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Article
Publication date: 29 November 2018

Aref Mehditabar and Gholam H. Rahimi

This study aims to explain the characterization of cyclic behavior of a tube made of functionally graded material (FGM) under different combinations of internal pressure…

Abstract

Purpose

This study aims to explain the characterization of cyclic behavior of a tube made of functionally graded material (FGM) under different combinations of internal pressure and cyclic through-thickness temperature gradients.

Design/methodology/approach

The normality rule, nonlinear kinematic hardening Chaboche model and Von Mises yield criterion were used to model the constitutive behavior of an FG tube in the incremental form. The material properties and hardening parameters of the Chaboche model vary according to the power-law function in the radial direction. The backward Euler integration scheme combined with return mapping algorithm which relies on the solution of a nonlinear equation performs the numerical procedure. The algorithm is implemented within the user subroutine UMAT in ABAQUS/standard.

Findings

The published works on FG components considering only the mechanical and physical properties as a function of spatial coordinate and nonlinear kinematic hardening parameters have not been considered to be changed continuously from one surface to another. Motivated by this, the present paper has deliberately been targeted to tackle this kind of problem to simulate the cyclic behavior of an FG tube as accurately as possible. In addition, to classify various behaviors the FG tube under cyclic thermomechanical loadings, Bree’s interaction diagram as an essential tool in designing of the FG pressure vessels in many engineering sectors is presented.

Originality/value

Provides a detailed description of the FG parameters of Chaboche kinematic hardening parameters in the adopted constitutive equations. In this paper, the significant effects of internal pressure values, kinematic hardening models and also FG inhomogeneity index related to the hardening rule parameters on plastic deformation of the FG tube are illustrated. Finally, the various cyclic behaviors of the FG tube under different combinations of thermomechanical loading are fully explored.

Details

Engineering Computations, vol. 36 no. 1
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 15 February 2021

Hala Messai, Salim Meziani and Athmane Fouathia

The purpose of this paper is to highlight the performance of the Chaboche model in relation to the database identification, tests with imposed deformations were conducted…

Abstract

Purpose

The purpose of this paper is to highlight the performance of the Chaboche model in relation to the database identification, tests with imposed deformations were conducted at room temperature on 304L stainless steel specimens.

Design/methodology/approach

The first two tests were performed in tension-compression between ±0.005 and ±0.01; in the third test, each cycle is composed of the combination of a compression tensile cycle between ±0.01 followed by a torsion cycle between ±0.01723 (non-proportional path), and the last, uniaxial ratcheting test with a mean stress between 250 MPa and −150 MPa. Several identifications of a Chaboche-type model were then performed by considering databases composed of one or more of the cited tests. On the basis of these identifications, the simulations of a large number of ratchet tests in particular were carried out.

Findings

The results present the effect of the optimized parameters on the prediction of the behavior of materials which is reported in the graphs, Optimizations 1 and 2 of first and second tests and Optimization 4 of the third test giving a good prediction of the increasing/decreasing pre-deformation amplitude.

Originality/value

The quality of the model's predictions strongly depends on the richness of the database used for the identification of the parameters.

Details

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

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Article
Publication date: 1 September 2002

C.P. Providakis and S.G. Kourtakis

The feasibility of advanced viscoplastic models for non‐linear boundary element analysis of metallic structural components with dependence on thermomechanical history is…

Abstract

The feasibility of advanced viscoplastic models for non‐linear boundary element analysis of metallic structural components with dependence on thermomechanical history is investigated. Several numerical examples are presented using the boundary element implementation of two different internal state variable viscoplastic models to the solution of time‐dependent inelastic problems arising in creeping metallic structural components under the combined action of high temperature loading gradients and quasi‐static mechanical loading conditions. To demonstrate the efficiency of the implemented viscoplastic models, the results obtained using the direct boundary element methodology are compared with those obtained by both analytical and finite element solution as well as, for different numerical results of plane strain thermoviscoplastic deformation problems under general thermomechanical loading.

Details

Engineering Computations, vol. 19 no. 6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 February 1986

H. Burlet and G. Cailletaud

A formulation of non‐linear kinematic hardening in plasticity is given, with a short description of the model properties under cyclic loading. A resolution algorithm based…

Abstract

A formulation of non‐linear kinematic hardening in plasticity is given, with a short description of the model properties under cyclic loading. A resolution algorithm based on the initial stress method is implemented in a two‐dimensional finite element code (ZEBULON). The procedure is tested on examples including mechanical and thermal loading. Some remarks are made on the maximum increment size, the relative efficiency of ‘radial return’ and ‘secant stiffness method’ is discussed. Finally, the possibilities of the model concerning ratchetting, cyclic hardening and softening are shown.

Details

Engineering Computations, vol. 3 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 25 October 2018

Dylan Agius, Kyriakos I. Kourousis and Chris Wallbrink

The purpose of this paper is to examine the mechanical behaviour of additively manufactured Ti-6Al-4V under cyclic loading. Using as-built selective laser melting (SLM…

Abstract

Purpose

The purpose of this paper is to examine the mechanical behaviour of additively manufactured Ti-6Al-4V under cyclic loading. Using as-built selective laser melting (SLM) Ti-6Al-4V in engineering applications requires a detailed understanding of its elastoplastic behaviour. This preliminary study intends to create a better understanding on the cyclic plasticity phenomena exhibited by this material under symmetric and asymmetric strain-controlled cyclic loading.

Design/methodology/approach

This paper investigates experimentally the cyclic elastoplastic behaviour of as-built SLM Ti-6Al-4V under symmetric and asymmetric strain-controlled loading histories and compares it to that of wrought Ti-6Al-4V. Moreover, a plasticity model has been customised to simulate effectively the mechanical behaviour of the as-built SLM Ti-6Al-4V. This model is formulated to account for the SLM Ti-6Al-4V-specific characteristics, under the strain-controlled experiments.

Findings

The elastoplastic behaviour of the as-built SLM Ti-6Al-4V has been compared to that of the wrought material, enabling characterisation of the cyclic transient phenomena under symmetric and asymmetric strain-controlled loadings. The test results have identified a difference in the strain-controlled cyclic phenomena in the as-build SLM Ti-6Al-4V when compared to its wrought counterpart, because of a difference in their microstructure. The plasticity model offers accurate simulation of the observed experimental behaviour in the SLM material.

Research limitations/implications

Further investigation through a more extensive test campaign involving a wider set of strain-controlled loading cases, including multiaxial (biaxial) histories, is required for a more complete characterisation of the material performance.

Originality/value

The present investigation offers an advancement in the knowledge of cyclic transient effects exhibited by a typical α’ martensite SLM Ti-6Al-4V under symmetric and asymmetric strain-controlled tests. The research data and findings reported are among the very few reported so far in the literature.

Details

Rapid Prototyping Journal, vol. 24 no. 9
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 7 August 2017

Martin Neuenschwander, Claudio Scandella, Markus Knobloch and Mario Fontana

This paper aims to investigate with strain-rate controlled uniaxial cyclic compression tests the softening behavior of concrete and its elastic stiffness degradation with…

Abstract

Purpose

This paper aims to investigate with strain-rate controlled uniaxial cyclic compression tests the softening behavior of concrete and its elastic stiffness degradation with increasing plastic straining.

Design/methodology/approach

Such tests at ambient temperature show that concrete exhibits the phenomenon of elastic stiffness degradation, which can be captured by damage-plasticity models.

Findings

The experimentally derived evolutions of the elastic stiffness with plastic strain confirm the suitability of the damage-plasticity modeling concept for concrete in compression at elevated temperatures and provide novel calibration data.

Originality/value

Temperature-dependent concrete models implementing this modeling concept are often used presently in structural fire engineering, despite the lack of experiment-based validation data.

Details

Journal of Structural Fire Engineering, vol. 9 no. 1
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 5 March 2018

Dylan Agius, Mladenko Kajtaz, Kyriakos I. Kourousis, Chris Wallbrink and Weiping Hu

This study presents the improvements of the multicomponent Armstrong–Frederick model with multiplier (MAFM) performance through a numerical optimisation methodology…

Abstract

Purpose

This study presents the improvements of the multicomponent Armstrong–Frederick model with multiplier (MAFM) performance through a numerical optimisation methodology available in a commercial software. Moreover, this study explores the application of a multiobjective optimisation technique for the determination of the parameters of the constitutive models using uniaxial experimental data gathered from aluminium alloy 7075-T6 specimens. This approach aims to improve the overall accuracy of stress–strain response, for not only symmetric strain-controlled loading but also asymmetrically strain- and stress-controlled loading.

Design/methodology/approach

Experimental data from stress- and strain-controlled symmetric and asymmetric cyclic loadings have been used for this purpose. The analysis of the influence of the parameters on simulation accuracy has led to an adjustment scheme that can be used for focused optimisation of the MAFM model performance. The method was successfully used to provide a better understanding of the influence of each model parameter on the overall simulation accuracy.

Findings

The optimisation identified an important issue associated with competing ratcheting and mean stress relaxation objectives, highlighting the issues with arriving at a parameter set that can simulate ratcheting and mean stress relaxation for load cases not reaching at complete relaxation.

Practical implications

The study uses a strain-life fatigue application to demonstrate the importance of incorporating a technique such as the presented multiobjective optimisation method to arrive at robust parameters capable of accurately simulating a variety of transient cyclic phenomena.

Originality/value

The proposed methodology improves the accuracy of cyclic plasticity phenomena and strain-life fatigue simulations for engineering applications. This study is considered a valuable contribution for the engineering community, as it can act as starting point for further exploration of the benefits that can be obtained through material parameter optimisation methodologies for models of the MAFM class.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 2
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 1 April 1985

H. Ishikawa and H. Lippmann

The stress analysis of structures subjected to cyclic loading requires stress—strain relations simple enough to be usable efficiently in computer program and yet adequate…

Abstract

The stress analysis of structures subjected to cyclic loading requires stress—strain relations simple enough to be usable efficiently in computer program and yet adequate to describe the essential features of the plastic behaviour of the material reasonably well. The constitutive equation for cyclic plasticity incorporating the motion of the centre of the loading surface is proposed. Using the modified plastic work, the dependency of the loading history of materials is taken into account. The Ramberg—Osgood law which is applied to each stress—strain loop from the current centre of the loading surface plays an important role. This computer simulation for stress—strain relation of cyclic loading is justified from the point of view of several kinds of experiments on type 304 austenitic stainless steel.

Details

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

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Article
Publication date: 28 May 2010

Jianguo Yu and Daniel Kujawski

The paper aims to shed some light on the effect of the notch/crack‐tip stresses and their role on the cyclic plasticity and crack growth behavior in…

Abstract

Purpose

The paper aims to shed some light on the effect of the notch/crack‐tip stresses and their role on the cyclic plasticity and crack growth behavior in compression‐compression fatigue.

Design/methodology/approach

Compression precracking was studied using 2D finite element analysis for CT specimen. The final crack length and the shape of the crack front were compared with those obtained experimentally.

Findings

It has been found that cyclic plasticity and stress redistribution govern the observed fatigue crack growth behavior in compression‐compression precracking. Only the internal stress corresponding to Pmax shows a significant redistribution with the crack extension whereas the stress corresponding Pmin is not affected by the increase of crack length.

Research limitations/implications

This results are limited to Mode I cracking.

Practical implications

It supports that two thresholds, ΔKth and Kmaxth, govern the fatigue crack behavior. When the contribution from the internal tensile stress is not big enough to make Kmax exceed Kmaxth the crack will self arrest.

Originality/value

It has been found that cyclic plasticity and stress redistribution govern the observed fatigue crack growth behavior in compression‐compression precracking. The comparison of the numerical results with experimental data in terms of final crack length and crack front shape indicated a fair agreement.

Details

International Journal of Structural Integrity, vol. 1 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

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Article
Publication date: 8 May 2018

Riccardo Fincato and Seiichiro Tsutsumi

Many practical problems in engineering require fast, accurate numerical results. In particular, in cyclic plasticity or fatigue simulations, the high number of loading…

Abstract

Purpose

Many practical problems in engineering require fast, accurate numerical results. In particular, in cyclic plasticity or fatigue simulations, the high number of loading cycles increases the computation effort and time. The purpose of this study is to show that the return mapping technique in the framework of unconventional plasticity theories is a good compromise between efficiency and accuracy in finite element analyses.

Design/methodology/approach

The accuracy of the closest point projection method and the cutting plane method implementations for the subloading surface model are discussed under different loading conditions by analyzing the error as a function of the input step size and the efficiency of the algorithms.

Findings

Monotonic tests show that the two different implicit integration schemes have the same accuracy and are in good agreement with the solution obtained using an explicit forward Euler scheme, even for large input steps. However, the closest point projection method seems to describe better the evolution of the similarity centre in the cyclic loading analyses.

Practical implications

The purpose of this work is to show two alternative implicit integration schemes of the extended subloading surface method for metallic materials. The backward Euler integrations can guarantee a good description of the material behaviour and, at the same time, reduce the computational cost. This aspect is particularly important in the field of low or high cycle fatigue, because of the large number of cycles involved.

Originality/value

A detailed description of both the cutting plane and closest point projection methods is offered in this work. In particular, the two integrations schemes are compared in terms of accuracy and computation time for monotonic and cyclic loading tests.

Details

Engineering Computations, vol. 35 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

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