摘要:

AbstractAn explicit time‐domain transmitting boundary for the analysis of dam‐reservoir interactions is presented. This transmitting boundary is a semi‐analytical solution of the governing wave equation of the far field of the reservoir. By using this transmitting boundary, the radiation condition and water compressibility can readily be incorporated in the time‐domain analysis of dam‐reservoir systems. Therefore, the finite element method can be used to accurately analyse a dam‐reservoir system including the semi‐infinite reservoir while maintaining its efficiency in time‐domain analysis. Numerical results have excellent agreement with the available analytical solution. Results also show that the proposed explicit transmitting boundary is more efficient computationally than the implicit transmitting boundary presented

ISSN:0029-5981    

DOI:10.1002/nme.1620361102

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractAn algorithm for generating unstructured tetrahedral meshes by the advancing front technique is presented. Emphasis is placed on the construction of tetrahedral elements. Several measures are employed to prevent difficult situations. A control line/surface scheme is used to specify element size. Numerical examples are provided to show the performance of the algorithm.

ISSN:0029-5981    

DOI:10.1002/nme.1620361103

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe present study investigates the elastic stability of skew laminated composite plates subjected to biaxial inplane follower forces by the finite element method. The plate is assumed to follow first‐order shear deformation plate theory (FSDPT). The kinetic and strain energies of skew laminated composite plate and the work done by the biaxial inplane follower forces are derived by using tensor theory. Then, by Hamilton's principle, the dynamic mathematical model to describe the free vibration of this problem is formed. The finite element method and the isoparametric element are utilized to discretize the continuous system and to obtain the characteristic equations of the present problem. Finally, natural vibration frequencies, buckling loads (also the instability types) and their corresponding mode shapes are found by solving the characteristic equations. Numerical results are presented to demonstrate the effects of those parameters, such as various inplane force combinations, skew angle and lamination scheme, on the elastic stability of skew laminated composite plates subjected to biaxial inplane follower force

ISSN:0029-5981    

DOI:10.1002/nme.1620361104

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper presents results obtained by the implementation of a hybrid Laplace transform finite element method to the solution of quasiparabolic problem. The present method removes the time derivatives from the quasiparabolic partial differential equation using the Laplace transform and then solves the associated equation with the finite element method. The numerical inverse of the Laplace transform is realized by solving linear overdetermined systems and a polynomial equation of thekth order. Test examples are used to show that the numerical solution is comparable to the exact solution of the initial‐boundary value problem at the given grid point

ISSN:0029-5981    

DOI:10.1002/nme.1620361105

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis is the first of a two‐part paper on plate bending elements with shear effects included. This paper presents a new three‐node, nine‐d.o.f. triangular plate bending element valid for the analysis of thick to thin plates. The element, called DKMT, has a proper rank (contains no spurious zero‐energy modes), passes the patch test for thin and thick plates in an arbitrary mesh and is free of shear locking. Very good results have been obtained for thin and thick plates' by the element. An extended DKQ element for thick‐plate bending analysis is evaluated in

ISSN:0029-5981    

DOI:10.1002/nme.1620361106

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis is the second part of a two‐part paper on plate bending elements with shear effects included.This paper presents a new four‐node, 12‐d.o.f. quadrilateral plate bending element valid for the analysis of thick to thin plates. The element called DKMQ, has a proper rank (contains no spurious zero‐energy modes), passes the patch test for thin and thick plates in an arbitrary mesh and is free of shear locking. Very good results have been obtained for thin and thick plates by the element. An extended DKT element for thick‐plate bending analysis is evaluated in

ISSN:0029-5981    

DOI:10.1002/nme.1620361107

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe stress intensity factors for cracks in three‐dimensional, thermally stressed structures are computed by using the boundary element method. While many boundary and volume‐integral‐based formulations are available for the treatment of thermoelastic problems in solids, the present analysis is based on a recently developed boundary‐only formulation. The accuracy of the solutions in the present work is improved by using special elements at the crack front that accurately model the variation of displacement, temperature fields and singularity of traction, flux

ISSN:0029-5981    

DOI:10.1002/nme.1620361108

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractHigh‐order elements are an option for providing an enhanced rate of convergence. However, it is not widely known that if a high‐order element based on a mapping from a master‐element space is distorted by displacing one of the side nodes slightly from the traditional midside position then the rate of convergence drops one order. The proof for a three‐node element in one dimension has been given previously. Here, a numerical demonstration is presented to show how quickly the rate is lost as the second node is moved from the midpoint. For a six‐node triangular element, a similar convergence study is performed in two dimensions in which one of the side nodes is moved off centre along a straight line joining the vertices of the triangle. Again, a loss in the order of convergence is shown although the loss is only apparent for sufficiently small element size. To prevent this drop in the rate of convergence as a side node is displaced, a procedure is given for developing the element stiffness matrix without formulating element basis functions. For the six‐node triangle, a complete quadratic representation is retained, but at the expense of element compatibility between nodes. The numerical investigation shows that convergence appears to be retained but that the error associated with the incompatibility is greater than the error obtained with the use of distorted isoparametric elements. The results of this study are particularly appropriate for domains with curved boundaries and for non‐linear problems in which node positions are updated according to the deform

ISSN:0029-5981    

DOI:10.1002/nme.1620361109

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA convex, multilevel decomposition algorithm is proposed in this paper for the solution of static analysis problems involving non‐monotone, possibly multivalued laws. The theory is developed here for a model structure with non‐monotone interface or boundary conditions. First the non‐monotone laws are written in the form of a difference of two monotone functions. Under this decomposition, the non‐linear elastostatic analysis problem is equivalent to a system of convex variational inequalities and to non‐convex min‐min problems for appropriately defined Lagrangian functions. The solution(s) of each one of the aforementioned problems describe the position(s) of static equilibrium of the considered structure. In this paper a multilevel optimization scheme, due to Auchmuty,1is used for the numerical solution of the problem. The most interesting feature of this method, from the computational mechanics' standpoint, is the fact that each one of the subproblems involved in the multilevel algorithm is a convex optimization problem, or, in terms of mechanics, an appropriately modified monotone ‘unilateral’ problem. Thus, existing algorithms and software can be used for the numerical solution with minor modifications. Numerical results concerning the calculation of elastic and rigid stamp problems and of material inclusion problems with delamination and non‐monotone stick‐slip frictional effects il

ISSN:0029-5981    

DOI:10.1002/nme.1620361110

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620361101

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY