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DYNAMICS OF A ROTATING FLEXIBLE MANIPULATOR WITH TIP LOAD

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Acta mechanica Solida Sinica 1998年第4期11卷 365-373页

作者： Hu, ZD Hong, JZ Shanghai Jiao Tong Univ Dept Engn Mech Shanghai 200030 Peoples R China

The dynamics of a flexible manipulator is investigated in this paper. From the point of view of dynamic balance, the motion equations of a rotating beam with tip load are established by us ing Hamilton' s principle. By taking into account the effects of dynamic stiffening and dynamic softening, the stability of the system is proved by employing Lyapunov' s approach. Furthermore, the method of power series is proposed to find the exact solution of the eigenvalue problem The effects of rotating speed and tip load on the vibration behavior of the flexible manipulator are shown in numerical results.

关键词： flexible manipulator large rigid motion dynamic stiffening stability of System Lyapunov functional eigenvalue problem

MODES COMPUTATION AND ANALYSIS FOR LONG MULTI-SPAN BUNDLE CONDUCTORS OF POWER TRANSMISSION LINES WITH GALLOPING CONTROL DEVICES

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Acta mechanica Solida Sinica 2002年第4期15卷 350-357页

作者： Zhao Gaoyu He Zeng Huazhong Univ Sci & Technol Dept Engn Mech Wuhan 430074 Peoples R China

A new type of element which is suitable for solving the modes of thegalloping long multi-span bundle conductor structures is presented. The element is composed of allsub-conductor segments between two spacers. Based on the linearized governing differential equationsof the conductors, the mass matrix and stiffness matrix of the element in consideration of theconstrained relations imposed on the conductors by spacers are derived. The dynamic characteristicsof the galloping control devices can be directly added to the element. The modes for an actual powerline structure are computed by using the element formula and FEM procedures, where seven cases ofdifferent galloping control device allocations are considered. Compared with the measured data, themethod is shown to be reliable and effective. Analysis and discussions of the computational resultsare given. Some hints that are helpful to further investigation of galloping are also obtained .

关键词： bundle conductors galloping control devices finite element method modes of free vibration

Ship Hull Slamming Analysis with Nonlinear Boundary Element Method

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China Ocean Engineering 1997年第4期12卷 411-418页

作者： Lu, CH He, YS Shanghai Jiao Tong Univ Dept Mech Engn Shanghai 200030 Peoples R China

A boundary element method is developed for calculating the flare ship hull slamming problem. The nonlinear free surface elevation and the linear element assumption are employed. The method has been verified by comparisons with results for the water entry of wedges with various deadrise angles. Numerical results show that the pressure distribution varies greatly with the ship hull with different curvilinear equations, and the slamming features are also different; From the numerical simulation, the authors found that the structural damage of the flare hull might be caused by the increasing hydrodynamic pressure over an extensive area on the flare when the upper part of the flare comes into contact with water.

关键词： slamming boundary element method ship full slamming analysis

BASIC SOLUTION FOR THE THREE-PHASE COMPOSITE CONSTITUTIVE MODEL IN ANTIPLANE PIEZOELECTRICITY

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Acta mechanica Solida Sinica 2000年第2期13卷 134-140页

作者： Wang, X Shen, YP Xian Jiao Tong Univ Dept Engn Mech Xian 710049 Peoples R China

A basic solution in series form for the three-phase composite cylindrical model in antiplane piezoelectricity subjected to the action of a singularity in the intermediate matrix region is presented. The solution is obtained through the complex potential approach in conjunction with the techniques of analytical continuation, singularity analysis, Laurent series expansion in an annular region and Cauchy integral formulae, etc. Based on the complex potentials obtained, explicit expressions for the distribution of stress and electric displacement in the three regions are also derived.

关键词： antiplane piezoelectricity three-phase composite constitutive model complex potential vector holomorphic function

THE VALIDITY OF THE MODIFIED MORI-TANAKA METHOD FOR COMPOSITES WITH SLIGHTLY WEAKENED INTERFACE

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Acta mechanica Solida Sinica 1997年第2期10卷 108-117页

作者： Zhai, J Luo, HA SHANGHAI JIAO TONG UNIV DEPT ENGN MECHSHANGHAI 200030PEOPLES R CHINA

This paper presents a direct Mori-Tanaka approach to calculate the effective moduli of particle-reinforced composites and fiber-reinforced composites with spring-like imperfect interfaces. By a comparison between these results and those obtained from the approximate Mori-Tanaka method developed by Qu for composites with slightly weakened interface, the validity of the Qu's method is revealed.

关键词： composite materials imperfect interface effective moduli Mori-Tanaka method

A STUDY ON STRESS INTENSITY FACTORS AND SINGULAR STRESS FIELDS OF THREE-DIMENSIONAL INTERFACE CRACK

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Acta mechanica Solida Sinica 1999年第1期12卷 43-50页

作者： Chen Mengcheng Gao Chuang Tang Renji Shanghai Jiao Tong Univ Dept Engn Mech Shanghai 200030 Peoples R China

By using the finite-part integral concepts and limit technique,the hypersingular inte- grodifferential equations ofthree-dimensional(3D)planar interface crack were obtained; then thedominant-part analysis of 2D hypersingular integral was further usedto investigate the stress fields near the crack front theoretically,and the accurate formulae were obtained for the singular stressfields and the complex stress intensity factors.

关键词： three-dimensional planar interface crack hypersingularintegrodifferential equation

BUCKLING AND POST-BUCKLING OF PIEZOELECTRIC PLATES USING FINITE ELEMENT METHOD

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Acta mechanica Solida Sinica 1999年第4期12卷 340-347页

作者： Tian, XG Shen, YP Gao, JX Xian Jiao Tong Univ Dept Engn Mech Xian 710049 Peoples R China

The finite element equations considering the geometrical nonlinearity of piezoelectric smart structures are derived based on the total Lagrange method under the assumption of weak coupling between electricity and mechanics. Buckling and post-buckling of piezoelectric-plate with various boundary conditions are investigated. The calculated results show that piezoelectric effects and external voltage can hardly affect the buckling and post-bucking characteristics of piezoelectric-plate under uniaxial pressure while the buckling caused by displacement in-plane has much to do with the electric field.

关键词： geometrical nonlinearity buckling and post-buckling piezoelectric effect finite element method

Robust positively invariant sets of discrete-time convex polyhedral system family

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Chinese Science Bulletin 1999年第19期44卷 1760-1763页

作者： Weihua Jiang Lin Huang Tianguang Chu Harbin inst Technol Dept Math Harbin 150006 Peoples R China Peking Univ Dept Mech & Engn Sci Beijing 100871 Peoples R China

Certain problems concerning state constraints and control constraints can often be reduced to the study of positive invariance of some subsets of the state space of dynamical systems. The robust positive invariance of given linear state constraint sets of uncertain discrete-time systems is studied by the mixed monotone decomposition method. Necessary and suffi-

关键词： discrete-time system family robust positively invariant sets mixed monotone decomposition method vertex results.

THE PROBABILITY STABILITY OF VISCOELASTIC PLATES

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Acta mechanica Solida Sinica 2002年第2期15卷 182-188页

作者： Li Yinghui Gao Qing SW Jiaotong Univ Dept Appl Mech & Engn Chengdu 610031 Peoples R China

The almost sure stability of homogeneous viscoelastic platessubjected to a random wide-band stationary in-plane load isinvestigated. The viscoelastic behavior of the plate is described interms of the Bo- ltzmann superposition principle, the relaxationkernels of which are represented by the sums of exponents. On theassumption that the in-plane load is random wide-band stationaryprocess, sufficient conditions for al- Most sure stability ofviscoelastic plates are obtained by the applications of Lyapunov'sdirect method.

关键词： almost sure stability viscoelastic plate integral constitutive law Lyapunov's direct method