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1998年 第19卷 第5期    刊出日期：1998-05-18

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论文

ON THE STRESS CONCENTRATION IN THICK CYLINDRICAL SHELLS WITH AN ARBITRARY CUTOUT

胡超;刘殿魁;马兴端;王本利

1998, 19(5):  399-410. 

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In this paper, based on the theory of thick shells including effects of transverseshear deformations, a complex variables analytic me method to solve stress concentrationsin circular cylindrical shells with a small cutout is established. A general solution andexpression satisfying the boundary conditions on the edge of arbitrary’ cutouts areobtained. The stress problem can be reduced ic the solution of an infinte algebraicequation series, and can be normalized by means of this method. Numerical results forstress concentration factors of the shell with a small circular and elliptic elliptic arepresented.

POSTBUCKLING OF IMPERFECT STIFFENED CYLINDRICAL SHELLS UNDER COMBINED EXTERNAL PRESSURE AND HEATING

沈惠申

1998, 19(5):  411-423. 

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A postbuckling analysis is presented for a stiffened cylindrical shell of finitelength subjected to combined loading of external pressure and uniform temperaturerise. The formulations are based on a boundary layer theory of shell buckling, whichincludes the effects of nonliear prebuckling deformations, nonlinear large deflectonsin the postbuckling range and initial geometrical imperfections of the shell. The "smeared sitffener" approach is adopted for the sitffeners. The analysis uses a singular perturbation technique to determine the interactive buckling loads and the postbucklingequilibruium paths. Numerical examples cover the performances of perfect and imperfect, stringer and ring stiffened cylindrical shells. Typical resuts are presented in dimensionless graphical form.

SOME EXACT RESULTS CONCERNING THERMOELASTIC PROPERTIES OF HOLLOW SPHERE COMPOSITES

何陵辉;成振强;刘人怀

1998, 19(5):  427-435. 

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Thermoelastic properties of hollow sphere coloposites are studied based on the uniform malrix-field concept proposed here. Some connections bewteen local thermal and mechanical fields produced by certain homogeneous boundary conditins arederived, and furthermore, exact relations are also obtained between the effectivethermoelastic properties of the compostites. For a macroscopically isotropic compositewith a certain ratio of the outer radius to the inner radius, it is found that the effectivebulk modules and the linear coefficient of thermal expansion can be exactlydetermined, if the thermal expansion coeffieient of the matrix and that of the sphereare the same.

THE GENERAL STRESS STRAIN RELATION OF SOILS INVOLVING THE ROTATION OF PRINCIPAL STRESS AXES

刘元雪;郑颖人;陈正汉

1998, 19(5):  437-444. 

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In the light of matrix theory, the charader of siress increment which causes the rotation of principal stress axes is analysed and the general stress increment isdecomposed into two parts: coaxial part and rolational part. Based on these, thecomplex three dimensional(3-D)problem involving the rotation of principal stress axesis simplified to the combination of the 3-D coaxial model and the theory about pureroation of principal stress axes that is only around one principal stress axes. Thedifficulty of analysis is reduced significantly. The concrete calculating method ofgeneral 3-D problem is provided and other applications are also presented.

THE APPROXIMATE ANALYTICAL SOLUTION FOR THE BUCKLING LOADS OF A THIN-WALLED BOX COLUMN WITH VARIABLE CROSS-SECTION

谢用九;宁钦海;陈明伦

1998, 19(5):  445-456. 

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For a thin-walled box column with varable cross-section, the three governingequations for torsional-flexural buckling are ordinary differential equations of the second or fourth order with variable coefficients, so if is very difficult to solve them bymeans of an analytic method. In this paper, polynomials are used to approximate the geometric properties of cross-section and certain coefficients of the differentialequations. Based on the energy principle and the Galerkin’s method the approximateformulas for calculating the flexural and torsional buckling loads of this kind of columns are developed respectively, and numerical examples are used to verify the correctness of the soltuions obtained. The results calculated in this paper provide the basis for demonstrating the stability of thin-walled box colunns wiht variable corsssection. This paper is of practical value.

THE STABILITY IN NEURAL NETWORKS WITH INTERNEURONAL TRANSMISSION DELAYS

曹进德;李继彬

1998, 19(5):  457-462. 

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In this paper, some sufficient conditions are obtained for the global asympticestability of the equilibrium of neural networks wiht interneurnonal transmission delaysof the type


A CRACK EMANATING FROM THE TIP OF BONDED DISSIMILAR MATERIALS

钱俊;长谷部宣男

1998, 19(5):  463-478. 

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A crack is assumed to emanate from the tip of bonded dissiumilar materils wiht the crack on the bisector of one of the bonded wedges. The problem is firstly dividedinto symmetric and anti-symmetric modes accrding to the characteristics of the local geometry. By eigenexpansion method. the eigenequaitons for two modes arederived, respectively, and the corresponding eigenvalues are obtained wiht differentratios of dissimilar moaterial constants and angles of the wedges. The singularity of the crack is then analyzed by the eigenvalues that are less than one. The fields of displacement and stress in the vicinity of the tip of the crack are finally derived in anexplicit form.

INTEGRATION METHOD FOR THE DYNAMICS EQUATION OF RELATIVE MOTION OF VARIABLE MASS NONLINEAR NONHOLONOMIC SYSTEM

陈向炜;罗绍凯

1998, 19(5):  479-488. 

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In this paper, the integration methods of dynamics equations of relative motion of variable mass nonlinear nonholonomic system are given such as the gradient method,the single-component method and thefield method. Firstly, the dynamics equations arewritten in the canonical form and the field form. Secondly, the gradient method, thesingle-component method and the field method are used to integrate the dynamicsequations of the corresponding constant mass holonomic system in inerial referenceframe respectively. With the restriction of nonholonomic constraints to the initialconditions being considered, the solutions of the dynamics equations of variable massnonlinear nonholonomic system in noninertial reference frame are obtained.

THE SEMI-DISCRETE METHOD FOR SOLVING HIGH-DIMENSION WAVE EQUATION

吴建成;蔡日增

1998, 19(5):  489-495. 

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The article gives a semi-discrete method for solving high-dimension wave equationBy the method, high-dimension wave equation is converted by, means of diseretizationinto I-D wave equation system which is well-posed. The convergence of the semidijcrete method is given. The numerical calculating resulis show that the speed of convergence is high.

A NEW HIGH-ORDER ACCURACY EXPLICIT DIFFERENCE SCHEME FOR SOLVING THREE-DIMENSIONAL PARABOLIC EQUATIONS

马明书

1998, 19(5):  497-501. 

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In this paper, a new three-level explicit difference scheme with high-orderaccuracy is proposed for solving three-dimensional parabolic equations. The stabilitycondition is r＝△t/△x² ＝△t/△y²＝△t/△z²≤1/4, and the trumcation error is O(△t²+△x⁴).