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ACOUSTIC REFLECTION FROM A BAFFLED ELASTIC/PIEZOELECTRIC PLATE

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Acta Mechanica Solida Sinica 2002年第2期15卷 156-162页

作者： Zhao Hanzhong (department of mechanics,{2.,wuhan 43.074,china) department of mechanics Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

A finite difference/boundary integral procedure to determine theacoustic reflected pressure from a fluid-loaded bi-laminated plate isdescribed. The bi-laminate is composed of a piezoelectric layer andan elastic layer in contact with the fluid, and is held by anacoustically hard baffle. In the numerical model, the fluid pressureat fluid/solid interface is replaced by a continuum of point sourcesweighted by the normal acceleration of the elastic plate, and thegoverning equation system is solved in the solid domain.

关键词： acoustic reflection baffled palte finite difference boundary integral

LAMINATED VISCOELASTIC PLATE WITH INCLUSIONS FOR PASSIVE UNDER-WATER ACOUSTIC CONTROL

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Acta Mechanica Solida Sinica 2002年第1期15卷 23-29页

作者： Zhao Hanzhong (department of mechanics,{2.,wuhan 43.074,china) department of mechanics Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The effectiveness of a fluid-loaded sandwiched viscoelastic layerin suppressing acoustic scat- tering and radiation has been estimatedusing the Thomson-Haskell matrix method. The GU (Gaunaurd andUberall) resonance theory has been adopted to handle three types ofviscoelastic substrates with air -filled in- Clusions. The effects ofthe varying thickness of the substrates, the volume fractions of theinclusions and fre- Quencies of incident waves have been studied todetermine the optimal strategies of signal reduction. In theInvestigation, the monopole resonance phenomena of the inclusionshave been taken into account.

关键词： underwater acoustic control laminated viscoelastic plate air-filledinclusion

ACOUSTIC REFLECTION FROM A PERIODIC ELASTIC/PIEZOELECTRIC PLATE

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Acta Mechanica Solida Sinica 2003年第4期16卷 321-326页

作者： Zhao Hanzhong (department of mechanics,{2.,wuhan 43.074,china) department of mechanics Huazhong Univ. of Sci./Technology Wuhan 430074 China

The acoustic reflected pressure from a periodic elastic/piezoelectric laminated plate is studied for the purpose of acoustic reflection control.A finite difference/boundary integral procedure to determine the reflected pressure from the fluid-loaded plate is *** the numerical model,a Green's function in the form of infinite sum is employed and a boundary integral is performed to replace the fluid pressure at fluid/solid interface by a continuum of point sources weighted by the normal acceleration of the elastic *** equation system is then solved only in the solid *** is demonstrated that an appropriate applied voltage potential across the piezoelectric layer has the effect of cancelling the fundamental propagating mode,and there,is no reflection for frequencies up to the cut-off frequency of the next propagating mode if the fundamental mode has been eliminated.

关键词： acoustic reflection periodic plate finite difference boundary integral

Convergence analysis for general linear methods applied to stiff delay differential equations

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Progress in Natural science:Materials International 2002年第6期12卷 16-22页

作者： ZHANG Chengjian(department of Mathematics, huazhong university of science and technology, {2., china) huazhong Univ Sci & Technol Dept Math Wuhan 430074 Peoples R China

For Runge-Kutta methods applied to stiff delay differential equations (DDEs), the concept of D-convergence was proposed, which is an extension to that of B-convergence in ordinary differential equations (ODEs) . In this paper, D-convergence of general linear methods is discussed and the previous related results are improved. Some order results to determine D-convergence of the methods are obtained.

关键词： D-convergence general linear methods stiff delay differential equations.

GREEN'S FUNCTIONS FOR A 2. ANISOTROPIC MEDIUM WITH A HYPERBOLIC BOUNDARY

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Acta Mechanica Solida Sinica 2000年第1期13卷 17-24页

作者： Hu Yiantai Huang Yuying Chen Chuanyao (department of mechanics,{2.,wuhan 43.074,china) huazhong Univ Sci & Technol Dept Mech Wuhan 430074 Peoples R China

By using Stroh's formalism and the conformal mapping technique,this paper derives simple exphcit Green's functions of a piezoelectric anisotropic body with a free or fixed hyperbolic *** corresponding elastic fields in the medium are obtained,*** particular,degenerated solutions of an ex- ternal crack from those of a hyperbolic problem are analysed in *** the singular stress fields and the fracture mechanics parameters are *** solutions obtained are valid not only for plane and antiplane problems but also for the coupled ones between inplane and outplane deformations.

关键词： Stroh's formalism conformal mapping Green's functions external crack stress intensity factors

HOPF BIFURCATION OF A NONLINEAR RESTRAINED CURVED PIPE CONVEYING FLUID BY DIFFERENTIAL QUADRATURE METHOD

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Acta Mechanica Solida Sinica 2003年第4期16卷 345-352页

作者： Wang Lin Ni Qiao Huang Yuying (department of mechanics,{2.,wuhan 43.074,china) department of mechanics Huazhong University of Science and Technology Wuhan 430074 China

This paper proposes a new method for investigating the Hopf bifurcation of a curved pipe conveying fluid with nonlinear spring *** nonlinear equation of motion is derived by forces equilibrium on microelement of the system under *** spatial coordinate of the system is discretized by the differential quadrature method and then the dynamic equation is solved by the Newton-Raphson *** numerical solutions show that the inner fluid velocity of the Hopf bifurcation point of the curved pipe varies with different values of the parameter, nonlinear spring *** on this,the cycle and divergent motions are both found to exist at specific fluid flow velocities with a given value of the nonlinear spring *** results are useful for further study of the nonlinear dynamic mechanism of the curved fluid conveying pipe.

关键词： curved fluid conveying pipe Hopf bifurcation nonlinear vibration DQM

A low frequency piezoelectric power harvester using a spiral-shaped bimorph

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science china(Physics,{2. & Astronomy) 2006年第6期49卷 649-659页

作者： HU Yuantai1,2.HU Hongping2.& YANG Jiashi3 1. Institute of mechanics and Sensing technology,Central South {2.,Changsha 410083,china 2. department of mechanics,huazhong university of science and technology,wuhan 43.074,china 3. department of Engineering mechanics,{2. of Nebraska,Lincoln,NE 68588-052.,USA 1. Institute of mechanics and Sensing technology Central South University Changsha 410083 China 2. department of mechanics Huazhong University of Science and Technology Wuhan 430074 China 3. department of Engineering mechanics University of Nebraska Lincoln NE 68588-0526 USA

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources. A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size. It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

关键词： spiral-shaped bimorph,piezoelectric harvester,power density.

D-CONVERGENCE AND STABILITY OF A CLASS OF LINEAR MULTISTEP METHODS FOR NONLINEAR DDES

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Journal of Computational Mathematics 2000年第2期18卷 199-206页

作者： Cheng-jian Zhang Xiao-xin Liao (department of Mathematics, huazhong university of science and technology, {2., china) 华中科技大学湖北武汉 430074

Presents information on a study which dealt with the error behavior and the stability analysis of a class of linear multistep methods with the Lagrangian interpolation as applied to the nonlinear delay differential eq... 详细信息

关键词： D-convergence stability multistep methods nonlinear DDEs

A delay differential equation solver based on the parallel Adams algorithms

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Communications in Nonlinear science and Numerical Simulation 2001年第1期6卷 28-34页

作者： Chengjian ZHANG and Hongbing YU(department of Mathematics, huazhong university of science and technology, {2.,china) department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China

This paper constructs a class of parallel Adams algorithms for the systems of delay differential equations. The results on convergence and stability are given. The theoretical analysis and numerical test shows that th... 详细信息

关键词： parallel algorithms Adams algorithms delay differential equations