References of "Habraken, Anne"
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See detail3D thermal finite element analysis of laser cladding processed Ti-6Al-4V part with microstructural correlations
Tran, Hoang Son ULg; Tchuindjang, Jérôme Tchoufack ULg; Paydas, Hakan ULg 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 detailInfluence of Si precipitates on fracture mechanisms of AlSi10Mg parts processed by Selective Laser Melting
Delahaye, Jocelyn ULg; Rigo, Olivier; Lecomte-Beckers, Jacqueline ULg et al

Conference (2017, June 28)

Al alloy AlSi10Mg processed by Selective Laser Melting displays a very fine cellular eutetic microstructure (melt pool fine, MP fine) due to fast cooling rate from the melt. Such microstructural ... [more ▼]

Al alloy AlSi10Mg processed by Selective Laser Melting displays a very fine cellular eutetic microstructure (melt pool fine, MP fine) due to fast cooling rate from the melt. Such microstructural refinement results in high tensile strength and hardness. Studies have shown that a coarser cells region (melt pool coarse, MP coarse) as well as a heat affected zone (HAZ) can be observed at the melt pool boundary caused by a change of thermal history [1]. Those microstructural inhomogeneities act like a weak zone as demonstrated by the laser tracks observed on fracture features after tensile test [2]. This study aims at investigating in which zone fracture occurs. To do so, MP fine, MP coarse and HAZ were analyzed. Si precipitates spacing was compared with dimples size observed on fracture features. The Si precipitates fraction were quantified by image analysis. Hardness tests were performed in the 3 different zones by nanoindentation. [1] Thijs et al., Acta Mater. 61 (2013) pp. 1809-1819 [2] Tang et al., JOM 69 (2017) pp. 516-522 [less ▲]

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See detailWear behaviour of laser clad High Speed Steels thick deposits
Hashemi, Seyedeh Neda ULg; Tchuindjang, Jérôme Tchoufack ULg; Dedry, Olivier ULg et al

Conference (2017, June 28)

The wear behaviour of 4 different High Speed Steel (HSS) thick coatings (one cast material and 3 laser clad deposits with varying Mo, V and W contents) was investigated at 2 different test temperatures, i ... [more ▼]

The wear behaviour of 4 different High Speed Steel (HSS) thick coatings (one cast material and 3 laser clad deposits with varying Mo, V and W contents) was investigated at 2 different test temperatures, i.e. at room temperature and at 300°C. For all four materials under both test conditions, oxidative wear was identified as the main wear mechanism. The 3 laser clad deposits exhibit a higher wear resistance compared to the conventional cast reference material, and this effect was mainly attributed to their strongly refined microstructures. Moreover, a detailed comparison of the wear behaviour of the 3 laser clad deposits, in correlation with their microstructures, allows a better understanding of the effect of the different carbides and of their morphology. [less ▲]

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See detailOPTIBRI Opening and Project Overview
Habraken, Anne ULg; Duchene, Laurent ULg; Bouffioux, Chantal ULg 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 detailThermal history modelling to understand microstructures observed in repair technology of Ti-6Al-4V
Tran, Hoang Son ULg; Tchuindjang, Jérôme Tchoufack ULg; Hakan, Paydas et al

in Extended Abstract book of 14th Conf. on Computer Methods in Materials Technology KomPlasTech 2017 (2017, January)

Laser cladding is a metal deposition technique used to fabricate or repair components. In the present work Ti-6Al-4V deposits with a variable thickness are studied to assess the use of laser cladding as a ... [more ▼]

Laser cladding is a metal deposition technique used to fabricate or repair components. In the present work Ti-6Al-4V deposits with a variable thickness are studied to assess the use of laser cladding as a repair technology [1]. Solidification following melting and partial remelting of pre-existing layers is coupled with heat treatment of the solidified material due to the repeated heating and cooling cycles during building. The effect of the building strategy on the metallurgical characteristics of the material for a decreasing track length (DTL) or a constant track length (CTL) strategy is analyzed. Depending on the possible heat accumulation, the nature of the phases are determined by metallography and hardness maps of the deposits. Optical Microscopy (OM), Stereo Microscopy (SM), and Scanning Electron Microscopy (SEM) were used in order to study the microstructure. The generation of the microstructure results from the material thermal history. This one is computed by Finite Element Method and a careful analysis establishes the link between the phase state and the detailed thermal history. [less ▲]

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See detailOptimal use of High Strength Steel grades within bridge
Habraken, Anne ULg; Duchene, Laurent ULg; Bouffioux, Chantal ULg 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 ULg; Duchene, Laurent ULg 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 ULg; 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 ULg; Duchene, Laurent ULg; 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 ULg; 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 ULg; Guzmán Inostroza, Carlos Felipe ULg; Duchene, Laurent ULg 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 detail2D and 3D FE models of laser cladding process
Jardin, Ruben; Hoang, Son Tran; Hashemi, Seyedeh Neda ULg et al

in Booklet of the conference with extended abstract and short paper of less than 6 pages (2016, July)

Lien entre le champ thermique 2D et 3D calculé pour un cas de laser cladding d acier au chrome

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See detailSafe, flexible and efficient sheet metal forming: formability - fracture, incremental sheet forming & rolling
Banabic, Dorel; Habraken, Anne ULg; Yoon, Jeong Whan

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

Editorial of the thematic issue

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See detailSingle point incremental forming simulation with adaptive remeshing technique using solid-shell elements
Sena, José; Lequesne, Cedric; Duchene, Laurent ULg 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 detailNumerical Simulations of a Two Roll Round Bar Straightener
Flipon, Baptiste; Lawrjaniec, Didier; Papeleux, Luc ULg et al

in AIP Conference Proceedings 1769, 120001 (2016); (2016, April 28)

A 2-roll bar straightener is a finishing process applied after the rolling operation of round steel bars. During the straightening, the bar rotation is induced by the two rotating rolls. It also undergoes ... [more ▼]

A 2-roll bar straightener is a finishing process applied after the rolling operation of round steel bars. During the straightening, the bar rotation is induced by the two rotating rolls. It also undergoes an alternate bending in such a way that the bar section is finally deformed uniformly. The purpose of this process is to correct the curvature defaults of the rolled bar. Indeed, the bar must be straight before being sent to the client and a straightened uniform surface layer is appreciated. With the apparition of new grades and also new diameters of steel round bars, it becomes essential to better understand the straightening process in order to (i) have a better knowledge of what the round bar undergoes during the process, (ii) precisely understand the straightening process, the effect of each component and the process parameters. [less ▲]

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See detailAbout the Enhanced Formability of Single Point Incremental Forming
Habraken, Anne ULg; Guzmán Inostroza, Carlos Felipe ULg

Scientific conference (2016, February 09)

Analysis of the formability in Single Point Incremental Forming Process: deformation mechanism, link witth Forming Limit Curves and damage approach, bad prediction of Gurson model for DC01 steel.

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See detailLocal thermal history during the laser additive manufacturing of steel
Mertens, Anne ULg; Hashemi, Seyedeh Neda ULg; Tchuindjang, Jérôme Tchoufack ULg et al

Conference (2016, February 09)

Laser additive manufacturing techniques – such as laser cladding − were developed in the late 1990s as economic layer-by-layer near-net-shape processes allowing for the production or restoration of ... [more ▼]

Laser additive manufacturing techniques – such as laser cladding − were developed in the late 1990s as economic layer-by-layer near-net-shape processes allowing for the production or restoration of complex metallic parts. These techniques are characterised by ultra-fast solidification and cooling rates, thus giving rise to ultra-fine out-of-equilibrium microstructures with potentially enhanced mechanical properties. However, the general quality of a component, as well as its dimensional accuracy, microstructure and final usage properties are strongly influenced by the local thermal history experienced during fabrication. As a consequence, a deeper understanding of the influence of the various processing parameters on the local thermal history during fabrication is of paramount importance, and it can only be reached by combining detailed experimental studies and modeling. Keeping this in mind, the present paper reviews on-going investigations carried out in the Metallic Materials Science Unit of the University of Liege in the laser additive manufacturing of HSS and of stainless steel 316L. [less ▲]

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See detailComparison of residual stresses on long rolled profiles measured by X-ray diffraction, ring core and the sectioning methods and simulated by FE method
Bouffioux, Chantal ULg; Pesci, Raphaël; Boman, Romain ULg et al

in Thin-Walled Structures (2016), 104

Sheet piles are produced by hot rolling, a cooling step and, if required, by a straightening operation. Numerical simulations indicate that the stress field is almost homogeneous through the thickness ... [more ▼]

Sheet piles are produced by hot rolling, a cooling step and, if required, by a straightening operation. Numerical simulations indicate that the stress field is almost homogeneous through the thickness, justifying the comparison of X-ray diffraction, ring core and the sectioning methods applied after the cooling step and after the straightening process. The equipment, the steps of the experimental procedures and the results are detailed, showing the limits, the specificities and the advantages of each method. Moreover, the amplitude and the distribution of the stresses along the width of the sections present good agreement with results of numerical simulations. [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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