摘要:

AbstractThe extended interior penalty function formulation is implemented. A rational method for determining the transition between the interior and extended parts is set forth. The formulation includes a straightforward method for avoiding design points with some negative components, which are physically meaningless in structural analysis. The technique, when extended to problems involving parametric constraints, can facilitate closed form integration of the penalty terms over the most important parts of the parameter interval. The method lends itself well to the use of approximation concepts, such as design variable linking, constraint deletion and Taylor series expansions of response quantities in terms of design variables.Examples demonstrating the algorithm, in the context of planar orthogonal frames subjected to ground motion, are included.

ISSN:0029-5981    

DOI:10.1002/nme.1620100102

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractQuadratic isoparametric elements which embody the inverse square root singularity are used in the calculation of stress intensity factors of elastic fracture mechanics. Examples of the plane eight noded isoparametric element show that it has the same singularity as other special crack tip elements, and still includes the constant strain and rigid body motion modes. Application to three‐dimensional analysis is also explored. Stress intensity factors are calculated for mechanical and thermal loads for a number of plane strain and three‐dimensional probl

ISSN:0029-5981    

DOI:10.1002/nme.1620100103

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractA finite element formulation is presented to study the non‐linear buckling of arbitrary shallow elastic thin shells with general boundary conditions and subjected to conservative pressure loading. Pre and post buckling behaviour of a large number of shallow and semi deep doubly curved shells is studied in detail. Unsymmetrical bifurcation paths of a shallow spherical shell subjected to uniform inward pressure are also investigate

ISSN:0029-5981    

DOI:10.1002/nme.1620100104

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractA method is presented to calculate the eigenvalues of the Helmholtz equation Δ2ø +k2ø = 0 in a two‐dimensional area when ø vanishes on the boundary. The method is based on an integral equation, which can be easily solved numerically. Results obtained for circular and rectangular geometries are also given and compared to the exact v

ISSN:0029-5981    

DOI:10.1002/nme.1620100105

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractAn ‘Extended Matrix Transfer Method’ is presented which has an automatic root search capability that can be guaranteed to determine all the roots of the problem with the exception of those roots lying within prescribed tolerance bandwidths.The power and generality of the method is demonstrated by application to a specially synthesized prob

ISSN:0029-5981    

DOI:10.1002/nme.1620100106

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThis paper presents the results of an aeroelastic optimization study. In this study the weight of a large aspect ratio panel immersed in high Mach number supersonic flow is minimized subject to the requirement that a critical aeroelastic parameter for flutter be held within specified limits. A refined finite element technique is used to model the panel flutter equilibrium equations, equations which act as constraints on the design search. The optimization mechanism itself is studied and discussed to provide qualitative results which may be useful to the solution of other aeroelastic optimization problems. The numerical results of this investigation are compared to converged numerical results to illustrate finite element accuracy. The results of the study show that the weight savings and material distribution found with an effective finite element model are comparable to those found by more complicated numerical methods.

ISSN:0029-5981    

DOI:10.1002/nme.1620100107

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe equations for the meridional through‐flow in a turbomachine are formulated as a quasi‐harmonic non‐linear equation. This equation is then solved iteratively by the finite element method and in order to obtain convergence an under‐relaxation factor has to be introduced. Comparisons with experimental results in single and multistage axial compressors show very good agreement. The finite element method is thus shown to be an efficient tool for this type of

ISSN:0029-5981    

DOI:10.1002/nme.1620100108

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThis paper presents theory and examples of partial approximation as a modification of the displacement method in the finite element analysis. This method requires different shape functions for different terms in the potential energy expression to curtail the processes in the standard displacement method. Explanation of the theory is given by use of a simple example for Poisson's equation. It can also be effectively utilized to give mathematical foundation to some finite element models based on physical reasonings, such as Melosh's rectangular element for plate bending and beam element approximation of circular arches.

ISSN:0029-5981    

DOI:10.1002/nme.1620100109

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThis paper describes a procedure for the calculation of branch flows in a directed network in which the node‐to‐node flows are prescribed.The node‐to‐node paths of the network are enumerated using a combinatorial process. Procedures based on the path list are used to allocate the node‐to‐node flows to the alternative paths of the network according to Wardrop's first principle. The calculation, although necessarily iterative, is rapidly convergent.The method has been implemented as a computer program and the results obtained for a typical network are discussed.A linear relationship between branch potential and branch flow has been used, but the method can be extended to piece‐wise linear and non‐linea

ISSN:0029-5981    

DOI:10.1002/nme.1620100110

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractIn the present paper it is shown how to achieve special interpolation functions that can be applied to the finite element method, least squares methods or other related numerical techniques. We call these functions sequential interpolation functions since one of the main characteristics of this technique refers to the fact that the refinement of the solution does not require the redefinition of the interpolation funtions used in a previous step, as the case for instance in the FEM.The present theory and the FEM using an isoparametric element were compared for a plane stress problem. The results show that both have the same degree of accuracy. The choice of the sequential interpolation functions is easier than those used in the finite element formulation and the computer time was reduced by about 50 per cent.

ISSN:0029-5981    

DOI:10.1002/nme.1620100111

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY