摘要:

AbstractPlane stress structures of any shape and boundary conditions are simulated by finite element models with homogeneous stress and strain fields in each element. Besides the given live loads, dead loads (such as self‐weight) depending on the unknown thickness distribution are allowed for. Possible practical requirements on geometry (minimum thickness, areas of equal thickness, areas of thickness variation in a prescribed way) are taken into account. Yield surfaces of the materials are piecewise linearized. On this basis the minimum weight design problem is formulated in terms of a linear program. This program is dualized and the pair of dual programming problems is discussed. The mechanical interpretation leads to the generalization of some known limit design theory results.Some numerical examples are given at the en

ISSN:0029-5981    

DOI:10.1002/nme.1620040402

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractTwo FORTRAN IV subroutines that generate the stiffness, mass and geometric matrices for plate bending and plane stress elements using displacement models are described. The elements can be of either rectangular or triangular shape with anisotropic properties together with a linear variation in thickness. Although such a formulation is straightforward theoretically, emphasis has been placed on the programming technique where the amount of algebra involved in the matrix manipulations is avoided. Exact integration is automatically performed since a closed‐form solution con be obtaine

ISSN:0029-5981    

DOI:10.1002/nme.1620040403

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractRecent published research on structural optimization subject to dynamic constraints is reviewed, and suggestions for further work are offered. Both methods for handling constraints on natural frequencies and methods for treating the more difficult constraints on quantities directly related to the dynamic response are discussed. Computational aspects are emphasized throughout.

ISSN:0029-5981    

DOI:10.1002/nme.1620040404

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe weighted residual and finite element methods are combined to yield a numerical solution scheme for the linerizedBGKBoltzmann equation which describes the dynamic behaviour of gases in all flow régimes ranging from the free molecular to the continuum régime.The potential of the proposed method is illustrated by application to the problem of cylindrical Couette flow. Numerical results are compared with alternate numerical solutions and experimental dat

ISSN:0029-5981    

DOI:10.1002/nme.1620040405

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThis paper presents a method of numerical solution of boundary value problems governed by a set of ordinary differential equations. The highest derivative is chosen as the unknown function. Governing equations are transformed into a set of integral equations. The kernels of integral equations turn out to be influence functions for deflection and/or bending moments of a corresponding beam, and can, therefore, be computed using well‐known methods of structural analysis. Finally, the unknown function (highest derivative) is approximated in a defined manner and the solution is obtained through numerical integratio

ISSN:0029-5981    

DOI:10.1002/nme.1620040406

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe method presented in Part I of this paper1is extended to problems governed by a system of partial differential equations. The basic clarity and simplicity of the method is preserved.The domain of integration is covered by a net of orthogonal (not necessarily equidistant) straight lines. Choosing again highest derivatives with respect to each of the co‐ordinates as unknowns, it is possible to reduce the problem to a system of integral equations along the lines of the adopted net.The subsequent procedure is basically the same as in Part I. The results prove to be of remarkable accuracy even for very coarse net

ISSN:0029-5981    

DOI:10.1002/nme.1620040407

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe convergence and accuracy characteristics of two commonly used finite difference schemes, namely the central and the upwind difference, are compared with a scheme recently proposed by Spalding. For a simple two‐dimensional problem with conduction and convection, it is shown that the scheme proposed by Spalding is preferable choice both from the point of view of accuracy and that of the convergence. The extension of the conclusion to a general case must await further substantiatio

ISSN:0029-5981    

DOI:10.1002/nme.1620040408

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractIt is shown that the upwind difference scheme of formulating differential expressions, in problems involving transport by simultaneous convection and diffusion, is superior to the central differences scheme, when the local Peclet number of the grid is large. Even better schemes are derived and discussed. It is pointed out that the best finite differences analogues are found by approximating differential expressions as a whole, and that simple (e.g. one‐dimensional) exact solutions form a useful, legitimate and independent source of these optimum algebraic formula

ISSN:0029-5981    

DOI:10.1002/nme.1620040409

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe task of optimum design of structures is one that involves non‐linear Programming. This is particularly the case when deflection as well as stress limitation are imposed as design criteria. In this paper a Fundamental approach is presented for the minimum weight design of statically indeterminate elastic structure subject to non‐linear deflection and stress constrains.The matrix force method is adopted to formulate the problem. The constraints thus derived prove to have separable variables and therefore can be linearized in a piecewise manner. The computation aspects concerning the restricted entry in to the simplex tableau are briefly discussed and illustrative examples are given to verify the validity of the proposed met

ISSN:0029-5981    

DOI:10.1002/nme.1620040410

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractA procedure for the acceleration of convergence in non‐linear analysis using the modified Newton–Raphson problem is described. The process has been found useful in plasticity and large deformation studies and its application elsewhere can be envisa

ISSN:0029-5981    

DOI:10.1002/nme.1620040411

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY