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Article
Publication date: 5 October 2012

Oscar A.G. de Suarez, Rodrigo Rossi and Cláudio R.A. da Silva

The purpose of this paper is to investigate the approximation performance of a family of piecewise rational polynomial shape functions, which are enriched by a set of…

Abstract

Purpose

The purpose of this paper is to investigate the approximation performance of a family of piecewise rational polynomial shape functions, which are enriched by a set of monomials of order p to obtain high order approximations. To numerically demonstrate the features of the enriched approximation some examples on the mechanical elastic response and free‐vibration of axisymmetric plates and shells are carried out.

Design/methodology/approach

The global approximation is based on a particular family of weight function, which is defined on the parametric domain of the element, ξ∈[−1,1], resulting in shape functions with compact support, which have regularity C0k,k=0,2,4… in the global domain Σ. The PU shape functions are enriched by a set of monomials of order p to obtain high order approximation spaces.

Findings

Based on the numerical results of elastic axisymmetric plates and shells, it is demonstrated that the proposed methodology produces satisfactory results in terms of keeping the ill‐conditioning of the system of equations under accepted levels. Comparisons are established between linear and Hermitian shape functions showing similar results. The observed results for the free‐vibration problem of plates and shells show the potential of the proposed approximation space.

Research limitations/implications

In this paper the formulation is limited to the modeling of axisymmetric plate and shell problems. However, it can be applied to model other problems where the high regularity of the approximation is required.

Originality/value

The paper presents an alternative approach to construct partition of unity shape functions based on a particular family of weight function.

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Article
Publication date: 7 August 2019

Marie Tirvaudey, Robin Bouclier, Jean-Charles Passieux and Ludovic Chamoin

The purpose of this paper is to further simplify the use of NURBS in industrial environnements. Although isogeometric analysis (IGA) has been the object of intensive…

Abstract

Purpose

The purpose of this paper is to further simplify the use of NURBS in industrial environnements. Although isogeometric analysis (IGA) has been the object of intensive studies over the past decade, its massive deployment in industrial analysis still appears quite marginal. This is partly due to its implementation, which is not straightforward with respect to the elementary structure of finite element (FE) codes. This often discourages industrial engineers from adopting isogeometric capabilities in their well-established simulation environment.

Design/methodology/approach

Based on the concept of Bézier and Lagrange extractions, a novel method is proposed to implement IGA from an existing industrial FE code with the aim of bringing human implementation effort to the minimal possible level (only using standard input-output of finite element analysis (FEA) codes, avoid code-dependent subroutines implementation). An approximate global link to go from Lagrange polynomials to non-uniform-rational-B-splines functions is formulated, which enables the whole FE routines to be untouched during the implementation.

Findings

As a result, only the linear system resolution step is bypassed: the resolution is performed in an external script after projecting the FE system onto the reduced, more regular and isogeometric basis. The novel procedure is successfully validated through different numerical experiments involving linear and nonlinear isogeometric analyses using the standard input/output of the industrial FE software Code_Aster.

Originality/value

A non-invasive implementation of IGA into FEA software is proposed. The whole FE routines are untouched during the novel implementation procedure; a focus is made on the IGA solution of nonlinear problems from existing FEA software; technical details on the approach are provided by means of illustrative examples and step-by-step implementation; the methodology is evaluated on a range of two- and three-dimensional elasticity and elastoplasticity benchmarks solved using the commercial software Code_Aster.

Details

Engineering Computations, vol. 37 no. 1
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 February 1987

Ghazi Abu‐Farsakh

A new triangular shell finite element ‘TNTE.1’ (Ten Node Triangular Element, Model 1) is presented. The formulation is based on Sanders' theory which involves the…

Abstract

A new triangular shell finite element ‘TNTE.1’ (Ten Node Triangular Element, Model 1) is presented. The formulation is based on Sanders' theory which involves the inclusion of the normal rotation Φn in the bending‐strain relations only. The element displacement functions are complete cubic polynomials for inplane displacements u and v. For out‐of‐plane displacement w, three new singular rational shape functions were added at the element corners. Thus a conforming triangular element with twenty seven degrees‐of‐freedom is obtained after eliminating the internal displacements by static condensation. The formulation of this element is new in that an integration technique is developed and applied to the element stiffness matrix and load vector. This technique is based on performing all the necessary integrations externally (i.e. outside the main computer program) and then modifying the formulation of the element matrices to account for this change. Hence, such a method allows the inclusion of higher‐order integration rules without any loss of economy, due to computer time, in the main program. Results using this element showed good agreement with other finite element and closed form solutions.

Details

Engineering Computations, vol. 4 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 February 2001

Suvranu De and Klaus‐Jürgen Bathe

Computational efficiency and reliability are clearly the most important requirements for the success of a meshless numerical technique. While the basic ideas of meshless…

Abstract

Computational efficiency and reliability are clearly the most important requirements for the success of a meshless numerical technique. While the basic ideas of meshless techniques are simple and well understood, an effective meshless method is very difficult to develop. The efficiency depends on the proper choice of the interpolation scheme, numerical integration procedures and techniques of imposing the boundary conditions. These issues in the context of the method of finite spheres are discussed.

Details

Engineering Computations, vol. 18 no. 1/2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 March 2000

Stephen Cope

This article assesses a rational-choice model of bureaucratic behaviour - the bureau-shaping model - as an explanation of budget-making in British local government. The…

Abstract

This article assesses a rational-choice model of bureaucratic behaviour - the bureau-shaping model - as an explanation of budget-making in British local government. The bureau-shaping model is essentially a reconstructed rational-choice model of bureaucratic behaviour in liberal democratic states, which emerged from critiques of its rival budgetmaximising model. The explanatory power of the bureau-shaping model is significantly superior to the budget-maximising model. However, the explanatory power of the bureaushaping model is limited because, as a supply-side model, it cannot explain how budgets are demanded and controlled by political sponsors, who in turn are constrained politically. Budgetary decision-making takes place in a political arena where both supply and demand are mediated; a supply-side model, at best, can explain only half the budget-story.

Details

Journal of Public Budgeting, Accounting & Financial Management, vol. 12 no. 4
Type: Research Article
ISSN: 1096-3367

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Book part
Publication date: 31 October 2014

Michael J. Thompson

To defend the thesis that the base-superstructure hypothesis central to Marxist theory is also central paradigm of the tradition of Critical Theory. This is in opposition…

Abstract

Purpose

To defend the thesis that the base-superstructure hypothesis central to Marxist theory is also central paradigm of the tradition of Critical Theory. This is in opposition to those who see this hypothesis as determinist and eliminating the possibilities for the autonomy of social action. In doing so, it is able to retard and atrophy the critical capacities of subjects.

Design/methodology/approach

Emphasis on the return to a structural-functionalist understanding of social processes that places this version of Critical Theory against the more domesticated forms that consider “discourse ethics” and an “ethic of recognition” as the normative research program for Critical Theory. Also, an analysis of the purpose and logic of functional arguments and their relation to Marx’s concept of “determination” is undertaken.

Findings

The essence of Critical Theory hinges upon the ways that social structures are able to deform and shape structures of consciousness of modern subjects to predispose them to forms of domination and to view the prevailing hierarchical structures of extractive domination as legitimate in some basic sense.

Research limitations/implications

The foundations of Critical Theory need to be rooted in a renewed understanding of the relation between social structure and forms of consciousness. This means a move beyond theories of social practices into the realm of social epistemology as well as the mechanisms of consciousness and their relation to ideology.

Originality/value

Few analyses of the relation between the base and the superstructure or material organization of society and the social-epistemological layer of consciousness delineate the mechanisms involved in shaping consciousness. I undertake an analysis that utilizes insights from the philosophy of mind such as the theory of intentionality as well as the sociological approach to values through Parsons.

Details

Mediations of Social Life in the 21st Century
Type: Book
ISBN: 978-1-78441-222-7

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Article
Publication date: 1 August 2002

T.J. Wetzel and H.E. Bez

This paper describes a method for the construction of rational polynomial paths that does not require the apriori specification of either vertices or weights. An algebra…

Abstract

This paper describes a method for the construction of rational polynomial paths that does not require the apriori specification of either vertices or weights. An algebra of rational paths is developed within which paths with positive weights can be generated from more elementary paths with the same property. Case studies demonstrate that the path algebra can provide a simple means of obtaining exact rational representations of paths defined in non‐rational terms.

Details

Engineering Computations, vol. 19 no. 5
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 30 December 2020

Jacob Agyemang, Kelum Jayasinghe, Pawan Adhikari, Abongeh Tunyi and Simon Carmel

This paper examines how a “quasi-formal” organisation in a developing country engages in informal means of organising and decision-making through the use of calculative measures.

Abstract

Purpose

This paper examines how a “quasi-formal” organisation in a developing country engages in informal means of organising and decision-making through the use of calculative measures.

Design/methodology/approach

The paper presents a case study of a large-scale indigenous manufacturing company in Ghana. Data for the study were collected through the use of semi-structured interviews conducted both onsite and off-site, supplemented by informal conversations and documentary analysis. Weber's notions of rationalities and traditionalism informed the analysis.

Findings

The paper advances knowledge about the practical day-to-day organisation of resources and the associated substantive rational calculative measures used for decision-making in quasi-formal organisations operating in a traditional setting. Instead of formal rational organisational mechanisms such as hierarchical organisational structures, production planning, labour controls and budgetary practices, the organisational mechanisms are found to be shaped by institutional and structural conditions which result from historical, sociocultural and traditional practices of Ghanaian society. These contextual substantive rational calculative measures consist of the native lineage system of inheritance, chieftaincy, trust and the power concealed within historically established sociocultural practices.

Originality/value

This paper is one of a few studies providing evidence of how local and traditional social practices contribute to shaping organising and decision-making activities in indigenous “quasi-formal” organisations. The paper extends our understanding of the nexus between “technical rational” calculative measures and the traditional culture and social practices prevailing in sub-Saharan Africa in general, and Ghana in particular.

Details

Accounting, Auditing & Accountability Journal, vol. 34 no. 2
Type: Research Article
ISSN: 0951-3574

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Article
Publication date: 1 April 1990

Christine Barbier, Philip J. Clark, Peter Bettess and Jacqueline A. Bettess

The use of algebraic languages such as REDUCE makes possible the automatic generation, from fairly concise data, of the main families of two and three dimensional C0…

Abstract

The use of algebraic languages such as REDUCE makes possible the automatic generation, from fairly concise data, of the main families of two and three dimensional C0 continuous finite element shape functions, with a high confidence in their correctness. This paper gives a tutorial introduction to the REDUCE language and describes how it was used to generate shape function routines.

Details

Engineering Computations, vol. 7 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 3 August 2010

Jung‐Suk Yu and M. Kabir Hassan

The purpose of this paper is to examine the existence of rational speculative bubbles in the Middle East and North African (MENA) stock markets.

Abstract

Purpose

The purpose of this paper is to examine the existence of rational speculative bubbles in the Middle East and North African (MENA) stock markets.

Design/methodology/approach

To complement shortcomings of the traditional bubble tests, such as unit root tests and cointegration tests, mainly relying on expectations of future steams of dividends, the authors employ fractional integration tests and duration dependence tests.

Findings

Despite recent extreme fluctuations of MENA stock markets, fractional integration tests built on autoregressive fractionally integrated moving average models do not support the possibility of bubbles in the MENA stock markets. Similarly, duration dependence tests based on nonparametric Nelson‐Aalen hazard functions not only reject the existence of bubbles but also support equality of hazard functions between domestic and the US‐based investors without regard to the rapid financial liberalization and integration in the MENA stock markets.

Originality/value

The reliable results of bubble tests of the MENA stock markets provide domestic and international investors as well as policy makers with invaluable benchmark to better understand the irregular and highly fluctuating stock market behaviors of the MENA stock markets compared to other developed and emerging stock markets. For domestic and international investors, the formal analysis of MENA stock markets behavior including rational speculative bubbles will help them in their portfolio decisions and hedging purposes. Similarly, the empirical results of bubble tests in the paper will be also helpful to policymakers in MENA countries to take actions to improve the functioning of these dynamic markets.

Details

Studies in Economics and Finance, vol. 27 no. 3
Type: Research Article
ISSN: 1086-7376

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