摘要:

AbstractThe method of infinite grid refinement is used to estimate the analytic form of some point singularities in three‐dimensional Laplacian and elasticity problem

ISSN:0748-8025    

DOI:10.1002/cnm.1630060502

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractDesign sensitivity analysis is performed for the finite‐element system arising from the discretization of non‐linear potential problems using isoparametric Lagrangian elements. The calculated sensitivity formulae are given in a simple matrix form. Applications to the design of electromagnets and airfoils are gi

ISSN:0748-8025    

DOI:10.1002/cnm.1630060503

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA curved triangular element is presented for thin Kirchhoff plates. A mixed, two‐field formulation is used, based upon the Marcus decomposition, in which the familiar biharmonic equation is supplanted by a pair of coupled Poisson‐type equations. Several examples of simply supported plates are given to illustrate the behaviour of this new formulat

ISSN:0748-8025    

DOI:10.1002/cnm.1630060504

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe object of this work is to analyse the computational aspects of the finite‐element method for the elastic wave equations. The necessary numerical techniques are analysed from the point of view of accuracy, performance and storage requirements when implemented in scalar and vector processors with large storage capacity. The method is implemented on an IBM 3090 with vector facility.For this implementation we consider five different time integration schemes (explicit and implicit central difference, Houbolt, constant average acceleration and Wilson), and in the implicit case, both direct (Gaussian decomposition) and iterative (successive over‐relaxation, Jacobi semi‐iterative, Jacobi conjugate gradient) sparse linear systems solvers. These solvers are taken from the ITPACK2C and ESSL libraries using in each case the adequate representation scheme; skyline, row‐wise and compressed diagonal.From our results it is concluded that constant average acceleration and explicit central difference are the most adequate integration methods and Jacobi conjugate gradient is the most efficient

ISSN:0748-8025    

DOI:10.1002/cnm.1630060505

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractEquivalent variational formulations are found for a generalized linear boundary‐value problem which covers a wide class of engineering applications. The results presented yield as special cases the well‐known elasticity variational princip

ISSN:0748-8025    

DOI:10.1002/cnm.1630060506

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA practical algorithm is described for the computation of the transition matrix and its integral of a time‐invariant state‐space system. It is based on the partial Taylor expansion of the matrices, and methods for reducing computations and increasing accuracy are gi

ISSN:0748-8025    

DOI:10.1002/cnm.1630060507

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThis contribution deals with the development of a fundamental solution for an elastic plate supported by an elastic half‐space. The author briefly discusses problems associated with using an existing fundamental solution, and then develops an alternative solution using an approximate foundation reaction function which is obtained from the concept of equivalent thickness and Boussinesq's solution for an elastic half‐space. The singular solution can be easily incorporated into existing boundary‐element codes, and makes use of material parameters which are directly related to the material properties of each layer. An approximation to the fundamental solution is also suggested. Comparisons between approximate and exact solutions are presented, and limitations are disc

ISSN:0748-8025    

DOI:10.1002/cnm.1630060508

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe performance of the iterative procedure used for the explicit characteristic—Galerkin method in the solution of advection‐dominated problems is investigated here in the implicit case. The procedure is conditionally stable, and here its stability limit is compared to that of time stepping. It is shown that in a limited range of values of the implicitness parameter θ it is possible to generate explicit methods by use of the iterative solution procedure. This is true, in particular, at θ = ⅓; with this choice the algorithm generated is more accurate, has a wider stability margin and lower cost (for linear problems) than the usual choice θ = 0. Because of these properties, this algorithm might be used for further improvement of the performance of fluid‐dyna

ISSN:0748-8025    

DOI:10.1002/cnm.1630060509

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA useful and simple algorithm is presented for interactively generating B‐spline interpolation curves and surfaces from B‐spline approximation solutions. The difference between the data points and the B‐spline approximation is used to modify the control vertices in order to generate a succession of B‐spline approximations which converge rapidly to the interpolation solution. The intermediate B‐spline approximations can be viewed interactively and the most appropriate solution selected for a particular ap

ISSN:0748-8025    

DOI:10.1002/cnm.1630060510

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe most general case of perturbation of a repeated eigenvalue of a derogatory eigenproblem is considered. It is shown that Puiseux expansions of the perturbed eigensolutions are inevitable in the degenerated case where the Taylor expansions are erroneous.

ISSN:0748-8025    

DOI:10.1002/cnm.1630060511

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY