摘要:

AbstractFormulae are derived for exact inextensional bending solutions for arbitrary quadrilateral shell finite elements of bilinear parametric representation. It is found that the polynomial degree of parametric representation of the rectangular components of displacement requires to be at least cubic in order to describe any inextensional bending modes.

ISSN:0029-5981    

DOI:10.1002/nme.1620200802

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractStiffness matrices for three‐dimensional beam elements that include the effect of warping restraint on elastic torsional response have been derived by various investigators. Using one of the available stiffness matrices and assuming that the warping boundary conditions can be specified on a member‐by‐member basis, an elastic ‘warping’ support is introduced to represent conditions of partial warping restraint at the member ends. The concept of a ‘warping indicator’ is then introduced to facilitate use of warping springs. Following this, static condensation is used to eliminate the restrained warping degrees‐of‐freedom. The condensed stiffness matrices for the elements can then be assembled to yield a global stiffness matrix. In the global matrix, continuous warping degrees‐of‐freedom, that is, those internal to a member represented by several elements, are expressed in local co‐ordinates. The remainder are expressed in global co‐ordinates. In the force recovery phase, it is shown that an ‘indirect’ method yields most accurate results for the bimoment and warping torsion when the twist function is represented by a cubic polynomial. Solutions to examples of linear elastic analysis are compared with well‐known analytical solutions to demonstrat

ISSN:0029-5981    

DOI:10.1002/nme.1620200803

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA simply‐supported rhombic plate with obtuse angle equal to 150 degrees is analysed by the finite element method, using both theh‐version and the newerp‐version. Results obtained using the computer code CONE (C1‐continuity) for plate bending problems are compared with theoretical predictions and with computational results reported in the literature. If accuracy in terms of the number of degrees‐of‐freedom is used as a criterion, the solutions presented here are the most efficient that have been publis

ISSN:0029-5981    

DOI:10.1002/nme.1620200804

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe paper describes the development of an eight‐node plane rectangular finite dynamic element and presents detailed descriptions of the associated numerical formulation involving the higher order dynamic correction terms pertaining to the related stiffness and inertia matrices. Numerical test results of free vibration analyses are presented in detail for the newly developed eight‐node element and also the corresponding four‐node element in order to make a clear comparison of the relative efficiencies of the corresponding finite element and dynamic element procedures. Such results indicate a superior pattern of solution convergence of the presently developed dynamic el

ISSN:0029-5981    

DOI:10.1002/nme.1620200805

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA computational strategy for the evaluation of delamination stresses in multilayered fibre‐reinforced composites is presented. The approach uses special inter‐laminar shear elements and an iterative procedure in the calculation of out‐of‐plane stresses. Both regular and singular elements for the free edge are presented. The solutions are carried on by switching between direct matrix solution methods of small systems of equations and an iterative conjugate gradient method. The proposed discretization avoids ill‐conditioning problems, modelling difficulties and large computational cost associated with three‐dimensional analysis of delamination of holes, cut‐outs, joints and areas of complex

ISSN:0029-5981    

DOI:10.1002/nme.1620200806

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA general, consistent and accurate procedure for obtaining difference equations from differential equations is presented and illustrated by several examples. The procedure is an extension of the integral method and incorporates what is known of the solution to the differential equation in the formation of the corresponding difference equation. For the same accuracy, large increases in grid size over that obtained by standard Taylor's series approximations are possible. Both boundary‐value and initial‐value problems are trea

ISSN:0029-5981    

DOI:10.1002/nme.1620200807

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe standard isoparametric transformation for finite element analysis is shown to be only a special case of a more general transformation which allows for flexibility in locating side and interior element nodes. Side nodes positioned at the same relative distance from corner nodes in both local and global space, and interior nodes positioned such that they do not affect the Jacobian of the co‐ordinate transformation, provide improved accuracy over nodes positioned locally without regard for the global configuration. This concept is demonstrated in the context of two‐dimensional quadratic quadrilateral isoparametrics, but is also applicable to higher orders and dimensions. In the test cases examined, the new formulation provides a reduction in error of up to three orders of magnitude and also provides accurate solutions for nodal placements which are not allowed using the standard transformati

ISSN:0029-5981    

DOI:10.1002/nme.1620200808

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA weighting function by which the mass matrix is made to be diagonal is deduced on the two‐dimensional simplex element. Adopting the weighted residual method with the deduced weighting function for spatial domain and the two‐step Lax–Wendroff method for time differentiation, the two‐dimensinoal tidal flow in a model basin is calculated by means of the explicit finite element method. The water mass transport integrated over one tidal period at some cross‐sections of the basin is also estimated, in order to verify the water mass conservation. It is found that the water mass is nearly conserved in the present method, although the usual lumped mass matrix technique fails to conserve.The present explicit finite element method with the conservative form of governing equations is also investigated and the water mass conservation is found to be a little more improved in this case than in the case of non‐conservative forms. Application to a real bay indicates that the method with the conservative form of equations could be used for the estimation of tidal re

ISSN:0029-5981    

DOI:10.1002/nme.1620200809

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractIn this work, the plastic stress–strain relation and the incremental elastoplastic stiffness matrix for materials obeying the principal stress yield criterion are derived in the context of the associated theory of plasticity. Particular attention is paid to the treatment of the singularity conditions associated with this yield criterio

ISSN:0029-5981    

DOI:10.1002/nme.1620200810

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractIt is demonstrated that the residual in a compatible (displacement) finite element solution can be partitioned into local self‐equilibrating systems on each element. An aposteriorierror analysis is then based on a complementary approach and examples indicate that the guaranteed upper bound on the energy of the error is preserve

ISSN:0029-5981    

DOI:10.1002/nme.1620200811

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY