摘要:

AbstractWe extend the variation principle used in the global element method for self‐adjoint elliptic problems1, to problems containing advective terms. Used with the global element formalism, the extended principle yields a uniform framework for treating advective or boundary layer problems, with the attractive feature that the implicit treatment of interface conditions between elements yields an effective decoupling between ‘boundary layer’ and ‘interior’ parts of the solution. As a numerical example, we solve the one‐dimensional model problem of Christie and Mitchell3, obtaining high accuracy for Peclet numbers up to 106with no sign of instability. These results suggest that, given a suitable choice of global elements, the decoupling is very effective in damping the oscillations found in standard finite difference or finite elemen

ISSN:0029-5981    

DOI:10.1002/nme.1620150202

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractA simple approximation by nonconforming finite elements is presented that passes the patch test of Irons and Strang but does not yield approximate solutions converging to the solution of the given boundary value problem. It is constructed from continuous piecewise linear functions perturbed by step functions. Further, strange convergence properties of such approximations are explained in all details because they may be typical for the behaviour of nonconforming finite elements violating the basic precondition for convergence.

ISSN:0029-5981    

DOI:10.1002/nme.1620150203

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractA unified approach is presented for the static and transient dynamic linear and geometrically nonlinear analysis of Mindlin plates including initial imperfections. The effects of transverse shear deformation and rotatory inertia are automatically taken into account. A finite element idealization is adopted and the quadratic Lagrangian Mindlin plate element is used together with selective integration. Several numerical examples are presented and compared with results from other sources.

ISSN:0029-5981    

DOI:10.1002/nme.1620150204

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractThe solution of incompressible, viscous flow problems using the primitive variable finite element approach is formulated in a coherent and physically reasoned exposition. In particular, it is shown that terms associated with changes in momentum caused by lack of mass conservation should logically be included in the governing equations. Previous formulations have not considered this possibility. Numerical results are presented to show the effect of inclusion of these extra terms; however, it is concluded from the numerical results for the specific case which was tested that there is no obvious benefit obtained by including these terms.

ISSN:0029-5981    

DOI:10.1002/nme.1620150205

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractSeveral computer codes have incorporated the ‘overlay’ material models: the volume element, which is characteristic of the material, is composed of sub‐elements with different kinematic hardening, perfectly plastic or even viscoplastic flow rules and different elastic properties, these sub‐elements exhibiting all, however, the same total strain.1,2In this paper it is demonstrated how the simple mathematical framework we first proposed for elastic‐plastic structures with kinematic hardening material,3and we extended to some elastic viscoplastic ones,4can easily be applied to these particular ‘overlay’ materials.One of the interesting advantages of this approach is a straightforward analysis of structural response under cyclic loadings by applying the linear ela

ISSN:0029-5981    

DOI:10.1002/nme.1620150206

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractA dual load method of truss analysis is presented that allows highly nonlinear member behaviour to be followed. In particular, a brittle type of strut behaviour is considered. The method assumes that the inelastic strut response is known and that piecewise linearization of the behaviour is acceptable. An example is given to illustrate the type of problem that can be handled. The example involves negative stiffness of the members and consequently attention must be given to the equation solving procedure for the structure. A comparison is made with some observed test results.

ISSN:0029-5981    

DOI:10.1002/nme.1620150207

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractLarge amplitude vibrations of Mindlin plates are studies using Lagrangian, isoparametric, quadrilateral elements with selective integration. Square, rectangular, circular and elliptical plates with clamped and simply supported boundary conditions are considered.

ISSN:0029-5981    

DOI:10.1002/nme.1620150208

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractThis paper presents numerical results calculated by the extended field method for the problem of the forced harmonic vibration of two plates—one rectangular and one triangular. The numerical results demonstrate that the extended field method, which is a deflection‐based series solution method, is capable of producing converged stress solutions suitable for being bases of comparison for other approximate methods of analy

ISSN:0029-5981    

DOI:10.1002/nme.1620150209

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractStudies of the convergence and performance of the mixed finite element method in plane elasticity are reported. A completeness criterion is proposed, and convergence rates for stresses and strain energy, as predicted elsewhere, are quoted. An eigenvalue analysis of the mixed element matrix is carried out for various combinations of interpolations for displacements and stresses in a triangular and a rectangular element, and the results are discussed in relation to the completeness criterion. Finally, a triangular element with linear interpolations for stresses and displacements is formulated and its use is demonstrated on several numerical examples.

ISSN:0029-5981    

DOI:10.1002/nme.1620150210

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractA numerical Laplace transform inversion technique is described, which is a modification of the inversion method using an exponential series representation. By adding an auxiliary function and using Erdélyi's inversion formula, the proposed technique provides the inverse approximation with improved accuracy neart= 0. Numerical illustrations shows that this procedure also works in cases when the original method of schapery fails to give satisfactory results

ISSN:0029-5981    

DOI:10.1002/nme.1620150211

出版商:John Wiley&Sons, Ltd    

年代:1980

数据来源: WILEY