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Article
Publication date: 1 January 1992

ZHI‐HUA ZHONG and JAROSLAV MACKERLE

Contact problems are among the most difficult ones in mechanics. Due to its practical importance, the problem has been receiving extensive research work over the years…

Abstract

Contact problems are among the most difficult ones in mechanics. Due to its practical importance, the problem has been receiving extensive research work over the years. The finite element method has been widely used to solve contact problems with various grades of complexity. Great progress has been made on both theoretical studies and engineering applications. This paper reviews some of the main developments in contact theories and finite element solution techniques for static contact problems. Classical and variational formulations of the problem are first given and then finite element solution techniques are reviewed. Available constraint methods, friction laws and contact searching algorithms are also briefly described. At the end of the paper, a bibliography is included, listing about seven hundred papers which are related to static contact problems and have been published in various journals and conference proceedings from 1976.

Details

Engineering Computations, vol. 9 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 January 1993

KENNETH RUNESSON, MAREK KLISINSKI and RAGNAR LARSSON

Finite element implementations of the classical (stick‐slip) and a regularized (elastic‐slip) friction laws are compared for a class of non‐linear slip criteria. The fully…

Abstract

Finite element implementations of the classical (stick‐slip) and a regularized (elastic‐slip) friction laws are compared for a class of non‐linear slip criteria. The fully implicit method is used for integrating the friction law. A novel implementation of the stick‐slip law, that involved transformation to a non‐orthogonal coordinate system at each contact point, is assessed. A numerical comparison is carried out for a simple problem, that has previously been analysed in the literature. The convergence of the elastic‐slip law for increasing stiffness is evaluated in addition to convergence behaviour of the adopted Newton iterations for a given law.

Details

Engineering Computations, vol. 10 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 July 1995

Andreas Heege, Pierre Alart and Eugenio Oñate

A consistent formulation for unilateral contact problems includingfrictional work hardening or softening is proposed. The approach is based onan augmented Lagrangian…

Abstract

A consistent formulation for unilateral contact problems including frictional work hardening or softening is proposed. The approach is based on an augmented Lagrangian approach coupled to an implicit quasi‐static Finite Element Method. Analogous to classical work hardening theory in elasto‐plasticity, the frictional work is chosen as the internal variable for formulating the evolution of the friction convex. In order to facilitate the implementation of a wide range of phenomenological models, the friction coefficient is defined in a parametrised form in terms of Bernstein polynomials. Numerical simulation of a 3D deep‐drawing operation demonstrates the performance of the methods for predicting frictional contact phenomena in the case of large sliding paths including high curvatures.

Details

Engineering Computations, vol. 12 no. 7
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 July 1949

A series of articles explaining in simple language the fundamentals of Lubrication

Abstract

A series of articles explaining in simple language the fundamentals of Lubrication

Details

Industrial Lubrication and Tribology, vol. 1 no. 7
Type: Research Article
ISSN: 0036-8792

Article
Publication date: 1 April 1936

S. Hoerner

AS aircraft become aerodynamically cleaner, an ever‐increasing proportion of the drag becomes pure skin drag. The known laws of the drag of flat plates enable the friction

Abstract

AS aircraft become aerodynamically cleaner, an ever‐increasing proportion of the drag becomes pure skin drag. The known laws of the drag of flat plates enable the friction drags which occur at the Reynold's Numbers met in high‐speed flight to be approximately calculated. In addition, the very important effects of surface roughness which occur at high speeds may be assessed in a practical manner for aircraft from the known data on flat plates.

Details

Aircraft Engineering and Aerospace Technology, vol. 8 no. 4
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 13 June 2016

Xin Zhao and Zili Li

– The purpose of this paper is to develop a numerical approach to solve the transient rolling contact problem with the consideration of velocity dependent friction.

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Abstract

Purpose

The purpose of this paper is to develop a numerical approach to solve the transient rolling contact problem with the consideration of velocity dependent friction.

Design/methodology/approach

A three dimensional (3D) transient FE model is developed in elasticity by the explicit finite element method. Contact solutions with a velocity dependent friction law are compared in detail to those with the Coulomb’s friction law (i.e. a constant coefficient of friction).

Findings

The FE solutions confirm the negligible influence of the dependence on the normal contact. Hence, analysis is focussed on the tangential solutions under different friction exploitation levels. In the trailing part of the contact patch where micro-slip occurs, very high-frequency oscillations are excited in the tangential plane by the velocity dependent friction. This is similar to the non-uniform sliding or tangential oscillations observed in sliding contact. Consequently, the micro-slip distribution varies greatly with time. However, the surface shear stress distribution is quite stable at different instants, even though it significantly changes with the employed friction model.

Originality/value

This paper proposes an approach to solve the transient rolling contact problem with the consideration of velocity dependent friction. Such a problem was usually solved in the literature by the simplified contact algorithms, with which detailed contact solutions could not be obtained, or with the assumption of steady rolling.

Details

Engineering Computations, vol. 33 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 13 November 2009

A.E. Tekkaya and P.A.F. Martins

The purpose of this paper is to provide industrial, education and academic users of computer programs a basic overview of finite elements in metal forming that will enable…

1861

Abstract

Purpose

The purpose of this paper is to provide industrial, education and academic users of computer programs a basic overview of finite elements in metal forming that will enable them to recognize the pitfalls of the existing formulations, identify the possible sources of errors and understand the routes for validating their numerical results.

Design/methodology/approach

The methodology draws from the fundamentals of the finite elements, plasticity and material science to aspects of computer implementation, modelling, accuracy, reliability and validation. The approach is illustrated and enriched with selected examples obtained from research and industrial metal forming applications.

Findings

The presentation is a step towards diminishing the gap being formed between developers of the finite element computer programs and the users having the know‐how on the metal forming technology. It is shown that there are easy and efficient ways of refreshing and upgrading the knowledge and skills of the users without resorting to complicated theoretical and numerical topics that go beyond their knowledge and most often are lectured out of metal forming context.

Originality/value

The overall content of the paper is enhancement of previous work in the field of sheet and bulk metal forming, and from experience in lecturing these topics to students in graduate and post‐graduate courses and to specialists of metal forming from industry.

Details

Engineering Computations, vol. 26 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 June 1995

A. Moal and E. Massoni

A complete thermo‐mechanical model for the simulation of theinertia welding process of two similar parts is described. The materialbehaviour is represented by an…

Abstract

A complete thermo‐mechanical model for the simulation of the inertia welding process of two similar parts is described. The material behaviour is represented by an incompressible viscoplastic Norton—Hoff law in which the rheological parameters are dependent on temperature. The friction law was determined experimentally and depends on the prescribed pressure and the relative rotating velocity between the two parts. The mechanical problem is solved considering the virtual work principle including inertia terms. The computation of the three components of the velocity field such as radial, longitudinal and rotational velocity, in an axisymmetric approximation allows to take into account the torsional effects. The domain is updated based on a Lagrangian formulation. The non‐linear heat transfer equation with boundary conditions (convection, radiation and friction flux) is solved separately for each time step. Error estimators on mechanical and thermal computation are devised to adapt the mesh in an automatic way. Finally, numerical results concerning evolution of parts shape, strain, temperature, rotating velocity, upsetting are compared with actual industrial welds.

Details

Engineering Computations, vol. 12 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 27 July 2018

Junxia Li and Shaowei Liang

The study of the friction law and wear characteristics of the middle trough material can better select the appropriate material for the scraper conveyor of fully…

Abstract

Purpose

The study of the friction law and wear characteristics of the middle trough material can better select the appropriate material for the scraper conveyor of fully mechanized working face and provide theoretical support for the wear-resistant treatment technology.

Design/methodology/approach

This paper investigated friction and wear of the middle trough in a scraper conveyor under different media. Lignite, coking coal and anthracite were selected media, and middle trough wear was maximum for anthracite and minimum for lignite, with coking coal being intermediate.

Findings

Wear increased linearly with increasing load nonlinearly with increasing sliding speed. Middle trough wear also increased with increasing media granularity up to approximately 0.4 mm (40 mesh), but had little effect beyond that.

Originality/value

It can provide a reference for the scraper conveyor running resistance. At the same time, it has great social significance and economic benefits for the safe, green and efficient coal mine industrial adjustment, etc.

Details

Industrial Lubrication and Tribology, vol. 70 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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…

4059

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.

Details

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

Keywords

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