THE INCOMPLETE PARAMETER METHOD IN SYNTHESISING PLANAR SIX-BAR MECHANISM

28 to 70 nonlinear equations are required to solve for the path synthesis of planar six-bar mechanism when using the method of displacement matrix, this brings on a great deal difficuties in solving the problem and heavily limits the applied scope of the method. In this paper an incomplete parameter synthesis is presented in which the synthesis of six-bar mechanism is sim-plified to those of bar-group or four-bar machanism so that the solution becomes much easier.     

ANALYSIS OF THE ZERO SOLUTION STABILITY OF LAMINAR BOUNDARY LAYER EQUATION

Two-dimensional incompressible laminar boundary layer equation can be changed into Blasius equation by means of similarity transformation. In this paper, Blasius equation 2f" '+ff"=0 is transferred into a nonlinear and autonomous system of second order by variable transforming. Taking the advantage of its approximation to linear system, the stability near zero solution can be discussed.     

Equivalent Duffing System Method of Nonlinear System Dynamic Reliability Analysis

Equivalent linear system method is the main method of nonlinear structural system random response analysis. While it would generate big error when the results of equivalent linear system method are used to analyze the structural dynamic reliability. Through minimum mean square error principle, general nonlinear system was converted to equivalent Duffing nonlinear system, based on which the structural dynamic reliability was analyzed. The accurate steady state analytic solution of Duffing nonlinear system can be worked out by FPK equation, so it is not only convenient but also accurate to analyze structural dynamic reliability by using the equivalent nonlinear system method. It is also shown that the analysis results of equivalent nonlinear system method presented here is reliable and the calculation accuracy is higher than equivalent linear system method apparently through the example analysis.     

THE REIMPROVEMENT FOR IMPULSE OF G. I. TAYLOR THEORY OF PLASTIC DEFORMATION IN IMPACT OF CYL1NDICAL PROJECTILES

In this paper the reimprovement for G. I. Taylor theory of plastic deformation in impact of cylindical projectiles is done. The impulse in the reimproved theory is G. I. Taylor' s 1/2, and 3/4 of G. I. Taylor' s improved theory. The analytical solution of the reimproved theory shows that it gives better agreement with exprimental results than those of the original Taylor' s theory and, the improved theory.     

THE ARC-LENGTH METHOD OF SECANT RIGIDITY IN FRAME ANALYSIS

The secant rigidity is used for the are-length method to solve the nonlinear finite elements problems. The advantage of this method is unnecessary of calculating the initial resistance term caused by the incremental step. The computational work is less and the programing is easier as compared with initial are-length method. This method can be widely used to solve nonlinear problems.     

THE APPLICATION OF MULTIBODY DISCRETE METHOD IN RING''S VIBRATION ANALYSIS

A ring's muJtibody discrete model is discussed in this paper. The ring's plane geometric nonlinear vibration equations are derived. Compared with the finite element and lump mass methods, this method is better. In the last pa it of the paper, the eigenvalues, the first 9 modes of the ring, the geometric nonlinear dynamic responses of the ring are calculated.     

对偶性与特大增量步算法在复杂平面框架中的应用

特大增量步算法（LIM）是一种基于力法和广义逆矩阵理论的迭代算法，在简单桁架和刚架非线性初步应用中，达到相同计算精度下有同等甚至超过位移有限元的计算效率。针对工程中的复杂杆系结构，利用平衡与协调的对偶性，探讨LIM在复杂平面框架结构中的应用，建立了平面框架结构的LIM基本方程，提出了针对典型支座约束以及组合结点的处理方法。该处理方法的线弹性问题算例表明，与位移有限元相比具有至少同等的精度和相当的计算效率。在支座本身不考虑塑性的情况下，该处理方法同样适用于弹塑性问题，为LIM在复杂杆系结构的弹塑性分析中奠定了基础。     

LARGE DEFLECTION OF A CIRCULAR PLATE ON PASTERNAK FOUNDATION UNDER A CONCENTRATED LOAD AT THE CENTER

Based on Karman's nonlinear foundamental differential equations, the new method combines perturbation method with integral equation method is forward to solve nonlinear bending of a clamped circular plate on Pasternak foundation under a concentrated load at the center. This method is simple and easy to use. The numerical results show that the present solution is reliable.     

Singularly Perturbation of the Nonlinear Three Species Prey-predator Reaction Diffusion System

A class of nonlinear three species in the biomathematics is considered with the prey-predator singularly perturbed problems for the reaction diffusion system method of differential inequalities. Under suitable conditions, the existence and asymptotic behavior of solution for the initial boundary value problems are studied with the theory of differential inequalities. The theory of differential inequalities is really to constructing two auxiliary functions, which are super and lower solutions of the system respectively. And then the super and lower solutions are satisfied corresponding inequalities. Finally, there is a solution of the system between the super solution and lower solution. Then the existence of the solution for the system is proved and the asymptotic estimation is obtained.     

Practical Method of Form-finding of Semi-rigid Structures

Based on the discussion of the simulation for the cable prestress, the rigidity theory was used to identify the geometrical dimensions of semi-rigid structures in zero state. When the structural geometry in initial state is given, the geometrical dimension in zero state is determined by the initial prestress distribution. The contribution-matrix method is firstly applied to get the initial lack of fit. However, the influencing factor of initial lack of fit on the displacement of control point is linear superposition, that is, the structural response is linear, and it is irreconcilable with the geometry nonlinear of semi-rigid structure. In order to reduce the error of nonlinear structural response, the influencing factor in the contribution-matrix method is revised, and modified contribution-matrix method is put forward. Programs by ANSYS parameter design language APDL are worked out for the form-finding analysis of beam-string structure of a practical project. The numerical results show that the modified contribution-matrix method reduces the errors of the assumption of structural linear response. And it can be applied to the form-finding of semi-rigid structures with small stiffness.     

ANALYSIS OF NONLINEAR PROBLEMS OF LAMINATED PLATES BY USE OF PERTURBATION AND WEIGHTEDRESIDUAL METHOD

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.     

THE EQUATION OF STBING IN THE EXTERNAL FIELDS

The classical equations of string in the external fields deduced with Kaluza's method. A solution of the equations for uniform magnetic field is got by means of differential geometry technlqde.     

Water/oil radial flow behavior near well bore zones in oil reservoir

The flow behavior of water and oil near well bore zones in oil reservoir is radial flow. Based on the fluid displacement experiments in radial systems, the equation describing radial flow is investigated and analytical solution about the relationship between relative permeability ratio and saturation is obtained. The analytical solution is used to treat the experiment results and the two phase flow behavior of water and oil is characterized. The results show that the analytical solution can characterize the actual flow of water and oil near well bore zone. According to the radial experiments, the saturation scope in which the relative permeability ratio and saturation is linear is smaller. The flow behavior of water and oil near well bore zones is complex and nonlinear.     

Optimization of Extracting Fremitus Derivative Based on Modified Ibrahim Time Domain Method

The experimental task was very large for solving fremitus derivative of bridge by free vibration method proposed by R.H.Scanlan.And in the process of extracting cross derivative, it was difficult that the frequency ratio and damping ratio under vertical motion and torsional motion were kept the same in all wind speed.Besides, the discriminating error of uncoupled derivative would be coupled in derivative.Considering these, an improved method based on Modified Ibrahim Time domain Method was proposed.With the application, it was found that this method was better than least square method.     

基于智能算法优化SVM的横向通风过程中温度场预测方法探究

将改进的智能预测技术应用于储粮横向通风过程中的粮堆温度预测,为粮食通风智能预测与决策提供了一种新思路。选取河北清苑国家粮食储备库冬季横向通风的实时监测数据,在分析主要影响因素的基础上,应用三种智能优化算法——网格寻优算法、GA遗传算法寻优、PSO粒子群算法,结合回归支持向量机理论,对粮堆的通风过程进行建模。结果表明,优化过的回归预测模型能较好地拟合粮食温度与其他变量之间的非线性关系,尤其是当样本数量较为有限时,该方法具有更高的拟合精度,更适合对储粮通风这一强非线性过程的预测研究,对于人工干预操作具有一定的现实指导意义。     

Post-buckling and mode jumping analysis of angle-ply composite laminates

The governing partial differential equations (PDEs) are deduced from the asymptotically correct, geometrically nonlinear theory to research the bucking and mode jumping behavior of biaxially antisymmetric angle-ply composite laminates. The PDEs are transformed into a system of nonlinear ordinary differential equations (ODEs) by using the generalized Galerkin method. Then, the post-buckling behavior is analyzed by using the solution extension software. At last, the paths of buckling mode jumping and critical loads for the composite laminates under the in-plane boundary condition of straight edge are determined. An example of 4-layer composite laminates shows that the numerical results in the primary post-buckling region from the present method agree with the finite element analysis (FEA); while the FEA may lose its convergence when solution comes close to the secondary bifurcation point, the analytic method has the capability to explore deeply into the post-secondary bucking realm and capture the mode jumping phenomenon.     

K近邻的自适应谱聚类快速算法

利用时域递归展开算法对墙体内热湿耦合传递方程进行求解。以木板为例,应用该算法进行了热湿耦合传递的分析计算,在时间域和空间域上分别运用递归展开法和控制容积法进行离散,从而得到递归形式的线性方程组,运用MATLAB软件对这一过程进行求解。计算结果与有限差分算法、解析解计算结果以及实验数据吻合良好,表明该算法能够用于求解多孔介质热湿耦合传递模型。时间步长的改变对计算结果影响较小,可通过增加时间步长方法来减少工作量。     

THE APPLICATION OF SAND-GRAVEL-CUSHION TECHNIOUE IN THE FOUNDATION OF MOUNTAINOUS AREA

This paper presents the application of sand-gravel-cushion technique in thefoundation of mountainous area inhomogeneity and analyges non-uniformity of the foundation inmountainous,It is different from the traditional theory of sand-cushion,This is a new developmentand able to make a full use of the rock debris fill and the combinational soil-rock foundation in the mountainous areas.     

春谷幼穗发育阶段与叶龄指数关系的研究

经三年观察研究,十个不同熟性春谷品种的幼穗发育开始时间是随着它们生育日数长短而变化,并与拔节始期有着密切的关系.同时,春谷不同熟性品种的叶龄指数又与幼穗发育阶段呈回归直线关系.因此,春谷不同熟性品种利用其叶龄指数,求出适宜的系数,再代入改进的直线回归关系式,即可以较准确地判断出谷子的幼穗发育阶段.     

Deformation of Soft Ground with Consideration of the Concomitant Damage

On the basis of continuum damage mechanics theory, the effective stress theory of damaged porous media was presented and its modified self contained seepage differential equation was deduced. The traditional Drucker Prager yield criterion subsequently was modified, and a coupled seepage and damage finite element computer program compiled that was combined with the modified Biot consolidation equation. A simple roadbed foundation model then was analyzed and calculated using the computer program we compiled, and the typical node settlement, pore pressure, and damage variables were discussed and compared with those from the analytic solution. The results show that the damage finite element program we compiled is reasonable and effective.