摘要:

AbstractIn this paper we show how an adaptive, error‐controlled, mesh‐refinement procedure can be used effectively to capture localization and shear banding phenomena. Use of directionally elongated meshes is also discus

ISSN:0748-8025    

DOI:10.1002/cnm.1630060202

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper presents a simple new algorithm for constructing second‐order models for any given flexible structure, with these models satifsfying the constraint that each leading principal submatrix of the mass matrix must have a specified condition number. Now, the effects of rounding errors in practical computation generally increase with increasing condition number, i.e. as the matrix considered approaches singularity. Thus, the new models should prove useful for the systematic testing of the numerical properties of many algorithms in the dynamics and control of flexible structure

ISSN:0748-8025    

DOI:10.1002/cnm.1630060203

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630060204

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA procedure based on changing of independent variables is proposed. It allows one to reduce one‐dimensional (1D) and two‐dimensional (2D) singular integrals arising in fracture mechanics (in 2D and 3D problems, respectively). The final non‐singular expressions are exact and usually simpler than the original functions. They may therefore simplify analytical developments, and allow significant reduction of the computational time and an increase in the accuracy of numerical applica

ISSN:0748-8025    

DOI:10.1002/cnm.1630060205

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe Delaunay triangulation has recently received attention as a viable method for construction computational meshes. However, an arbitrary boundary definition which must be preserved in the triangulation process will not, in general, satisfy the geometrical definition on which the Delaunay construction is founded. The effect of this is that the integrity of the given boundary edges will be violated and the computational mesh will not conform to the applied geometrical shape. A method is proposed whereby boundary data are supplemented with points to ensure that imposed boundary edges are preserved during the Delaunay triangulation. The method is illustrated on a geometry of an estuary which exhibits highly complex geometrical features.

ISSN:0748-8025    

DOI:10.1002/cnm.1630060206

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractIn the context of the direct boundary‐element method (DBEM) for most general two‐dimensional elastostatics, new particular integrals are presented in this paper to account for inertial and centrifugal body forces, as well as for those cases of three‐dimensional behaviour where the assumption of plane strain (or stress) may remain approximately valid despite the presence of non‐zero strain (or stress) in the out‐ofplane direction. These integrals have been implemented in a general‐purpose multi‐region boundary‐element code (namely, GPBEST) and test

ISSN:0748-8025    

DOI:10.1002/cnm.1630060207

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630060208

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA finite‐element numerical model for immiscible two‐phase fluid flow in a deforming porous media is presented. The displacements, the pressures and the saturations of wetting phase are taken as primary unknowns of the model as the constraint about the capillary pressure between two fluid phases is applied. The governing equations and their finite‐element formulations are given in the paper. An unconditionally stable staggered solution procedure is devised for the integration of the formulations in the time domain. The stability analysis of the solution scheme is also carrie

ISSN:0748-8025    

DOI:10.1002/cnm.1630060209

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractIn the finite‐element stress analysis of a mass concrete structure, owing to the effect of age of the concrete, it is necessary to compute a stiffness matrix and its inverse for every time increment. The computation is quite lengthy. In this paper a generalized substructure method is offered. It is assumed that the structure, consisting ofmzones of different materials, is divided intomsubstructures, one for each zone. As every substructure is a homogeneous solid, the computation relevant to the substructure is required at the beginning only, and can be utilized repeatedly thereafter. Thus the computation is simplified remarkabl

ISSN:0748-8025    

DOI:10.1002/cnm.1630060210

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractWhile one of the distinguishing features of air pollution problems is the presence of a large number of randomly scattered discrete soucrces, little attention has been devoted to the proper treatment of such souces in standard numerical techniques. In this paper we consider a model air pollution problem in two space variables which can be transformed to the one‐dimensional diffusion equation with a Dirac delta function as the initial conditon. the primary purpose of this study is to investigate the effect of two ways of representing thishighly singular initial condition, namely by L2projection and by mollification, in commonly used numerical methods basedc on a Galerkin semi‐discretization together with the θ method in the marching direction. We report the results of extensive numerical experiments which demonstrate, for example, that in general the numerical solution obtained with mollified initial data is more accurate near the intial point than that obtained using projected initial data. Moreover, it is verified that the‘smoothed’ Crank‐Nicolson method, in which the first two Crank‐Nicolson steps are replaced by four steps of the backward Euler method, is the most effective marchi

ISSN:0748-8025    

DOI:10.1002/cnm.1630060211

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY