摘要:

AbstractFür die Elemente der Inversen von Bandmatrizen mit konstanten Elementen in den Schrägzeilen wird unter zusätzlichen Voraussetzungen eine Abschätzung hergeleitet, die vom Format der Matrizen unabhängig ist. Diese Abschätzung wird benutzt, um für formale Reihenlösungen partieller Differentialgleichungen mit mehrgliedrigem Hauptbestandteil die Konvergenz nachz

ISSN:0044-2267    

DOI:10.1002/zamm.19800601002

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractEs ist üblich, Diskretisierungsfehler durch den Defekt in Gleichungen höherer Genauigkeit und die Lösung benachbarter Gleichungen zu schätzen. Wir zeigen, wie sich diese Techniken aus der Idee des Verfahrens der Nachiteration ableiten lassen, und geben ein Extrapolationsverfahren für lokale Diskretisierungsfehler in Gleichungen zweiter Ar

ISSN:0044-2267    

DOI:10.1002/zamm.19800601003

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractWe consider the construction of certain families of direct fourth‐order methods based on four function‐evaluations for the general second‐order initial‐value problem: y″ = f(x, y, y′), y(x0) = A, y′(x0) = B. We obtain these families of methods from the set of conditions sufficient for order four (see Hairer and Wanner [3], Table 2). We obtain a four‐parameter family of methods in the general case, whereas in each of the four special cases we obtain a three‐parameter family of methods. The classical Runge‐Kutta‐Nyström method is a member of the family of methods in one of the special cases. While determining particular methods from these families we require that when these methods are applied to the linear differential equation y″ ‐(α + β)y′ + αβy = 0, the measure of the relative error F, introduced by Rutishauser [5], should have the properties that (i) when α = −β, F should not deteriorate, (ii) when α = –β, F should be least. It was pointed out by Rutishauser [5] that the classical Runge‐Kutta‐Nyström method lacks these properties; it is interesting to note that by a suitable adjustment of some of the parameters, we obtain a new Runge‐Kutta‐Nyström type method which possesses the above two desirable properties. Some particular methods are listed and illustrated by numerical examples; it will be observed from the numerical examples that all these methods perform far better than the classical Ru

ISSN:0044-2267    

DOI:10.1002/zamm.19800601004

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractExplicit, m‐stage Runge‐Kutta methods are derived for which the maximal stable integration step per right hand side evaluation is proportional to m when applied to semi‐discrete parabolic initial‐boundary value problems. The internal stability behaviour of these methods is compared with that of similar Runge‐Kutta methods proposed in the literature. Both by analysis and by numerical experiments we show that the value of m in the schemes proposed in this paper is not restricted by internal inst

ISSN:0044-2267    

DOI:10.1002/zamm.19800601005

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractDie Strömung eines magnetfeldfreien Plasmas wird durch hydrodynamische Gleichungen beschrieben. Unter geeigneten Anfangs‐ und Randbedingungen werden Existenz‐ und Einzigkeitsaussagen gem

ISSN:0044-2267    

DOI:10.1002/zamm.19800601006

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractUnsteady flow of a binary fluid past an infinite, porous, vertical plate has been analysed on taking into account (1) constant suction velocity (2) oscillating free stream (3) constant heat flux at the plate (4) presence of a foreign mass. Approximate solutions to coupled non‐linear equations are derived. Effects of various parameters like Gr (Grashof number), Gm (modified Grashof number), E (Eckert number), Sc (Schmidt number) and ω (frequency) on the velocity and temperature are discuss

ISSN:0044-2267    

DOI:10.1002/zamm.19800601007

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractBy including the length, shape and elastic moduli as additional parameters the problem of elastic stability acquires a new formulation permitting us to establish stability criteria independent of the usual manipulation of the Rayleigh quotient, or of the Rayleigh‐Ritz, or Galerkin schemes. Moreover, this technique permits us to establish two‐sided estimates concerning the values of critical loads in a manner much simpler than the Weinstein or Fichera procedu

ISSN:0044-2267    

DOI:10.1002/zamm.19800601008

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractAnsätze aus der Literatur zur Beschreibung aller Verfestigungstypen werden in eine einheitliche Standardformulierung (8) gebracht. Diese ist der Sonderfall eines allgemeinen Vorschlages des Autors für inelastisches Material [3]. Die Auswahl der Verfestigungsgesetze wird auf Folgefließflächen des Types der quadratischen Formen beschränkt. Die Standardformulierung wird in der Mehrzahl allein durch Umformung, in speziellen Fällen durch sinnvolle Approximationen err

ISSN:0044-2267    

DOI:10.1002/zamm.19800601009

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractIn the present paper, we consider the problem of thermal stresses in an infinite plate with two circular inclusions, which are of different materials, under uniform heat flow. The analysis is developed on the basis of the Airy's stress function in the generalized plane stress and by applying bipolar coordinates. Here the plate is supposed to be insulated and the boundaries are free from the traction. Numerical calculations are worked out in some detail in order to clarify the effects of inclusions.

ISSN:0044-2267    

DOI:10.1002/zamm.19800601010

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractIn this investigation an analytical procedure for the non‐linear elastic analysis of a cantilever circular beam subjected to a concentrated co‐planar force at its free end is presented. According to this method the non‐linear differential equations, describing the equilibrium of the deformed beam, were decoupled and a closed‐form solution under the form of elliptic integrals was o

ISSN:0044-2267    

DOI:10.1002/zamm.19800601011

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY