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Article
Publication date: 1 May 1992

H.J. ANTÚNEZ and S.R. IDELSOHN

The pseudo‐concentration method is applied to the analysis of transient processes. A simple, easy‐to‐handle model is obtained by keeping an Eulerian description: it does not…

23

Abstract

The pseudo‐concentration method is applied to the analysis of transient processes. A simple, easy‐to‐handle model is obtained by keeping an Eulerian description: it does not require remeshing after a certain amount of plastic deformation. The range of applicability of the method is extended to non‐confined (even with several free surfaces) processes. It is shown the need of distinct handling of free surfaces according to their orientation to the direction of the flow. A seamless tube rolling process, a cylinder upsetting and a backward extrusion are modelled. Experimental data and results obtained by other methods are used to compare and discuss the performance of the model.

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Engineering Computations, vol. 9 no. 5
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 March 1995

M. Kleiber, T.D. Hien, H. Antúnez and P. Kowalczyk

The general problem of sizing, material and loading parameter sensitivity of non‐linear systems is presented. Both kinematic and path‐dependent material non‐linearities are…

133

Abstract

The general problem of sizing, material and loading parameter sensitivity of non‐linear systems is presented. Both kinematic and path‐dependent material non‐linearities are considered; non‐linear sensitivity path is traced by an incremental solution strategy. The variational approach employed is quite general and can be employed for studying sensitivity of various path‐dependent highly non‐linear phenomena. Both the direct differentiation method (DDM) and adjoint system method (ASM) are discussed in the context of continuum and finite element mechanics. The merits of using the consistent tangent matrix and the necessity of accumulation of design derivatives of stresses and internal parameters are indicated. Aspects of sensitivity problems in metal forming are also discussed. A number of examples illustrate the paper.

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Engineering Computations, vol. 12 no. 3
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 May 1994

N. Brännberg and J. Mackerle

This paper gives a review of the finite element techniques (FE)applied in the area of material processing. The latest trends in metalforming, non‐metal forming and powder…

1467

Abstract

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming and powder metallurgy are briefly discussed. The range of applications of finite elements on the subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for the last five years, and more than 1100 references are listed.

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Engineering Computations, vol. 11 no. 5
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 May 2001

Stefan Schwarz and Ekkehard Ramm

The present contribution deals with the sensitivity analysis and optimization of structures for path‐dependent structural response. Geometrically as well as materially non‐linear…

1170

Abstract

The present contribution deals with the sensitivity analysis and optimization of structures for path‐dependent structural response. Geometrically as well as materially non‐linear behavior with hardening and softening is taken into account. Prandtl‐Reuss‐plasticity is adopted so that not only the state variables but also their sensitivities are path‐dependent. Because of this the variational direct approach is preferred for the sensitivity analysis. For accuracy reasons the sensitivity analysis has to be consistent with the analysis method evaluating the structural response. The proposed sensitivity analysis as well as its application in structural optimization is demonstrated by several examples.

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Engineering Computations, vol. 18 no. 3/4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 August 1998

Jaroslav Mackerle

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder…

4563

Abstract

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

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Engineering Computations, vol. 15 no. 5
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 April 1993

EDUARDO N. DVORKIN and EVA G. PETÖCZ

In order to develop an engineering tool for modelling 2D metal forming processes we implemented in the flow formulation the pseudo‐concentrations technique and a quadrilateral…

70

Abstract

In order to develop an engineering tool for modelling 2D metal forming processes we implemented in the flow formulation the pseudo‐concentrations technique and a quadrilateral element based on mixed interpolation of tensorial components (QMITC). By doing this we obtained a reliable and efficient Eulerian formulation for modelling steady and transient metal forming problems. Some cases were analysed in order to test the performance of the formulation.

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Engineering Computations, vol. 10 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 April 2006

Jaroslav Mackerle

To provide a selective bibliography for researchers working with bulk material forming (specifically the forging, rolling, extrusion and drawing processes) with sources which can…

4751

Abstract

Purpose

To provide a selective bibliography for researchers working with bulk material forming (specifically the forging, rolling, extrusion and drawing processes) with sources which can help them to be up‐to‐date.

Design/methodology/approach

A range of published (1996‐2005) works, which aims to provide theoretical as well as practical information on the material processing namely bulk material forming. Bulk deformation processes used in practice change the shape of the workpiece by plastic deformations under forces applied by tools and dies.

Findings

Provides information about each source, indicating what can be found there. Listed references contain journal papers, conference proceedings and theses/dissertations on the subject.

Research limitations/implications

It is an exhaustive list of papers (1,693 references are listed) but some papers may be omitted. The emphasis is to present papers written in English language. Sheet material forming processes are not included.

Practical implications

A very useful source of information for theoretical and practical researchers in computational material forming as well as in academia or for those who have recently obtained a position in this field.

Originality/value

There are not many bibliographies published in this field of engineering. This paper offers help to experts and individuals interested in computational analyses and simulations of material forming processes.

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Engineering Computations, vol. 23 no. 3
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 April 1994

R. Codina, U. Schäfer and E. Oñate

In this paper we consider several aspects related to the application ofthe pseudo‐concentration techniques to the simulation of mould fillingprocesses. We discuss, in particular…

101

Abstract

In this paper we consider several aspects related to the application of the pseudo‐concentration techniques to the simulation of mould filling processes. We discuss, in particular, the smoothing of the front when finite elements with interior nodes are employed and the evacuation of air through the introduction of temporary free wall nodes. The basic numerical techniques to solve the incompressible Navier—Stokes equations are also briefly described. The main features of the numerical model are the use of div‐stable velocity—pressure interpolations with discontinuous pressures, the elimination of the pressure via an iterative penalty formulation, the use of the SUPG approach to deal with convection‐dominated problems and the temporal integration using the generalized trapezoidal rule. At the end of the paper we present some numerical results obtained for a two‐dimensional test problem showing the ability of the method to capture complicated flow patterns.

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International Journal of Numerical Methods for Heat & Fluid Flow, vol. 4 no. 4
Type: Research Article
ISSN: 0961-5539

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Book part
Publication date: 28 May 2019

Serafín Antúnez, Patricia Silva and Charles L. Slater

Directing schools of high complexity in disadvantaged social contexts with high rates of emigration requires skills for emotional leadership. Directors with self-managing…

Abstract

Directing schools of high complexity in disadvantaged social contexts with high rates of emigration requires skills for emotional leadership. Directors with self-managing capacities are needed to manage their own emotions. They also need to mobilise people (teachers, students and families) by focussing on their feelings of satisfaction, identification with the group, belonging, joy, success, unity and cohesion.

The content of this chapter presents the study of the emotional management of directors who perform their work in two highly complex schools in Catalonia, Spain. The views of these directors as well as teachers and families examine: (1) the construction of their professional identity, (2) their social and ethical commitment to the community, (3) the orientation towards the values of social justice and (4) their emotional leadership practices focussed on personal attention towards all of the actors in the school community.

The chapter concludes with 10 suggestions that can be useful to improve the professional practice of school directors. These should also be taken into account when designing and implementing initial and ongoing training programmes for school leaders and to inspire ideas for future research.

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Emotion Management and Feelings in Teaching and Educational Leadership
Type: Book
ISBN: 978-1-78756-011-6

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Article
Publication date: 1 December 2001

Catarina F. Castro, Luísa Costa Sousa, C.A.C. António and J.M.A. César de Sá

An optimisation method for design of intermediate die shapes needed in some forging operations is presented. The basic problem consists of finding an optimal two‐step forging…

407

Abstract

An optimisation method for design of intermediate die shapes needed in some forging operations is presented. The basic problem consists of finding an optimal two‐step forging sequence by automatically designing the shape of the preforming tools. The optimisation problem is defined based on an inverse formulation. The objective function of the optimisation problem is a function describing the quality of the obtained part by measuring the die underfill. The finite element method is used to simulate the forging problem. The optimisation method is based on a modified sequential unconstrained minimisation technique and a gradient method. The sensitivity‐dependent algorithm requires computing the derivatives of the objective function with respect to the design variables defining the preform shapes. A direct differentiation method has been developed for this purpose. The optimisation scheme is demonstrated with two axisymmetric forging examples in which optimal preform dies are obtained.

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Engineering Computations, vol. 18 no. 8
Type: Research Article
ISSN: 0264-4401

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