References of "Habraken, Anne"
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See detailModel identification and FE simulations: effect of different yield loci and hardening laws in sheet forming
Flores, Paulo; Duchene, Laurent ULg; Lelotte, Thomas et al

in Smith, L. M.; Pourboghrat, F.; Yoon, J. W. (Eds.) et al On the Cutting Edge of Technology NUMISHEET 2005, Proceedings of the 6th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes (2005)

The bi-axial experimental equipment [1] developed by Flores enables to perform Baushinger shear tests and successive or simultaneous simple shear tests and plane-strain tests. Such experiments and ... [more ▼]

The bi-axial experimental equipment [1] developed by Flores enables to perform Baushinger shear tests and successive or simultaneous simple shear tests and plane-strain tests. Such experiments and classical tensile tests investigate the material behavior in order to identify the yield locus and the hardening models. With tests performed on two steel grades, the methods applied to identify classical yield surfaces such as Hill or Hosford ones as well as isotropic Swift type hardening or kinematic Armstrong–Frederick hardening models are explained. Comparison with the Taylor-Bishop-Hill yield locus is also provided. The effect of both yield locus and hardening model choice will be presented for two applications: Single Point Incremental Forming (SPIF) and a cup deep drawing. [less ▲]

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See detailFinite element simulations of the swift effect
Duchene, Laurent ULg; El Houdaigui, Fouad; Habraken, Anne ULg

in Bariani, P. F. (Ed.) Proceedings of the ICTP 2005 International Conference on Technology of Plasticity (2005)

Numerical simulations of the experimental free-end torsion tests [1] of copper cylindrical bars were analysed in the present paper. The self-made Finite Element (FE) code Lagamine with polycrystal ... [more ▼]

Numerical simulations of the experimental free-end torsion tests [1] of copper cylindrical bars were analysed in the present paper. The self-made Finite Element (FE) code Lagamine with polycrystal plasticity models computed numerical prediction of the Swift effect, i.e. the lengthening of the cylinder during the torsion. The used constitutive law was coupled with two plastic crystal models, taking or not into account strain rate effect. Results such as axial strain and predicted textures were analysed. The ones obtained for shear strains lower than 1.0 were in good agreement with experiments; while, for shear strains larger than 1.0, the FE results were currently unfair. A research about remeshing is in progress to improve the accuracy of the results for large shear strains. [less ▲]

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See detailAnalysis of Texture Evolution and hardening Behavior during Deep drawing with an improved mixed type FEM Element
Duchene, Laurent ULg; de Montleau, Pierre; El Houdaigui, Fouad et al

in Smith, L. M.; Pourboghrat, F.; Yoon, J. W. (Eds.) et al On the Cutting Edge of Technology, NUMISHEET 2005, 6th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes (2005)

In the present study, deep drawing simulations were investigated using a recently developed mixed type finite element (FE): the BWD3D. The main formulation of the element is described, with particular ... [more ▼]

In the present study, deep drawing simulations were investigated using a recently developed mixed type finite element (FE): the BWD3D. The main formulation of the element is described, with particular focus on the shear locking treatment. Two hardening models used in the presented simulations are described: the isotropic Swift’s model and the physically based microstructural Teodosiu and Hu model. Finally, deep drawing results, in terms of earing profile, are compared to experiment. Special attention is paid to the effects of texture evolution and hardening models; the method used to implement Teodosiu and Hu hardening model is also discussed. [less ▲]

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See detailDetermination of the optimal forging conditions of a Cr-Mo-V high alloy steel through a microstructural, thermophysical and mechanical study
Bouffioux, Chantal ULg; Carton, Marc ULg; Lecomte-Beckers, Jacqueline ULg et al

in Banabic, D. (Ed.) Proceedings of the 8th ESAFORM Conference on Material Forming (Vol. 1) (2005)

The forging process of cylinders requires the knowledge of material recrystallisation conditions to prevent crack appearance. Due to the continuous recrystallisation during forging, very large ... [more ▼]

The forging process of cylinders requires the knowledge of material recrystallisation conditions to prevent crack appearance. Due to the continuous recrystallisation during forging, very large deformations can be applied as the generated dislocations do not yield to hardening but to recrystallisation phenomenon. This paper summarizes the data identification of a FEM recrystallisation model and defines the optimal forging process for one roll. [less ▲]

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See detailDevelopment of an experimental equipment for the identification of constitutive laws
Flores, Paulo; Rondia, Etienne ULg; Habraken, Anne ULg

in International Journal of Forming Processes (2005), (Special Issue), 117-137

An experimental testing equipment for sheet samples is built in order to identify material parameters ofcomplex phenomenological constitutive laws. This equipment consists in a bi-axial test machine able ... [more ▼]

An experimental testing equipment for sheet samples is built in order to identify material parameters ofcomplex phenomenological constitutive laws. This equipment consists in a bi-axial test machine able to perform plane strain and simple shear tests separately or simultaneously and a Miyauchi simple shear test device. An optical extensometer is used to identify the strain field. The article is focused on the validation of the results of this new equipment by comparing with results obtained by finite elements (FE) simulations of already identified materials. The results are satisfactory and the bases for further material identification are established. [less ▲]

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See detailAnalysis of the sensivity of FEM predictions to numerical parameters in deep drawing simulations
Duchene, Laurent ULg; Habraken, Anne ULg

in European Journal of Mechanics A : Solids (2005), (24), 614-629

In this study, deep drawing finite element (FE) simulations are compared with experimental results. The steel grade, the geometry and the parameters of the experimental deep drawing processes are detailed ... [more ▼]

In this study, deep drawing finite element (FE) simulations are compared with experimental results. The steel grade, the geometry and the parameters of the experimental deep drawing processes are detailed in this paper. Particular attention is paid to numerical models. The main part of the article is dedicated to a broad sensitivity study. The influence of several numerical parameters on the predicted punch force and earing profile is analysed. A quadratic [Hill, R., 1948. A theory of the yielding and plastic flow of anisotropic metals. Proc. Roy. Soc. London Ser. A 193, 281–297] constitutive law is compared with more sophisticated micro-macro constitutive laws. The sensitivity of these laws to the initial data characterizing material behaviour is presented. A significant influence of the FE type and the number of FE layers is noticed. Finally, it also appears that friction parameters (penalty coefficient and Coulomb friction coefficient) have a significant influence on numerical results. The low anisotropy of the steel sheet increases the influence of several numerical parameters. That influence would not be observed with a highly anisotropic steel. [less ▲]

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See detailModélisation du comportement (clinchage des tôles minces)
Pietrapertosa, C.; Habraken, Anne ULg; Jaspart, Jean-Pierre ULg

in Techniques de l'ingénieur (2005), 4(BM 7 820), 1-8

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See detailFinite element modeling of incremental forming of aluminium sheets
He, S.; Van Bael, A.; Van Houtte, P. et al

in Advanced Materials Research (2005), 6/8

Incremental forming is an innovative and flexible sheet metal forming technology for small batch production and prototyping, which does not require any dedicated die or punch to form a complex shape. This ... [more ▼]

Incremental forming is an innovative and flexible sheet metal forming technology for small batch production and prototyping, which does not require any dedicated die or punch to form a complex shape. This paper investigates the process of single point incremental forming of an aluminum cone with a 50-degree wall angle both experimentally and numerically. Finite element models are established to simulate the process. The output of the simulation is given in terms of final geometry, the thickness distribution of the product, the strain history and distribution during the deformation as well as the reaction forces. Comparison between the simulation results and the experimental data is made. [less ▲]

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See detailThermo-mechanical-metallurgical model to predict geometrical distortions of rings during cooling phase after ring rolling operations
Casotto, Silvia; Pascon, Frédéric ULg; Habraken, Anne ULg et al

in International Journal of Machine Tools & Manufacture (2005), 45(6), 657-664

The paper presents a validated numerical model able to predict geometrical distortions of rings during cooling phase after hot ring rolling operations. The model is capable to take into account the ... [more ▼]

The paper presents a validated numerical model able to predict geometrical distortions of rings during cooling phase after hot ring rolling operations. The model is capable to take into account the effects of all the phenomena resulting from the coupling of thermal, mechanical and metallurgical events. As simulation results strongly depend on the accuracy of input data, physical simulation experiments on real-material samples are developed and carried out to characterize material behaviour during phase transformation. The numerical model is then validated by an industrial case proving its effectiveness in predicting final ring distortions at room temperature. [less ▲]

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See detailComparison of FEM simulations for the incremental forming process
Henrard, Christophe ULg; Habraken, Anne ULg; Szekeres, A. et al

in Advanced Materials Research (2005), 6-8

Incremental forming is an innovative and highly flexible sheet metal forming technology for small batch production and prototyping that does not require any adapted dies or punches to form a complex shape ... [more ▼]

Incremental forming is an innovative and highly flexible sheet metal forming technology for small batch production and prototyping that does not require any adapted dies or punches to form a complex shape. The purpose of this article is to perform FEM simulations of the forming of a cone with a 50-degree wall angle by incremental forming and to investigate the influence of some crucial computational parameters on the simulation. The influence of several parameters will be discussed: the FEM code used (Abaqus or Lagamine, a code developed at the University of Liège), the mesh size, the potential simplification due to the symmetry of the part and the friction coefficient. The output is given in terms of final geometry (which depends on the springback), strain history and distribution during the deformation, as well as reaction forces. It will be shown that the deformation is localized around the tool and that the deformations constantly remain close to a plane strain state for this geometry. Moreover, the tool reaction clearly depends on the way the contact is taken into account. [less ▲]

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See detailDevelopments in finite element simulations of continuous casting
Castagne, Sylvie; Pascon, Frédéric ULg; Blès, Guilhem et al

in Journal de Physique IV (2004), 120

Two complementary approaches of steel continuous casting modelling using the finite element code LAGAMINE have been developed in the M&S Department. We propose here a description of the context in which ... [more ▼]

Two complementary approaches of steel continuous casting modelling using the finite element code LAGAMINE have been developed in the M&S Department. We propose here a description of the context in which the study started, then a description of both macroscopic and mesoscopic approaches. The first one describes the whole continuous casting process, from the free surface in the mould and through the entire machine, including thermal and mechanical behaviour of the steel. The second approach focuses on the prediction of cracks and is developed at the grain scale. Some results are also presented for both models. [less ▲]

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See detailIdentification of material parameters using bi-axial machine
Flores, Paulo; de Montleau, P.; Mathonet, V. et al

in Stören, Sigurd (Ed.) Proceedings of the 7th ESAFORM conference on Materials Forming (2004)

Experimental testing equipment is built in order to identify material parameters of complex phenomenological constitutive laws. This equipment consists in a bi-axial test machine able to perform plane ... [more ▼]

Experimental testing equipment is built in order to identify material parameters of complex phenomenological constitutive laws. This equipment consists in a bi-axial test machine able to perform plane strain and simple shear tests separately or simultaneously and a Miyauchi simple shear test device; an optical extensometer is used to identify the strain field. The article focus on the validation of the results of this new equipment by comparing with results obtained by standard machines and/or by using FEM simulations of already identified materials. The first results show that the bi-axial machine performs the plane strain test optimally and some modifications are proposed in order to improve the results for the simple shear test. Miyauchi device shows a good performance and the experimental results are compared with a FEM simulation. [less ▲]

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See detailFinite-element simulations of cup drawing using the taylor and the lamel model
Van Bael, A.; He, S.; Van Houtte, P. et al

in Stören, Sigurd (Ed.) Proceedings of the 7th ESAFORM conference on Materials Forming (2004)

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See detailFinite element prediction of the swift effect based on Taylor-type polycrystal plasticity models
Duchene, Laurent ULg; Delannay, L.; Habraken, Anne ULg

in Stören, Sigurd (Ed.) Proceedings of the 7th ESAFORM conference on Materials Forming (2004)

This paper describes the main concepts of the stress-strain interpolation model that has been implemented in the non-linear finite element code Lagamine. This model consists in a local description of the ... [more ▼]

This paper describes the main concepts of the stress-strain interpolation model that has been implemented in the non-linear finite element code Lagamine. This model consists in a local description of the yield locus based on the texture of the material through the full constraints Taylor’s model. The prediction of the Swift effect is investigated: the influence of the texture evolution is shown up. The LAMEL model is also investigated for the Swift effect prediction. [less ▲]

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See detailDeep drawing simulations with different polycrystalline models
Duchene, Laurent ULg; de Montleau, P.; Bouvier, S. et al

in Gosh, Somnath; Castro, Jose M.; Lee, June K. (Eds.) Materials Processing and Design: Modeling, Simulation and Applications (NUMIFORM 2004) (2004)

The goal of this research is to study the anisotropic material behavior during forming processes, represented by both complex yield loci and kinematic-isotropic hardening models. A first part of this ... [more ▼]

The goal of this research is to study the anisotropic material behavior during forming processes, represented by both complex yield loci and kinematic-isotropic hardening models. A first part of this paper describes the main concepts of the ‘Stress-strain interpolation’ model that has been implemented in the non-linear finite element code Lagamine. This model consists of a local description of the yield locus based on the texture of the material through the full constraints Taylor’s model. The texture evolution due to plastic deformations is computed throughout the FEM simulations. This ‘local yield locus’ approach was initially linked to the classical isotropic Swift hardening law. Recently, a more complex hardening model was implemented: the physically-based microstructural model of Teodosiu. It takes into account intergranular heterogeneity due to the evolution of dislocation structures, that affects isotropic and kinematic hardening. The influence of the hardening model is compared to the influence of the texture evolution thanks to deep drawing simulations. [less ▲]

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See detailDeep drawing process with different elasto-plastic law
de Montleau, P.; Duchene, Laurent ULg; Bouvier, S. et al

in Stören, Sigurd (Ed.) Proceedings of the 7th ESAFORM conference on Material Forming (2004)

Recently, a combination of a texture based yield locus and of the Teodosiu's hardening model has been implemented in the Finite Element code LAGAMINE of the department M&S of the University of Liège. The ... [more ▼]

Recently, a combination of a texture based yield locus and of the Teodosiu's hardening model has been implemented in the Finite Element code LAGAMINE of the department M&S of the University of Liège. The yield locus is able to take into account the texture updating during a FE simulation. The texture evolves with respect to the crystalographic rotations due to the plastic deformations. Two hardening models are considered: the classical Swift istropic hardening model and the Teodosiu's hardening model that is a physically-based microstructural model. It takes into account intergranular heterogeneity due to the evolution of dislocation structures, that affects the isotropic and the kinematic hardening. The aim of the paper is to compare the influence of the hardening with the influence of the yield shape updating due to the texture evolution, on the final plastic anisotropy, for a deep drawing simulation. The tests are performed for the steel FeP06t that presents a non negligible initial anisotropy. [less ▲]

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See detailModelling the plastic anisotropy of metals
Habraken, Anne ULg

in Archives of Computational Methods in Engineering (2004), 11

This work is an overview of available constitutive laws used in finite element codes to model elastoplastic metal anisotropy behaviour at a macroscopic level. It focuses on models with strong links with ... [more ▼]

This work is an overview of available constitutive laws used in finite element codes to model elastoplastic metal anisotropy behaviour at a macroscopic level. It focuses on models with strong links with the phenomena occurring at microscopic level. Starting from macroscopic well-known models such as Hill or Barlat’s laws, the limits of these macroscopic phenomenological yield loci are defined, which helps to understand the current trends to develop micro-macro laws. The characteristics of micro-macro laws, where physical behaviour at the level of grains and crystals are taken into account to provide an average macroscopic answer are described. Some basic knowledge about crystal plasticity models is given for non-specialists, so every one can understand the microscopic models used to reach macroscopic values. The assumptions defining the transition between the microscopic and macroscopic scales are summarized: full constraint or relaxed Taylor’s model, self-consistent approach, homogenisation technique. Then, the two generic families of micromacro models are presented: macroscopic laws without yield locus where computations on discrete set of crystals provide the macroscopic material behaviour and macroscopic laws with macroscopic yield locus defined by microscopic computations. The models proposed by Anand, Dawson, Miehe, Geers, Kalidindi or Nakamachi belong to the first family when proposals by Montheillet, Lequeu, Darrieulat, Arminjon, Van Houtte, Habraken enter the second family. The characteristics of all these models are presented and commented. This paper enhances interests of each model and suggests possible future developments. [less ▲]

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See detailStructural optimisation of steel frames for industrial applications
Mathonet, V.; Degée, Hervé ULg; Habraken, Anne ULg et al

in Proceedings of the Inverse Problems Design and Optimization Symposium (2004)

The paper reports the first results of a work carried out in close collaboration between Astron Buildings SA, a manufacturer of industrial steel buildings, and different groups of civil engineers and ... [more ▼]

The paper reports the first results of a work carried out in close collaboration between Astron Buildings SA, a manufacturer of industrial steel buildings, and different groups of civil engineers and mathematicians of the University of Liège to develop an automatic design method for structures with tapered members. This research aims at improving the current method of trialerror followed by experienced engineers to optimize the frames constrained by a chosen national construction code and the technological constraints of the producer. The main benefit of this collaboration arises through the application of a mathematical algorithm based on the sequential quadratic programming method (SQP) in order to reduce, in the first step, the weight of the building, under the great number of constraints. The second step, not yet started, will be devoted to the minimization of the real cost of the frame. This report introduces the first results of this industrial application. [less ▲]

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See detailMesoscopic model of intergranular cracks in low carbon steel during cooling of continuous casting
Castagne, S.; Pascon, Frédéric ULg; Lecomte-Beckers, Jacqueline ULg et al

in Lamberigts, M. (Ed.) Proceedings of the 2nd international conference of thermomechanical processing of steels (TMP 2004) (2004)

This paper addresses the problem of transverse cracking during the continuous casting of low carbon steel. The damage mechanisms occurring at high temperature during this process are identified and a ... [more ▼]

This paper addresses the problem of transverse cracking during the continuous casting of low carbon steel. The damage mechanisms occurring at high temperature during this process are identified and a numerical approach for the modelling of these phenomena at the grain scale is proposed. Experiments allowing the identification of the model’s parameters are described. Finally, the first results obtained with the model are presented. [less ▲]

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See detailA trust region algorithm for automatic identification of elasto-viscoplastic model parameters in metallurgical finite element model
Jeunechamps, Pierre-Paul ULg; Walmag, Jérôme; Duysinx, Pierre ULg et al

in Steel Grips 2 (2004), Supplement Metal Forming 2004

Simulation of manufacturing processes, here metal forming, has made major progresses during the last years. The virtual simulation of the manufacturing process being now quite well established, a natural ... [more ▼]

Simulation of manufacturing processes, here metal forming, has made major progresses during the last years. The virtual simulation of the manufacturing process being now quite well established, a natural step ahead consists in trying to find automatic procedures to optimize it. Another perspective is also to take care of the influence of the manufacturing constraints upon the design, which is the long term objective of the present research project. It aims at optimizing the design subject to both service constraints (stiffness and strength) and manufacturing constraints. A preliminary stage is to be able to build high fidelity digital models. Complex models require more and more material parameters for behavior laws (e.g. material constitutive and friction laws), which have to be identified numerically from experimental data. In this material parameter identification process, three steps can be identified. At first, an experimental testing is carried out. The second step consists in building a simulation model of the experiment. Finally, the unknown model parameters are determined to match the experimental data. A standard identification procedure consists in minimizing a given norm (here the Euclidean norm) of the error between the model predictions and the experimental results. Even if the identification problem is generally quasi-unconstrained, it has the same complexity as structural optimization problems because of the highly nonlinear and implicit character of the functions, which is especially amplified by the large deformation simulation analysis. In this paper, we use an approach of elastoplastic calculation by finite elements combined with two optimization algorithms: a Levenberg-Marquardt algorithm, which is rather classical in the literature for solving identification problems (see [2]) and a trust-region one (see [1]), which is a rather novel approach at least for structural problems. The results obtained with these two methods are then compared and discussed on two test cases. The first application is an academic test case to validate the identification method. The second one, the compression of a cylinder, takes into account an actual experiment. In this application, the material is assumed to be elasto-viscoplastic and described by a Norton-Hoff behavior law and an isotropic strain hardening law. The parameters to be identified are the coefficients of the Norton-Hoff law. [less ▲]

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