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HYDRODYNAMIC FORCES ACTING ON AN ELASTIC CIRCULAR CYLINDERIN COMBINED WAVE AND CURRENT FLOW AT HIGH REYNOLDS NUMBERS

In this paper, wave forces acting on a submerged circular cylinder movingforward with a constant velocity in regular waves are investigated experimentally. TheReynolds numbers and the Keulegan──Carpenter numbers are in the range: 0.61 × 10￣5Re6.01 × 10￣5,4.61 Kc74.80,The surface pressures of the cylinder and the cylinder’svibrations caused by the hydrodynamic forces are measured,from which the drag and inertiacoefficients(C_D, C_M)in Morison’s formular are analyized, the fiuctuating drag and liftcoefficien...

1995, 27(1): 1-9. doi: 10.6052/0459-1879-1995-1-1995-399

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WIND TUNNEL AEROELASTIC MODELLING OF THE CHINESE CENTRALTVTOWER

A spline aeroelastic model of the Chinese Central television ( CCTV)tower,was designed according to the law of similarity and was tested in an atmospheric boundarylayer wind tunnel. The dynamic bending moment was measured using strain gauge.Thelocus of wind induced vibration of the antenna tip and the tower building wais taken by useof the method of light-point of optical fibers,The dvnamic characteristic of response of theTV tower to wind was obtained.

1995, 27(1): 10-17. doi: 10.6052/0459-1879-1995-1-1995-400

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FRACTAL EFFECTS OF DYNAMIC CRACK PROPAGATION

Crack extension paths are often irregular, producing rough fracture surfaceswhich have a fractal geometry.In this paper, crack tip motion along a fractal crack trace isanalysed. A fractal kinking model of the crack extension path is established to describe ir-regular crack growth. A formula is derived to describe the effects of fractal crack propagationon the dvnamic stross intensity factor and on crack velocity. The ratio of the dvnamic stressintensity factor to the applied stress intensity factor,K(l(t),V...

1995, 27(1): 18-27. doi: 10.6052/0459-1879-1995-1-1995-401

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FRACTAL MECHANISM OF SPALLAIION AND RELAIION BETWEEN FRACTALDIMENSION AND COALESCENCE THRESHOLD

In the light of the dynamical analysis of microcrack coalescence, this paperpresents a statistical fractal modeI to describe the damage evolution of spailation. Themodel demonstrates that the mechanisnl of fractal surfaces formed in spallatioii is cioselyrelated to the dynainic processes of the cascade coalescence of lnicrocracks.A unimodalrelation between the fractal dimension and the coalescence threshold based on the modelcan qualitatively explain the challenging observation of fractal dimension versus t...

1995, 27(1): 28-37. doi: 10.6052/0459-1879-1995-1-1995-402

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THELINEAR COMPLEMENTARYPROBLEM FOR ELASTO-PLASTIC ANALYSIS

In order to achieve non-iterative algofithm of the elasto-plastic problems,thelinear complementary equations are derived from a simple and stict way in this paper.Compared with otlier non-iterative methods, the scale of linear complementary problemgiven here is much smaller. The well-posedness of the solution is discussed.The practicalalgorithm for solving engineering problems is given, and two examples are also calculated.

1995, 27(1): 38-47. doi: 10.6052/0459-1879-1995-1-1995-403

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DYNAMIC BUCKLING OF ELASTIC-PLASTIC CYLINDRICAL SHELLS UNDER AXIAL TWO PARAMETERS IMPULSIVE LOADING

The inelastic dynamic buckling of cylindrical shells under axial two parametersimpulsive loading is discussed. The basic equations of structure are derived from a minimumprinciple in dynamics of elastic-plastic continua at finite deformation and the flow theoryof plasticity is employed. Two phases(a pre-critical and post-critical phase)can be distin-guished at an early stage of dynamic buckling of inelastic shell.The effects of peak valueand during time of loading, initial imperfections, geometric dimension...

1995, 27(1): 48-57. doi: 10.6052/0459-1879-1995-1-1995-404

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ON THE CALCULATION OF NORMALFORM COEFFICIENTS OF NONLINEARDYNAMIC SYSTEMS

In this paper, a ncw method determining the normal form coefficients term byterm is contructed,it can be used efficiently in general nonlinear dynamic systems in whichhigh orer of normal form is required.

1995, 27(1): 58-68. doi: 10.6052/0459-1879-1995-1-1995-405

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GENERALIZEDMULTI-TRANSMITTINGBOUNDARY:SCALAR WAVE CASE

The multi-transmitting boundary condition has been generalized using spaceextrapolation to improve accuracy of the boundary condition in the time domain computa-tion. Refiection coefficients of the boundary in the frequency domain are formulated for twocases, in which the total wave fields are composed of the incident wave only and the incidentwave plus the fully developed refiecti on wave,respectively. The reflection coefficients arethen analyzed from a viewpoint of accuracv of the boundary in the time dom...

1995, 27(1): 69-78. doi: 10.6052/0459-1879-1995-1-1995-406

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A SEMI-ANALYTICAL METHOD FOR STRESS ANALYSIS OF MULTIPLANAR TUBULAR JOINTS

There are many multiplanar tubular joints in offshore structures. The stressanalvsis of these joints is far from being solved with satisfaction due to the complexity ingeonietry and ioad cases.A semi-analytical (analytic-numerical) method for stress analysis ofmultiplanar tubular joints subjected to any loads is presented in this paper. Some advantagesof the computer program compiled based on semi-analytical method are discussed. Twonumerical examples and comparison of the computed results with that by expe...

1995, 27(1): 79-85. doi: 10.6052/0459-1879-1995-1-1995-407

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THE CONSERVATION LAWSAND PATH-INDEPENDENT INTEGRALS FOR PIEZOELECTRIC MEDIA

Motivated by concepts of Jacobi integral and cyclic integral in analytical me-chanics and energy-momentum tensor in electro-magntic field,the conservation laws forpiezoelectric materials were derived, from which the path independent integrals can be ob-tained.

1995, 27(1): 86-92. doi: 10.6052/0459-1879-1995-1-1995-408

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AN OPTIMUMARITHMETIC FOR RELATIVE PERMEABILITY OF UNCONSOLIDATED CORE CONTAINING HEAVY PETROLEUM

Aiming at obtaining the relative permeability curves of unconsolidated Corecontaining heavy petroleum,a set of governing equations are obtalned based on porousmedium flow theory and optimum theory. The optimum problems are solved by means of constraint Variable metric method.The sensitivity and blockage of results to initial data iseliminated.Several examples are included to illustrate the reliability and usefulness of this method.

1995, 27(1): 93-98. doi: 10.6052/0459-1879-1995-1-1995-409

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THE STUDY ON ALGEBRAIC TRANSPORT TURBULENCE MODEL BASED ON RNG THEOBY

In this paper, investigations on a RNG based algebraic transport turbulentmodel is carried out.Aproper way proposed here to choose a suitable root for the eddyviscosity from solutions of a cubic equation derived from the renormalization group theoryhas resonable physical meaning. In addition, two-peak average method is used to determinethe thickness of boundary layers inside separation regions,which has improved the way ofBaldwin-Lomax algebraic turbulence model and can be applied in engineering calculation...

1995, 27(1): 99-103. doi: 10.6052/0459-1879-1995-1-1995-410

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STUDY ON SLOSH OF SPINNING LIQU

The slosh problem of spinning liquid in an axisymmetric container has beeninvestigated in the present paper. A PEG method has been suggested here to remedy thetheoretical defect caused by using the traditional PBG method. This paper also analyses thestability of free vibration of spinning liquid in the rotating container with constant angularvelocity.

1995, 27(1): 104-109. doi: 10.6052/0459-1879-1995-1-1995-411

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OPTIMAL CORRECTION OF FREQUENCYERRORS ANDSELECTION METHOD OF PARAMETERS TO BE MODIFIED

This paper deals with the correction of frequency errors of structure with randomdesign parameters and the selection problem for parameters to be modified.The conceptsof ideal parameter to be modified,optimal parameter to be modified and optimal parametergroup in which all parameters are optimal parameters to be modified are introduced. Theoptimal parameters to be modified,which make the expectation of the root-mean-square fre-quency errors taking the minimum value, and their quantities to be modified are o...

1995, 27(1): 110-116. doi: 10.6052/0459-1879-1995-1-1995-412

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SOLUTION OF VISCOELASTIC AND ORIHOTROPIC HALF-SPACE SUBJECTED TO TORSION

The general formulation of displacement and stress in a half-space under axi-symmetrical torsion is obtained by means of HankeI transformation. The investigations aremainly focused on the behaviors on linear elastic, viscoelastic and orthotropic semi-spacesubjected to a concentrated torque. The analytical expressions of displacements and stressesare derived.

1995, 27(1): 117-121. doi: 10.6052/0459-1879-1995-1-1995-413

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THREE-DIMENSIONAL MEASURING AND VISULIZATION OF AFREE JET BY MEANS OF TWO-RELECTION

Three-dimensional PIV of a free jet is given by means of the photogrammetryand image prcessing. In this paper,a new double-reflection method is being used to solve theproblems of synchronism and precision in the three-dimensional measuring of a high speedjet. The indices of refraction in water and air are considered,so the calculation of particle’s3-D position is correct. A succession of 3-D, global, instantaneous fields of particles andtheir velocity vectors have been reconstriicted by means of microcomput...

1995, 27(1): 122-125. doi: 10.6052/0459-1879-1995-1-1995-414

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1995 Vol. 27, No. 1

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