力学学报

THE CALCULATION OF INTERNAL AND EXTEKNAL FLOW FIELD NEAR RING WING

A numerical method is presented here to solve the internal and eXternal flow near/ between ring wing and hulls of submerged weapons.The internal and external flow of full domain can be solved together by adopting semi-staggered grid system in which the boundary conditions of foils of the ring wing and hull are convenient to implement.The calculation of pressure is based on a continuity equation formulation which is similar to the artificial compressible method.The internal and external flow are calculated w...

1994, 26(6): 641-648. doi: 10.6052/0459-1879-1994-6-1995-592

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THE RESEARCH OF TESTING TECHNIQUE ON 2-D ADAPTlVE FLEXIBLE WALL WIND TUNNEL

It has been reported that two-dimensional self-streamlining flexible walled testsection eliminates the top and bottom wall interfereiice effects on large blockage aerofoiltesting.The iterative stratd.gies of subsonic flow test and transonic flow test and one stepmethod for high subsonic test was discribed.The experimentaI tests have been performed toverify the methods. The results show that theeffects of wall interference can be eliminatedby the methods effectively on iarge blockage aerofoil in twodimension...

1994, 26(6): 649-656. doi: 10.6052/0459-1879-1994-6-1995-593

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SIMULATION OF THE STRONGLY SWIRLING GAS-PARIICLE TURBULENT FLOW BY STOCHASTIC TRAJECTORY MODEL

The particle stocliastic trajectory model, integrating with a new version algebraic Reynolds stress model, was employed to numerically simulate the strongly swirling gas-particle turbulent flow in a iiovel vortex combustor(VC).The calculated distributions of theparticle density and tangential mass fiux agree with the measured test data。The simulationresults elucidate the following features of the VC gas-particle flow:peak values of the particle density occurring near the combustor outer wall,prolonged part...

1994, 26(6): 657-663. doi: 10.6052/0459-1879-1994-6-1995-594

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THE EXTENSIONAL FLOW OF POLYACBYL ONITRILE

The R.K. Gupta’s extentional viscometer improved by the authors was used tomeasure the extentional flow properities of polyacrylonitrile (PAN).It showed that modifiedJeffery Model developed by us could describe both the shear flow and elongational flow forpolyacrylonitrile. In the modified-model,compared with Jeffery Model, we have got a newcharicteristic parameter which only effect elongational flow.

1994, 26(6): 664-670. doi: 10.6052/0459-1879-1994-6-1995-595

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THE PROPAGATION OF SPHERICAL SHOCK WAVES IN DUSTY GAS

For this paper, based on two phase flow model of dilute partical suspension in a gas,the GRP scheme of finite difference method with high resolution and the second order Mac Cor mack sche me are applied to the numerical analysis of the propagatfon of spherical shock waves in dusty gas for four kinds of initial states. The results indicate that the propagating process of spherical shock waves and the flow field developed behind it possess more complicated properties as compared with that in a pure gas. The r...

1994, 26(6): 671-678. doi: 10.6052/0459-1879-1994-6-1995-596

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ANALYSIS OF SHEAR FRACTURE OF ROLLER COMPACTED CONCRETE LAYER

The shear strength of the compacted layer is one of the important factorsdetermining the stability of the roller compacted concrete dam。Anew shear fracture modelcombining the direct shear test with the finite element calculation is put forward in thispaper. The new model considers the non-linear distribution stresses and includes the effectof the softening stress-displacement stage in the compacted layer.Thust,the shear strengthparameters determined by the aforementioned method are about thirty percent high...

1994, 26(6): 679-689. doi: 10.6052/0459-1879-1994-6-1995-597

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PLASMA EQUILBRIUM IN A NON-UNIFORM TOROIDAL MAGNETIC FIELD

The distortion of magnetic confined plasma,caused by non-uniformity in toroidalmagnetic field, was discussed. For the cases of surface and volume current distribution,the relationships between the distortion of magnetic surfaces and various parameters wereobtalned. A restriction on the non-uniformity in magnetic field was given for the equilibriumof a plasma.

1994, 26(6): 690-698. doi: 10.6052/0459-1879-1994-6-1995-598

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THE DUAL OPTIMIZATION METHOD BY ORIGINAL/RECIPROCAL VARIABLES’EXPANSION BASED ON CUMULATIVE INFORMATION AI TWO POINTS

In this paper,we propose and prove following results:1.an expansion“criteria”of improving conservative approkimation and corresponding theorms;2.an approkimateEORCT(expansion of original/reciprocal variables based on cumulative informations attwo points)and its advantage of identical convex or concave character with primal function;3.a dual optimization method by using EORCT approximation and numerical collvegencyof its application to truss structures;4.relating convergent theorms of the optimizationmethol

1994, 26(6): 699-710. doi: 10.6052/0459-1879-1994-6-1995-599

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EXPERIMETAL INVESTIGAIION ON INTERFACE SHEAR

In this paper the Moire Interferametry was used to investigate the interfaceshear behavior of four point shearing beam of bi-material with edge crack in the interface. Bi-materical beam is composed of aluminum and epoxy.The shear strain distrabution alongthe interface and the U and V displacement field adjacent to the interface are obtained.

1994, 26(6): 711-718. doi: 10.6052/0459-1879-1994-6-1995-600

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STUDY ON SHAKEDOWN OF STRUCTURES UNDER DIFFERENT STRAIN-HARDENING MODELS

It is important in engineering applications to study the shakedown of structures under loads changing with time. The shakedown of structures is related to the strain-hardening models of materials used. The present paper considers the shakedown problems of structures under several strain-hardening models. The shakedown conditions of kinematic-hardening and mixed -hardening structures are given. The conclusions obtained here simplify the shakedown analysis of strain-hardening structures.

1994, 26(6): 719-727. doi: 10.6052/0459-1879-1994-6-1995-601

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TWO THEOREMS ON LINEAR CREEP PROBLEMS AND THEIR APPLICATIONS

In this paper,based on linear creep assumption,(1) tWo theorems about creepcoefficient C(t)and relaxation coefficient K_p(t,)are dirived, i.e.if the time, the creep coefficient and relaxation coefficient satisfy the following equations:(2)the recurrence formula of solving the relaxation coefficient K_p(t,)directly from thecreep coefficient C(t)is presented;(3)the general recurrence formulas of initial strainmethod and initial stress method for any kinds of expressions of C(t,)and K_P(t, )aredirived,they can...

1994, 26(6): 728-738. doi: 10.6052/0459-1879-1994-6-1995-602

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MEAN FUNCTIONS AND MEAN MODIFICATION OF FINITE ELEMENT BASIS FUNCTION

A method is proposed to mean-modify finite element basis functions. In manydspects the meanmodified functions behave much like the unmodified ones,but are muchsmoother,and the non-conformity between elements are completely eliminiated.Also diss-cussed are the change induced in the processes of element forming and assembling.

1994, 26(6): 739-743. doi: 10.6052/0459-1879-1994-6-1995-603

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MOIRE METHOD FOR MEASURING CREEP OF MAIN STEAM PIPE AT HIGH TEMPERAIURE

In this paper,The long-term creep of main steam pipe at high teniperatureis measured with moire method.The principle of measurement and explanation on moirefringes of cylindrial surface are discussed.The creep meaJsurement accuracy is improvedby elimination of the off-plane deflection.The good results verify that it is an applicablemethod

1994, 26(6): 744-751. doi: 10.6052/0459-1879-1994-6-1995-604

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HOPF BIFURCATIONS IN PLAN POLSEUILLE FLOW

We calculated the development of the 2D finiteamplitude waves in planePoiseuille flow by means of direct numerical simulation. We obtained the 2D nonlinear stable equilibrias and Hopf bifurcations occur when the equilibriaJs loss the stability in Re 3950. While second bifurcations occur,eddy near the walls moves into the core and act as the core flow. As the Revnolds number Re increases further,the flow changes into all random.

1994, 26(6): 752-756. doi: 10.6052/0459-1879-1994-6-1995-605

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FRACTAL KINEMAIICS OF CRACK PROPAGAtiON IN BRITTLE MAtERIALS

Experimental results indicate that the crack propagation path of a brittle mate-rials is irregular and tortuous,and fracture surfaces are roughness,which behave as fractal. Applied fractal geometry,the author derives formula of fractal kinematics of the crack prop-agation in brittle materials.The correlation of dynamic and static fracure toughnesses withcrack velocity,crack length,microstructure parameter and fractal dimension is obtained. From equations of estimating crack velocity and fractal dimension de...

1994, 26(6): 757-762. doi: 10.6052/0459-1879-1994-6-1995-606

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1994 Vol. 26, No. 6

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