On the Derivation of Shell Theories by Direct Approach

1974 ◽  
Vol 41 (1) ◽  
pp. 173-176 ◽  
Author(s):  
A. E. Green ◽  
P. M. Naghdi
Keyword(s):  
General Theory ◽  
Direct Approach ◽  
Recent Developments ◽  
Cosserat Surface ◽  
Theory Of Shells

A constrained theory of shells by a direct approach, based on a general theory of a Cosserat surface, is derived and its relation to other recent developments obtained by direct procedures is indicated.

On thermal effects in the theory of shells

1979 ◽  
Vol 365 (1721) ◽  
pp. 161-190 ◽  
Keyword(s):  
Thermal Effects ◽  
Second Law Of Thermodynamics ◽  
Middle Surface ◽  
Material Point ◽  
Direct Approach ◽  
Temperature Fields ◽  
Elastic Plates ◽  
Temperature Changes ◽  
Cosserat Surface ◽  
Theory Of Shells

This paper is concerned with thermomechanics of thin shells by a direct approach based on the theory of a Cosserat surface comprising a two-dimensional surface and a single director attached to every point of the surface. In almost all previous developments of the thermo-mechanical theory of shells by direct approach, only one temperature field has been admitted. This allows for the characterization of temperature changes along some reference surface, such as the middle surface, of the (three-dimensional) shell-like body, but not for temperature changes along the shell thickness. A main purpose of the present study is to incorporate the latter effect into the theory; and, in the context of the theory of a Cosserat surface, this is achieved by a recent approach to thermomechanics (Green & Naghdi 1977) which provides a natural way of introducing two (or more) temperature fields at each material point of the surface. Apart from full discussion of thermomechanics of shells and thermodynamical restrictions arising from the second law of thermodynamics for shells, attention is given to a discussion of symmetries (including material symmetries) and thermal effects in the nonlinear theory of elastic shells with detailed discussion of the linear theory of elastic plates.

On the General Theory of Thin Shells

1950 ◽  
Vol 17 (4) ◽  
pp. 396-398
Author(s):  
W. R. Osgood ◽  
J. A. Joseph
Keyword(s):  
General Theory ◽  
Thin Shells ◽  
Theory Of Shells

Abstract In the general theory of shells expressions are obtained for the changes of curvature and the twist, and revisions are introduced in the equations of equilibrium.

scholarly journals From mathematical axioms to mathematical rules of proof: recent developments in proof analysis

2019 ◽  
Vol 377 (2140) ◽  
pp. 20180037 ◽  
Author(s):  
Sara Negri ◽  
Jan von Plato
Keyword(s):  
General Theory ◽  
Simple Proof ◽  
Proof Theory ◽  
Theme Issue ◽  
Short Text ◽  
David Hilbert ◽  
Proof Analysis ◽  
Recent Developments ◽  
Mathematical Problems

A short text in the hand of David Hilbert, discovered in Göttingen a century after it was written, shows that Hilbert had considered adding a 24th problem to his famous list of mathematical problems of the year 1900. The problem he had in mind was to find criteria for the simplicity of proofs and to develop a general theory of methods of proof in mathematics. In this paper, it is discussed to what extent proof theory has achieved the second of these aims. This article is part of the theme issue ‘The notion of ‘simple proof’ - Hilbert's 24th problem’.

A General Theory of Shells and the Complementary Potentials

1986 ◽  
Vol 53 (4) ◽  
pp. 881-885 ◽  
Author(s):  
G. Wempner
Keyword(s):  
Finite Elements ◽  
General Theory ◽  
Linear Function ◽  
Transverse Shear ◽  
Surface Deformation ◽  
Reference Surface ◽  
Shear Deformations ◽  
Theory Of Shells

This theory incorporates the attributes which are essential to the approximation of shells by finite elements. It is limited only by one assumption: Displacement is a linear function of distance along the normal to a reference surface. Deformation is decomposed into rotation and strain; the rotation carries elements of the reference surface to the same surface in any subsequent state. Transverse-shear deformations accommodate simple elements. The theory is couched in the potential Pv and in the complementary potential Pc; these have the property, Pv + Pc= 0 for all admissible (equilibrated) states. The theory is also cast in the complementary functional P¯c of stress and displacement, and the functional P¯v of displacement, strain and stress; P¯c and P¯v are akin to the functionals of Hellinger-Reissner and Hu-Washizu. These alternate functionals provide the means to develop various hybrid elements.

A general theory of a Cosserat surface

1965 ◽  
Vol 20 (4) ◽  
pp. 287-308 ◽  
Author(s):  
A. E. Green ◽  
P. M. Naghdi ◽  
W. L. Wainwright
Keyword(s):  
General Theory ◽  
Cosserat Surface

From Psychological Science to the Psychological Humanities: Building a General Theory of Subjectivity

2017 ◽  
Vol 21 (4) ◽  
pp. 281-291 ◽  
Author(s):  
Thomas Teo
Keyword(s):  
General Theory ◽  
Science And Technology Studies ◽  
Postcolonial Studies ◽  
Psychological Science ◽  
The Arts ◽  
Social Theories ◽  
Recent Developments ◽  
Genetic Science ◽  
The Aesthetic ◽  
Theories Of Subjectivity

The development of psychology as a science and the struggle for scientific recognition has disrupted the need to interrogate the discipline and the profession from the perspective of the humanities, the arts, and the concept-driven social sciences. This article suggests that some of the humanities contribute significantly to an understanding of human subjectivity, arguably a core topic within psychology. The article outlines the relevance of the psychological humanities by reclaiming subjectivity as a core topic for general psychology that is grounded in theoretical reconstruction, integration, and advancement. The argument relies on a variety of disciplines to achieve a deeper understanding of subjectivity: Philosophy provides conceptual clarifications and guidelines for integrating research on subjectivity; history reconstructs the movement of subjectivity and its subdivisions; political and social theories debate the process of subjectification; indigenous, cultural, and postcolonial studies show that Western theories of subjectivity cannot be applied habitually to contexts outside of the center; the arts corroborate the idea that subjective imagination is core to the aesthetic project; and science and technology studies point to recent developments in genetic science and information technology, advances that necessitate the consideration of significant changes in subjectivity. The implications of the psychological humanities as an important, justifiable tradition in psychology and for a general theory of subjectivity are discussed.

Thermostatics of an elastic Cosserat plate containing a circular hole

1971 ◽  
Vol 70 (1) ◽  
pp. 169-174 ◽  
Author(s):  
İ. T. Gürgöze
Keyword(s):  
Temperature Gradient ◽  
General Theory ◽  
Circular Hole ◽  
Thermal Stresses ◽  
Plate Theory ◽  
The Other ◽  
Uniform Temperature ◽  
Classical Plate Theory ◽  
Cosserat Surface ◽  
Limiting Case

AbstractIn this paper, the general theory of a Cosserat surface given by Green, Naghdi and Wainwright(1), has been applied to the problem of a thermo-elastic Cosserat plate containing a circular hole of radius a. We assume that the major surfaces of the plate and the boundary of the hole are thermally insulated and that a uniform temperature gradient τ exists at infinity. In the limiting case, when h/a → 0, where h is the thickness of the plate, the thermal stresses at the circular hole reduce to those obtained by Florence and Goodier (4), by means of the classical plate theory. Results for the other limiting case h/a → ∞ are also given.

Medium as a basic concept of sociology: contributions from systems theory

2006 ◽  
Vol 45 (4) ◽  
pp. 539-560 ◽  
Author(s):  
Domenico Tosini
Keyword(s):  
General Theory ◽  
Conceptual Framework ◽  
Special Reference ◽  
Systems Theory ◽  
Social Theory ◽  
Basic Concept ◽  
Social Systems ◽  
Sociological Analysis ◽  
Recent Developments

The main purpose of this article is to present the fundamental concepts of a theory of social systems, with special reference to the concepts of medium and form, and their application in sociology. By challenging the indifference and opposition shown by most contemporary sociologists to the ontological and theoretical questions of social theory (e.g. in the case of micro-sociologists’ aversion to Parsons), systems theory has, from the beginning, represented an attempt at an analysis focusing on the fundamental concepts (and on their coherent relations) of a general theory of society. Ignoring the elaboration of these concepts may be tantamount to reducing sociology to countless collections of facts of a limited informative value. Indeed, only an adequate conceptual framework will suffice. Certain recent developments in systems theory offer useful tools. Some of these developments are illustrated in this article, which marshals a network of concepts, each dealing with specific aspects relating to sociological analysis.

scholarly journals Recent Developments in Economic Theory and their Application to Insurance

1963 ◽  
Vol 2 (3) ◽  
pp. 322-341 ◽  
Author(s):  
Karl Borch
Keyword(s):  
Economic Theory ◽  
General Theory ◽  
Rapid Development ◽  
Supply And Demand ◽  
Scientific Basis ◽  
Economic Activities ◽  
Apparent Paradox ◽  
Goods And Services ◽  
Actuarial Mathematics ◽  
Recent Developments

The very title of this paper may cause some surprise, since economic theory so far has found virtually no application in insurance. Insurance is obviously an economic activity, and it is indeed strange that general economic theory should seem inapplicable to insurance.This apparent paradox may to some extent be explained by the historic development. Actuarial mathematics and the essential scientific basis of insurance were developed into a self-contained and fairly complete theory long before economists could claim the name of science for their subject. Actuaries and other insurance people may from time to time have turned to economic theory for help on their problems. In most cases they must have turned away in disappointment, being convinced that actuarial mathematics was well ahead of general economic theory.The last point is brought out clearly in a paper on the safety loading of insurance premiums which Tauber (19) presented at the Sixth International Congress of Actuaries in Vienna in 1909. In the introduction to this paper Tauber seems to consider risk bearing as a service and appears to assume that it like all other goods and services must have a price, determined by supply and demand in the market. Tauber did not develop this idea, apparently because the economic theory of his time was utterly unable to analyse the problem. That his approach was sound, and that the problem can be formulated and solved by modern economic theory, has been indicated in a previous paper (6).During the last thirty years there has been an extremely rapid development in economic theory. The “General Theory” of Keynes (12) which appeared in 1936, is usually considered to have caused a revolution in economic theory. However, this “revolution” has not lead to any developments which seem to have an immediate application in insurance. Post- and pre-Keynesian economics are equally powerless when confronted with the problem which Tauber tried to formulate. It is therefore premature to conclude from the title of this paper that economic theory has caught up with actuarial science, and that the theory of insurance has now become a part of a general theory comprising all economic activities.

Political Studies and the Contextual Turn: A Methodological/Normative Critique

2008 ◽  
Vol 56 (3) ◽  
pp. 584-603 ◽  
Author(s):  
Stephanie Lawson
Keyword(s):  
General Theory ◽  
General Point ◽  
General Development ◽  
Cultural Contexts ◽  
Political Analysis ◽  
Political Studies ◽  
Recent Developments ◽  
Key Aspects ◽  
Traditional Approaches ◽  
Narrative Account

Recent developments in political studies have seen much greater attention paid to ideas about history, culture and associated notions of context. This reflects, at least in part, a dissatisfaction with positivism and modernist empiricism and an interest in alternative methodologies and epistemologies. As part of this general development, the language of non-traditional approaches to politics has become replete with the language of contextualism, emphasising specificity, particularity and contingency. There is certainly much to be welcomed in the turn away from an ahistorical, objectivist and materialist positivism towards more nuanced approaches. Contingency attends virtually every development in human affairs, making predictability a very inexact science. And facts simply do not speak for themselves. They are made to speak in different ways by different people located in varying positions of power and influence and with particular agendas or projects. Thus the notion that adequate explanations of political practices and actions can be obtained in the absence of a narrative account of the beliefs that sustain them is indeed difficult to defend. Even so, critiques of objectivist approaches which substitute specific historical and/or cultural contexts for universals may turn out simply to be using another method of objectification. Furthermore, far from providing a critique of domination, I argue that key aspects of the contextualist turn actually reinforce it. So while agreeing with the general point that attention to context, both historical and cultural, is essential to good political analysis, this article is nonetheless critical of key aspects of contextual approaches. In addition, it highlights certain difficulties in devising a general theory of context due to some important contradictions between cultural and historical versions of methodological contextualism which have so far gone unnoticed.

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