力学学报

THE COMPLETE BOUNDARY INTEGRAL FORMULATION FOR GENERALIZED STOKES EQUATION AND ITS APPLICATION TO THE SOLUTION OF NAVIER-STOKES EQUATION

In order to decouple the variables in Navier-Stokes equations, the Peace-man-Rachford operator splitting method is used in this paper to discretize the time dependent Navir-Stokes equations into linear and nonlinear subproblems. In these subproblems the coupling tioned above is avoided. The linear subproblems are quite close to the genearlized Stokes equations A multi-reciprocity method is used to obtain the complete boundary integral formulation for the solution of the generalized Stokes equation to reduce...

1992, 24(6): 645-652. doi: 10.6052/0459-1879-1992-6-1995-787

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EXPERIMENTAL AND ANALYTICAL STUDY OF THE MECHANISM OF POWDER PRODUCTION BY THE SUPERSONICS GASDYNAMICAL ATOMIZATION METHOD

According to the simulating experimental observations, this paper presents the atomization model. The model is qualitatively explained and quantitatively described by the available supersonics gasdynamical knowledge. The analytical expressions of particle size distribution and cooling rate are given. The above mentioned results are conductive to improl-ving atomization technology.

1992, 24(6): 653-660. doi: 10.6052/0459-1879-1992-6-1995-788

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INVARIANCE OF INTERACTIVE-STRUCTURE BETWEEN CONVECTION AND DIFFUSION

In this paper three invariant theorems of interactive-structure between convection and diffusion for incompressible laminar shear flow and its ten inferences are presented. The invariance of interactive-structure means that the laminar shear flow and its linearized and nonlinear disturbance fields have the same interactive-structure between convection and diffusion and the same physical scales (including the time, spatial and velocity scales). In illustration of the present theoretical application, we deriv...

1992, 24(6): 661-670. doi: 10.6052/0459-1879-1992-6-1995-789

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THREE-DIMENSIONAL ROTATING BOUNDARY LAYER CALCULATION WITH NORMAL PRESSURE GRADIENTS

The N-S equations have been reduced to a set of three-dhnensional boundarylayer equations in an arbitrarily non-orthogonal-curvilinear rotating coordinate system by means of the order-of-magnitude analysis, and the effects of rotation on boundary layer are analyzed. A new pressure gradient iteration method is proposed to deal with the problem caused by nonzero normal pressure gradients. On the basis of BOX method, a numerical scheme and corresponding FORTRAN program are developed for solving the three-dimen...

1992, 24(6): 671-679. doi: 10.6052/0459-1879-1992-6-1995-790

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TRANSIENT AXISYMMETRIC ELASTIC WAVES IN FINITE CIRCULAR CYLINDRICAL SHELLS

In this paper, the equations of motion governing the axisymmetric elastic deformation of finite circular cylindrical shells, including the effect of transverse shear and rotational inertia, are considered. By applying Generalized Ray Method, the ray formulus of the displacements and the internal resultant forces of the shell in the phase space are derived, then the solutions of transient elastic waves in the finite cylindrical shell subjected to the axisymmetric impact are obtained numerically by using FFT.

1992, 24(6): 680-690. doi: 10.6052/0459-1879-1992-6-1995-791

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THREE VARIABLES ITERATION METHOD FOR OBTAINING THE PERIODIC SOLUTIONS AND THEIR STABILITY OF FULLY STRONG NONLINEAR AUTONOMOUS SYSTEMS

In this paper the three variables iteration method is suggested to find the periodic solutions and determine their stability of fully strong nonlinear autonomous systems of 2nd order. The comparison between the results obtained by our method and those obtained by numerical method shows that the three variables iteration method is both effective and of high accuracy.

1992, 24(6): 691-699. doi: 10.6052/0459-1879-1992-6-1995-792

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GENERAL SOLUTION FOR A CLASS OF SYSTEM OF PARTIAL DIFFERENTIAL EQUATIONS AND ITS APPLICATION IN THE THEORY OF SHELLS

In this paper, the method to construct general solution for a class of system of partial differential equations is given. This general solution is complete. By this method, the general solutions of the static equations of cylindrical shells and the dynamic equations of conical shells are constructed.

1992, 24(6): 700-707. doi: 10.6052/0459-1879-1992-6-1995-793

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THE SEMI-ANALYTICAL METHOD BASED ON GURTIN VARIATIONAL PRINCIPLES TO SOLVE DYNAMIC RESPONSE OF ONE DIMENSION

The semi-analytical method derived by the authors based on Gurtin varia-tional principle to solve dynamic response 'akes finite element discretization in space domain and series in time domain. The numerical examples show that this method is effective for obtaining the solutions of dynamic response. The formulas of this paper can solve the dynamic response of one dimension with all kinds of initial conditions and all applied loads by introducing a kind of displacement function of nods.

1992, 24(6): 708-716. doi: 10.6052/0459-1879-1992-6-1995-794

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DEGENERATE BIFURCATIONS OF CODIMENSION TWO IN NONLINEAR OSCILLATOR UNDER COMBINED PARAMETRIC AND FORCING EXCITATION

In this paper, first we study normal form theory with Z2-symmetry and universal unfolding theory of the degenerate vector field. Then we use above mentioned theory to study degenerate bifurcations of codimension two in nonlinear oscillator under combined parame-tric and forcing excitation. Thereby stability problems with double zero eigenvalues can be solved. Finally the curves for homoclinic bifurcaron in parameter plane are given by using Melnikov's method and the existence of global bifurcation is discus...

1992, 24(6): 717-727. doi: 10.6052/0459-1879-1992-6-1995-795

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ONE DIMENSIONAL NON-LINEAR VISCOELASTIC CONSTITUTIVE EQUATION OF BITUMINOUS MIXTURE

A one-dimensional nonlinear constitutive equation for describing both long period viscous effect and short period elastic effect has been presented according to Frechet series given by Green-Rivlin. The parameter vers of constitutive equation were determined by means of curvilinear regression of experimental data in the creep tests for a sort of asphalt mixture.The results indicate that the constitutive equation is valid for the strain response with different histories of stress.

1992, 24(6): 728-734. doi: 10.6052/0459-1879-1992-6-1995-796

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THREE-DIMENSIONAL DISPLACEMENT-FIELD MEASURED BY PARTIALLY COHERENT LIGHT MOIRE INTERFEROMETRY

This paper presents a method to measure the three dimensional displacement field, the in-plane and the out-of-plane conponents, by partially coherent light Moire interfer-rometry. It needs simple optical set-up and low demand on vibration isolation, and is valid for the measurement of the displacements on the sarface of engineering structures.The related formulas are derived by the theories of wave-front inteference and Fourir op-ties. The in-plane (v0 v45, v90) and the out-of-plane(w) displacement fields a...

1992, 24(6): 735-741. doi: 10.6052/0459-1879-1992-6-1995-797

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ON THE STABILITY OF ISOTHERMAL DISCONTINUITY

In this paper the stability of isothermal discontinuity in a iluid is studied. It is shown that there may exist three kinds of steady shock waves: shock wave with smooth transition region unstable isothermal shock and stable isothermal shock. The conditions for the appearance of a stable isothermal shock are derivedaccording to the general principle. For ideal gases we obtaine:p1/p0>r/2-r.

1992, 24(6): 742-746. doi: 10.6052/0459-1879-1992-6-1995-798

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MATRIX PERTURBATION FOR LINEAR VIBRATION DEFECTIVE SYSTEMS

In this paper, matrix perturbation for linear vibration defective systems is discussed. According to this perturbation theory, the effect of the structural parameter modifications on the dynamic characteristics of the defective systems can be determined. Thus, the theory is usful for investigating the changes of the dynamic characteristics of the defective systems. A simple example is given to show the correctness and effectiveness of the matrix perturbation presented in this paper.

1992, 24(6): 747-753. doi: 10.6052/0459-1879-1992-6-1995-799

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THE ANALYTICAL SOLUTION OF DIFFERENTIAL EQUATION OF ELASTIC CURVED SURFACE OF STEPPED THIN RECTANGULAR PLATE ON WINKLER'S FOUNDATION

In this paper, the differential equation of e'astic curved surface of stepped thin rectangular plate on Winkler's foundation is established by using step function. The analytical expressions of the solution of this differential equation are obtained by initial parametric method and W operator developed in author's earlier papers. As application of present methods, an example is given.

1992, 24(6): 754-762. doi: 10.6052/0459-1879-1992-6-1995-800

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1992, 24(6): 763-771. doi: 10.6052/0459-1879-1992-6-1995-801

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1992 Vol. 24, No. 6

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