References of "Habraken, Anne"
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See detail2D and 3D FE models of laser cladding process
Jardin, Ruben; Hoang, Son Tran; Hashemi, Seyedeh Neda ULiege 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 ULiege; 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 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 detailNumerical Simulations of a Two Roll Round Bar Straightener
Flipon, Baptiste; Lawrjaniec, Didier; Papeleux, Luc ULiege 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 ULiege; Guzmán Inostroza, Carlos Felipe ULiege

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 ULiege; Hashemi, Seyedeh Neda ULiege; Tchuindjang, Jérôme Tchoufack ULiege 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 ULiege; Pesci, Raphaël; Boman, Romain ULiege 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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See detail2D Thermal model of powder injection laser cladding of high speed steels (HSS)
Hashemi, Seyedeh Neda ULiege; Gilles, Gatën; Tomé Jardin, Ruben Antonio ULiege et al

Conference (2015, October 23)

A two-dimensional multi-layer model for the transient temperature field analysis of Laser cladding process is developed. This model allows studying the thermal field of the multilayer deposits during ... [more ▼]

A two-dimensional multi-layer model for the transient temperature field analysis of Laser cladding process is developed. This model allows studying the thermal field of the multilayer deposits during their development by laser, and the "flat" substrate on which the deposition is carried. [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 detailStudy of the Crystallization Behavior and the Subsequent Martensitic Transformation in a High Chromium Cast Steel submitted to Different Austenitization Temperatures
Tchuindjang, Jérôme Tchoufack ULiege; Habraken, Anne ULiege; Lecomte-Beckers, Jacqueline ULiege

Conference (2015, September)

The crystallization behavior a High Chromium Cast Steel (HCCS) has been determined under Equilibrium conditions with ThermoCalc® software, and under non-Equilibrium conditions through Differential Thermal ... [more ▼]

The crystallization behavior a High Chromium Cast Steel (HCCS) has been determined under Equilibrium conditions with ThermoCalc® software, and under non-Equilibrium conditions through Differential Thermal Analyses (DTA). The results are compared to each other and the differences between the predicted solidification path and the actual one obtained from DTA (Figure 1) are highlighted. The microstructure in the as-cast conditions is characterized while using both scanning electron microscopy (SEM) and hardness measurements. The SEM analysis involves a combination of methods such as backscattered electron observation, energy dispersive spectrometry and backscattered-electron diffraction with X rays, which ensure proper identification of complex solidification carbides and the matrix made of martensite and retained austenite (Figure 2a). Solid state transformations occurring during the heating stage up to the austenitization temperature are studied towards both DTA and dilatometry, especially the dissolution/precipitation reactions. Different austenitization temperatures are considered prior to cooling down to room temperature during dilatometry tests to determine the starting points (Ms) for martensite transformation. In addition a cryogenic quenching within liquid nitrogen is performed which allows the completion of the martensitic transformation (Figure 2b) and help determining the critical point for the end of the martensitic reaction (Mf points). An enhanced discussion based on the influence of the cooling rate and the undercooling is developed to explain the differences that are observed between equilibrium and non-equilibrium conditions, which are mainly related to the solidification sequence and the carbides formed. The influence of the austenitization temperature and the matrix composition/supersaturation on both Ms and Mf points is also discussed. [less ▲]

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See detailImplementation of a damage evolution law for dual-phase steels in Gurson-type models
Balan, Tudor; Lemoine, Xavier; Maire, eric et al

in Materials and Design (2015), (88), 1213-1222

This paper is a contribution to the phenomenological modeling of damage evolution in DP steels in the framework of Gurson’s approach. It is based on recent results of X-ray tomography in-situ tensile ... [more ▼]

This paper is a contribution to the phenomenological modeling of damage evolution in DP steels in the framework of Gurson’s approach. It is based on recent results of X-ray tomography in-situ tensile tests and subsequent one-dimensional metallurgical void nucleation models proposed in [C. Landron et al., Scripta Materialia 63 (2010) 973—976]. A macroscopic void nucleation law for DP steels is proposed, covering a wide range of stress triaxialities. The respective effects of nucleation, growth and coalescence are clearly separated. Validations with respect to experimental porosity measurements were performed for several monotonic loading cases and for two loading sequences involving large strains and strain-path changes. [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 detailComparison of fracture prediction models on sheet metal blanking simulations
Canales Cardenas, Cristian ULiege; Boman, Romain ULiege; Bussetta et al

Conference (2015, July)

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See detailDetermination of Stress and Strain Fields in Cast and Heat Treated Bimetallic Rolling Mill Rolls
Neira Torres, Ingrid; Tchuindjang, Jérôme Tchoufack ULiege; Sinnaeve, Mario et al

in Proceedings of the Iron & Steel Technology Conference and Exposition (AISTech 2015 & ICSTI) (2015, May)

Efficient work rolls for Hot Strip mill roughing stands are usually produced as bimetallic spun cast rolls with a core material made of Spheroidal Graphite Iron (SGI) and a shell material made of High ... [more ▼]

Efficient work rolls for Hot Strip mill roughing stands are usually produced as bimetallic spun cast rolls with a core material made of Spheroidal Graphite Iron (SGI) and a shell material made of High Chromium Steel alloy, semi-High speed steel or adapted High Speed steel chemistry. In this paper, the evolution of stress fields and microstructure during post casting cooling and subsequent heat treatment of a standard high chromium steel is targeted. This knowledge is a first step to analyze the different events that could happen during these production stages and provides the residual stress fields as well as the final roll microstructure which are interesting data for roll service life. As far as roughing mill work rolls for roughing mills are concerned, current trends in terms of work roll design are forcing the roll producer to go towards higher usable shell thicknesses or increased residual shell thickness after scrap diameter in order to delay potential fatigue phenomena at the shell-core interface. One important parameter could not be evaluated in this study, it concerns the pollutions of the core material by alloying elements of the shell during production, which could affect to some extent the mechanical properties and microstructure of the core. The macroscopic thermo-mechanical-metallurgical Finite Element model used to perform simulations, takes into account coupled effects. Input data parameters are identified by experimental tests such as compression tests at constant strain rate and numerical procedures such as inverse method. After the model presentation, the material data set is commented. Whole experimental campaign could not be presented, however interested readers are referred to [1] where more details on the material study of High Chromium Steel alloy can be found. The section of simulation results show the phase transformation histories and stress profiles of a typical roll of diameter 1.2 m and shell thickness of 0.08 m. An additional sensitivity analysis of the results to some material data such as induced plasticity transformation coefficient and shift of the martensitic transformation start temperature parameters is reported. Finally, some conclusions analyze the interest and drawbacks of the described model and its results. [less ▲]

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See detailModelling of stress field evolution in bimetallic rolling mill rolls during the manufacturing process
Gilles, G.; Neira Torres, I.; Tchuindjang, Jérôme Tchoufack ULiege et al

in Proceedings of the 5th Conference on rolling mill rolls for metals processing Rolls 5 2015 (2015, April 22)

This paper presents a study of the phase transformation histories and stress profiles in a typical bimetallic roll subjected to a post-casting cooling followed by a tempering heat treatment. The ... [more ▼]

This paper presents a study of the phase transformation histories and stress profiles in a typical bimetallic roll subjected to a post-casting cooling followed by a tempering heat treatment. The simulations are performed using the non-linear finite element code "Lagamine" and a thermo-mechanical-metallurgical model able to take into account coupled effects. The sensitivity of the finite element results to some parameters which are not accurately identified is investigated. [less ▲]

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See detailAssessment of damage and anisotropic plasticity models to predict Ti-6Al-4V behavior
Guzmán Inostroza, Carlos Felipe ULiege; Tuninetti, Víctor; Gilles, Gaëtan ULiege et al

in Key Engineering Materials [=KEM] (2015, April), 651-653

The plastic behavior of the Ti-6Al-4V alloy includes several features as strength differential effect, anisotropy and yield strength sensitivity to temperature and strain rate. Monotonic tensions in the ... [more ▼]

The plastic behavior of the Ti-6Al-4V alloy includes several features as strength differential effect, anisotropy and yield strength sensitivity to temperature and strain rate. Monotonic tensions in the three orthogonal directions of the material are performed to identify the Hill ’48 yield criterion. Monotonic compression and plane strain tensile tests are also included in the experimental campaign to identify the orthotropic yield criterion of CPB06. An assessment of the two models is done by comparing the yield loci and the experimental data points for different levels of plastic work. A first approach of the damage modelling of the Ti-6AL-4V alloy is investigated with an extended Gurson-Tvergaard-Needleman damage model based on Hill ’48 yield criterion. Finite element simulations of the experiments are performed and numerical results allows checking force-displacement curves until rupture and local information like displacement and strain fields. The prediction ability of the Hill ’48, CPB and extended Gurson models are assessed on simple shear and notched tensile tests until fracture. [less ▲]

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See detailAnisotropy and tension-compression asymmetry modeling of the room temperature plastic response of Ti-6A1-4V
Tuninetti, Victor; Gilles, Gaëtan ULiege; Pardoen, Thomas et al

in International Journal of Plasticity (2015), 67

The mechanical behavior of the alloy Ti-6A1-4V is characterized using uniaxial tension, uniaxial compression, simple shear and place strain tests in three orthogonal material directions. The experimental ... [more ▼]

The mechanical behavior of the alloy Ti-6A1-4V is characterized using uniaxial tension, uniaxial compression, simple shear and place strain tests in three orthogonal material directions. The experimental results reveal tension/compression asymmetry, anisotropic yielding and anisotropic strain-hardening. These features are incorporated into an elasto-plastic constitutive law based on the macroscopic orthotropic yield criterion "CPB06" adapted to hexagonal metals. A new identification method for the yield criterion parameters is proposed by inverse modeling of the axial strain field compression specimens in the three orthogonal directions of the material. The sensitivity of different sets of material parameters to the identification method is also analysed and the capacity of the model to accurately predict the forces and displacement field is discussed. A validation of the best set of identified CPB06material parameters is performed by comparing the load-displacement curves in different loading directions for tensile tests on notched round bars with different levels of stress triaxiality and for compression tests on elliptical cross-section specimens, both tests involving multiaxial strain fields and large deformations. [less ▲]

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See detailPhase Transformations and Crack Initiation in a High-Chromium Cast Steel Under Hot Compression Tests
Tchuindjang, Jérôme Tchoufack ULiege; Neira Torres, Ingrid; Fores, Paulo et al

in Journal of Materials Engineering and Performance (2015), 24(5), 2025-2041

The mechanical behavior of the fully austenitic matrix of high-chromium cast steel (HCCS) alloy is determined by external compression stress applied at 300 and 700 C. The microstructure is roughly ... [more ▼]

The mechanical behavior of the fully austenitic matrix of high-chromium cast steel (HCCS) alloy is determined by external compression stress applied at 300 and 700 C. The microstructure is roughly characterized toward both optical and scanning electron microscopy analyses. Dilatometry is used during heating from room temperature up to austenitization to study the solid-state phase transformations, precipitation, and dissolution reactions. Two various strengthening phenomena (precipitation hardening and stress-induced bainite transformation) and one softening mechanism (dynamic recovery) are highlighted from compression tests. The influence of the temperature and the carbide type on the mechanical behavior of the HCCS material is also enhanced. Cracks observed on grain boundary primary carbides allow establishing a rough damage model. The crack initiation within the HCCS alloy is strongly dependent on the temperature, the externally applied stress, and the matrix strength and composition. [less ▲]

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