THE ANALYSES OF THE THREE-DIMENSIONAL STRESS STRUCTURE NEAR THE CRACK TIP OF MODE Ⅰ CT SPECIMENS IN ELASTICPLASTIC STATE(Ⅱ)—THE ANALYSES OF THE STRESS STRUCTURE

Based on[1],the stress structures of the smooth region and shear lip of thespecimens have been investigated in the paper.The characteristics of the stress structure inthe smooth region have been found that the variable z can separated out;the stressesin the midsection can be obtained by the plane strain FEM results or HRR structuremodified by the stress triaxiality.The effects of load level and thickness on the stressstructure can be reflected by the distribution of CTOD along the thickness direction.The obtained expressions of the stresses are very simple and visualized.The analysesof the stress structure in the shear lip show that the stresses can be obtained bydifferent methods of interpolation to a certain precise degree.A new degree parameter of the plane strain state has been put forward andstudied.The parameter can reflect relatively well the variation of the kind andthickness of the specimen as well as the load level.The fracture parameter has alsobeen investigated to be sure that it can be obta     

THE ANALYSES OF THE THREE-DIMENSIONAL STRESS STRUCTURE NEAR THE CRACK TIP OF MODE I CT SPECIMENS IN ELASTICPLASTIC STATE(Ⅰ)—THE ANALYSES OF CONSTRAINT PARAMETERS AND FRACTURE PARAMETERS

In the present paper, three dimensional analyses of some general constraint parameters and fracture parameters near the crack tip. of Mode I CT specimens in two different thicknesses are carried out by employing ADINA program. The results reveal that the constraints along the thickness direction are obviously separated into two parts: the keeping similar high constraint field (Z₁) and rapid reducing constraints one (Z₂). The two fields are experimentally confiremed to correspond to the smooth region and the shear lip on the fracture face respectively. So the three dimensional stress structure of Mode I specimens can be derived through discussing the two fields respectively. The distribution of the Crack Tip Opening Displacement (CTOD) along the thickness direction and the three dimensional distribution of the void growth ratio (V_g) near the crack tip are also obtained. The two fracture parameters are in similar trends along the thickness direction, and both of them can reflect the effect of thickness and that of the loading level to a certain degree.     

THE ANALYSES OF THE THREE-DIMENSIONAL STRESS STRUCTURE NEAR THE CRACK TIP OF MODE I CT SPECIMENS IN ELASTICPLASTIC STATE(Ⅰ)—THE ANALYSES OF CONSTRAINT PARAMETERS AND FRACTURE PARAMETERS

In the present paper,three dimensional analyses of some general constraintparameters and fracture parameters near the crack tip of Mode I CT specimens in twodifferent thicknesses are carried out by employing ADINA program.The results revealthat the constraints along the thickness direction are obviously separated into twoparts:the keeping similar high constraint field(Z_1)and rapid reducing constraintsone(Z_2).The two fields are experimentally confiremed to correspond to the smoothregion and the shear lip on the fracture face respectively.So the three dimensionalstress structure of Mode I specimens can be derived through discussing the two fieldsrespectively.The distribution of the Crack Tip Opening Displacement(CTOD)alongthe thickness direction and the three dimensional distribution of the void growth ratio(V_9 )near the crack tip are also obtained.The two fracture parameters are in similartrends along the thickness direction,and both of them can reflect the effect ofthickness and that of the loading l     

THE METHOD OF TRANSFORMATION OF THE BOUNDARIES FOR STRUCTURE THE ADMISSIBLE DISPLACEMENTS

In this paper the method of transformation of the boundaries for structure theadmissible displacements with various boundary conditions is presented What is called themethod of transformation of the boundaries is that. first we transform the actual systeminto the basic system and additional boundary forces and displacements on the basis of thesuperposition principle, then apply variational principles to the basic system,finally find thepermissible displacement of the actual system by means of the method of transformation ofthe series.In this paper, we also give mixed energy prinapies under Variation of boundaryconditions. The mixed energy principles as the potential and complementary energyprinciples under variation of boundary conditions are all the chief theoretical fundamentalof the method of transformation of the boundaries.Applying the method of transformation of the boundaries. we form the permissibledisplacements of rectangular plates of plane stress and bending problems with various edgeconditio     

THE IMPROVEMENT OF THE GENERAL EXPRESSION FOR THE STRESS FUNCTION φ OF THE TWO-DIMENSIONAL PROBLEM

In this paper,it is pointed that the general expression for the stress functionφ_0 of theplane problem in polar coordinates is incomplete.The problems of the curved bar with anarbitrary distributive load at the boundries can’t be solved by this stress function.For thisreason,we suggest two new stress functions and put them into the general expression.Then,the problems of the curved bar applied with an arbitrary distributive load at r=a,bboundaries can be solved.This is a new stress function including geometric boundaryconstants.     

REMABKS ON THE STRUCTURE OF EVOLUTION EQUATIONS

ＲＥＭＡＢＫＳＯＮＴＨＥＳＴＲＵＣＴＵＲＥＯＦＥＶＯＬＵＴＩＯＮＥＱＵＡＴＩＯＮＳＪ．Ｂａｄｕｒ；ＳｕｎＢｏｈｕａ（孙博华）（Ｒｕｈｒ－ＵｎｉｒｅｒｓｉｔＢｏｃｈｕｍ，ＬｅｈｒｓｔｕｈｌｆｒＡｌｌｇｅｍｅｉｎｅＭｅｃｈａｎｉｋＤ－４４７８０Ｂｏｃｈｕ...     

THEOREMS ON THE LIMIT ANALYSIS DEALING WITH THE YIELD CONDITION EXPRESSED BY THE SUM OF THE HOMOGENEOUS LINEAR FORM OF STRESS TENSOR AND THE HOMCGENEOUS QUADRATIC FORM OF STRESS TENSOR

In this paper a generelized variational principle on the limitanalysis dealing With the yield condition expressed by thesum of the homogeneous linear form of stress tensor and thehomogeneous quadratic form of stress tensor is suggested.Thisvariational principle can be applied to the limit analgsis inrock mechanics and it takes the situation.in which the yieldcondition is expressed by the homogeneous linear form of stresstensor or the homogeneous quadrdtic form of stress tensor.asits special case.     

THE NEW CRITERIA OF ELASTIC AND FATIGUE FAILURE IN THE COMPONENT OF COMPLEX STRESS STATES

In this paper, a total criterion on elastic and fatigue failure in complex stress, that is, octahedral stress strength theory on dynamic and static states on the basis of studying modern and classic strength theories. At the same time, an analysis of an independent and fairly comprehensive theoretical system is set up. It gives generalized failure factor by 36 materials and computative theory of the 11 states of complex stresses on a point, and derives the operator equation on generalized allowable strength and a computative method for a total equation can be applied to dynamic and static states. It is illustrated that the method has a good exactness through computation of eight examples of engineering. Therefore, the author suggests applying it to engineering widely.     

ON THE DYNAMICAL STRUCTURE OF THE WIND FIELD OF JUPITER''''S GREAT RED SPOT

Based on the geographic approximation the two-dimensional dynamical structure of the wind fields of Jupiterls Great Red Spot and White Oval BC is obtained. The results of calculation are in good agreement with the observations. Thus, an explanation of the observed dispersion of the velocities along the horizontal streamline is given. The major physical mechanism of this dispersion is as follwos: The distance between two adjacent elliptical streamlines varies along the elliptical streamline; leading to the variance of the normal pressure gradient. Thus, the horizontal velocity V_T has to vary correspondingly so that the Coriolis force can approximately balance the normal pressure gradient Another less important factor, i.e., the change of the Coriolis force parameter with the latitude, is also taken into account. The distributions of the vorticities of GRS and White Oval BC are also calculated.     

THEOREM OF THE UNIQUENESS OF DISPLACEMENT AND STRESS FIELDS OF LINE-LOADED INTEGRAL EQUATION METHOD

According to Fredholm＇s theorem,this paper proves that due to the virtualfundaemenial loads which satisfy the boundary conditions and being distributed outside theelastic body occupied region the displacement and stress fields in the elastic body occupiedregion are unique.This theorem forms a theoretical basis of the applications of theline-loaded integral equation method.     

ON THE STRUCTURE OF CONTINUA AND THE MATHEMATICAL PROPERTIES OF ALGEBRAIC ELASTODYNAMIC OF A TRICLINIC STRUCTURAL SYSTEM

This paper is neither laudatory nor derogatory but it simply contrasts with what mightbe called elastostatic(or static topology),a proposition of the famous six equations.Theextension strains and the shearing strainsfor all i,j,k=1,2,3.which were derived by A.L.Cauchy,are linearly expressed in terms of nine partialderivatives of the displacement function(u_i,u_j,u_k)(?)u(x~i,x~j,x~k)and it is impossiblefor the inverse proposition to sep up a system of the above six equations in expressing thenine components of matrix((?)(u_i,u_j,u_k)/(?)(x~i,x~j,x~k)).This is due to the fact that ourgeometrical representations of deformation at a given point are as yet incomplete .On theother hand,in more geometrical language this theorem is not true to any triangle,exceptorthogonal,for“squared length”in space.The purpose of this paper is to describe some mathematic laws of algebraicelastodynamics and the relationships between the above-mentioned important questions.     

ON THE EQUIVALENCE OF NON-CONFORMING ELEMENT AND HYBRID STRESS ELEMENT

This paper is intended to show thet the non-conforming ele-ment by wilson et al, al,and the hybrid stress element byPian are equivalent.     

THE EFFECTS OF ROUGHNESS CHANGE ON THE SURFACE LAYER OF THE ATMOSPHERE(Ⅰ)—THE VARIATIONS OF WIND SPEED AND SHEAR STRESS

A general four-layer structure linear theory for predicting the effects of arbitrarilydistributed roughness change on the variations of wind speed and shear stress in the surfacelayer of3D and2D atmospheres was presented.The results derived by the theory wereagreeable to the previous ones.     

THE CALCULATION OF THE MULTIPLY－CONNECTED ELASTIC PLANE PROBLEMS BY MEANS OF STRESS FUNCTIONS OF MULTIPLE COMPLEX VARIABLES

ＴＨＥＣＡＬＣＵＬＡＴＩＯＮＯＦＴＨＥＭＵＬＴＩＰＬＹ－ＣＯＮＮＥＣＴＥＤＥＬＡＳＴＩＣＰＬＡＮＥＰＲＯＢＬＥＭＳＢＹＭＥＡＮＳＯＦＳＴＲＥＳＳＦＵＮＣＴＩＯＮＳＯＦＭＵＬＴＩＰＬＥＣＯＭＰＬＥＸＶＡＲＩＡＢＬＥＳｗａｎｇＬｉｎｄｉａｎｇ（王林江）Ｌ...     

THE EFFECTS OF ROUGHNESS CHANGE ON THE SURFACE LAYER OF THE ATMOSPHERE (I)——THE VARIATIONS OF WIND SPEED AND SHEAR STRESS

A general four-layer structure linear theory for predicting the effects of arbitrarily distributed roughness change on the variations of wind speed and shear stress in the surface layer of 3D and 2D atmospheres was presented. The results derived by the theory were agreeable to the previous ones.     

DETERMINING THE STRESS INTENSITY FACTOR BY USING THE PRINCIPLE OF MINIMUM POTENTIAL ENERGY

Expressing the total potential energy of the system of a cracked body Ⅱ byWilliams’infinite series solution of stress and displacement components containingcoefficients A_n(n=1,2,...), we obtain a set of simultaneous linear equations of unknowncoefficients A_n by using the principle of minimum potential energy.When the set ofequutions is solved,the stress intensity factor K_1 can be easily, determined.It is equal to(2πα)~(1/2)A_1.Take a sample plate as an example.A single-edge-cracked plate under tension,withthe ratio of crack length to the width of the plate being 0.5 and the ratio of half plate heightto the wiath of the plate being 2.0 and 2.5, has been calculated Only 20-30 coefficents aretaken,and the errors in stress intensity factors are within 5%.     

A NUMERICAL STUDY OF THE STRESS DISTRIBUTION IN HOPPER FLOW

The stress distributions of granular flow in a cylindrical hopper with fiat bottom are investigated by means of a combined approach of discrete element method (DEM) and averaging method. The filling and discharge of the hopper flow are first simulated at a particle level by means of a modified DEM. The results are then used to determine the velocity and stress profiles of the hopper flow by means of an averaging method. The analysis is focused on a central section plane of the hopper due to the relatively perfect axial symmetry. The velocity profiles are illustrated to be consistent with those obtained by the previous experiments, confirming the validity of the proposed approach. The distributions of four components of the planar stress tensor at different heights are quantified. It is shown that the vertical normal stress increases with increasing the height near the central axis, the horizontal normal stress varies more slowly at a higher level and is almost constant when the height is equal to or greater than about 12 particle diameter, and the magnitudes of two shear stresses are equal at the central zone of the hopper but not so at the points near the walls. The dependence of stress distributions on the wall mechanical properties such as sliding resistance and rolling resistance is also discussed.     

STRESS ANALYSIS OF THICK RING SHELL SUBMITTED TO THE ACTION OF INTERNAL PRESSURE

ＳＴＲＥＳＳＡＮＡＬＹＳＩＳＯＦＴＨＩＣＫＲＩＮＧＳＨＥＬＬＳＵＢＭＩＴＴＥＤＴＯＴＨＥＡＣＴＩＯＮＯＦＩＮＴＥＲＮＡＬＰＲＥＳＳＵＲＥＺｈａｏＸｉｎｇ－ｈｕａ（赵兴华）（ＳｈａｎｇｈａｉＵｎｉｖｅｒｓｉｔｙ．ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＡ...     

THE DESIGN AND ANALYSIS OF VIBRATION STRUCTURE OF VERTICAL DYNAMIC BALANCING MACHINE

I. INTRODUCTION The shape of some ?ying objects (called workpieces) is similar to that of shafts. These ?ying objectsoften have a large size. Their dispersion e?ect a?ects the ?ying control and the precision in hitting atarget. The dispersion e?ect is the statistical deviation when ?ying objects depart from their preconcerted?ying orbits. As the unevenness of mass distribution is the major cause of the dispersion e?ect, thedouble-plane vertical dynamic balancing technique for ?ying ob…     

THE WARP AND STRESS TRANSMISSION IN THE JOINT OF AN OPEN THIN WALL BEAM

The regularities of the warp in the sections of an open thin-wall beam have beendiscussed using the MODERN ENGINEERING THEORY OF BEAM.Thus,thetransmission relationship between the warp displacements and the double-moments in thejoints of open thin-wall beams which are connected in different ways has been deduced.Meanwhile,experiments conducted by the author and some conclusions reached from theseexperiments as well as the tentative idea for further perfection are briefly presented here.