摘要:

AbstractIn this novelforecasting algorithmto calculate the unit‐impulse response matrix of an unbounded medium to analyse dynamic medium‐structure interaction in the time domain based on the substructure method, afinite‐element regionadjacent to the structure–medium interface consisting of two or three rows only is introduced. Its exterior boundary is chosen to besimilarto the interior boundary which coincides with the structure–medium interface. At similar boundaries of the unbounded medium the unit‐impulse response matrices are a function of the dimensionless time. The unit‐impulse response matrix at the exterior boundary can beforecastedfrom that at the interior boundary via this dimensionless time by taking advantage of thetime delayof waves propagating between these two boundaries. The forecasting algorithm based solely on the finite‐element method is exact in the finite‐element sense in modelling the

ISSN:0029-5981    

DOI:10.1002/nme.1620380702

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractWe present a new first‐principle framework for the prediction of effective properties and statistical correlation lengths for multicomponent random media. The methodology is based upon a variational hierarchical decomposition procedure which recasts the original multiscale problem as a sequence of three scale‐decoupled subproblems. The focus of the current paper is the computationally intensive mesoscale subproblem, which comprises: Monte‐Carlo acceptance–rejection sampling; domain generation and parallel partition based on Voronoi tesselation; parallel Delaunay mesh generation; homogenization‐theory formulation of the governing equations; finite‐element discretization; parallel iterative solution procedures; and implementation on message‐passing multicomputers, here the Intel iPSC/860 hypercube. Two (two‐dimensional) problems of practical importance are addressed: heat conduction in random fibrous composites, and creeping flow through random fibro

ISSN:0029-5981    

DOI:10.1002/nme.1620380703

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAn implicit–explicit procedure for the solution of the compressible Navier–Stokes equations on unstructured triangular and tetrahedral meshes is outlined. A procedure for constructing continuous lines, made up of edges in the mesh, is employed and the implicit equation system is solved via line relaxation. The problem of generating, and adapting, unstructured meshes for viscous flow simulations is addressed. A number of examples are included which demonstrate the numerical performance of the proposed procedu

ISSN:0029-5981    

DOI:10.1002/nme.1620380704

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAn extension of recent work1on the simultaneous optimization of material and structure to address the design of structures under multiple loading conditions is presented. Material properties are represented in the most general form possible, namely, as elements of the unrestricted set of positive‐semi‐definite constitutive tensors of a linearly elastic continuum. Existence of solutions can be shown when the objective is a weighted average of compliances and a resource constraint measured as the 2‐norm or the trace of the constitutive tensors is included. The optimized material properties can be derived analytically. The optimization of the layout of the material leads to a sizing problem of structural optimization involving a non‐linear, non‐smooth elasticity analysis. The computational solution of this problem is discussed and illustrated with

ISSN:0029-5981    

DOI:10.1002/nme.1620380705

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this paper a finite element method is developed to treat stability problems in finite elasticity. For this purpose the constitutive equations are formulated in principal stretches which allows a general representation of the derivatives of the strain energy function with respect to the principal stretches. These results can then be used to derive an efficient numerical scheme for the computation of singular points.

ISSN:0029-5981    

DOI:10.1002/nme.1620380706

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA new kind of approach to formulate an isotropic thin plate bending element is presented. The strain energy of the element is decomposed into two parts: an integral concerning the first strain invariant and a line integral around the elemental boundary. The former can be discretized by quasi‐conforming technique1and the latter can be directly calculated using the interpolation of the deflection and its normal slope along the element boundary. By this method, an assumed first strain invariant quadrilateral element (AFSIQ) is derived. The procedure of formulating the element and the numerical examples show that the new kind of element not only simplifies the formulation considerably but also has excellent accurac

ISSN:0029-5981    

DOI:10.1002/nme.1620380707

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractLocal analysis schemes capable of detailed representations of the micro‐features of a problem are integrated with a macro‐scale BEM technique capable of handling complex finite geometries and realistic boundary conditions. The micro‐scale effects are introduced into the macro‐scale BEM analysis through an augmented fundamental solution obtained from an integral equation representation of the micro‐scale features. The proposed hybrid micro‐macro BEM formulation allows decomposition of the complete problem into two sub‐problems, one residing entirely at the micro‐level and the other at the macro‐level. This allows for investigations of the effects of the micro‐structural attributes while retaining the macro‐scale geometric features and actual boundary conditions for the component or structure under consideration. As a first attempt, elastic fracture mechanics problems with interacting cracks at close spacings are considered. The numerical results obtained from the hybrid BEM analysis establish the accuracy and effectiveness of the proposed micro–macro computational scheme for this class of problems. The proposed micro–macro BEM formulation can easily be extended to investigate the effects of other micro‐features (e.g. interfaces, short or continuous fibre reinforcements, voids and inclusions, in the context of linear elasticity) on macroscopic failure modes observ

ISSN:0029-5981    

DOI:10.1002/nme.1620380708

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620380709

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620380710

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620380701

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY