共查询到10条相似文献,搜索用时 156 毫秒
1.
A kind of calculating method for high order differentials expanded by the wavelet scaling functions and the integral of their
product used in Galerkin FEM is proposed, so that we can use the wavelet Galerkin FEM to solve boundary-value differential
equations with orders higher than two. To combine this method with the Generalized Gaussian integral method in wavelet theory,
we can find that this method has many merits in solving mechanical problems, such as the bending of plates and those with
variable thickness. The numerical results show that this method is accurate.
This project is supported by the National Natural Science Foundation of China (No. 19772014) and the National Outstanding
Young Scientist Foundation of China (No. 19725207). 相似文献
2.
The symmetric Galerkin boundary element method (SGBEM) instead of the finite element method is used to perform lower bound
limit and shakedown analysis of structures. The self-equilibrium stress fields are constructed by a linear combination of
several basic self-equilibrium stress fields with parameters to be determined. These basic self-equilibrium stress fields
are expressed as elastic responses of the body to imposed permanent strains and obtained through elastic-plastic incremental
analysis. The complex method is used to solve nonlinear programming and determine the maximal load amplifier. The limit analysis
is treated as a special case of shakedown analysis in which only the proportional loading is considered. The numerical results
show that SGBEM is efficient and accurate for solving limit and shakedown analysis problems.
Project supported by the National Natural Science Foundation of China (No. 19902007), the National Foundation for Excellent
Doctorial Dissertation of China (No. 200025) and the Basic Research Foundation of Tsinghua University. 相似文献
3.
Both the inplane and out-of-plane transverse vibrations of a viscoelastic cable subjected to an initial stress distributing
uniform on the cross section are studied. The constitution of the cable material is assumed to be of the hereditary integral
type. The partial differential-integral equations of motion are derived first. Then by applying Galerkin's method, the governing
equations are reduced to a set of second-order nonlinear differential-integral equations which are solved by finite difference
numerical integration procedures. Finally, the effects of the viscosity parameter and the elastic parameter on the transient
amplitudes of the first mode are investigated by numerical simulation.
Project supported by the National Natural Science Foundation of China (No. 59635140) and the National Postdoctoral Foundation
of China. 相似文献
4.
A new algorithm for the solution of quadratic programming problems is put forward in terms of the mixed energy theory and
is further used for the incremental solution of elastic-plastic truss structures. The method proposed is different from the
traditional one, for which the unknown variables are selected just in one class such as displacements or stresses. The present
method selects the variables in the mixed form with both displacement and stress. As the method is established in the hybrid
space, the information found in the previous incremental step can be used for the solution of the present step, making the
algorithm highly efficient in the numerical solution process of quadratic programming problems. The results obained in the
examples of the elastic-plastic solution of the truss structures verify what has been predicted in the theoretical analysis.
Project supported by the National Natural Science Foundation of China (No. 50178916, No. 19732020 and No. 19872016), the National
Key Basic Research Special Foundation (No. G1999032805), the Special Funds for Major State Basic Research Projects and the
Foundation for University Key Teachers by the Ministry of Education of China. 相似文献
5.
How to solve the partial differential equation has been attached importance to by all kinds of fields. The exact solution to a class of partial differential equation with variable-coefficient is obtained in reproducing kernel space. For getting the approximate solution, give an iterative method, convergence of the iterative method is proved. The numerical example shows that our method is effective and good practicability. 相似文献
6.
黄典贵 《应用数学和力学(英文版)》2006,27(6):757-763
A unified numerical scheme for the solutions of the compressible and incompressible Navier-Stokes equations is investigated based on a time-derivative preconditioning algorithm. The primitive variables are pressure, velocities and temperature. The time integration scheme is used in conjunction with a finite volume discretization. The preconditioning is coupled with a high order implicit upwind scheme based on the definition of a Roe's type matrix. Computational capabilities are demonstrated through computations of high Mach number, middle Mach number, very low Mach number, and incompressible flow. It has also been demonstrated that the discontinuous surface in flow field can be captured for the implementation Roe's scheme. 相似文献
7.
This paper presents a method for estimating the upper and lower bounds of eigenvalues of structures with uncertainties. The
uncertain parameters are described by the convex model. A numerical example of the frame structure is given to illustrate
the efficiency of the method.
This work is supported by the National Natural Science Foundation of China(No. 19872028). 相似文献
8.
By using the logarithmic strain, the finite deformation plastic theory, corresponding to the infinitestimal plastic theory,
is established successively. The plastic consistent algorithm with first order accuracy for the finite element method (FEM)
is developed. Numerical examples are presented to illustrate the validity of the theory and effectiveness of the algorithm.
Project supported by the National Natural Science Foundation of China (No. 19772973). 相似文献
9.
This paper presents an improved precise integration algorithm for transient analysis of heat transfer and some other problems.
The original precise integration method is improved by means of the inverse accuracy analysis so that the parameterN, which has been taken as a constant and an independent parameter without consideration of the problems in the original method,
can be generated automatically by the algorithm itself. Thus, the improved algorithm is adaptive and the accuracy of the algorithm
is not dependent on the length of the time step in the integration process. It is shown that the numerical results obtained
by the method proposed are more accurate than those obtained by the conventional time integration methods such as the difference
method and others. Four examples are given to demonstrate the validity, accuracy and efficiency of the new method.
Project supported by the National Natural Science Foundation of China (No. 19872016, 19872017), the National Key Basic Research
Special Foundation (G1999032805) and the Foundation for University Key Teachers by the Ministry of Education of China. 相似文献
10.
XIAO Yong-gang 《应用数学和力学(英文版)》2005,26(8):963-972
IntroductionThe moderate thickness plates on elastic foundation are a kind of important structure instructural engineering. The mechanic characters of the plates on elastic foundation withdifferent boundary conditions have been received considerable atten… 相似文献