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1.
Based on the strain energy considering the effect of dead loads, the general form static equilibrium differential equations were formulated by means of the potential energy principle. The approximate solutions of live load or later load displacement including the effect of dead loads for the clamped rectangular plate and the simply supported rectangular plate were generated by the Galerkin method. These formulas are simple and clear, and their physical concepts are explicit. The correctness of these formulas was verified by the finite element method. The dead loads and other factors that influence the effect of dead loads are shown by these formulas. The effect of dead loads on the two different boundary condition rectangular plate were analyzed by these approximate solutions. The effect of dead loads improves the bending stiffness of plate and minimizes the displacement of live loads or later loads. The key physical factors governing the effects of dead loads on plates are the dead load, the ration of span to thickness and boundary condition etc. This effect of dead loads is not negligible, especial in thinner plates or plates with smaller stiffness, more attention should be paid to the effect of dead load in the calculation and analysis for plates.  相似文献   

2.
The varied-axial force beam-column is widely used in practice. Unlike the academic method, the numerical method is usually used only to solve its stability problem, but not to give the general answer a series of problems for beam-column. In this paper, firstly, a new conception of dimensionless beam column is presented. Secondly, based on the column deflection curve (CDC) method, the calculation formula for critical load of variable-axial force beam-column is derived. Thirdly, the numerical results under axial symmetric load are derived. Finally, the interaction formula on the critical load of beam-column under concentrated axial load, even distributed axial load and triangular distributed axial load and under these loads acted simultaneously are proposed respectively. The method given in this paper expands the application of CDC.  相似文献   

3.
In this paper trial functions of the second Tchebychev's polynomials is used with Cantorovich variational method in energy functional of thin plate. Bending deformaion of rectangle plate under even loads or concentrate force with several bearing and critical pressure in buckling is resolved. Though the first similar is used but calculations indicate that this method is simple and exact in engineering.  相似文献   

4.
In mechanical design and application, in order to calculate torsion angle and shear stresses of prismatic bars with seetorial cross-section undergoing extemal couples, the numerical method is presented. The torsion equation is nonhomogeneous partial differential equation. First, using the method of separation of variables, torsion stress function is acquired in polar coordinate. Then, the method of boundary collocation is improved to calculate the undetermined parameters. Finally,approximate numerical solutions of stress function and shear stresses in cross-section are obtained. It is given the several calculation results of shear stresses of prismatic bars with different vertex angles. These results show that the method has some precision and application feasibility in engineering design. The method of separation of variables is combinied with the method of boundary collocation simplified calculation process.  相似文献   

5.
This paper discusses the Reissner's plates on elastic foundation.The elastic foundation is considered as two- paramerer and its effect to thick plates are taken into account by a set of govering differential equations. According to the foundamental solutions for bending problem on two- parameter foundation derived, three boundary integral equations denoted by generalized displacement functions are established. This method is suitable to solve the bending problem of thin or thick plates on two- parameter foundation with arbitary boundary condition, arbitary shape and arbitary load conditions  相似文献   

6.
A novel modal parameter identification method based on stratified sampling and optimism complex Morlet wavelet is proposed for short data sequences. Stratified sampling is applied to divide the structure response signal into different layers which called sub samples with different thresholds, and then free decrement response signal of each layer is extracted by random decrement technique. The optimism complex Morlet wavelet transform is applied to identify modal parameter of each layer, and the weight of the layer is also determined based on the sample standard deviation. The modal parameter of the structure can be obtained by weighted calculation.The engineering application shows that the proposed method has the ability to identify modal parameter accurately, decouple low frequency intensive modal composition and restrain high frequency fake modal effectively.  相似文献   

7.
Based on the selaxaticn t echnique, a new approach to solving quadratic programming is presented in this paper. The idea of parametric programming is introduced in the process of solving the problem,and the optimal solution can be obtained through a finite numfer of search iterations. The features of the proposed method are few regurements for the initial values and little computation. It can also be used to solve the parametric quadratic programming. As an example of application, it is applied to solve a real power secure economic dispatch problem in electric power systems,and its calculation results are given.  相似文献   

8.
In this paper,the boundary element methods are applied to analyse the plates ontwo-parameter elastic foundation according to two boundary integral equations.The bending mo-ment,torsion and shear force at any point of plates are discussed by means of the theory of elasticitymechanics.An example and a plate in practital engineering are analysed.The resulta show that thereare high efficiency,good accuracy and little storage with this method.  相似文献   

9.
Compared with column bored pile,the bored pile with branches and plates is a new type of piles with higher bearing capacity and lower settlement.Field comparative tests related to ultimate bearing capacity of both the bored piles with branches and plates and column bored piles at the same site in Huzhou city of province Zhejiang in China were studied through self-balanced method under static pressure.The results testify that,compared with column bored pile under the same geological conditions,the bored pile with branches and plates can obtain better economic benefit such as: increasing ultimate compressive bearing capacity and ultimate extraction bearing capacity used per cubic meter concrete over 75.3%and 118.9%respectively,while dropping consumption of reinforced concrete upwards of 41.9%and 44.1% respectively,reducing settlement and pile length under the same loading.The tests will present an objective reference to the new type of piles in both theoretic study and application to analogous engineering.  相似文献   

10.
The problem of old urban district regeneration has to be solved in process of ur-ban development.According to the practice of urban construction and the current situation of urbandevelopment in our country,solving this problem is very urgent. At present.there is fewer discussionon old urban district regeneration from its economic and social effect; In this paper.by means of an-alyzing old urban district regeneration and its investment effect, a set of criteria evaluating the in-vestment effect of old urban district regeneration is eastablished. For the first tirne, a new method. Set Statistics-AHP (The Analytic Hierarchy Process)-Entropy method is adopted to evaluate the in-vestment effect,and successfully solve two critical problems,individual criterion evaluation and crit-era' s weight.  相似文献   

11.
With theoretic analysis, lab experiment and engineering application, it is indicated that the SZJ grounding system is a new type grounding system which distinctly reduces the grounding impedance of grounding grids, especially of grounding grids in the zones with high-resistivity or grounding grids with scanty area. The design and calculation method for application of SZJ grounding system is also studied.  相似文献   

12.
介绍了斜缀管式和平缀管式等截面钢管混凝土格构柱骨架曲线的计算方法并进行评价分析。研究表明,不同缀管布置形式的钢管混凝土格构柱,其抗震性能具有共性。借鉴钢管混凝土单肢柱的计算框架,开展等截面钢管混凝土格构柱骨架曲线的统一算法研究,对弹性刚度、水平峰值荷载、峰值荷载位移、下降段刚度等主要参数的计算方法进行了深入探讨和算例分析,并以干海子大桥格构柱墩为研究对象,采用OpenSEES有限元程序,对骨架曲线算法进行工程实例验证。研究结果表明,计算值与试验值及有限元计算结果均吻合良好。最后提出了适合工程应用的等截面钢管混凝土格构柱骨架曲线的统一简化算法,为钢管混凝土计算理论的进一步完善和规程编撰提供参考。  相似文献   

13.
An improvement method is given to detect small weak targets. It predicts the background gray and the actual gray of the current pixel molded by two predicting windows. The method can not only solve the edge blur problem of the traditional method, but fit for the detection of the bipolar targets. It can perform at a high calculation speed, which is an important improvement in the filed. In the process of real-time missile-tracking. The reliability and stability of detection require that the method cannot only solve the edge blur problem of the traditional method, but work well with the background no matter it is bright or dark. According to the experiment using the images provided by DX-1 missile-tracking project, the method is proved effective.  相似文献   

14.
Displacement of stress-resultants computation technique of semi-rigidly connected steel frames inclucing stiffness matrix method,hand calculation method has been proposed. Hand calculation includes substitute rigid frame method under horizontal loads and moment distribution or decomposed storey method under vertical loads. Connection stiffness for five widely used type has systematically computed and practical values of beam stiffness to column stiffness has been summarized and issued.  相似文献   

15.
Domain engineering is an activity for building reusable components. Domain engineering addresses the systematic creation of domain models and architectures. Domain analysis is a software engineering process that identifies, captures, organizes, analyzes, and represents information about a software domain to determine software architecture, framework, and component, and to support the reuse or software components. This method is one of the key techniques to solve the reuse problem. The article introduces the Feature-Oriented Domain Analysis (FODA), developed at the Software Engineering Institute (SEI). The article mainly discusses the application of FODA in the MIS development reusable component. It proves that FODA is an effective and efficient way to develop reusable component.  相似文献   

16.
This paper solves the geometrically nonlinear problems of symmetric, cross-ply laminated anisotropic rectangular plates subjected to uniformly distributed load by the higher-order shear deformation theory and taking an advantage of the perturbation and the weightedresidual method. First, with the help of the perturbation, the nonlinear partial equations have been changed into linear ones. This paper can solve these linear ones by the weighted-residual method. The combination of quintic B-spline functions are chosen as the basis of trial function and Dirac delta functtion, the weighted function. The method used in this paper is simple, direct and efficient. The numerical results show a good convergence and they are in good agreement with the available data.  相似文献   

17.
By using mixed triangle series,this paper discusses the calculation of rectangular stiffened plates with simply supported edge along direction of stiffeners under several local loads,such as uniform load on local rectangular area,concentrated force,concentrated moment of couple,line loads,line moments of equal and some equivalent concentrated forces acting on a line with equaldistance among them.All analytical solutions of both displacements and internal forces are derived.A numerical example to treat an engineering problem is given.  相似文献   

18.
甜菜基因工程研究进展及其展望   总被引:1,自引:1,他引:0  
甜菜基因工程是目前甜菜研究领域的热门课题之一,目前已取得一定研究进展,其基本思路是通过分子生物学手段和转基因技术来获得具有优良性状的甜菜新品种(系)。从植物基因工程在甜菜中的应用、转基因研究方法、安全性评价等几个方面对甜菜基因工程研究的近期成果进行了综述,并分析了转基因甜菜研究过程中存在的问题及其研究展望。  相似文献   

19.
A method is proposed to measure the thickness of nano-scale thin film. Based on the differences about mechanical property between the film and the base, a required scratching will be obtained with the proper tool scratching the film directly, which is through the film touching the base and without any effects to the surface of the base. Scanning the scratching area by using atomic force microscope, some data will be obtained and the average thickness of nano-scale thin film can be calculated in the scratching area. The thickness of the TiO2 nano-scale thin film was measured by this method, the experiment result showed that the average thickness of the film is 71.6 nm, which is consistent with the reported result of the reference. This method has high measuring precision, wider application area, more intuitive images, simpler calculation and operation.  相似文献   

20.
The application of the element-free method in the bending problems of plates has not been found since it was proposed.In this paper,the element-free method is applied to compute the deflection and the moment of the elastic foundation plate with free boundary,and the corresponding formulas as well as the computer program are developed.Numerical examples show that the accuracy of the method used in the foundation plate problem is satisfactory.Therefore,it is reasonable and feasible for using the element-free method in the plate bending problems.  相似文献   

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