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Zhenghua Qian - One of the best experts on this subject based on the ideXlab platform.
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propagation behavior of ultrasonic Love Waves in functionally graded piezoelectric piezomagnetic materials with exponential variation
Mechanics of Materials, 2020Co-Authors: Hamdi Ezzin, Bin Wang, Zhenghua QianAbstract:Abstract The current research is devoted to studying the propagation behavior of Love Waves in a functionally graded piezoelectric film perfectly bound to a homogeneous piezomagnetic substrate named FGPPM. All the material properties are supposed to be exponential through the piezoelectric film. Using the stiffness matrix method (SMM), the phase and group velocities are numerically calculated for magneto-electrically open and shorted cases. A detailed investigation of the gradient coefficient effect on the dispersion curve, the magneto-electromechanical coupling factor, the cutoff wave-number, and the modal shape is undertaken. It is found that quite a high magneto-electromechanical coupling factor for the structure at some appropriate wave number can be achieved by a simple adjustment of the gradient coefficient. As the variation of magneto-electromechanical properties of the film changes gradually with depth, and since the initial stress is supposed negligible during the manufacturing process, this calculation model could serve as a perfect match for the laminated piezoelectric-piezomagnetic structures used as surface acoustic wave devices (SAW). Thus, it can provide a theoretical basis for the design of the SAW devices with high performance.
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Piezoelectric Love Waves in an FGPM Layered Structure
Mechanics of Advanced Materials and Structures, 2011Co-Authors: Zhenghua Qian, Feng Jin, Sohichi HiroseAbstract:An analytical approach is used to investigate the existence and propagation behavior of surface electro-elastic Love Waves in an ideally layered structure consisting of a functionally graded piezoelectric substrate and a dielectric layer. The piezoelectric substrate is polarized in the direction perpendicular to the wave propagation plane and its material parameters change continuously along the thickness direction. The dispersion equations for the existence of surface Love Waves with respect to phase velocity are obtained for electrically open and shorted cases, respectively. A detailed investigation of the effects of material gradient on dispersion curve, phase velocity, group velocity, and electromechanical coupling factor is carried out. Numerical results show that material gradient significantly affects the fundamental mode of Love Waves but has only negligible effects on the high order modes. Large electromechanical coupling factors could be achieved by an appropriate adjustment of gradient coeffici...
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effect of initial stress on Love Waves in a piezoelectric structure carrying a functionally graded material layer
Ultrasonics, 2010Co-Authors: Zhenghua Qian, Kikuo Kishimoto, T J Lu, Sohichi HiroseAbstract:The effect of initial stress on the propagation behavior of Love Waves in a piezoelectric half-space of polarized ceramics carrying a functionally graded material (FGM) layer is analytically investigated in this paper from the three-dimensional equations of linear piezoelectricity. The analytical solutions are obtained for the dispersion relations of Love wave propagating in this kind of structure with initial stress for both electrical open case and electrical short case, respectively. One numerical example is given to graphically illustrate the effect of initial stress on dispersive curve, phase velocity and electromechanical coupling factor of the Love wave propagation. The results reported here are meaningful for the design of surface acoustic wave (SAW) devices with high performance.
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propagation behavior of Love Waves in a functionally graded half space with initial stress
International Journal of Solids and Structures, 2009Co-Authors: Zhenghua Qian, Feng Jin, Kikuo KishimotoAbstract:Abstract The propagation behavior of Love Waves in a functionally graded material layered non-piezoelectric half-space with initial stress is taken into account. The Wentzel–Kramers–Brillouin (WKB) technique is adopted for the theoretical derivations. The analytical solutions are obtained for the dispersion relations and the distributions of the mechanical displacement and stress along the thickness direction in the layered structure. First, these solutions are used to study the effects of the initial stress on the dispersion relations and the group and phase velocities, then the influences of the initial stress on the distributions of the mechanical displacement and shear stresses along the thickness direction are discussed in detail. Numerical results obtained indicate that the phase velocity of the Love Waves increases with the increase in the magnitude of the initial tensile stress, while decreases with the increase in the magnitude of the initial compression stress. The effects on the dispersion relations of the Love wave propagation are negligible as the magnitudes of the initial stress are less than 100 MPa. Some other results are obtained for the distributions of field quantities along thickness direction. The results obtained are not only meaningful for the design of functionally graded structures with high performance but also effective for the evaluation of residual stress distribution in the layered structures.
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propagation behavior of Love Waves in a piezoelectric layered structure with inhomogeneous initial stress
Smart Materials and Structures, 2005Co-Authors: Zhenghua Qian, Zikun Wang, Kikuo KishimotoAbstract:For the piezoelectric layer/substrate structure with slowly varying inhomogeneous initial stress in the layer, the influence of the initial stress on the properties of Love wave propagation is studied. The Wentzel?Kramers?Brillouin?(WKB) approximate approach is adopted for analytical derivations. Numerical results obtained for the BaTiO3 layer/borosilicate glass substrate combination system indicate that, under certain conditions, initial stress in the layer can markedly affect the propagation of the Love wave. The analysis is meaningful for the theoretical analysis and engineering applications of Love Waves.
N C Mahanti - One of the best experts on this subject based on the ideXlab platform.
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Love Waves in a fluid saturated porous layer under a rigid boundary and lying over an elastic half space under gravity
Applied Mathematical Modelling, 2010Co-Authors: Anjana P Ghorai, S K Samal, N C MahantiAbstract:Abstract In this paper, mathematical modeling of the propagation of Love Waves in a fluid-saturated porous layer under a rigid boundary and lying over an elastic half-space under gravity has been considered. The equations of motion have been formulated separately for different media under suitable boundary conditions at the interface of porous layer, elastic half-space under gravity and rigid layer. Following Biot, the frequency equation has been derived which contain Whittaker’s function and its derivative that have been expanded asymptotically up to second term (for approximate result) for large argument due to small values of Biot’s gravity parameter (varying from 0 to 1). The effect of porosity and gravity of the layers in the propagation of Love Waves has been studied. The effect of hydrostatic initial stress generated due to gravity in the half-space has also been shown in the phase velocity of Love Waves. The phase velocity of Love Waves for first two modes has been presented graphically. Frequency equations have also been derived for some particular cases, which are in perfect agreement with standard results. Subsequently the lower and upper bounds of Love wave speed have also been discussed.
Zimao Zhang - One of the best experts on this subject based on the ideXlab platform.
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Love Waves in an inhomogeneous fluid saturated porous layered half space with linearly varying properties
Soil Dynamics and Earthquake Engineering, 2006Co-Authors: Yuesheng Wang, Zimao ZhangAbstract:The paper is concerned with the propagation of the Love Waves in an inhomogeneous transversely isotropic fluid saturated porous layered half-space with linearly varying properties. The analysis is based on Biot's theory. Firstly, the dispersion equation in the complex form for the Love Waves in an inhomogeneous porous layer is derived. Then the equation is solved by an iterative method. Detailed numerical calculation is presented for an inhomogeneous fluid saturated porous layer overlying a purely elastic half-space. The dispersion and attenuation of the Love Waves are discussed. In addition, the upper and lower bounds of the Love wave speed are explored.
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propagation of Love Waves in an inhomogeneous fluid saturated porous layered half space with properties varying exponentially
Journal of Engineering Mechanics-asce, 2005Co-Authors: Yuesheng Wang, Zimao ZhangAbstract:Based on Biot's theory for transversely isotropic fluid saturated porous media, the complex dispersion equation for Love Waves in a transversely isotropic fluid-saturated porous layered half-space is derived with the consideration of the inhomogeneity of the layer. The equation is solved by an iterative method. Detailed numerical calculation is presented for an inhomogeneous fluid-saturated porous layer overlying a purely elastic half-space. The dispersion and attenuation of Love Waves are discussed. In addition, the upper and lower bounds of Love wave speed are also explored.
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propagation of Love Waves in a transversely isotropic fluid saturated porous layered half space
Journal of the Acoustical Society of America, 1998Co-Authors: Yuesheng Wang, Zimao ZhangAbstract:The dispersion equation for Love wave propagation in a layer lying over a half-space is derived. Both media are assumed to be transversely isotropic fluid-saturated poroelastic solids with principal axes perpendicular to the surface. The analysis is based on the Biot’s theory. The dissipation due to fluid viscosity is considered and therefore the dispersion equation is complex and intractable analytically. An iterative procedure is developed to solve this equation. Two situations are discussed in detail: (i) an elastic layer overlying a poroelastic half-space and (ii) a poroelastic layer lying over an elastic half-space. Dispersion curves and attenuation curves of Love Waves are plotted for these two cases. In addition, the upper and lower bounds of Love wave speeds are also explored.
Kikuo Kishimoto - One of the best experts on this subject based on the ideXlab platform.
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effect of initial stress on Love Waves in a piezoelectric structure carrying a functionally graded material layer
Ultrasonics, 2010Co-Authors: Zhenghua Qian, Kikuo Kishimoto, T J Lu, Sohichi HiroseAbstract:The effect of initial stress on the propagation behavior of Love Waves in a piezoelectric half-space of polarized ceramics carrying a functionally graded material (FGM) layer is analytically investigated in this paper from the three-dimensional equations of linear piezoelectricity. The analytical solutions are obtained for the dispersion relations of Love wave propagating in this kind of structure with initial stress for both electrical open case and electrical short case, respectively. One numerical example is given to graphically illustrate the effect of initial stress on dispersive curve, phase velocity and electromechanical coupling factor of the Love wave propagation. The results reported here are meaningful for the design of surface acoustic wave (SAW) devices with high performance.
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propagation behavior of Love Waves in a functionally graded half space with initial stress
International Journal of Solids and Structures, 2009Co-Authors: Zhenghua Qian, Feng Jin, Kikuo KishimotoAbstract:Abstract The propagation behavior of Love Waves in a functionally graded material layered non-piezoelectric half-space with initial stress is taken into account. The Wentzel–Kramers–Brillouin (WKB) technique is adopted for the theoretical derivations. The analytical solutions are obtained for the dispersion relations and the distributions of the mechanical displacement and stress along the thickness direction in the layered structure. First, these solutions are used to study the effects of the initial stress on the dispersion relations and the group and phase velocities, then the influences of the initial stress on the distributions of the mechanical displacement and shear stresses along the thickness direction are discussed in detail. Numerical results obtained indicate that the phase velocity of the Love Waves increases with the increase in the magnitude of the initial tensile stress, while decreases with the increase in the magnitude of the initial compression stress. The effects on the dispersion relations of the Love wave propagation are negligible as the magnitudes of the initial stress are less than 100 MPa. Some other results are obtained for the distributions of field quantities along thickness direction. The results obtained are not only meaningful for the design of functionally graded structures with high performance but also effective for the evaluation of residual stress distribution in the layered structures.
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propagation behavior of Love Waves in a piezoelectric layered structure with inhomogeneous initial stress
Smart Materials and Structures, 2005Co-Authors: Zhenghua Qian, Zikun Wang, Kikuo KishimotoAbstract:For the piezoelectric layer/substrate structure with slowly varying inhomogeneous initial stress in the layer, the influence of the initial stress on the properties of Love wave propagation is studied. The Wentzel?Kramers?Brillouin?(WKB) approximate approach is adopted for analytical derivations. Numerical results obtained for the BaTiO3 layer/borosilicate glass substrate combination system indicate that, under certain conditions, initial stress in the layer can markedly affect the propagation of the Love wave. The analysis is meaningful for the theoretical analysis and engineering applications of Love Waves.
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Love Waves propagation in a piezoelectric layered structure with initial stresses
Acta Mechanica, 2004Co-Authors: Zhenghua Qian, Zikun Wang, Kikuo KishimotoAbstract:The propagation behavior of Love Waves in a piezoelectric layered structure with inhomogeneous initial stress is studied. Solutions of the mechanical displacement and electrical potential function are obtained for the isotropic elastic layer and transversely isotropic piezoelectric substrate, respectively, by solving the coupled electromechanical field equations. Firstly, effects of the inhomogeneous initial stress on the dispersion relations and phase velocity of Love wave propagation are discussed. Then the influence of the initial stress gradient coefficient on the stress, mechanical displacement and electrical potential distribution in the layer and the substrate is investigated in detail. The results reported in this paper are not only meaningful for the design of surface acoustic wave (SAW) devices with high performance, but also effective for evaluating the residual stress distribution in the layered structures.
P Kielczynski - One of the best experts on this subject based on the ideXlab platform.
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direct sturm liouville problem for surface Love Waves propagating in layered viscoelastic waveguides
Applied Mathematical Modelling, 2018Co-Authors: P KielczynskiAbstract:Abstract This paper presents theoretical model for shear-horizontal (SH) surface acoustic Waves of the Love type propagating in lossy waveguides consisting of a lossy viscoelastic layer deposited on a lossless elastic half-space. To this end, a direct Sturm–Liouville problem that describes Love Waves propagation in the considered viscoelastic waveguides was formulated and solved, what constitutes a novel approach to the state-of-the-art. To facilitate the solution of the complex dispersion equation, the Author employed an original approach that relies on the separation of its real and imaginary part. By separating the real and imaginary parts of the resulting complex dispersion equation for a complex wave vector k = k0 + jα of the Love wave, a system of two real nonlinear transcendental algebraic equations for k0 and α has been derived. The resulting set of two algebraic transcendental equations was then solved numerically. Phase velocity vp and coefficient of attenuation α were calculated as a function of the wave frequency f, thickness of the surface layer h and its viscosity η44. Dispersion curves for Love Waves propagating in lossy waveguides, with a lossy surface layer deposited on a lossless substrate, were compared to those corresponding to Love surface Waves propagating in lossless waveguides, i.e., with a lossless surface layer deposited on a lossless substrate. The results obtained in this paper are original and to some extent unexpected. Namely, it was found that: 1) the phase velocity vp of Love surface Waves increases as a function of viscosity η44 of the lossy surface layer, and 2) the coefficient of attenuation α has a maximum as a function of thickness h of the lossy surface layer. The results obtained in this paper are novel and can be applied in geophysics, seismology and in the optimal design and development of viscosity sensors, bio and chemosensors.
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group and phase velocity of Love Waves propagating in elastic functionally graded materials
Archives of Acoustics, 2015Co-Authors: P Kielczynski, Marek Szalewski, Andrzej Balcerzak, Krzysztof WiejaAbstract:This paper presents a theoretical study of the propagation behaviour of surface Love Waves in nonhomogeneous functionally graded elastic materials, which is a vital problem in acoustics. The elastic properties (shear modulus) of a semi-infinite elastic half-space vary monotonically with the depth (distance from the surface of the material). Two Love wave waveguide structures are analyzed: 1) a nonhomogeneous elastic surface layer deposited on a homogeneous elastic substrate, and 2) a semi-infinite nonhomogeneous elastic half-space. The Direct Sturm-Liouville Problem that describes the propagation of Love Waves in nonhomogeneous elastic functionally graded materials is formulated and solved 1) analytically in the case of the step profile, exponential profile and 1 cosh 2 type profile, and 2) numerically in the case of the power type profiles (i.e. linear and quadratic), by using two numerical methods: i.e. a) Finite Difference Method, and b) Haskell-Thompson Transfer Matrix Method. The dispersion curves of phase and group velocity of surface Love Waves in inhomogeneous elastic graded materials are evaluated. The integral formula for the group velocity of Love Waves in nonhomogeneous elastic graded materials has been established. The results obtained in this paper can give a deeper insight into the nature of Love Waves propagation in elastic nonhomogeneous functionally graded materials.
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inverse procedure for simultaneous evaluation of viscosity and density of newtonian liquids from dispersion curves of Love Waves
Journal of Applied Physics, 2014Co-Authors: P Kielczynski, M Szalewski, A BalcerzakAbstract:Simultaneous determination of the viscosity and density of liquids is of great importance in the monitoring of technological processes in the chemical, petroleum, and pharmaceutical industry, as well as in geophysics. In this paper, the authors present the application of Love Waves for simultaneous inverse determination of the viscosity and density of liquids. The inversion procedure is based on measurements of the dispersion curves of phase velocity and attenuation of ultrasonic Love Waves. The direct problem of the Love wave propagation in a layered waveguide covered by a viscous liquid was formulated and solved. Love Waves propagate in an elastic layered waveguide covered on its surface with a viscous (Newtonian) liquid. The inverse problem is formulated as an optimization problem with appropriately constructed objective function that depends on the material properties of an elastic waveguide of the Love wave, material parameters of a liquid (i.e., viscosity and density), and the experimental data. The results of numerical calculations show that Love Waves can be efficiently applied to determine simultaneously the physical properties of liquids (i.e., viscosity and density). Sensors based on this method can be very attractive for industrial applications to monitor on-line the parameters (density and viscosity) of process liquid during the course of technological processes, e.g., in polymer industry.
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attenuation of Love Waves in low loss media
Journal of Applied Physics, 1997Co-Authors: P KielczynskiAbstract:A theory of Love Waves propagating in a viscoelastic surface layer deposited on a perfect elastic substrate was considered. In the case of low losses (ωη44/μB0≪1) an analytical formula relating the attenuation coefficient of the Love wave and the viscoelastic parameters of the waveguide structure was established. This makes it possible to apply the obtained analytical formula in nondestructive testing for determining the rheological parameters of viscoelastic bodies. The established theory of Love Waves in viscoelastic media can also be applied in seismology and integrated optics.
