References of "Habraken, Anne"
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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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See detailPrediction of distortion during cooling of steel rolled rings using thermal-mechanical-metallurgical finite element model
Pascon, Frédéric ULg; Blès, Guilhem; Bouffioux, Chantal ULg et al

in Steel Grips 2 (2004), Supplement Metal Forming 1-3

This work takes place in the framework of a CRAFT European project gathering three universities, three companies who produce rings through the ring rolling process and a manufacturer of temperature and ... [more ▼]

This work takes place in the framework of a CRAFT European project gathering three universities, three companies who produce rings through the ring rolling process and a manufacturer of temperature and dimension measurement devices. The final goal of the project is to develop and set up a system, integrated in the industrial process, capable of predicting the geometrical characteristics of final pieces just after the ring rolling stage and to allow the rolling process to avoid dimensional defects through online adaption. In fact, ring rolling production does not imply only the rolling process, but also the cooling and quench stages of steel rings. During all these phases, the dimensions of the pieces change dramatically. In particular, due to the lack of symmetry in the cooling conditions, ring distortions include contraction and rotation of the ring section. The modeling of the cooling phase requires taking into account a large number of phenomena resulting from the coupling of thermal, mechanical and metallurgical effects. A numerical model has been implemented in the non-linear finite element code LAGAMINE, developed by the University of Liège. Such a model can help to better understand the evolution of the geometry during the cooling phase and also the effects of each physical and microstructural parameter implemented in the model on the ring final shape. Effectively, several parameters can affect the ring distortions and the model should take them into account; in particular, the mechanical and thermal behavior of each phase present in the material (metastable austenite, ferrite, pearlite, bainite and martensite). Phase transformation modeling implies the integration of a wide data base of material properties (thermo-physical and mechanical properties of the phases, TTT and CCT diagrams, enthalpy and strain of phase transformation, strain of transformation plasticity…) but only a few of these data are available in literature. Some of them have been found for the reference material (42CrMo4 steel), but additional laboratory experiments have been performed at the Universities of Padua and Liège in order to characterize thermal, mechanical and plastic behaviour of phases. Finally, this paper presents the model validation on an industrial case (measurements of temperature and dimensions of rings have been provided by the manufacturer). Then, some applications are presented, demonstrating the importance of some factors such as some material properties, the shape of the rings, the type of cooling (and the cooling rate) or the symmetry of the cooling scheme on final ring distortion. [less ▲]

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See detailAnisotropic elasto-plastic finite element analysis using a stress-strain interpolation method based on a polycrystalline model
Habraken, Anne ULg; Duchene, Laurent ULg

in International Journal of Plasticity (2004), 20(Issue 8-9), 1525-1560

This paper describes a stress–strain interpolation method to model the macroscopic anisotropic elasto-plastic behavior of polycrystalline materials. Accurate analytical descriptions of yield loci derived ... [more ▼]

This paper describes a stress–strain interpolation method to model the macroscopic anisotropic elasto-plastic behavior of polycrystalline materials. Accurate analytical descriptions of yield loci derived from crystallographic texture [Int. J. Plasticity 19 (2003) 647; J. Phys. IV France 105 (2003) 39] are an interesting alternative to finite element models, where the macroscopic stress is provided by an averaging of microscopic stresses computed on a set of representative crystallites [Acta Metal 22 (1985) 923; Int. J. Plasticity 5 (1989) 67]. The parameters of the analytical functions modeling the yield locus are identified by comparison with a high number of stress tensors computed, for instance, by the well-known Taylor model [J. Inst. Metal 62 (1938) 307]. This identification method depends on the crystallographic texture and should be applied each time that the plastic strain has induced a significant texture evolution. The stress–strain interpolation method accurately describes the anisotropic material behavior in a narrow stress direction defined by only five stress points. The cost of texture updating is then greatly reduced compared to a full analytical function of the yield locus. After the mathematical description of the stress–strain interpolation method, its validity is demonstrated on two non-radial strain paths. The simulations of a deep drawing experiment allow comparing model predictions and measurements. Accuracy and CPU time of the interpolation stress–strain method are judged against two other models, respectively based on a complete analytical yield locus and on the averaging of crystallite stresses. [less ▲]

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See detailStudy of the cooling process of an extruded aluminium profile
Bouffioux, Chantal ULg; Carton, Marc ULg; Lecomte-Beckers, Jacqueline ULg et al

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

The prediction of the final axial stresses and the residual strains of complex extruded aluminium profiles requires a good knowledge of the material behavior and of the industrial process. This paper is ... [more ▼]

The prediction of the final axial stresses and the residual strains of complex extruded aluminium profiles requires a good knowledge of the material behavior and of the industrial process. This paper is focused on the methods required to provide the whole set of data: material ones and process ones. Scanning differential calorimetry, dilatometry and diffusivity tests identify thermophysic material properties and hot tensile tests identify parameters of the elastovisco- plastic Norton-Hoff law. The description of the industrial process and its simulations are described. Then a sensitivity analyzis provides the cooling key parameters causing the undesired final curvature during the industrial process. [less ▲]

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See detailLingopti project: semi-continuous casting process of copper-nickel alloys
Pecquet, Etienne ULg; Volles, Ralf; Lecomte-Beckers, Jacqueline ULg et al

in Proceedings of the 21st International Congress of Theoritical and Applied Mechanics (2004)

The following text deals with casting of copper-nickel alloys. They are high added values materials. The research contains two main parts. Laboratory tests (completed with bibliography) that provide ... [more ▼]

The following text deals with casting of copper-nickel alloys. They are high added values materials. The research contains two main parts. Laboratory tests (completed with bibliography) that provide thermal and mechanical properties of the ingot and the mould but also heat transfer coefficients between the ingot and its environment (mould, air and water). These parameters are required in the second part : development and validation of numerical modelization by the finite element method to optimise the industrial process. [less ▲]

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See detailIdentification of elastoplastic model in large deformation problems
Jeunechamps, Pierre-Paul ULg; Walmag, Jérôme ULg; Delhez, Eric ULg et al

in Cinquini, Carlo (Ed.) Proceedings of the 5th World Congress of Structural and Multidisciplinary Optimization WCSMO5 (2003, May)

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the ... [more ▼]

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the classic Levenberg-Marquardt algorithm. The second one is a trust-region algorithm based on a quadratic model. The two algorithms are compared on two cases, one of them being an actual experiment. [less ▲]

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See detailApplication of a damage model to an aluminium alloy
Castagne, Sylvie; Habraken, Anne ULg; Cescotto, Serge ULg

in International Journal of Damage Mechanics (2003), 12(1), 5-30

An energy-based isotropic elastoplastic model coupled to damage is implemented in the finite element code LAGAMINE developed for more than fifteen years in the MSM department. In this model, based on the ... [more ▼]

An energy-based isotropic elastoplastic model coupled to damage is implemented in the finite element code LAGAMINE developed for more than fifteen years in the MSM department. In this model, based on the local approach of ductile fracture, effective stresses associated to damage variables are introduced. The damage law allows a continuous description of crack appearance. After a brief description of the model, its identification and its validation for an aluminum alloy are presented. Finally, the research of a global rupture criterion associated to this model is introduced. [less ▲]

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See detailIdentification of elastoplastic model parameters in large deformation problems using gamma methods
Jeunechamps, Pierre-Paul ULg; Walmag, J.; Mathonet, V. et al

in Proceedings of the 5th World Congress on Structural and Multidisciplinary Optimization (2003)

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the ... [more ▼]

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the classic Levenberg-Marquardt algorithm. The second one is a trust-region algorithm based on a quadratic model. The two algorithms are compared on two cases, one of them being an actuel experiment. [less ▲]

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See detail2D1/2 thermo-mechanical model of continuous casting using FEM
Pascon, Frédéric ULg; Habraken, Anne ULg

in Brucato, V. (Ed.) Proceedings of the 6th International ESAFORM Conference on Material Forming (2003)

Two complementary approaches of steel continuous casting modelling using the finite element code LAGAMINE have been developed in the M&S Department. The first one (at a macroscopic scale) describes the ... [more ▼]

Two complementary approaches of steel continuous casting modelling using the finite element code LAGAMINE have been developed in the M&S Department. The first one (at a macroscopic scale) 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 grain scale. We present in this paper a description of the context in which the study started, the description of the macroscopic approach and some results. [less ▲]

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See detailFinite element analysis of continuous steel casting
Castagne, S.; Pascon, Frédéric ULg; Miesse, G. et al

in Proceedings of the First International Conference Finite element for process analysis (2003)

In order to analyse the behaviour of steel during continuous casting and to improve the process, two complementary models of steel continuous casting using the finite element code LAGAMINE have been ... [more ▼]

In order to analyse the behaviour of steel during continuous casting and to improve the process, two complementary models of steel continuous casting using the finite element code LAGAMINE have been developed. We propose here 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. Results concerning the optimisation of the mould taper and the analysis of transverse cracks initiation are presented as industrial applications. [less ▲]

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See detailDevelopments in finite element simulations of continuous casting
Castagne, S.; Pascon, Frédéric ULg; Bles, G. et al

in Proceedings of the 2nd International Conference on Thermal Process Modelling and Computer Simulations (ICTPMCS) (2003)

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 detailInvestigation of transverse cracks initiation in continuous steel casting using a finite element approach
Castagne, S.; Habraken, Anne ULg

in Advances in Computational & Experimental Engineering (2003)

A numerical model for steel at elevated temperature which is based on a mesoscopic finite element approach is presented. The objective of the research is the analysis of damage evolution in the material ... [more ▼]

A numerical model for steel at elevated temperature which is based on a mesoscopic finite element approach is presented. The objective of the research is the analysis of damage evolution in the material using information from the macroscopic and microscopic scales. As a final application our results are used to study the industrial process of continuous casting of low carbon steel. [less ▲]

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See detailMicro-macro analysis of steel sheet behaviour in finite element simulations. Application to deep-drawing process.
Duchene, Laurent ULg; Godinas, A.; Cescotto, Serge ULg et al

in Journal de Physique IV (2003), 105

This paper presents a constitutive law based on taylor's model implemented in our non-linear finite element code LAGAMINE. The yield locus is only locally described and a particular interpolation method ... [more ▼]

This paper presents a constitutive law based on taylor's model implemented in our non-linear finite element code LAGAMINE. The yield locus is only locally described and a particular interpolation method has been developed. This local yield locus model uses a discrete representation of the material's texture. The interpolation method is presented and a deep-drawing application is simulated in order to show up the influence of the texture evolution during forming processes. [less ▲]

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See detailNumerical modelling of metal forming - current practice and advanced applications
Cescotto, Serge ULg; Duchene, Laurent ULg; Pascon, Frédéric ULg et al

in Iu, V. P.; Lamas, L. N.; Li, Y. P. (Eds.) et al Computational Methods in Engineering and Science, lu et al. (eds), Proceedings of the 9th International Conference of enhancement and Promotion of Computing Methods for Engineering and Science (2003)

This paper first summarizes the current possibilities and the perspectives of effective modeling of metal forming processes. Practical considerations on manpower requirement and data availability are ... [more ▼]

This paper first summarizes the current possibilities and the perspectives of effective modeling of metal forming processes. Practical considerations on manpower requirement and data availability are included in the discussion. Then, two examples of advanced applications are presented: the micro-macro approach for the modeling of sheet metal forming and the modeling of continuous casting. [less ▲]

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