应用数学和力学

1997 Vol. 18, No. 12

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T-Y Tube Model of Human Ascending Aortic Input Impedance

Wu Wangyi, Dai Guohao

1997, 18(12): 1049-1058.

Abstract(1815) PDF(623)

Abstract:
This paper proposed a T-Y tube model to simulate foe input impedance of arterial system. It improves and extends the asymmetric T-tube model which was firstproposed by O'Rourke^[1] and developed laier by Liu et al.^[2]. Based on foe asymmetricT-tube model. a T-Y tube model was proposed by adding branching tubes which represem the iliac arteries.All the tubes are considered to be uniform,viscoelastic longitudinally tethered cylindrical tubes.The upper tube terminates with a windkessel model, while the terminal arterioles of the lowr tube are expressed as a resistance.After proper eraluation of the parameters.the impedance of the arterial system iscalculated under normal physiological and hypertensive condition.The model canpredict impedance in good agreement with the experimentally obtained data no matterin normal physiological condition or in pathological condition In comparison with theasymmeric T-tube model,T-Y tube model is closer to anatomy structure of the human arlerial system and at the sametime much simpler than the extremely complex multiple-branching tube model Therefore it will be a valuable model in studying the influences of various parameters on aorta impedance and ventricular-vascular coupling.

Kármán-Type Equations for a Higher-order Shear Deformation Plate Theory and Its Use in the Thermal Postbuckling Analysis

Shen Huishen

1997, 18(12): 1059-1073.

Abstract(2518) PDF(890)

Abstract:
Kármán-type nonlinear large deflection equations are derived occnrding to the Reddy's higher-order shear deformation plate theory and used in the thermal postbuckling analysis The effects of initial geometric imperfections of the plate are included in the present study which also includes the thermal effects.Simply supported,symmetric cross-ply laminated plates subjected to uniform of nomuniform parabolic temperature distribution are considered. The analysis uses a mixed Galerkin-perlurbation technique to determine thermal buckling louds and postbuckling equilibrium paths.The effects played by transverse shear deformation plate aspeclraio, total number of plies thermal load ratio and initial geometric imperfections arealso studied.

Convergence of Attractors

Qin Wenxin, Liu Zengrong

1997, 18(12): 1075-1080.

Abstract(2069) PDF(535)

Abstract:
The system of coupled oscillators and its time-discretization (with constantstepsize h) are considered in this paper. Under some conditions, it is showed that the discrete systems have one-dimensional global attroctors l_h converging to I which is the global attractor of continuous system.

Some Identity Relations between Plane Problems for Visco-and Elasticity

Yang Xiao, Cheng Changjun

1997, 18(12): 1081-1088.

Abstract(3791) PDF(604)

Abstract:
In this paper.the boundary value problems of plane problems with a simply-or multiply-connected domain for isotropic linear visca-elosticity are first established by terms of Airy stress function F(X_u,t). Secondly some identity relations between displacements and stresses for plane problems of sisco-and elasticity are discussed indetait and some meaningful conclusions are obtained As an example the deformation response for viscoelastic plate with a small circular hote at the center is analyzed undera uniasial uniform extension.

The Stationary Value Property of Hamilton’s Principle in Non-Holonomic Systems

Liang Lifu, Liang Zhonghong, Shi Zhifei

1997, 18(12): 1089-1096.

Abstract(2671) PDF(586)

Abstract:
This paper proves that Hanlilton's prmciple of both using the Appell-Chetaevcondition and not using the Appell-CHETAEV conditiion is the variational principle of stationary action.The relevant problems are discussed.

Bifurcation Problem of Critical Points for Quadratic Differential Systems

Zhang Xiang

1997, 18(12): 1097-1110.

Abstract(2364) PDF(564)

Abstract:
In this paper foe bifurcation of critical points for the quadratic systems of type (Ⅱ) and (Ⅲ) is investigated. and an answer to the problem given in [1] is given.

Uniqueness of Solutions for a Class of Non-Linear Volterra Integral Equations without Continuity

Dong Wei

1997, 18(12): 1111-1116.

Abstract(2125) PDF(426)

Abstract:
In this paper, the fixed point theorem of increasing opera for with non-continuityis uilized to discuss foe exislence and uniqueness of positire solution for a class of nonlinear Volterra integral equations. An important condition of continuity can bereplaced by weak condition.

The Distribution of Zeroes of Solutions of Neutral Equations

Zhou Yong, Wang Zhicheng

1997, 18(12): 1117-1123.

Abstract(2384) PDF(503)

Abstract:
The purpose of ibis paper is to study the distribution of zerocs of solutions of the neutral delay differential equations. An estimate is estublished for the distance between adjacenlt zeroes of the solutions of such equations under less restritive hypotheses on the variable coefficients.The results obtained improve and extend scme known resultsin the literature.

A Necessary and Sufficient Condition for the Oscillation of Solutions of Lienard Type System with Multiple Singular Points

Sun Jitao, Zhang Yinping

1997, 18(12): 1125-1129.

Abstract(2375) PDF(607)

Abstract:
In this paper, a necessary and sufficient condition for teh solution of Lienard typesystem with muliiple singular points to oscillation under the more general assumptionis given.Results of the papers [1-4] are also extended and improved in this paper.

An Elastic Oscillation Model for Goods in a Shortage Market

Gao Longchang

1997, 18(12): 1131-1138.

Abstract(2050) PDF(604)

Abstract:
In this paper, an oscillated model,which results from the shortage action in market economy with elastic replacement of goods is obtained.And some natural relations between the model and a typically oscillatory model are established The results can interpret some market phenomena and provied the theoretical tools for theeconomic program.

An Investigation on Material Properties of Non-Homogeneous Cylindrically Orthotropic Circular Plates

Qin Shengli, Yan Kezhu, Hu Xiangling, Huang Jiayin

1997, 18(12): 1139-1143.

Abstract(1833) PDF(565)

Abstract:
It has been been reported that the reduced stiffness of non-homogeneous cylindrically orthotrpic circular plate varing exponentially with radius r is obtained by using the bending theory of a simple beam.The aim of this paper is to verify the effect of radius on the materal properties. According to the flat stress-strain relation, the values of material properties E_r E_a and v_θr which are the functions of radius r are obtained.Compared with the experimental values, the analytical values of the material properties are in essential agreement with them.