Phase Velocity Of SH-wave Research Articles

Parametric influence of magneto elasticity, initial stresses, porosity and thickness ratio on the phase and attenuation traits of SH-waves

The present study is devoted to investigate the traversal of shear horizontal wave (SH-waves) in an initial-stressed fluid saturated porous stratum bounded between an initial-stressed magneto-elastic upper stratum and an initial-stressed elastic substrate. We have obtained the exact solution of the governing equations and explained in detail for various effective parameters. The displacement relation is developed with the help of Maxwell’s fundamental equations and Maxwell’s tensor. The impact of diverse parameters such as initial stress, porosity, magneto-elasticity, thickness ratio of attenuation coefficient and phase velocity of SH-wave has been discussed extensively by means of graphical depictions. Results indicate that such parameters possess a great positive impact on attenuation coefficient. This model contains a huge potential to deal with many commercial and industrial applications in Geo-technical, earthquake engineering and Geophysics.

Characterization of Polarized Shear Waves in FGPM Composite Structure with Imperfect Boundary: WKB Method

Propagation behavior of horizontally polarized shear waves (SH-waves) in a piezo-composite structure is discussed, using the Wentzel–Kramers–Brillouin (WKB) method. The considered model is made by combining the Functionally Graded Piezoelectric Material (FGPM) layer and piezoelectric orthotropic substrate. The linear form spring model is considered to delineate the imperfection of interface. Moreover, the material properties of FGPM layer are varying linearly along the thickness direction. Dispersion relation is obtained for both electrically open and short cases. Numerical example and graphical representation have been provided to illustrate the effect of different parameters on the phase velocity of SH-waves. As a special case, dispersion relation has been obtained when the boundary is perfect. Results are compared for different orthotropic materials to add more specific observations. Finally, the outcome of this study is validated by matching it with classical Love wave result. Observations will be helpful in optimization of Love wave sensors and Surface Acoustic Wave (SAW) devices.

Effect of interfacial imperfection on shear wave propagation in a piezoelectric composite structure: Wentzel–Kramers–Brillouin asymptotic approach

The primary objective of this article is to investigate the behaviour of horizontally polarized shear (SH) wave propagation in piezoelectric composite structure consisting of functionally graded piezoelectric material layer imperfectly bonded to functionally graded porous piezoelectric material half-space. The linear form of functional gradedness varying continuously along with depth is considered in both functionally graded piezoelectric material layer and functionally graded porous piezoelectric material half-space. The interface of the composite structure is considered to be damaged mechanically and/or electrically. Wentzel–Kramers–Brillouin asymptotic approach is adopted to solve the coupled electromechanical field differential equations of both functionally graded piezoelectric material layer and functionally graded porous piezoelectric material half-space. An analytical treatment has been employed to determine the dispersion relations of propagating SH-wave for both electrically short and electrically open conditions, which further reduced to the pre-established and classical results as special case of the problem. The effect of various affecting parameters, namely, functional gradedness, wave number, mechanical/electrical imperfection parameters in the presence and absence of porosity on the phase velocity of SH-wave, has been reported through numerical computation and graphical demonstration. In addition, the variation of the coupled electromechanical factor with dimensionless wave number and cut-off frequency with different modes of propagation of wave for electrically short and electrically open cases has also been discussed.

Transference of SH waves through irregular interface between corrugated piezoelectric layer and prestressed viscoelastic substrate

ABSTRACTAn exact approach is used to investigate the horizontally polarized shear wave in an irregular piezoelectric layer with corrugated surface lying over prestressed viscoelastic substrate. Perturbation technique is used to solve the problem. Dispersion relations are obtained in closed form for electrically open and short cases. The main feature of the present work is its ability to investigate the effect of irregularity, corrugation, dielectric constant, piezoelectric constant, initial stress and viscoelastic parameter on the phase velocity of SH wave. Numerical example has been carried out to observe the profound effect of these affecting parameters on phase velocity of SH wave.

Influence of magnetic effect, anisotropy, irregularity, initial stress and heterogeneity on propagation of SH-wave in an irregular pre-stressed magnetoelastic monoclinic sandwiched layer

Monoclinic materials viz. quartz, lithium niobate and lithium tantalate are among the most abundant materials, finding numerous applications throughout the technological world. Moreover, the presence of irregularity, initial stresses, anisotropy and heterogeneity in a material medium is obvious. These facts motivate the study of magnetoelastic SH-wave propagation in an irregular monoclinic sandwiched layer between a heterogeneous isotropic layer and an isotropic half space, all under initial stress. The heterogeneity in the uppermost layer is caused due to exponential variation in rigidity, density and initial stress in terms of space variable pointing vertically downward. The dispersion relation has been obtained using first-order perturbation technique. The substantial effect of wave number, anisotropy, irregularity, width ratio of the layers, horizontal compressive/tensile initial stresses, heterogeneity and monoclinic-magnetoelastic coupling parameter associated with sandwiched layer on phase velocity of SH-wave has been studied and depicted by means of graph. Comparative study made for the case when pre-stressed irregular sandwiched layer is monoclinic-magnetoelastic to the case when it is isotropic magnetoelastic layer is one of the major highlights of the current study.

Dispersion of SH waves in a viscoelastic layer imperfectly bonded with a couple stress substrate

The paper deals with propagation of SH waves in a viscoelastic layer over a couple stress substrate with imperfect bonding at the interface. A dispersion equation of SH waves in a viscoelastic layer overlying the couple stress substrate with an imperfect interface between them has been obtained. Dispersion equations for propagation of SH waves with perfectly bonded interface and slippage interface between two media are also obtained as particular cases. Effects of the degree of imperfectness of the interface are studied on the phase velo- city of SH waves. The dispersion curves are plotted and the effects of material properties of both couple stress substrate and viscoelastic layer are studied. The effects of internal micro- structures of the couple stress substrate in terms of characteristic length of the material are presented. The effects of heterogeneity, friction parameter and thickness of the viscoelastic layer are also studied on the propagation of SH waves.

Propagation of SH-waves in two anisotropic layers bonded to an isotropic half-space under gravity

This study reports a theoretical investigation of the propagation of SH-wave in a piezoelectric layer superimposed on a self-reinforced layer overlying an isotropic gravitational half-space. The expressions of the dispersion relation of SH-wave have been established for electrically open and electrically short conditions in closed form. For the purpose of numerical computation, lithium niobate piezoelectric material has been considered. The dispersion curves have been depicted graphically and the prominent impacts of piezoelectric constant, dielectric constant, reinforced parameter, width ratio, and Biot’s gravity parameter on the phase velocity of SH-wave have been unraveled for both the electrical conditions. As a special case of the problem, it is found that the obtained dispersion relation concurs with classical Love wave equation for both the electrical conditions. Moreover, some important peculiarities have also been traced out through numerical computations for both the electrical cases.

Effects of Irregularity, Porosity, Reinforcement and Initial Stress on the Propagation of SH-wave in a Self-reinforced Layer Lying over an Initially Stressed Porous Half-space

The present paper devotes the propagation of SH-wave in an irregular anisotropic self-reinforced layer lying over an initially stressed porous half-space. The various affecting parameter viz. irregularity depth, initial stress and porosity have their prominent effects on the phase velocity of SH-wave. To detect the substantial effect of these affecting parameters on the phase velocity of SH-wave, analytical computation and correspondingly graphical demonstration have been done. The dispersion equation has been established in closed form and found to be in good agreement with the Classical Love wave equation. The comparative study has been made between with reinforcement and without reinforcement structure models. Moreover, as and illustration, the overall effects of reinforcement and without reinforcement consolidated with irregularity and porosity are accentuated through graphs.

Dispersion study of SH-wave propagation in an irregular magneto-elastic anisotropic crustal layer over an irregular heterogeneous half-space

This study investigates the effect of various parameters on the propagation of seismic SH-waves in a magneto-elastic anisotropic crustal layer with corrugated boundary surfaces, lying over a heterogeneous half-space. The shear elastic modulus and mass density of half-space are the exponential functions of depth. Inclusion of the concept of corrugated irregularity with magneto-elasticity in the anisotropic (Monoclinic) medium and heterogeneity in the half-space medium brings a novelty to the existing literature related to the study of SH-wave. The expression of general dispersion relation has been established in closed form by using suitable boundary conditions. The effects of magneto-elastic coupling, heterogeneity, corrugation, undulatory and position parameters on the phase velocity of SH-wave have been computed numerically and demonstrated graphically. Moreover, different cases of free and common surface corrugations are studied which serve as a focal theme of the study.

SH-wave velocity in a fiber-reinforced anisotropic layer overlying a gravitational heterogeneous half-space

Purpose – The purpose of this paper is to investigate the existence of SH-waves in fiber-reinforced layer placed over a heterogeneous elastic half-space. Design/methodology/approach – The heterogeneity of the elastic half-space is caused by the exponential variations of density and rigidity. As a special case when both the layers are homogeneous, the derived equation is in agreement with the general equation of Love wave. Findings – Numerically, it is observed that the velocity of SH-waves decreases with the increase of heterogeneity and reinforced parameters. The dimensionless phase velocity of SH-waves increases with the decreases of dimensionless wave number and shown through figures. Originality/value – In this work, SH-wave in a fiber-reinforced anisotropic medium overlying a heterogeneous gravitational half-space has been investigated analytically and numerically. The dispersion equation for the propagation of SH-waves has been observed in terms of Whittaker function and its derivative of second degree order. It has been observed that on the removal of heterogeneity of half-space, and reinforced parameters of the layer, the derived dispersion equation reduces to Love wave dispersion equation thereby validates the solution of the problem. The equation of propagation of Love wave in fiber-reinforced medium over a heterogeneous half-space given by relevant authors is also reduced from the obtained dispersion relation under the considered geometry.

The effect of initial stress on the propagation behavior of SH waves in piezoelectric coupled plates

This study analytically investigates the propagation of shear waves (SH waves) in a coupled plate consisting of a piezoelectric layer and an elastic layer with initial stress. The piezoelectric material is polarized in z-axis direction and perfectly bonded to an elastic layer. The mechanical displacement and electrical potential function are derived for the piezoelectric coupled plates by solving the electromechanical field equations. The effects of the thickness ratio and the initial stress on the dispersion relations and the phase and group velocities are obtained for electrically open and mechanically free situations. The numerical examples are provided to illustrate graphically the variations of the phase and group velocities versus the wave number for the different layers comparatively. It is seen that the phase velocity of SH waves decreases with the increase of the magnitude of the initial compression stress, while it increases with the increase of the magnitude of the initial tensile stress. The initial stress has a great effect on the propagation of SH waves with the decrease of the thickness ratio. This research is theoretically useful for the design of surface acoustic wave (SAW) devices with high performance.