摘要:

AbstractTreatment of the finite element method for an unbounded field problem was proposed by McDonald and Wexler in 1972. Their method is superior to others, because it can exclude the singularities of Green's functions. This paper explains the treatment of the method in our 1979 letter which had some revisions of McDonald and Wexler's and calculated the time‐harmonic field problems. Examples presented are electromagnetic fields of two‐dimensional tapers which are open‐ended. Electromagnetic waves propagate in the taper and radiate from the taper to free space. In this case, the exact solutions for radiation from tapers are not available because of the complicated shape, and so the finite element method is useful in solving these problems. Electromagnetic fields of tapers involving dielectric slabs are also calculated as examples of inhomogeneous pro

ISSN:0029-5981    

DOI:10.1002/nme.1620190202

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractA class of mixed finite element discretizations of the problem of limit analysis for plastic plates is analysed. For the discrete problem we discuss a linear programming approach based on linearization of the yield condition and a convex programming approach based on the exact Mises condition. Applying the method to rectangular plates with uniform load and concentrated loads we get improved and new results partly in disagreement with one of our references.

ISSN:0029-5981    

DOI:10.1002/nme.1620190203

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractIt is well known that one way to treat nonlinear periodic dynamical systems governed by ordinary differential equations is to find first the corresponding point mappings. This approach has many advantages but it has a main obstacle in that it is difficult to obtain the exact mapping except in very special cases. Presented in this paper is a procedure which allows us to determine the point mapping in a polynomial form up to any specific degree of accuracy. The procedure when applied to linear periodic systems reduces to the one proposed by Friedmannet al.22After presenting the algorithm for finding the point mappings, the method is applied to several problems in order to study the dynamical properties of the systems and to demonstrate the usefulness of the method.

ISSN:0029-5981    

DOI:10.1002/nme.1620190204

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe mini‐max dual method ia applied for solving the material selection structural optimization problems. A somewhat general objective function is introduced to consider structural weight and material cost simultaneously. It is expressed by the sum of scaled structural weight and material cost. The present formulation can yield minimum cost and minimum weight designs as two distinct special cases. It is shown that practically useful intermediate optimal designs can exist between the two extremes. Only truss structures are considered as a representative example. One numerical example is provided to illustrate the change in optimal material distribution when various objective functions are employed. A particular advantage in using the dual method for the material selection problem is also describe

ISSN:0029-5981    

DOI:10.1002/nme.1620190205

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractA shear‐flexible finite element is employed to investigate the transient response of isotropic, orthotropic and layered anisotropic composite plates. Numerical convergence and stability of the element is established using Newmark's direct integration technique. Numerical results for deflections and stresses are presented for rectangular plates under various boundary conditions and loadings. The parametric effects of the time step, finite element mesh, lamination scheme and orthotropy on the transient response are investigated. The present results agree very closely with the results available in the literature for isotropic plates, and the results for composite plates should serve as bench marks for future comparisons by other investigator

ISSN:0029-5981    

DOI:10.1002/nme.1620190206

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractProcedures for smoothing experimentally determined displacement fields are presented such that dynamic, non‐steady‐state metalworking processes can be analysed using the visioplasticity method. The procedure establishes a rectangular grid in which strain, strain rate and stress values may optionally be obtained at all points on the grid. The condition of material continuity is automatically satisfied by constraints during polynomial smoothing in position and time, using the Gram‐Schmidt orthogonalization technique. Examples are given of quasi‐static and dynamic plane strain upsetting ope

ISSN:0029-5981    

DOI:10.1002/nme.1620190207

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe finite element reduced scalar potential method of calculating magnetic fields is investigated by comparing it with a classical series method. Both methods are applied to two problems having a current band surrounding a ferromagnetic shell. The magnetic field distributions obtained by both methods are shown to be in generally good agreement.

ISSN:0029-5981    

DOI:10.1002/nme.1620190208

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe inclusion principle provides a qualitative characterization of the eigenvalues of a matrix. The principle has been shown to apply to systems described by a single Hermitian matrix, the most important of which being the real symmetric matrix. Self‐adjoint distributed systems, when discretized by either the classical Rayleigh‐Ritz method or by the finite element method, lead to algebraic eigenvalue problems described in terms of two real symmetric matrices. The algebraic eigenvalues problem derived by the classical Rayleigh‐Ritz method possesses the embedding feature required by the inclusion principle, but that derived by the finite element method in general does not. This paper demonstrates that the inclusion principle can be extended to discretized systems derived by the hierarchical finite element m

ISSN:0029-5981    

DOI:10.1002/nme.1620190209

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractBy using the finite element technique, stress intensity factors have been obtained for finite rectangular plates and the results have been given for varioush/a,W/aandL/Wratios. By using a three‐dimensional isoparametric element, the problem has been considered as a three‐dimensional one and the variation of stress intensity factor across the plate thickness has been found to be nonlin

ISSN:0029-5981    

DOI:10.1002/nme.1620190210

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620190211

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY