Table of Content

18 December 1994, Volume 15 Issue 12

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Articles

A SCREW DISLOCATION BY NONLINEAR CONTINUUM MECHANICS

Pan Ke-lin;Chen Zhi-da

1994, 15(12):  1093-1102. 

Abstract ( 559 )   PDF (552KB) ( 2002 )  

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Based on the nonlinear geometry field theory of continuum mechanics. this paper analyses the stress field due to a serew dislocation in an infinite an infinite medium. The results reveal the high-order effect of the stress field. When this effect is small. the result can be reduced to one of the classical linear elasticity. The body couple field of the serew dislocation is also investigated in this paper. The analytiecal expression of the body couple due to a serew dislocation is obtained with small rotation deformation. As the application of theoretical results. the stress and the body couple at the interface of the crystals are calculated when the serew dislocation is near the interface.

STRESS ANALYSIS OF THICK RING SHELL SUBMITTED TO THEACTION OF INTERNAL PRESSURE

Zhao Xing-hua

1994, 15(12):  1103-1111. 

Abstract ( 628 )   PDF (411KB) ( 412 )  

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In this paper. from asymptotic equations of thicking shell obtained on the basis of the equations of three dimensional elastic mechanics using geometric small parameter a=r₀/R₀. we find the solutions of the stresses and the deformations of thick ring shell submitted to the action of internal pressure q.

PLANE ELASTICITY IN SECTORIAL DOMAIN ANDTHE HAMILTONIAN SYSTEM

Zhong Wan-xie

1994, 15(12):  1113-1123. 

Abstract ( 638 )   PDF (578KB) ( 447 )  

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The governing equations of plane elasticity in sectorial domain are derived to be in Hamiltoinan form via variable substitutes and variationl principles. The method of separation of variables and eigenfunction expansion method are derive to solve the finite element analytically for the sectorial domain elasticity problem. so that such kind of analytical element can be installed into FEM program systems. It demonstrates the potential of the Hamiltonian system theory and symplectic mathematics.

A STABILITY STUDY OF NAVIER-STOKES EQUATIONS (Ⅲ)

Shi Wei-hui

1994, 15(12):  1125-1130. 

Abstract ( 594 )   PDF (320KB) ( 493 )  

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In this paper, the necessary conditions of the existence of C² solution. in someinitial problems of Navier-Stokes equations are given. and examples of instability ofinitial value (at t=0) problems are also given. The initial value problem ofNavier-Stokes equation is one of the most fundamental problem for this equationvarious authors studies this problem and contributed a number of results.J.Leray.aFrench professor, proved the existence of Navier-Stokes equation under certain definedinitial and boundary value conditions.In this paper,with certain rigorously definedkey.concepts,based upon the basic theory of J.Hadmard partial differentialequanous[1], gives a fundamental theory of instability of Navier-Stokes equations.Finally,many examples are given,proofs referring to Ref.[4].

A MIXED METHOD FOR THE CREEP OF A SKIN LAYER

Huang Li-du;Wang Qin-que;Mak Fak-tat Arthur

1994, 15(12):  1131-1138. 

Abstract ( 576 )   PDF (400KB) ( 490 )  

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The creep of a skin layer under a distributed surface pressure was solved by ananalysical method using Hankel transform and Laplace transform.The surface stressboundary conditions lead io a Volterra integral equation of the first kind, which was then solved by a numerical method.The IMSL subroutines DINLAP and DGORUL were employed to numerically obtain the Hankel-Laplace inversion. The calculateddisplacements at two distinctive moments were compared respectively with those obtained by an elastic solution for either incompressible or compressible solid. Thetransient creep responses of the skin layer were also presented.

THE STRESS ANALYSIS OF VESSEL WALL IN THE ENTRANCE REGIONOF A TAPERED VESSEL

Cen Ren-Jing;Tan Zhe-dong;Chen Zheng-zong

1994, 15(12):  1139-1147. 

Abstract ( 540 )   PDF (443KB) ( 422 )  

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The present paper deals with the flow in an entrance region of a tapered vessel.Pressure distribution formula. axial and radial distribution formulas,shear stressdistribution formula of.flow field and shear stress distribution formula of vessel wallare derived. Relative numerical computations are made and analyzed.Discussion of the effects of tapered angle on the pressure distribution and vessel wall stress distributionare emphasized.

SECOND ORDER EFFECTS IN AN ELASTIC HALF-SPACE ACTED UPONBY A NON-UNIFORM NORMAL LOAD

Liu You-wen;Guo Jian-lin

1994, 15(12):  1149-1168. 

Abstract ( 587 )   PDF (862KB) ( 481 )  

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A closed form solution to the second order elasticity problem, when an isotropiccompressible elastic half-space undergoes a deformation owing to a non-uniformlydistributed normal load,is presented,The method of integral transform is employedand the case when loading is distributed,in accordance with Hertz’x law, is discussed.The limiting solution for incompressible isotropic elastic material is also derived.Numerical calculations for the second order elastic material for the displacement and the normal stress in the z-direction are carried out.It is found that,in comparison to the linear elastic case,the displacement increases and the normal stress decreases in the second order elastic material.

SPATIAL-TEMPORAL DISCRETE COORDINATION OF FEM AND DIRECTINTEGRAL METHOD FOR TRANSIENT DYNAMIC PROBLEMS

Wang Huai-zhong

1994, 15(12):  1169-1175. 

Abstract ( 502 )   PDF (351KB) ( 433 )  

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In this paper, the coordination of spatial-temporal discrets of FEM and direct integral method is investigates.By analyzing the numespatial-temporal discrete,the principle of balancing the principle of balancing the energy error induced by spatialdiscrete and the energy error induced by temporal discrete is presented, and the prioriprocess and adaptive method for the coordination of spatial discerand temporal discrete is obtained.

A MODIFIED METHOD OF AVERAGING FOR SOLVING A CLASS OFNONLINEAR EQUATIONS

Zhang Bao-shan

1994, 15(12):  1177-1186. 

Abstract ( 603 )   PDF (432KB) ( 622 )  

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In this paper, we studied a method of averaging which decide a uniform valid solution for nonlinear equation and got the, modified forms for KB, method (Krylov-Bogoliubov method)and KBM method (Krytov-Bogoliubov-Mitropolski method). Through the comparison of two examples with the method of multiple scales it can be shown that the modifies averaging methods here are uniformly valid and thereby the applied area of the methodof averaging are extended.