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sh wave PROPAGATION ALONG A PERIODIC GRATING SURFACE WITH GROOVES IN A MAGNETO-ELECTRO-ELASTIC SUBSTRATE

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SH WAVE PROPAGATION ALONG A PERIODIC GRATING SURFACE WITH GR...

2016年全国压电和声波理论及器件应用研讨会

作者： Tai GE Yu PANG Wen-jie FENG Chuan-zeng ZHANG Department of Engineering Mechanics Shijiazhuang Tie Dao University Department of Civil Engineering University of Siegen

ISBN: (纸本)9781509011902

Background,Motivation and Objective A surface grating structure with the periodic grooves or strips is the most fundamental element of surface acoustic wave(SAW) *** main reason to use these gratings is to trap the wave energy on the surface to achieve certain performances of the SAW devices,such as reflectors,delay lines,resonators,filters and interdigital transducers,***,as a surface wave propagates across the grating surfaces,wave propagation characteristics may *** examples,surface waves may convert into bulk waves,band-gaps may occur,wave-slowing phenomenon may appear and new types of surface waves may be excited,*** phenomena or behaviors are indeed different from the surface waves propagating on a smooth/planar *** of Contribution/Methods In this paper,we investigate the shear horizontal wave(sh wave) propagating along the periodic grating surface with grooves in a magneto-electro-elastic(MEE) half-space or substrate.A Cartesian coordinate system is introduced with the x-axis along and the y-axis perpendicular to the grating *** theoretical derivation is given for an arbitrary surface profile described by y = hf(x),where h is the maximum height of the *** the case of h wavelength and the period of the profile,*** profile is traction-free and the electric/magnetic boundaries are adjacent to the *** using the Taylor-Mclaurin’s series,the mechanical,electric and magnetic boundary conditions at y = hf(x) are transformed into the equivalent boundary conditions at the reference surface y = ***,to apply the orthogonality condition of the wave modes,associated with the generalized displacements based on Bloch-Floquet theorem,the mechanical,electric and magnetic boundary conditions are further converted into an infinite set of linear homogeneous equations,whose determinant determines the dispersion relation ω=ω(β).In

关键词： sh wave Magneto-electro-elastic substrate Periodic grating surface Grooves

sh wave dispersion of the functionally graded piezoelectric hollow cylinder

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SH wave dispersion of the functionally graded piezoelectric ...

2011年全国压电和声波理论及器件应用研讨会

作者： Yong-Dong PAN ~(1,*) Zheng ZHONG~2 1 Institute of Acoustics,Tongji University,shanghai 200092,China 2 School of Aerospace Engineering and Applied Mechanics,Tongji University,shanghai 200092,China

＜正＞The sh wave propagation in a functionally graded piezoelectric hollow cylinder is *** the piezoelectricity of the hollow cylinder,the wave equations and system matrices for state vector are obtained for the sh w... 详细信息

关键词： Functionally graded piezoelectric hollow cylinder sh wave

SCATTERING OF sh-wave BY CRACKS ORIGINATING AT AN ELLIPTIC HOLE AND DYNAMIC STRESS INTENSITY FACTOR

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Applied Mathematics and Mechanics(English Edition) 2004年第9期25卷 1047-1056页

作者：刘殿魁陈志刚 School of Civil Engineering Harbin Engineering University Department of Civil Engineering Jinan University

The method of complex function and the method of Green's function are used to investigate the problem of sh-wave scattering by radial cracks of any limited length along the radius originating at the boundary of an elliptical hole, and the solution of dynamic stress intensity factor at the crack tip was given. A Green's function was constructed for the problem, which is a basic solution of displacement field for an elastic half space containing a half elliptical gap impacted by anti-plane harmonic linear source force at any point of its horizontal boundary. With division of a crack technique, a series of integral equations can be established on the conditions of continuity and the solution of dynamic stress intensity factor can be obtained. The influence of an elliptical hole on the dynamic stress intensity factor at the crack tip was discussed.

关键词： Fracture mechanics Green's function Integral equations Scattering Stress intensity factors Surface waves Crack tip Elastic half space Elliptic hole Griffith linear crack sh wave

Focusing phenomenon and near-trapped modes of sh waves

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Earthquake Engineering and Engineering Vibration 2016年第3期15卷 477-486页

作者： Jeng-Tzong Chen Jia-Wei Lee Ya-Ching Tu Department of Harbor and River Engineering Taiwan Ocean University Department of Mechanical and Mechatronic Engineering Taiwan Ocean University

In this study, the null-field boundary integral equation method （BIEM） and the image method are used to solve the sh wave scattering problem containing semi-circular canyons and circular tunnels. To fully utilize the analytical property of Circular geometry, the polar coordinates are used to expand the closed-form fundamental solution to the degenerate kernel, and the Fourier series is also introduced to represent the boundary density. By collocating boundary points to match boundary condition on the boundary, a linear algebraic system is constructed. The unknown coefficients in the algebraic system can be easily determined. In this way, a semi-analytical approach is developed. Following the experience of near-trapped modes in water wave problems of the full plane, the focusing phenomenon and near-trapped modes for the sh wave problem of the half-plane are solved, since the two problems obey the same mathematical model. In this study, it is found that the sh wave problem containing two semi-circular canyons and a circular tunnel has the near-trapped mode and the focusing phenomenon for a special incident angle and wavenumber. In this situation, the amplification factor for the amplitude of displacement is over 300.

关键词： sh wave null-field boundary integral equation method degenerate kernel focusing, near-trapped mode

Diffraction of plane sh waves by a semi-circular cavity in half-space

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Earthquake Science 2010年第1期23卷 5-12页

作者： Jianwen Liang Hao Luo Vincent W Lee Department of Civil Engineering Tianjin University Tianjin 300072 China HNTB Corporation SantaAna CA 92707 USA University of Southern California Los Angeles CA 90089-2531 USA

This paper presents a closed-form solution for diffraction of plane sh waves by a semi-circular cavity in half-space by using wave function expansion method. Accuracy of the solution is checked by the displacement residual and stress residual along the boundaries. Numerical results show that there are notable differences for response amplitudes between a semi-circular cavity and a whole-circular cavity in a half-space.

关键词： diffraction sh wave semi-circular cavity wave function expansion method closed-form solution

Effects of an initial stress on sh-type guided wave propagating in a piezoelectric/piezomagnetic bilayered structure

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Effects of an initial stress on SH-type guided wave propagat...

2011年全国压电和声波理论及器件应用研讨会

作者： Guo-quan Nie,Ming Li,Jinxi Liu (Department of Engineering Mechanics,shijiazhuang Tiedao University shijiazhuang,050043,China)

＜正＞The propagation of sh-type guided waves in a bilayered plate with a constant initial stress is studied, where a piezoelectric thin layer perfectly bonded on a piezomagnetic thick *** layers are transversely isotropic *** dispersion relations of the problem are obtained for four kinds of different electro-magnetic boundary *** effects of initial stress,thickness ratio and electro-magnetic boundary conditions on the propagation behaviors are discussed in *** numerical results show that:1) the positive initial stresses make the wave velocity increasing,while the negative initial stresses decrease the wave velocity;2) The smaller the thickness ratio of a piezoelectric layer to a piezomagnetic layer is,the larger the phase velocities are;3) the electrical boundary conditions play a dominant role in the propagating *** the phase velocities for the electrically shorted surface are smaller than that for the open *** results are useful for understanding and design of the electromagnetic acoustic wave and microwave devices.

关键词： piezoelectric material piezomagnetic material sh wave initial stress dispersion relation

Propagation, reflection, and transmission of sh-waves in slightly compressible, finitely deformed elastic media

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Applied Mathematics and Mechanics(English Edition) 2015年第8期36卷 1045-1056页

作者： M.CHATTERJEE A.CHATTOPADHYAY Department of Applied Mathematics Indian School of Mines

The propagation, reflection, and transmission of sh waves in slightly com- pressible, finitely deformed elastic media are considered in this paper. The dispersion relation for sh-wave propagation in slightly compressible, finitely deformed layer over- lying a slightly compressible, finitely deformed half-space is derived. The present paper Mso deals with the reflection and refraction （transmission） phenomena due to the sh wave incident at the plane interface between two distinct slightly compressible, finitely deformed elastic media. The closed form expressions for the amplitude ratios of reflection and refraction coefficients of the reflected and refracted sh waves are obtained from suit- able boundary conditions. For the numerical discussions, we consider the Neo-Hookean form of a strain energy function. The phase speed curves, the variations of reflection, and transmission coefficients with the angle of incidence, and the plots of the slowness sections are presented by means of graphs.

关键词： slightly compressible sh wave propagation inhomogeneity reflection,transmission slowness section

SCATTERING OF sh waveS BY A MODE III CRACK IN A PIEZOELECTRIC CUBIC CRYSTAL

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SCATTERING OF SH WAVES BY A MODE III CRACK IN A PIEZOELECTRI...

2016年全国压电和声波理论及器件应用研讨会

作者： Guo-lin WANG Jin-xi LIU Yan-ping KONG Department of Engineering Mechanics Shijiazhuang Tiedao University

Background, Motivation and Objective Due to their intrinsic electromechanical effect, piezoelectric materials have been widely used as sensors, filters, transducers and resonators, and so on. Almost all of piezoelectric materials are brittle, therefore they are liable to fracture and failure during. The reliability and integrity of piezoelectric devices or structures call for a better understanding for fracture behavior of piezoelectric solids. In the aforementioned applications, some piezoelectric devices operate under dynamic mechanical or electrical loads such as transient impacts and harmonic waves. Therefore, the study on dynamic fracture behavior of piezoelectric materials is very important. In the past decade, many investigations on the dynamic fracture problems have been carried out, but focused on piezoelectric materials with 6mm symmetry. In this paper, we study the scattering of a shear horizontal(sh) wave by a Mode III crack in cubic piezoelectric crystals. The main objective is to reveal the influences of material properties, piezoelectric effect and the incident angle of sh wave on the dynamic fracture behavior. Statement of Contribution/Methods An infinite cubic piezoelectric solid with a Mode III crack is subjected to a sh wave whose incident angle is arbitrary. The electrically permeable crack model is adopted. By using the Fourier transform and dislocation density function, the mixed boundary value problem is reduced to the Cauchy singular integral equation. The Cauchy singular integral equation is solved by employing the Chebyshev polynomials. Numerical calculations are carried out for the dynamic stress intensity factor(DSIF). Results The piezoelectric cubic materials used in the computation are Ga As, Ga P, In Sb, In As, Bi12 Ge O20 and Bi4Ge3O12. For the given frequency range, the peak value of DSIF in the crack right tip for Ga As increases with the increase of the incident angle, but the peak value of DSIF in the crack left tip decrease, wher

关键词： Piezoelectric cubic crystal sh wave Dynamic stress intensity factor

Simulation of the seismic response of sedimentary basins with constant-gradient velocity along arbitrary direction using boundary element method:sh case

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Earthquake Science 2010年第2期23卷 149-155页

作者： Zengxi Ge Department of Geophysics School of Earth and Space Sciences Peking University Beijing 100871 China

We presented a boundary element method using the approximate analytical Green＇s function given by Sanchez-Sesma et al. Coordinate transform is introduced to extend the method to deal with the model with constant-gradient velocity along oblique direction. The method is validated by comparing the numerical results with other independent methods. This method provides a useful tool for analyzing local site effects. We computed seismic response for two series of models. The results in both frequency and time domains are analyzed and show complex amplification patterns. The fundamental mode of resonance is dependent not only on the velocity at the free surface but also on the velocity distribution of the whole basin. For the higher modes of vibration the heterogeneous basin also has its own characteristic.

关键词： boundary element sh wave seismic response constant-gradient velocity