摘要:

AbstractA 3‐D refinement algorithm for tetrahedral meshes is presented and discussed. An empirical study of the reduction of solid angle size due to repeated subdivisions has shown the algorithm to be in practice a powerful and reliable tool for mesh refinement suitable to be combined with adaptive finite‐element methods and multi‐grid algor

ISSN:0748-8025    

DOI:10.1002/cnm.1630080502

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn conjunction with the quarter‐point element, a wide range of stress intensity factor computation techniques may be employed. Of these, the displacement correlation technique (DCT) and the quarter‐point displacement technique (QPDT) have been in common use. It has been suggested by various investigators that the DCT is more rational in formulation and should therefore be more accurate than the QPDT. However, published numerical studies provide conflicting results on the relative performance of either technique. To resolve this anomaly, this study provides a detailed investigation on the DCT and QPDT performance. On the basis of considering the second term in Westergaard's expression and supported by numerical experiments, it is concluded that the QPDT would generally perform better than the

ISSN:0748-8025    

DOI:10.1002/cnm.1630080503

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this paper a new algorithm for the computation of singular integrals (1/ror 1/r2) is presented. The limit of inner domain variables, as an inner point approaches the boundary, can be computed by this algorithm. Based on the difference between this limit and the corresponding given values in boundary conditions, an objective measurement of the accuracy of a BEM solution is suggested. This objective measurement is used to estimate the error of a BEM solution. Several numerical examples are given.

ISSN:0748-8025    

DOI:10.1002/cnm.1630080504

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractStructural stability problems under displacement‐dependent loads often take the form of non‐linear eigenvalue problems in which the eigenvalue is raised to an exponent. Iterative techniques are considered in this work for the solution of non‐linear eigenproblems of the form (K‐ λK1‐K2(λp))x= 0. The problem is linearized at each iteration using two alternative procedures: through updating the stiffness matrixKor else by updating the initial stress matrix. Numerical examples are used to illustrate the difficulties associated with the first technique, whereas it is shown that the second one yields better convergence rates than other existing

ISSN:0748-8025    

DOI:10.1002/cnm.1630080505

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe application of the Zienkiewicz and Zhu error estimator to three‐dimensional faceted shells presents some difficulties which arise from the lack ofC1continuity of the geometry. This paper presents a method to circumvent such difficulties based on the existence of a mapping from a flat reference configuration to the actual shell. This mapping is used not only to enable meshes to be generated in a two‐dimensional space, but also to define a stress measure – similar to the first Piola–Kirchhoff stress used in large deformation mechanics – which can be consistently smoothed over the reference configuration. A preliminary investigation of the method is provided by three simple

ISSN:0748-8025    

DOI:10.1002/cnm.1630080506

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe stability behaviour of a cantilever beam, carrying a concentrated mass at the free end and subjected to a uniformly distributed follower force, is studied by the finite‐element method. In the present finite‐element formulation, the Timoshenko beam theory is utilized to derive the governing equations of motion. In order to more quickly and efficiently obtain the critical load for such a non‐conservative system, a numerical technique which utilizes the eigenvalue sensitivity with respect to the follower force is introduced instead of the conventional trial‐and‐error technique. The high accuracy and rapid rate of convergence through the combination of the present finite‐element model and the numerical algorithm are demonstrated with the numerical ex

ISSN:0748-8025    

DOI:10.1002/cnm.1630080507

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe finite‐element package PLTMG was designed to solve a wide variety of non‐linear, scalar elliptic PDEs. In this paper we examine the application of PLTMG to the solution of a potential flow problem using the stream function formulation. The flow problem is that of irrotational steady flow through a shallow lake with prescribed inflows and outflows. A two‐dimensional (vertically integrated) model is used. One or more islands may be present. The paper focuses on the advantages of the stream function formulation for obtaining accurate streamlines and partial residence times as opposed to using a potential function formulation. If islands are present the stream values at the island boundaries are unknowns which must be determined to fulfil a condition of zero circulation round each island. Thus, ifNislands are present, anN‐fold linear continuation must be performed to determine the s

ISSN:0748-8025    

DOI:10.1002/cnm.1630080508

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630080501

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY