摘要:

AbstractThe presented solver uses the CroutL–Udecomposition method. Disk memory space requirements are reduced to an absolute minimum and disk input–output is spectacularly limited. Very extensive pivoting improves numerical accuracy and stability. Experimental test runs prove the overall efficiency of the sol

ISSN:0029-5981    

DOI:10.1002/nme.1620240203

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractAsimplemethod is proposed in this paper for improving the performance (accuracy and convergence) of quadratic elements. In this the physical domain of the problem, as well as the constitutive relationships, are transformed globally by implementing a suitable co‐ordinate transformation, and the problem is then solved in the mapped (transformed) domain using finite elements of the mapped space following the processes of the conventional FEM.Results show that the method significantly improves the performance of quadratic elements in both two and three dimensions. The mathematical implications of mapping in this way indicate that the method can also be applied for improved performance to higher‐order elements if requi

ISSN:0029-5981    

DOI:10.1002/nme.1620240204

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractAn adaptive procedure for the solution of the generalized linear eigenvalue problem within the hierarchical finite element method is described. The problem of finding for a given discretization, an upper limit eigenvalue that is accurate within a prescribed tolerance is especially studied. An error estimator is presented and a recomputational scheme for improved solutions is proposed. A numerical example is included.

ISSN:0029-5981    

DOI:10.1002/nme.1620240205

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA new error estimator is presented which is not only reasonably accurate but whose evaluation is computationally so simple that it can be readily implemented in existing finite element codes.The estimator allows the global energy norm error to be well estmated and alos gives a good evaluation of local errors. It can thus be combined with a full adaptive process of refinement or, more simply, provide guidance for mesh redesign which allows the user to obtain a desired accuracy with one or two trials.When combined with an automatic mesh generator a very efficient guidance process to analysis is avaiable.Estimates other than the energy norm have successfully been applied giving, for instance, a predetermined accuracy of stresses.

ISSN:0029-5981    

DOI:10.1002/nme.1620240206

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA new method for non‐linear programming in general and structural optimization in particular is presented. In each step of the iterative process, a strictly convex approximating subproblem is generated and solved. The generation of these subproblems is controlled by so called ‘moving asymptotes’, which may both stabilize and speed up the convergence of the general pr

ISSN:0029-5981    

DOI:10.1002/nme.1620240207

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThis paper presents a method for straightening curved interfaces arising in phase‐change problems. The method works on isoparametric finite elements, performing a second transformation which maps the master element onto a new one in which the interface looks like a straight line. This allows using the current Gaussian integration technique for squares to evaluate the integrals over each phase. The method provides a better estimation of the contribution of latent heat effects to the residual vector, compared to those obtained by using the assumption that the interface is straight. Appropriate guidelines for solving the non‐linear system of equations arising in this kind of problem are also given. Several numerical examples are presented to show the performance of the met

ISSN:0029-5981    

DOI:10.1002/nme.1620240208

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractWe consider finite element analysis of problems with discontinuous material coefficients. For applications in which the material interface crosses an element, we develop special elements with an embedded flux constraint at the interface. This new procedure is compared with the standard finite element method with interface coincident with the element boundary and with an existing method proposed by Steven.1Supporting numerical studies are conducted and rates of convergence for the solution and interface flux are examined. Some local superconvergence behaviour is observed.

ISSN:0029-5981    

DOI:10.1002/nme.1620240209

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA method of evaluating eigenvalues for any combination of the first, second and third boundary conditions of heat conduction in a plate, a solid cylinder or a hollow cylinder is described. Some general relationships between eigenvalues are derived. Based on these relationships a universal algorithm is developed. A list of a package of computer subroutines is included.

ISSN:0029-5981    

DOI:10.1002/nme.1620240210

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA new algorithm for the solution of the three‐dimensional Navier–Stokes equation using the mixed formulation and an incomplete factorization technique is presented. The linear system obtained at each modified Newton–Raphson iteration is solved by the preconditioned conjugate residual method (PCR) using an out‐of‐core incomplete LU factorization as preconditioning. This factorization is performed on a matrix stored by a new static storage method called the packed skyline method. The performance of the proposed algorithm is assessed for the wall‐driven cubic cavity problem using theQ 1+−P1e

ISSN:0029-5981    

DOI:10.1002/nme.1620240211

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA new algothm for the solution of two‐phase fluid flow problems is presented. The algorithm consisently ensures that the evolved volume fractions are all positive and sum to unity, even in the presence of large spatial and temporal gradients of volume fraction. The momentum equations are then solved using an iterative pressure correction method. Example calculations for buoyancy driven flows, with and without phase changes, are presente

ISSN:0029-5981    

DOI:10.1002/nme.1620240212

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY