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Article
Publication date: 1 June 2002

H.L. Xing and A. Makinouchi

In this paper, a strategy for analyzing a problem of the transient thermal coupling with the elastoplastic finite deformation is presented. A general constitutive equation…

Abstract

In this paper, a strategy for analyzing a problem of the transient thermal coupling with the elastoplastic finite deformation is presented. A general constitutive equation is deduced by assuming the material properties to be temperature‐dependent. The thermal and mechanical coupling problem is solved with a staggered algorithm, which partitions the coupled problem into an elasto‐plastic problem at the known temperature field and a pure heat transfer problem at the fixed configuration. In this procedure, the elasto‐plastic mechanical analysis is based on the static‐explicit solution algorithm, which applies the finite deformation theory to describe the nonlinear behavior of the deformation body and its contact interaction with the tools during the forming process induced by the ordinary external loading and the “thermal loading”. In addition, both the ordinary heat transfer boundary conditions and the mechanical terms are taken into account in the implicit finite element analysis of the heat transfer. A special method based on the R‐minimum strategy is presented to solve the interaction problem between the static‐explicit mechanical analysis and the implicit thermal analysis. Furthermore, as examples, the analyses of sheet warm forming processes are demonstrated.

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Engineering Computations, vol. 19 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 23 February 2015

Sachin Gautam and Ravindra Saxena

In an impact phenomenon the material is subjected to very short duration high force levels resulting large plastic deformations and rise in temperature at high strain…

Abstract

In an impact phenomenon the material is subjected to very short duration high force levels resulting large plastic deformations and rise in temperature at high strain rates. A circular rod impacting against a rigid surface called as Taylor rod impact test is widely used for determining the mechanical behaviour of materials subjected to high strain rates with associated increase in temperature. A three-dimensional large deformation, thermo-elasto-plastic, dynamic, contact, finite element formulation is developed to study the effect of temperature rise due to plastic deformation and surface friction on the deformation and stress fields. It is found that the predicted equivalent plastic strain values are influenced by temperature generated due to plastic deformation and surface friction. The values of the coefficient of friction have a profound effect on the location of fracture initiation on the impacting face in a circular rod.

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World Journal of Engineering, vol. 11 no. 6
Type: Research Article
ISSN: 1708-5284

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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…

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 August 1999

Jaroslav Mackerle

This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the…

Abstract

This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper contains references to papers, conference proceedings and theses/dissertations on the subject that were published between 1977‐1998. The following topics are included: ceramics – material and mechanical properties in general, ceramic coatings and joining problems, ceramic composites, ferrites, piezoceramics, ceramic tools and machining, material processing simulations, fracture mechanics and damage, applications of ceramic/composites in engineering; glass – material and mechanical properties in general, glass fiber composites, material processing simulations, fracture mechanics and damage, and applications of glasses in engineering.

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Engineering Computations, vol. 16 no. 5
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 July 2005

Boris Štok and Nikolaj Mole

To present numerical approaches to the solution of physically coupled non‐linear problems, which frequently happen to be characterized by their multi‐domain character.

Abstract

Purpose

To present numerical approaches to the solution of physically coupled non‐linear problems, which frequently happen to be characterized by their multi‐domain character.

Design/methodology/approach

By adopting coupled solution strategies a considerable attention is devoted, in order to obtain a computationally efficient numerical algorithm, to the selection of appropriate space and time discretization, as well as to a proper discrete approximation method used.

Findings

Coupling of two methods, the finite element method and the boundary element method, respectively, has proved to be computationally exceedingly advantageous, particularly in case of moving domains.

Practical implications

As specific case studies computer simulation of an induction heating problem and a mushy‐state forming problem are considered. A thorough discussion on the coupling effects, characterizing the evolutions of respective physical quantities' fields, is given, and their impact on those evolutions is identified.

Originality/value

This paper presents efficient numerical strategies for the solution of a certain class of multi‐physics and multi‐domain problems.

Details

Engineering Computations, vol. 22 no. 5/6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 January 2008

P. Sathiya, N. Siva Shanmugam, T. Ramesh and R. Murugavel

Friction stir welding (FSW), a process that involves joining of metals without fusion of filler materials. It is used already in routine, as well as critical application…

Abstract

Friction stir welding (FSW), a process that involves joining of metals without fusion of filler materials. It is used already in routine, as well as critical application for the joining of structural components made of Aluminum and its alloys. Indeed it has been convincingly demonstrated that the process results in strong and ductile joints, some times in systems, which have proved difficult using conventional welding techniques. The process is most suitable for components that are flat & long (plates & sheets) but it can be adapted for pipes, hollow sections and positional welding. The welds are created by the combined action of frictional heating and mechanical deformation, due to a rotating tool. Recently, a new technology called friction stir spot welding (FSSW) has been developed that has a several advantages over the electric resistance welding process widely used in automotive industry in terms of weld quality and process efficiency. This welding technology involves a process similar to FSW, except that, instead of moving the tool along the weld seam, the tool only indents the parts, which are placed on top of each other. The conditions under which the deposition process in FSSW is successful are not fully understood. However, it is known that only under specific thermo‐mechanical conditions does a weld formation occur. The objective of the present work is to analyze the primary conditions under which the cavity behind the tool is filled. For this, a fully coupled thermo‐mechanical three‐dimensional FE model has been developed in ABAQUS/Explicit using the adaptive meshing scheme and the Johnson‐Cook material law. The contact forces are modeled by Coulomb’s law of friction, making the contact condition highly solution dependent. Temperature graph in the radial direction as well as stress, strain plots are presented.

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Multidiscipline Modeling in Materials and Structures, vol. 4 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 6 August 2020

Niu-Jing Ma, Li-Xiong Gu, Long Piao and Xing-Zhi Zhang

Stiffened plates have been widely used in civil, marine, aerospace engineering. As a kind of thin-walled structure operating in complex environment, stiffened plates…

Abstract

Purpose

Stiffened plates have been widely used in civil, marine, aerospace engineering. As a kind of thin-walled structure operating in complex environment, stiffened plates mostly undergo a variety of dynamic loads, which may sometimes result in large-amplitude vibration. Additionally, initial stresses and geometric imperfections are widespread in this type of structure. Furthermore, it is universally known that initial stresses and geometric imperfections may affect mechanical behavior of structures severely, particularly in dynamic analysis. Thus, the purpose of this paper is to study the stress variation rule of a stiffened plate during large-amplitude vibration considering initial stresses and geometric imperfections.

Design/methodology/approach

The initial stresses are represented in the form of initial bending moments applying to the stiffened plate, while the initial geometric imperfections are considered by means of trigonometric series, and they are assumed existing in the plate along the z-direction exclusively. Then, the dynamic equilibrium equations of the stiffened plate are established using Lagrange’s equation as well as aforementioned conditions. The nonlinear differential equations of motion are simplified as a two-degree-of-freedom system by considering 1:2 and 1:3 internal resonances, respectively, and the multiscale method is applied to solve the equations.

Findings

The influence of initial stresses on the plate, stresses during internal resonance is remarkable, while that is moderate for initial geometric imperfections. (Upon considering the existence of initial stresses or geometric imperfections, the stresses of motivated modes are less than the primary mode for both and internal resonances). The influence of bidirectional initial stresses on the plate’s stresses during internal resonance is more remarkable than that of unidirectional initial stresses. The coupled vibration in 1%3A2 internal resonance is fiercer than that in internal resonance.

Originality/value

Stiffened plates are widely used in engineering structures. However, as a type of thin-walled structure, stiffened plates vibrate with large amplitude in most cases owning to their complicated operation circumstance. In addition, stiffened plates usually contain initial stresses and geometric imperfections, which may result in the variation of their mechanical behavior, especially dynamical behavior. Based on the above consideration, this paper studies the nonlinear dynamical behavior of stiffened plates with initial stresses and geometrical imperfections under different internal resonances, which is the originality of this work. Furthermore, the research findings can provide references for engineering design and application.

Details

Engineering Computations, vol. 38 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 7 October 2020

Liang Tian and Yu Luo

The purpose of this paper is to quantitatively investigate the effect of process parameters (including welding current, voltage and speed) and plate thickness on in-plane…

Abstract

Purpose

The purpose of this paper is to quantitatively investigate the effect of process parameters (including welding current, voltage and speed) and plate thickness on in-plane inherent deformations in typical fillet welded joint; meanwhile, the plastic strains remaining in the weld zone are also analyzed under different influencing factors.

Design/methodology/approach

To achieve the purpose of this study, a thermal-elastic-plastic finite element (TEP FE) model is developed to analyze the thermal-mechanical behavior of the T-welded joint during the welding process. Experimental measurements have verified the validity of the established TEP FE model. Using the effective model, a series of numerical experiments are performed to obtain the inherent deformations under the conditions of different influencing factors, and then the calculation results are discussed based on the relevant data obtained.

Findings

Through numerical simulation analysis, it is found that the longitudinal and transverse inherent deformations decrease with the increase of welding speed and plate thickness, whereas as the nominal heat input increases, the inherent deformations increase significantly. The longitudinal shrinkage presents a quasi-linear and nonlinear distribution in the middle and end of the weld, respectively. The plastic strains in the cross section of the T-joint also vary greatly because of the process parameters and plate thickness, but the maximum value always appears near the location of the welding toe, which means that this point faces a relatively large risk of fatigue cracking. The inherent deformations are closely related to the plastic strains remaining in the weld zone and are also affected by many influencing factors such as process parameters and plate thickness.

Research limitations/implications

In this study, relatively few influencing factors such as welding current, voltage, speed and plate thickness are considered to analyze the inherent deformations in the T-welded joint. Also, these influencing factors are all within a certain range of parameters, which shows that only limited applicability can be provided. In addition, only in-plane inherent deformations are considered in this study, without considering the other two out-of-plane components of inherent deformations.

Originality/value

This study can help to expand the understanding of the relationship between the inherent deformations and its influencing factors for a specific form of the welded joint, and can also provide basic data to supplement the inherent deformation database, thereby facilitating further researches on welding deformations for stiffened-panel structures in shipbuilding or steel bridges.

Details

Engineering Computations, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 25 November 2019

Rohit Pethe, Thomas Heuzé and Laurent Stainier

The purpose of this paper is to present a variational mesh h-adaption approach for strongly coupled thermomechanical problems.

Abstract

Purpose

The purpose of this paper is to present a variational mesh h-adaption approach for strongly coupled thermomechanical problems.

Design/methodology/approach

The mesh is adapted by local subdivision controlled by an energy criterion. Thermal and thermomechanical problems are of interest here. In particular, steady and transient purely thermal problems, transient strongly coupled thermoelasticity and thermoplasticity problems are investigated.

Findings

Different test cases are performed to test the robustness of the algorithm for the problems listed above. It is found that a better cost-effectiveness can be obtained with that approach compared to a uniform refining procedure. Because the algorithm is based on a set of tolerance parameters, parametric analyses and a study of their respective influence on the mesh adaption are carried out. This detailed analysis is performed on unidimensional problems, and a final example is provided in two dimensions.

Originality/value

This work presents an original approach for independent h-adaption of a mechanical and a thermal mesh in strongly coupled problems, based on an incremental variational formulation. The approach does not rely on (or attempt to provide) error estimation in the classical sense. It could merely be considered to provide an error indicator. Instead, it provides a practical methodology to adapt the mesh on the basis of the variational structure of the underlying mathematical problem.

Details

Engineering Computations, vol. 37 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 December 2004

Jaroslav Mackerle

Sheet metal forming is a process of shaping thin sheets of metal by applying pressure through male or female dies or both. In most of used sheet‐formating processes the…

Abstract

Sheet metal forming is a process of shaping thin sheets of metal by applying pressure through male or female dies or both. In most of used sheet‐formating processes the metal is subjected to primarily tensile or compressive stresses or both. During the last three decades considerable advances have been made in the applications of numerical techniques, especially the finite element methods, to analyze physical phenomena in the field of structural, solid and fluid mechanics as well as to simulate various processes in engineering. These methods are useful because one can use them to find out facts or study the processes in a way that no other tool can accomplish. Finite element methods applied to sheet metal forming are the subjects of this paper. The reason for writing this bibliography is to save time for readers looking for information dealing with sheet metal forming, not having an access to large databases or willingness to spend own time with uncertain information retrieval. This paper is organized into two parts. In the first one, each topic is handled and current trends in the application of finite element techniques are briefly mentioned. The second part, an Appendix, lists papers published in the open literature. More than 900 references to papers, conference proceedings and theses/dissertations dealing with subjects that were published in 1995‐2003 are listed.

Details

Engineering Computations, vol. 21 no. 8
Type: Research Article
ISSN: 0264-4401

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