Table of Content

18 August 1995, Volume 16 Issue 8

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Articles

RETHINKING TO FINITE DIFFERENCE TIME-STEP INTEGRATIONS

Zhong Wanxie;Zhu Jianping

1995, 16(8):  705-711. 

Abstract ( 640 )   PDF (405KB) ( 507 )  

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The numerical time step integrations of PDEs are mainly carried out by the finitedifference method to date. However,when the time step becomes longer, it causes theproblem of numerical instability,. The explicit integration schemes derived by the singlepoint precise integration method given in this paper are proved unconditionally stable.Comparisons between the schemes derived by the finite difference method and theschemes by the method employed in the present paper are made for diffusion andconvective-diffusion equations. Nunierical examples show the superiority of the singlepoint integration method.

PLASTIC POST-BUCKLING OF A SIMPLY SUPPORTED COLUMNWITH A SOLID RECTANGULAR CROSS-SECTION

Cheng Yaoshun;Lu Wenda;Fang Hong

1995, 16(8):  713-722. 

Abstract ( 699 )   PDF (541KB) ( 464 )  

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The plastic post-buckling of a simply supported column with a solid rectangularcross-section is analysed by a new approach. High order terms in the asymptotic post-buckling expansions are carried out. In some aspects, the method proposed in thispaper is similar io Hutchinson’s. However, the computation is simple since theintroduction is avoided of stretched coordinates. The method can be used to analyseinitial post-bifurcation of plates and shells in the plastic range.

EIGENFREQUENCIES OF THE THREE DIMENSIONAL EULER-BERNOULLIBEAM SYSTEM WITH DISSIPATIVE JOJNTS

William H. Paulsen

1995, 16(8):  723-746. 

Abstract ( 580 )   PDF (1198KB) ( 707 )  

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In this paper, we will compute the transfer matrices to find the eigenfrequenciesfor the vibrations of the general non-collinear Euler-Bernoulli or Timoshenko beamstructure with dissipative joints. We will allow the structure to be three dimensional,and thus we must consider all types of vibrations simulaneously, including longitudinaland torsional vibrations. The general structure considered will consist of any number ofbeams joined end to end to form a chain. Many, different kinds of dampers areallowed, even within the same structure. We also will allow different materials withinthe structure as well as different beam widths. We then will show. that asymptotic estimates can be used to find the eigenfrequencies approximately.

REMARKS ON THE STRUCTURE OF EVOLUTION EQUATIONS

J. Badur;Sun Bohua

1995, 16(8):  747-757. 

Abstract ( 530 )   PDF (705KB) ( 536 )  

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In the paper the evolution equations are discussed so as to enable aphenomenological description of microstruchtral behaviour e.g . partially reversible flowof Maxwellian gas, recovery structural relaxation and other experimental results coming from light scattering and molecular dynamics .The result deals with the revaluation of Zaremba s ansatz.It leads to resolution of problems with substantial and available nonlinearities in the transport equation.

GENERALIZED PROBABILISTIC PERTURBATION METHODFOR STATIC ANALYSIS

Zhang Yimin;Chen Suhuan;Zhou Zhenping;Liu Tieqiang

1995, 16(8):  759-764. 

Abstract ( 747 )   PDF (340KB) ( 419 )  

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This paper studies the static response and reliability of uncertain structures withvector-valued and matrix-valued functions.The finite element analysis method ofuncertain structures is based on matrix calculus,Kronecker algebra and pertrubationtheory ,Random variables and system derivatives are conveniently arranged into 2Dmatrices and generalized mathematical formulae for perturbation are obtained.

THE EXISTENCE AND UNIQUENESS OF THE DECAYING POSITIVE ENTIRESOLUTIONS FOR A CLASS OF SEMILINEAR ELLIPTIC EQUATIONS

Tian Genbao

1995, 16(8):  765-777. 

Abstract ( 648 )   PDF (569KB) ( 283 )  

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This paper first proves the following equations△u-m²u+f(x,u)=0, x(Rⁿ,n≥3 m>0 existence of decaying positive entire solution, then emphatically, proves this solution’suniqueness.

STRESS-STRAIN FIELD NEAR CRACK TIP AND CALCULATION OF CRITICAL STRESS OF CRACK PROPAGATION IN A PURE BENDING BEAM OF RECTANGULAR SECTION WITH ONE-SIDED MODE I CRACK

Liu Hanchi

1995, 16(8):  779-789. 

Abstract ( 579 )   PDF (660KB) ( 402 )  

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This paper studies the stress-sirain field near crack tip in a pure bending beam ofrectangular section with one-sided mode I crack by the analytic method of Rej [1],then it gives the stress and strain components at the crack tip when the crackpropagates and further it obtains the formulas of calculating the elastic deformed areawidth, the deformed intensity, area width and the equation groups of calculating thecritical stress of crack propagation, last the equation group of calculating criticalstress of crack propagation is verified by calculating instance. The maximum error is 0.18%.

SHAKEDOWN ANALYSIS OF ELASTO-PLASTIC STRUCTURES SUBJECTEDTO EXTERNAL LOADING AND TEMPERATURE VARIATION

Du Sentian;Liu Hanbing;Chen Suhuan;Lian Jianshe

1995, 16(8):  791-799. 

Abstract ( 579 )   PDF (477KB) ( 957 )  

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A new kinematical shakedown theorem is presented under the consideration thatexternal load and temperature change slowly . A incremental collapse criterion, whichis simple and applicable, is also derived based on the theorem. In the end of this paper,its application is illustrated by an example.

ENDOCHRONIC ANALYSIS FOR COMPRESSIVE BUCKLING OFTHIN-WALLED CYLINDERS IN YIELD REGION

Peng Xianghe;Chen Yuanqiang;Zeng Xiangguo

1995, 16(8):  801-813. 

Abstract ( 639 )   PDF (621KB) ( 348 )  

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The longitudinal compressive buckling of long and thin-walled cylinders in yield region is analyzed with the incremental and finite forms of the endochronic constitutive equation, respectively. The relations between the critical stress σ_crversus the ratio of R (the radius) versus h (the thickness of the wall) are derived. The critical stress of the thin-walled cylinders made of abuminum alloys AMГ and Д1T are analyzed and compared with the experimental data and the analytical results based on traditional theory of plasticity. It is seen that. except that the σ_cr of the cylinders made of 1Tpredicted by the finite form of the endochronic theory seems a little more conservative than that by traditional deformation theory of plasticity, in most cases, both forms of the endochornic constitutive equation provide more satisfactory results.