References of "Duchene, Laurent"
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See detailVisco-plastic Chaboche model for nickel-based alloys under anisothermal cyclic loading
Morch, Hélène ULiege; Duchene, Laurent ULiege; Habraken, Anne ULiege

in Proceedings of the XIV International Conference on Computational Plasticity (2017, September)

The mechanical behavior of visco-plastic materials such as nickel-based alloys is highly dependent on temperature. Some characteristics such as viscosity, hardening, static recovery, dynamic recovery have ... [more ▼]

The mechanical behavior of visco-plastic materials such as nickel-based alloys is highly dependent on temperature. Some characteristics such as viscosity, hardening, static recovery, dynamic recovery have more or less influence on the overall behavior depending on the considered temperature. The unified constitutive model developed by Chaboche [1] is very efficient in representing this complexity as it is very adaptable and can contain many features. A basic Chaboche model contains a viscosity law and one or several hardening equations. Within these hardening equations, it is possible to add several features that will represent the complex behavior of the material. The aim of this study is to understand the role of the different parameters and the influence of the different features in an advanced Chaboche model adapted to cyclic anisothermal loading. This specific model was also developed in [2],[3]. However, part of this study is based on particular cases where different features of the model are analyzed [4]–[6]. [less ▲]

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See detail3D thermal finite element analysis of laser cladding processed Ti-6Al-4V part with microstructural correlations
Tran, Hoang Son ULiege; Tchuindjang, Jérôme Tchoufack ULiege; Paydas, Hakan ULiege et al

in Materials & Design (2017), 128

In this study, a 3D thermal model of laser cladding by powder injection applied to Ti-6Al-4V is developed. The manufactured part is made of a Ti-6Al-4V substrate on which successive layers of laser melted ... [more ▼]

In this study, a 3D thermal model of laser cladding by powder injection applied to Ti-6Al-4V is developed. The manufactured part is made of a Ti-6Al-4V substrate on which successive layers of laser melted powder are added, leading to a thick deposit. The computed temperature field and its time evolution are compared to experimental measurements. The temperature distribution in the substrate allows the prediction of the depths of the melt pool and the heat affected zone. Correlations between simulated thermal histories and the final microstructure in the thick deposit are established, leading to the enhancement of a dynamic shift of the critical transformation points due to high thermal rates during laser processing. The nature of the phases present within the deposit is discussed. [less ▲]

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See detailFATIGUE CRACK PROPAGATION IN HSS S690QL WELDED CONNECTIONS IN BRIDGES
Bouffioux, Chantal ULiege; Canales Cardenas, Cristian ULiege; Duchene, Laurent ULiege et al

Conference (2017, June)

The fatigue and crack study of HSS S690QL steel welded pieces is first experimentally analyzed by fatigue tests on small samples of Base Material (BM), Heat Affected Zone (HAZ) and Weld Metal (WM ... [more ▼]

The fatigue and crack study of HSS S690QL steel welded pieces is first experimentally analyzed by fatigue tests on small samples of Base Material (BM), Heat Affected Zone (HAZ) and Weld Metal (WM) separately for several stress ratios, stress levels, on smooth and notched samples. The Lemaître-Chaboche fatigue model combined with the stress gradient method and the three sets of parameters are found to accurately describe the behavior of each material. Another experimental campaign with larger pieces (closer to the scale of the bridge connections) called "small scale samples", with/without welded stiffeners, with several geometries and with/without post-treatment has shown each effect separately: the scale and machining effects, residual stresses due to the welding, geometrical and post-treatments effects. Numerical simulations of these experiments are used to improve and validate the material data, with a study in real context and size. Then, the characterized fatigue damage model is coupled with the element deletion method to model the propagation of cracks along the welded samples and the numerical predictions are compared with experimental results in order to validate the approach. [less ▲]

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See detailCharacterization of Fatigue Behaviour, from Material Science to Civil Engineering Applications
Bouffioux, Chantal ULiege; Habraken, Anne ULiege; Duchene, Laurent ULiege et al

Conference (2017, May 03)

Method used to characterise and numerically study the fatigue behaviour of HSS welded plates

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See detailOPTIBRI Opening and Project Overview
Habraken, Anne ULiege; Duchene, Laurent ULiege; Bouffioux, Chantal ULiege et al

Conference (2017, May 03)

presentation of genesis of the project, his goal and objectives, the partnership, the task flowchart and main achievements

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See detailOptimal use of High Strength Steel grades within bridge
Habraken, Anne ULiege; Duchene, Laurent ULiege; Bouffioux, Chantal ULiege et al

Diverse speeche and writing (2017)

The use of high strength steel in bridges is studied through the welding, the fatigue and the stability for three designs and also in term of life cycle impacts.

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See detailDamage prediction in single point incremental forming using an extended Gurson model
Guzman, Carlos Felipe; Yuan, Sibo ULiege; Duchene, Laurent ULiege et al

in International Journal of Solids and Structures (2017)

Single point incremental forming (SPIF) has several advantages over traditional forming, such as the high formability attainable by the material. Different hypotheses have been proposed to explain this ... [more ▼]

Single point incremental forming (SPIF) has several advantages over traditional forming, such as the high formability attainable by the material. Different hypotheses have been proposed to explain this behavior, but there is still no straightforward relation between the particular stress and strain state induced by SPIF and the material degradation leading to localization and fracture. A systematic review of the state of the art about formability and damage in SPIF is presented and an extended Gurson–Tvergaard–Needleman (GTN) model was applied to predict damage in SPIF through finite element (FE) simulations. The line test was used to validate the simulations by comparing force and shape predictions with experimental results. To analyze the failure prediction, several simulations of SPIF cones at different wall angles were performed. It is concluded that the GTN model underestimates the failure angle on SPIF due to wrong coalescence modeling. A physically-based Thomason coalescence criterion was then used leading to an improvement on the results by delaying the onset of coalescence. [less ▲]

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See detailLaser Cladding Finite Element Modelling Application to Ti6Al4V,
Tran, Hoang Son ULiege; Brusten, Romain; Jardin, Ruben et al

Conference (2016, November 03)

Corrélation entre les champs thermiques prédits et la microstructure observée.

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See detailQuasicontinuum analysis of interaction between screw dislocation and coherent twin boundary
Tran, Hoang Son ULiege; Duchene, Laurent ULiege; Tummala, Hareesh et al

Conference (2016, September 07)

The interaction between pure screw dislocation with dislocation line directions lying parallel to the twin plane and Coherent Twin Boundary Σ3 of copper has been studied using Quasi-Continuum method. The ... [more ▼]

The interaction between pure screw dislocation with dislocation line directions lying parallel to the twin plane and Coherent Twin Boundary Σ3 of copper has been studied using Quasi-Continuum method. The coherent twin boundary provides high barrier to slip transmission. The dislocation pile-up modifies the stress field at its intersection with the grain boundary. We introduce a methodology to calculate the stress barriers during slip–GB interaction. Screw dislocation approaching the boundary from one side may either propagate into the adjacent twin grain by cutting through the twin boundary. Quantitative estimation of critical stress for transmission phenomena is performed by using virial stress. The mechanism and critical stress obtained were in line with the literature. Such information can be used as input for Discrete Dislocation Dynamics models [less ▲]

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See detailModeling the ductile fracture and the plastic anisotropy of DC01 steel at room temperature and low strain rates
Tuninetti, Victor; Yuan, Sibo ULiege; Gilles, Gaëtan et al

Scientific conference (2016, September)

This paper presents different extensions of the classical GTN damage model implemented in a finite element code. The goal of this study is to assess these extensions for the numerical prediction of ... [more ▼]

This paper presents different extensions of the classical GTN damage model implemented in a finite element code. The goal of this study is to assess these extensions for the numerical prediction of failure of a DC01 steel sheet during a single point incremental forming process, after a proper identification of the material parameters. It is shown that the prediction of failure appears too early compared to experimental results. Though, the use of the Thomason criterion permitted to delay the onset of coalescence and consequently the final failure. [less ▲]

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See detailSimulation of a two-slope pyramid made by SPIF using an adaptive remeshing method with solid-shell finite element
Velosa De Sena, José ULiege; Guzmán Inostroza, Carlos Felipe ULiege; Duchene, Laurent ULiege et al

in International Journal of Material Forming (2016), 9(3), 259-434

Single point incremental forming (SPIF) is an emerging application in sheet metal prototyping and small batch production, which enables dieless production of sheet metal parts. This research area has ... [more ▼]

Single point incremental forming (SPIF) is an emerging application in sheet metal prototyping and small batch production, which enables dieless production of sheet metal parts. This research area has grown in the last years, both experimentally and numerically. However, numerical investigations into SPIF process need further improvement to predict the formed shape correctly and faster than current approaches. The current work aims the use of an adaptive remeshing technique, originally developed for shell and later extended to 3D “brick” elements, leading to a Reduced Enhanced Solid-Shell formulation. The CPU time reduction is a demanded request to perform the numerical simulations. A two-slope pyramid shape is used to carry out the numerical simulation and modelling. Its geometric difficulty on the numerical shape prediction and the through thickness stress behaviour are the main analysis targets in the present work. This work confirmed a significant CPU time reduction and an acceptable shape prediction accuracy using an adaptive remeshing method combined with the selected solid-shell element. The stress distribution in thickness direction revealed the occurrence of bending/unbending plus stretching and plastic deformation in regions far from the local deformation in the tool vicinity. [less ▲]

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See detailSingle point incremental forming simulation with adaptive remeshing technique using solid-shell elements
Sena, José; Lequesne, Cedric; Duchene, Laurent ULiege et al

in Engineering Computations International Journal for Computer- Aided Engineering and Software (2016), 33(5), 1388-1421

Numerical simulation of the single point incremental forming (SPIF) processes can be very demanding and time consuming due to the constantly changing contact conditions between the tool and the sheet ... [more ▼]

Numerical simulation of the single point incremental forming (SPIF) processes can be very demanding and time consuming due to the constantly changing contact conditions between the tool and the sheet surface, as well as the nonlinear material behaviour combined with non-monotonic strain paths. The purpose of this paper is to propose an adaptive remeshing technique implemented in the in-house implicit finite element code LAGAMINE, to reduce the simulation time. This remeshing technique automatically refines only a portion of the sheet mesh in vicinity of the tool, therefore following the tool motion. As a result, refined meshes are avoided and consequently the total CPU time can be drastically reduced. [less ▲]

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See detail3-D finite element analysis of laser cladding process. Application to Ti-6Al-4V
Tran, Hoang Son ULiege; Brusten, Romain; Paydas, Hakan ULiege et al

Scientific conference (2016, May 20)

In this study, a 3-D thermal numerical modelling of laser cladding by powder injection as a repair technology applied to Ti-6Al-4V was developed. In order to implement the movement of the heat source in ... [more ▼]

In this study, a 3-D thermal numerical modelling of laser cladding by powder injection as a repair technology applied to Ti-6Al-4V was developed. In order to implement the movement of the heat source in the model and the addition of material, a C++ programme was developed. Transition refinement elements are used to reduce the number of degrees of freedom. The temperature distribution and its time evolution were computed which allowed the prediction of the heat affected zone and the fusion size of the substrate. Effects of heat source distribution, energy input are investigated. Temperature measurements validate the model. [less ▲]

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See detailOn the comparison of two solid-shell formulations based on in-plane reduced and full integration schemes in linear and non-linear applications
ben bettaieb, Amine; Velosa de Sena, J.I.; Alves de Sousa, Ricardo et al

in Finite Elements in Analysis and Design (2015), 107

In the present paper, a detailed description of the formulation of the new SSH3D solid-shell element is presented. This formulation is compared with the previously proposed RESS solid-shell element [1, 2 ... [more ▼]

In the present paper, a detailed description of the formulation of the new SSH3D solid-shell element is presented. This formulation is compared with the previously proposed RESS solid-shell element [1, 2]. Both elements were recently implemented within the LAGAMINE in-house research finite element code. These solid-shell elements possess eight nodes with only displacement nodal degrees of freedom (DOF). In order to overcome various locking pathologies, the SSH3D formulation employs the well known Enhanced Assumed Strain (EAS) concept originally introduced by Simo and Rifai [3] and based on the Hu-Veubeke-Washizu variational principle combined with the Assumed Natural Strain (ANS) technique based on the work of Dvorkin and Bathe [4]. For the RESS solid-shell element, on the other hand, only the EAS technique is used with a Reduced Integration (RI) Scheme. A particular characteristic of these elements is their special integration schemes, with an arbitrary number of integration points along the thickness direction, dedicated to analyze problems involving non-linear through-thickness distribution (i.e. metal forming applications) without requiring many element layers. The formulation of the SSH3D element is also particular, with regard to the solid-shell elements proposed in the literature, in the sense that it is characterized by an in-plane full integration and a large variety in terms of (i) enhancing parameters, (ii) the ANS version choice and (iii) the number of integration points through the thickness direction. The choice for these three parameters should be adapted to each problem so as to obtain accurate results and to keep the calculation time low. Numerous numerical examples are performed to investigate the performance of these elements. These examples illustrate the reliability and the efficiency of the proposed formulations in various cases including linear and non-linear problems. SSH3D element is more robust thanks to the various options proposed and its full in-plane integration scheme, while RESS element in more efficient from a computational point of view. [less ▲]

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See detailInteraction between dislocation and coherent twin boundary by quasicontinuum model
Hoang, Son Tran; Tummala, Hareesh; Duchene, Laurent ULiege et al

in Proceedings of XIII International Conference on Computational Plasticity. Fundamentals and Applications COMPLAS ebook open accesss XIII (2015, September 02)

methodAbstract.The interaction between lattice dislocations and Coherent Twin Boundary Σ3 {111} of copper has been studied using Quasi-Continuum method. The coherent twin boundary provides high barrier to ... [more ▼]

methodAbstract.The interaction between lattice dislocations and Coherent Twin Boundary Σ3 {111} of copper has been studied using Quasi-Continuum method. The coherent twin boundary provides high barrier to slip transmission. The dislocation pile-up modifies the stress field at its intersection with the grain boundary. A different reaction process compared with the case of single dislocations is noticed. One observes the nucleation of a Lomer-type dislocation with Burgers vector of ½ <110 > and its glide onthe (100) cube plane in the adjacent grain. This phenomenon has been observed with Transmission Electron Microscopy at room temperature and in other Molecular Dynamics simulations. We also show a novel interaction mechanism between Lomer-type dislocation and Coherent Twin Boundary. This interactionprocess leaves a dislocation with a Burgers vector coincident with the complete lattice shift of the Coherent Twin Boundary. Quantitative estimation of critical stress for various transmission phenomena is performed by using virial stress. Such information can be used as input for Discrete Dislocation Dynamics models [less ▲]

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See detailSize effects and temperature dependence on strain-hardening mechanisms in some face centered cubic materials
HUG, E.; DUBOS, P.A.; keller, C. et al

in Mechanics of Materials (2015), 91

The mechanical behaviour of face centered cubic metals is deeply affected when specimen dimensions decrease from a few The millimeters to a few micrometers. At room temperature, a critical thickness (t ... [more ▼]

The mechanical behaviour of face centered cubic metals is deeply affected when specimen dimensions decrease from a few The millimeters to a few micrometers. At room temperature, a critical thickness (t) to grain size (d) ratio (t/d)c, was previously highlighted, under which the sofiening of mechanical properties became very pronounced both in terms of Hall-Petch relation and work hardening mechanisms. In this work, new experimental results are provided concerning the influence of temperature on this size effect for copper, nickel and Ni-20wt.%Cr, representative of a wide range of deformation mechanisms (i.e. dislocation slip character). It is shown that multicrystalline samples (t/d < (t/d)c) are not deeply affected by an increase in temperature, independently of the planar or wavy character of dislocation glide. For pronounced wavy slip character metals, surface effects in polycrystals (t/d > (t/d)c) are not significant enough to reduce the gap between polycrystal and multierystal mechanical behaviour when the temperature increases. However, a transition from wavy slip to planar glide mechanisms induces a modification ofthe polycrystalline behaviour which tends tovard multicrystalline one with a moderate increase in temperature. This work demonstrates that surface effects and grain size influence can be successfully disassociated for the three studied materials using an analysis supported by the Kooks- Mecking formalism. All these results are supported by microscopic investigations of dislocation substructures and compared to numerical simulations using a stress gradient plasticity model. [less ▲]

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See detailEffect of stress path on the miniaturizatio size effect for nickel polycrystals
Keller, Clement; Hug, Eric; Duchene, Laurent ULiege et al

Conference (2015, January 04)

The mechanical behavior of mettalic materials deeply depends on the size of samples. For specimen dimensions de creasing from a few millimeters to a few micrometers, the general observed trend is a ... [more ▼]

The mechanical behavior of mettalic materials deeply depends on the size of samples. For specimen dimensions de creasing from a few millimeters to a few micrometers, the general observed trend is a softening of the mechanical behavior in tension which affects the stress level and the strain hardening. This effect is triggered by the derease of the number of grains across the thickness ( also called thickness"t" over grain size "d" ratio). The objective of this work is to provide new experimental results in order to analyse the miniaturization size effects for various stress paths without strain gradients across the thickness of the samples. To this aim, experimental tensil tests, large tensile tests and shear tests have been performed on Ni sheets ( 0.5mm) with various grain sizes ensuring different t/d ratios. Results show that the miniaturization softening is affected by triaxiality, the larger is this parameter, the lower is the mechanicval softening. These features seem to be linked to surface effects which are larger for low triaxiality stress paths. Attempts of numerical simulations using strain gradient crystal plasticity model are also performed to confirm the role played by surface effects. [less ▲]

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See detailEffect of stress path on the miniaturization size effect for nickel polycrystals
Keller, Clement; Hug, Eric; Habraken, Anne ULiege et al

in International Journal of Plasticity (2015), 64

The mechanical behavior of metallic materials deeply depends on the size of samples. For specimen dimensions decreasing from a few millimeters to a few micrometers, the general observed trend is a ... [more ▼]

The mechanical behavior of metallic materials deeply depends on the size of samples. For specimen dimensions decreasing from a few millimeters to a few micrometers, the general observed trend is a softening of the mechanical behavior in tension which affects the stress level and the strain hardening. The objective of this work is to provide new experimental results in order to analyze the miniaturization size effects for various stress paths without strain gradients across the thickness of the samples. To this aim, experimental tensile tests, large tensile tests and shear tests have been performed on Ni sheets with various grain sizes. Results show that the miniaturization softening is affected by triaxiality, the larger is this parameter, the lower is the mechanical softening. These features seem to be linked to surface effects which are larger for low triaxiality stress paths. From an industrial point of view, it is hence possible to improve the forming of microparts using suitable stress paths. [less ▲]

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See detailAssessment of a multiscale fatigue damage model associated with stress gradient effects
Duchene, Laurent ULiege; Marmi, Abdeljalil ULiege; Habraken, Anne ULiege

Poster (2014, September)

The aim of this research work is to develop a finite element numerical tool able to predict accurately the fatigue life of mechanical components. These components can have complex geometries, they can be ... [more ▼]

The aim of this research work is to develop a finite element numerical tool able to predict accurately the fatigue life of mechanical components. These components can have complex geometries, they can be submitted to a complex loading, leading to a specific stress field with possible stress concentration. Additionally, the successive cycles of loading are not necessarily identical. It is expected that the numerical tool can handle these demanding constraints. In this respect, a multiaxial fatigue damage model was implemented in our home-made finite element code Lagamine. The finite element method permits to account for the actual geometry of the mechanical part and the loading for the stress computation in the whole structure. The formulation of the multiaxial fatigue model is able to capture: - The non linear damage accumulation for multiblock and variable cyclic loading, - The effect of the mean (hydrostatic) stress, - The effect of the cycles below the fatigue limit if the damage was previously initiated. Finally, the occurrence of stress concentration will significantly reduce the life time of the studied piece. However, it is well-known that the subsequent local degradation of the material will be partly compensated by an enhanced load carrying contribution of the surrounding material, favourably leading to a reduction of the crack propagation. The stress gradients computed with different techniques are incorporated in the model so as to account for such beneficial influence. The physical roots of this model depart from the mesoscopic length scale, where the damage evolution is related to the mesoscopic accumulated plastic strain. Therefore, the variables of the model are defined at both macroscopic and mesoscopic scales and a specific scale transition method was implemented, based on the well-known simplified Zarka method but used at the multiscale level. The predictive capabilities of this multiscale multiaxial model are assessed by means of comparison with the classical Lemaitre-Chaboche model (implemented in the same FE code with stress gradient effects). For both models, the material parameters were identified from SN tests on smooth specimens of Ti-6Al-4V alloy, while the predictions of the models are validated thanks to comparison with experimental tests on notched samples, with stress gradient effects. [less ▲]

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See detailNumerical Simulation of a Conical Shape Made by Single Point Incremental Forming
Velosa De Sena, José ULiege; Duchene, Laurent ULiege; Habraken, Anne ULiege et al

in Incremental sheet forming (2014, May 08)

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