1987 Vol. 4 No. 4
1987, 4(4): 1-13.
Abstract：
An arbitrary shallow shell hybrid stress element with4-node was suggested in the paper.Taking account of the transverse shear it can be used for moderate thick and thin shell analysis·Based on Hellinger-Reissner variational principle the equilibrium equations in an. element can be relaxed. Taking the incompatible part of the assumed displacements in the element as Lagrangemultiplier and making the work done by the assumed stresses on the incompatible strain equal to zero the unnecessary stress parameters can be eliminated in the element. This element is invariant and contains the minimum number of stress parameters. The results of some examples show the nume rical function of this element is considerable good.
An arbitrary shallow shell hybrid stress element with4-node was suggested in the paper.Taking account of the transverse shear it can be used for moderate thick and thin shell analysis·Based on Hellinger-Reissner variational principle the equilibrium equations in an. element can be relaxed. Taking the incompatible part of the assumed displacements in the element as Lagrangemultiplier and making the work done by the assumed stresses on the incompatible strain equal to zero the unnecessary stress parameters can be eliminated in the element. This element is invariant and contains the minimum number of stress parameters. The results of some examples show the nume rical function of this element is considerable good.
Abstract：
An approximate solution for a uniformly loaded skew ard trapezoid plates with rigidly clamped edges and zero. Boundary normal stress and tangential displacement undergoing the moderately large deflection has been formulated by use of the perturbation method.
An approximate solution for a uniformly loaded skew ard trapezoid plates with rigidly clamped edges and zero. Boundary normal stress and tangential displacement undergoing the moderately large deflection has been formulated by use of the perturbation method.
Abstract：
In this paper, the symmetry matrix has been constructed by the use of the paper[5] with the change of the selected weighted Functions, so the familiar techanique of the symmetry matrix can de applied, and the solved scope can be expanded. lt can solve the problems of the system with the bars and beams. lf the assembling methods are used. The good precision results are obtained for examples.
In this paper, the symmetry matrix has been constructed by the use of the paper[5] with the change of the selected weighted Functions, so the familiar techanique of the symmetry matrix can de applied, and the solved scope can be expanded. lt can solve the problems of the system with the bars and beams. lf the assembling methods are used. The good precision results are obtained for examples.
Abstract：
In this paper the Novozhinov's formula about the flcxural center is extended to a multiply connected domain. Let R is a force applied at the end of a bar. Then it is proved that strain energy takes minimum if and only if the force R is applied at Trefftz's center of flexure.
In this paper the Novozhinov's formula about the flcxural center is extended to a multiply connected domain. Let R is a force applied at the end of a bar. Then it is proved that strain energy takes minimum if and only if the force R is applied at Trefftz's center of flexure.
1987, 4(4): 34-45.
Abstract：
Earthquake damages of a great deae of single-story mill buildings shoh such a rule:while the side-sway and torsion are appearing in the vibration of the bilding,the horizontal deformation of the roofing in both transverse anb longitudinal direction are produced.According to the surveying datas of the dynamic experiment and the horizontal defomation curve of the roof slab of several existing single-story mill buildings, the approximate value of the natura horizontal stiffness of the roof slab is obtained. In this paper,appropriate mechanical modelwith consideration of torsion and roof deformation and effective stiffness of the brick masonry wall is set up,and the "Series-parallel multiple lumped-mass system" is taken for the three-dimensional seismic analysis of the spatial structure subject to the two-way ground motion.The calculating results are approximately close to the rules of the earthquake damage of the damaged single-story mill buildings in tangshan earthquake.
Earthquake damages of a great deae of single-story mill buildings shoh such a rule:while the side-sway and torsion are appearing in the vibration of the bilding,the horizontal deformation of the roofing in both transverse anb longitudinal direction are produced.According to the surveying datas of the dynamic experiment and the horizontal defomation curve of the roof slab of several existing single-story mill buildings, the approximate value of the natura horizontal stiffness of the roof slab is obtained. In this paper,appropriate mechanical modelwith consideration of torsion and roof deformation and effective stiffness of the brick masonry wall is set up,and the "Series-parallel multiple lumped-mass system" is taken for the three-dimensional seismic analysis of the spatial structure subject to the two-way ground motion.The calculating results are approximately close to the rules of the earthquake damage of the damaged single-story mill buildings in tangshan earthquake.
1987, 4(4): 46-53.
Abstract：
GRP/composite have been widely used in various types of blades. This paper presents a optimal design of GRP/composite blades with constraint conditions of stress and lower limite on fundamental frequency. The shape of Blades cross section is hollow thin wall structure filled with foams.The laminates consist of the unidirectional layer and a surface layer.Both layers lay up along the blade axis. The design variables are thickness of the unidirectional layer. The thickness of the surface layer is specified by technologic and structural demands. Tne constraint conditions of lower limite and tapered thickness are also considered. The optimization is obtained by combining the optimality criterion and mathematical programming. The stress constraint is dealed with by using the full stress criterion. The frequency constraint is dealed with by using kuhu-tucker condition and weight-minim um operation is given to reduce the weight of blade. The Frequency-modification operation is also used to change the fundamental frequency into specific band. In order to obtain the frequencies, the discrete vibration equations for coupled flapwise bending and chordwise bending of a rotating blade are derived by Galerkin method. Finally two numerical examples are given.It is shown that the computional method is efficient for dynamic structural optimization of GRP/composite blades.
GRP/composite have been widely used in various types of blades. This paper presents a optimal design of GRP/composite blades with constraint conditions of stress and lower limite on fundamental frequency. The shape of Blades cross section is hollow thin wall structure filled with foams.The laminates consist of the unidirectional layer and a surface layer.Both layers lay up along the blade axis. The design variables are thickness of the unidirectional layer. The thickness of the surface layer is specified by technologic and structural demands. Tne constraint conditions of lower limite and tapered thickness are also considered. The optimization is obtained by combining the optimality criterion and mathematical programming. The stress constraint is dealed with by using the full stress criterion. The frequency constraint is dealed with by using kuhu-tucker condition and weight-minim um operation is given to reduce the weight of blade. The Frequency-modification operation is also used to change the fundamental frequency into specific band. In order to obtain the frequencies, the discrete vibration equations for coupled flapwise bending and chordwise bending of a rotating blade are derived by Galerkin method. Finally two numerical examples are given.It is shown that the computional method is efficient for dynamic structural optimization of GRP/composite blades.
Abstract：
In this paper C. V. Kloucek's method of distribution of deformation is extended from that there is only one node displacement to that there are two displacements at a node. We use matrixes of two orders (little matrixes) to indicate displacements, transmission coefficients as well as all the appropriate puanfities. After arranging and beriring we obtain the same forms with the method of distribution of deformation, then the signals in the formulas are not numbers but matrixes of two oders. After that an accurate solution of a continuous arch is presented. Combining "The manual of design of arch bridge" we are able to calculate the continuous arch bridge. In the end of the paper an engineering example isg iven and the result is satisfactory.
In this paper C. V. Kloucek's method of distribution of deformation is extended from that there is only one node displacement to that there are two displacements at a node. We use matrixes of two orders (little matrixes) to indicate displacements, transmission coefficients as well as all the appropriate puanfities. After arranging and beriring we obtain the same forms with the method of distribution of deformation, then the signals in the formulas are not numbers but matrixes of two oders. After that an accurate solution of a continuous arch is presented. Combining "The manual of design of arch bridge" we are able to calculate the continuous arch bridge. In the end of the paper an engineering example isg iven and the result is satisfactory.
Abstract：
In this paper,we divide shear-wall structure into several subdomains, then synthetize each subdomain by using two-dimensional single spline functions, Therefere the dynamic characteristics of structure can be obtained easily. It adopts analysis model of continuum-discrete in order to reflect real properties of structures. Due to using cubic B-spline for interpola tion,it overcomes difficulties for treatment of clamped boundary shear condition, The stiffness matrix and mass matrix shown in the paper are band matrices, and coupling problem do not exist at all. The methed proposed in the paper has great advantages over the finire element method, the framed methed and the finire strip method, that is, it is easy to edit computer programmes, saves the numbel of storage and is simple to input data. It can solve complex engineering problem in microcompurers or tmall computers, Calculation shows that it is a powerful and economical method.
In this paper,we divide shear-wall structure into several subdomains, then synthetize each subdomain by using two-dimensional single spline functions, Therefere the dynamic characteristics of structure can be obtained easily. It adopts analysis model of continuum-discrete in order to reflect real properties of structures. Due to using cubic B-spline for interpola tion,it overcomes difficulties for treatment of clamped boundary shear condition, The stiffness matrix and mass matrix shown in the paper are band matrices, and coupling problem do not exist at all. The methed proposed in the paper has great advantages over the finire element method, the framed methed and the finire strip method, that is, it is easy to edit computer programmes, saves the numbel of storage and is simple to input data. It can solve complex engineering problem in microcompurers or tmall computers, Calculation shows that it is a powerful and economical method.
1987, 4(4): 73-74.
Abstract：
This paper introduces combination of strain instruments and microcomputer, and gives some examples of spot strain measurement by using this system.
This paper introduces combination of strain instruments and microcomputer, and gives some examples of spot strain measurement by using this system.
Abstract：
This paper analyses factors effecting modulus of elasticity under various loading path and way as well as moisture content,and gets that average confining pressure, deviation of average confining pressure and moisture content are factors effecting mondulus of elasticity, presenting a general princpkle and method calculating modulus of elasticity. Final,the paper gives calculating formulation for argillaceous rock.
This paper analyses factors effecting modulus of elasticity under various loading path and way as well as moisture content,and gets that average confining pressure, deviation of average confining pressure and moisture content are factors effecting mondulus of elasticity, presenting a general princpkle and method calculating modulus of elasticity. Final,the paper gives calculating formulation for argillaceous rock.
1987, 4(4): 93-105.
Abstract：
A submarine pipeline under laying operation forms a long slender rod having the shape of a plane curve according to the effect of the gravity. The lower part lies on the sea bottom and the upper end is supported by a vessel. The vibration of the vessel induced by sea waves generates forced vibration of the pipeline in the vertical plane, and possibly gives rise to dynamic instability and generates parametric vibration off the plane. These vibrations are regarded as small motions about the large static deflection, and the instability regions and the response in these regions are studiod in this paper via the motion equations established. Approximate analytical methods are used in the solution so that the effects of the tension and the geometry of the static deflection curve on the vibrations and the stability can be expressed explicitly.
A submarine pipeline under laying operation forms a long slender rod having the shape of a plane curve according to the effect of the gravity. The lower part lies on the sea bottom and the upper end is supported by a vessel. The vibration of the vessel induced by sea waves generates forced vibration of the pipeline in the vertical plane, and possibly gives rise to dynamic instability and generates parametric vibration off the plane. These vibrations are regarded as small motions about the large static deflection, and the instability regions and the response in these regions are studiod in this paper via the motion equations established. Approximate analytical methods are used in the solution so that the effects of the tension and the geometry of the static deflection curve on the vibrations and the stability can be expressed explicitly.
1987, 4(4): 106-112.
Abstract：
The foundation of an arch dam often contains soft seams or consists of rock strata with diffrient properties. Therefore photoelastic stress analyses of an arch dam on non-homogeneous foundation are improtant and complicated. In this paper the stress analysis of a high arch dam together with its complex foundation by using photoelastic study of a three-dimensional model is presented. Some problems are described briefly such as casting combined model and loading analogy on it. The performance of the dam and the stress distribution in the dam under hydrostatic water load and silt pressure have been analyzed. Besides, the effects of variation in elastic modulus of foundation, asymmetry of the elastic moduli and existence of low modulus zones in the foundation on the stress in the dam are also disrcussed.
The foundation of an arch dam often contains soft seams or consists of rock strata with diffrient properties. Therefore photoelastic stress analyses of an arch dam on non-homogeneous foundation are improtant and complicated. In this paper the stress analysis of a high arch dam together with its complex foundation by using photoelastic study of a three-dimensional model is presented. Some problems are described briefly such as casting combined model and loading analogy on it. The performance of the dam and the stress distribution in the dam under hydrostatic water load and silt pressure have been analyzed. Besides, the effects of variation in elastic modulus of foundation, asymmetry of the elastic moduli and existence of low modulus zones in the foundation on the stress in the dam are also disrcussed.
1987, 4(4): 113-122.
Abstract：
By using the results of the model tests of a 43-storeyed main building and a 27-storeyed auxiliary building, the behavior, the defor mation property,the dynanmic property,the computing,and the analysis of the computed results of the core tube-rigid frome structures subjected to lateral loads are discussed tn this paper It is assumed that this type of space structure may be replaced by an equivalent plane structure sqstem in the analysis. Finally, the subsidiary building and the deformation of the main building floor slabs in their own plane which will have an effect on the behavior of the main building are also discussed in this paper.
By using the results of the model tests of a 43-storeyed main building and a 27-storeyed auxiliary building, the behavior, the defor mation property,the dynanmic property,the computing,and the analysis of the computed results of the core tube-rigid frome structures subjected to lateral loads are discussed tn this paper It is assumed that this type of space structure may be replaced by an equivalent plane structure sqstem in the analysis. Finally, the subsidiary building and the deformation of the main building floor slabs in their own plane which will have an effect on the behavior of the main building are also discussed in this paper.
Abstract：
Accoding to the principle of continuum mechanics,a class of wave eguations from seismic exploration have been introduced,in this paper,the awthor presents a boundary element method to solve above problems in freguency domain, ths methiod first takes fourier transform of the time variable,changes the wave eguation into the Helmholtz eguation,then solves the eguation with Boundary Element Method in frekency domain,and finae returns the results to the time domain This paper providesa concrete computing formula of the method.
Accoding to the principle of continuum mechanics,a class of wave eguations from seismic exploration have been introduced,in this paper,the awthor presents a boundary element method to solve above problems in freguency domain, ths methiod first takes fourier transform of the time variable,changes the wave eguation into the Helmholtz eguation,then solves the eguation with Boundary Element Method in frekency domain,and finae returns the results to the time domain This paper providesa concrete computing formula of the method.
