽  
Element Formulation ◽  
Displacement Fields ◽  
Element Analysis ◽  
Electroelastic Fields

An ad hoc one-dimensional finite element formulation is developed for the eigenanalysis of inplane singular electroelastic fields at material and geometric discontinuities in piezoelectric elastic materials by using the eigenfunction expansion procedure and the weak form of the governing equations for prismatic sectorial domains composed of piezoelectrics, composites or air. The order of the electroelastic singularities and the angular variation of the stress and electric displacement fields are obtained with the formulation. The influence of wedge angle, polarization orientation, material types, and boundary and interface conditions on the singular electroelastic fields and the order of their singularity are also examined. The simplicity and accuracy of the formulation are demonstrated by comparison to several analytical solutions for piezoelectric and composite multi-material wedges. The nature and speed of convergence suggests that the present eigensolution could be used in developing hybrid elements for use along with standard elements to yield accurate and computationally efficient solutions to problems having complex global geometries leading to singular electroelastic states.

scholarly journals Nonuniformly Loaded Stack of Antiplane Shear Cracks in One-Dimensional Piezoelectric Quasicrystals

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
G. E. Tupholme
Keyword(s):  
Electric Displacement ◽  
Polar Angle ◽  
Antiplane Shear ◽  
Shear Cracks ◽  
Intensity Factors ◽  
One Dimensional ◽  
Isotropic Solid ◽  
Special Cases ◽  
Field Intensity Factors ◽  
Explicit Representations

Representations in a closed form are derived, using an extension to the method of dislocation layers, for the phonon and phason stress and electric displacement components in the deformation of one-dimensional piezoelectric quasicrystals by a nonuniformly loaded stack of parallel antiplane shear cracks. Their dependence upon the polar angle in the region close to the tip of a crack is deduced, and the field intensity factors then follow. These exhibit that the phenomenon of crack shielding is dependent upon the relative spacing of the cracks. The analogous analyses, that have not been given previously, involving non-piezoelectric or non-quasicrystalline or simply elastic materials can be straightforwardly considered as special cases. Even when the loading is uniform and the crack is embedded in a purely elastic isotropic solid, no explicit representations have been available before for the components of the field at points other than directly ahead of a crack. Typical numerical results are graphically displayed.

Kinetic theory of surface wave propagation along a hot plasma column

1976 ◽  
Vol 16 (1) ◽  
pp. 47-55 ◽  
Author(s):  
V. Atanassov ◽  
I. Zhelyazkov ◽  
A. Shivarova ◽  
Zh. Genchev
Keyword(s):  
Dispersion Relation ◽  
Plasma Column ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Displacement Vector ◽  
Electric Displacement ◽  
Wave Dispersion ◽  
Axially Symmetric ◽  
Surface Wave Propagation ◽  
Hot Plasma

In this paper we propose an exact solution of Vlasov and Maxwell's equations for a bounded hot plasma in order to derive the dispersion relation of the axially-symmetric surface waves propagating along a plasma column. Assuming specular reflexion of plasma particles from the boundary, expressions for the components of the electric displacement vector are obtained on the basis of the Vlasov equation. Their substitution in Maxwell's equations, neglecting the spatial dispersion in the transverse plasma dielectric function, allows us to determine the plasma impedance. The equating of plasma and dielectric impedances gives the wave dispersion relation which, in different limiting cases, coincides with the well-known results.

A polycrystal hysteresis model for ferroelectric ceramics

2006 ◽  
Vol 462 (2069) ◽  
pp. 1573-1592 ◽  
Author(s):  
Y Su ◽  
G.J Weng
Keyword(s):  
Electric Field ◽  
Hysteresis Loop ◽  
Ferroelectric Properties ◽  
Electric Displacement ◽  
Hysteresis Loops ◽  
Ferroelectric Ceramics ◽  
Domain Growth ◽  
Thermodynamic Approach ◽  
Hysteresis Model ◽  
Self Consistent

Most key elements of ferroelectric properties are defined through the hysteresis loops. For a ferroelectric ceramic, its loop is contributed collectively by its constituent grains, each having its own hysteresis loop when the ceramic polycrystal is under a cyclic electric field. In this paper, we propose a polycrystal hysteresis model so that the hysteresis loop of a ceramic can be calculated from the loops of its constituent grains. In this model a micromechanics-based thermodynamic approach is developed to determine the hysteresis behaviour of the constituent grains, and a self-consistent scheme is introduced to translate these behaviours to the polycrystal level. This theory differs from the classical phenomenological ones in that it is a micromechanics-based thermodynamic approach and it can provide the evolution of new domain concentration among the constituent grains. It also differs from some recent micromechanics studies in its secant form of self-consistent formulation and in its application of irreversible thermodynamics to derive the kinetic equation of domain growth. To put this two-level micromechanics theory in perspective, it is applied to a ceramic PLZT 8/65/35, to calculate its hysteresis loop between the electric displacement and the electric field ( D versus E ), and the butterfly-shaped longitudinal strain versus the electric field relation ( ϵ versus E ). The calculated results are found to be in good quantitative agreement with the test data. The corresponding evolution of new domain concentration c 1 and the individual hysteresis loops of several selected grains—along with those of the overall polycrystal—are also illustrated.

A Piezoelectric Screw Dislocation Interacting with a Dielectric Crack in a Hexagonal Piezoelectric Material

2005 ◽  
Vol 9 ◽  
pp. 183-190
Author(s):  
Jin Xi Liu ◽  
X.L. Liu
Keyword(s):  
Electric Field ◽  
Screw Dislocation ◽  
Electric Displacement ◽  
Image Force ◽  
Mapping Method ◽  
Piezoelectric Medium ◽  
Intensity Factors ◽  
Potential Jump ◽  
Piezoelectric Screw Dislocation ◽  
Dielectric Crack

This paper is concerned with the interaction of a piezoelectric screw dislocation with a semi-infinite dielectric crack in a piezoelectric medium with hexagonal symmetry. The solution of the considered problem is obtained from the dislocation solution of a piezoelectric half-plane adjoining a gas medium of dielectric constant ε0 by using the conformal mapping method. The intensity factors of stress, electric displacement and electric field and the image force on the dislocation are given explicitly. The effect of electric boundary conditions on the dislocation-crack interaction is analyzed and discussed in detail. The results show that ε0 only influences the electric displacement and electric field intensity factors and the image force produced by the electric potential jump.

Wave Propagation in a Piezoelectric Coupled Solid Medium

2002 ◽  
Vol 69 (6) ◽  
pp. 819-824 ◽  
Author(s):  
Q. Wang
Keyword(s):  
Wave Propagation ◽  
Wave Velocity ◽  
Electric Potential ◽  
Solid Medium ◽  
Electric Displacement ◽  
Piezoelectric Medium ◽  
Wave Number ◽  
Mode Shapes ◽  
Coupled Structures ◽  
Shear Horizontal

Shear horizontal (SH) wave propagation in a semi-infinite solid medium surface bonded by a layer of piezoelectric material abutting the vacuum is investigated in this paper. The dispersive characteristics and the mode shapes of the deflection, the electric potential, and the electric displacements in the thickness direction of the piezoelectric layer are obtained theoretically. Numerical simulations show that the asymptotic phase velocities for different modes are the Bleustein surface wave velocity or the shear horizontal wave velocity of the pure piezoelectric medium. Besides, the mode shapes of the deflection, electric potential, and electric displacement show different distributions for different modes and different wave number. These results can be served as a benchmark for further analyses and are significant in the modeling of wave propagation in the piezoelectric coupled structures.

Isotropic polyconvex electromagnetoelastic bodies

2018 ◽  
Vol 24 (3) ◽  
pp. 738-747
Author(s):  
M Šilhavý
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Electromagnetic Field ◽  
Smart Materials ◽  
Equilibrium Solution ◽  
Deformation Gradient ◽  
Electric Displacement ◽  
The Body ◽  
Sufficient Condition ◽  
Energy Functions

The recent renewal of interest in nonlinear electromagnetoelastic interactions comes from the technological importance of electro- or magnetosensitive elastomers, smart materials whose mechanical properties change instantly on the application of an electric or magnetic field. We consider materials with free energy functions of the form [Formula: see text], where F is the deformation gradient, d is the electric displacement, and b is the magnetic induction. It was recently shown by the author that such an energy function is polyconvex if and only if it is of the form [Formula: see text] where [Formula: see text] is a convex function (of 31 scalar variables). Moreover, an existence theorem was proved for the equilibrium solution for a system consisting of a polyconvex electromagnetoelastic solid plus the vacuum electromagnetic field outside the body. The condition (8), is not just the combination of Ball’s polyconvexity of elastomers [Formula: see text] with the convexity in the electromagnetic variables. The differential constraints div [Formula: see text], div [Formula: see text] allow for the cross mechanical–electric and mechanical–magnetic terms Fd and Fb which substantially enlarge the class of energies covered by the theory. The result (*), applies to a material of any symmetry; this paper analyzes the condition in the case of isotropic materials. A broad sufficient condition for the polyconvexity is given in that case. Further, it is shown that the commonly used isotropic electroelastic or magnetoelastic invariants are polyconvex except for the biquadratic ones; the paper explicitly determines their quasiconvex envelopes and shows that they are polyconvex.

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