References of "Habraken, Anne"
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See detailComparison of mechanical efficiency of two microstructures of Ti5553 alloy in the case of bolted flanges submitted to tensile loading
Van Hoof, T.; Ben Bettaieb, Mohamed ULg; Lani, F. et al

in Steel Research International (2010), 81(9), 1148-1152

A combination of numerical and experimental methods is used to compare the efficiency of two microstructures of Ti5553 titanium alloy in an industrial test case. The test case consists in two parts of ... [more ▼]

A combination of numerical and experimental methods is used to compare the efficiency of two microstructures of Ti5553 titanium alloy in an industrial test case. The test case consists in two parts of sectors of aircraft engine stators linked together by an Inconel bolt and submitted to tensile loading. The efficiency of these microstructures is evaluated by using finite element (FE) models. The chosen FE models take into account elasto-visco-plastic material behaviors, contact with friction (bolt heads/flanges and flange/flange), and the initial bolt tightening. The parameters of the elasto-visco-plastic (EVP) material law are adjusted from experimental results extracted from tensile tests performed on Inconel, and Ti5553 alloys. Viscous properties are observed at different strain rates. The studied alloy is assumed to be plastically isotropic. In order to compare the fracture resistance of both microstructures, a micro-mechanical (damage based) rupture model ([4]) is used as a FE post-processing step. [less ▲]

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See detailOptimized Remeshing for Incremental Forming Simulation
Rabahallah, François ULg; Bouffioux, Chantal ULg; Duchene, Laurent ULg et al

in Proceedings of the Advances in Materials and Processing Technologies Conference (2010)

This work presents an advanced numerical methodology which aims to improve the simulations of incremental forming processes [3]. A specific numerical treatment is required to optimize the remeshing ... [more ▼]

This work presents an advanced numerical methodology which aims to improve the simulations of incremental forming processes [3]. A specific numerical treatment is required to optimize the remeshing procedure, in order to decrease the simulation CPU time and deals with the strong process nonlinearities. The algorithm remeshing procedure is implemented in the Lagamine FE code [2] developed at the University of Liège. An elastoplastic law is combined with an isotropic kinematic hardening model. The identification procedure for the material parameters determination takes into account a set of mechanical tests (inverse approach). Numerical simulations of the forming of a pyramid part with two wall angles are performed in order to address the robustness of the implementation and the ability of this numerical methodology to predict the force values. Comparisons between measured and predicted force values are performed. [less ▲]

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See detailMultiaxial fatigue damage modeling of Ti6Al4V alloy
Marmi, Abdeljalil ULg; Habraken, Anne ULg; Duchene, Laurent ULg

in Proceedings of the ICMFF9 Conference (2010)

The aim of this study is to present a new multiaxial fatigue model based on phenomenological approach for the proportional loading. The model estimations are compared to the classical Lemaitre-Chaboche [1 ... [more ▼]

The aim of this study is to present a new multiaxial fatigue model based on phenomenological approach for the proportional loading. The model estimations are compared to the classical Lemaitre-Chaboche [1] fatigue model and experimental results. The comparison is done by simulation of SN curves of notched and un-notched forged TA6V samples. To take into account the effect of stress gradient near notch root, the applied loads such as stress amplitude and Von Mises stress are affected by the triaxialty function introduced by Lemaitre [2]. The models enhanced by triaxialty function give correct results for life estimation of notched samples. [less ▲]

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See detailNumerical Modeling of Representative Cells of Ti-5553 Using Periodic Homogenization Technique
Gerday, Anne-Françoise ULg; Ben Bettaieb, Mohamed ULg; Pascon, Frédéric ULg et al

in Oñate, E.; Owen, D. R. J. (Eds.) Computational plasticity X. Fundamentals and applications (2009, September)

This article focuses on the modeling of representative cells of Ti-5553 using the periodic homogenization theory and a microscopic constitutive law.

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See detailCrystal Plasticity Modelling of Monotonic Shear Tests on Pure Titanium
Hammami, Walid ULg; Bouvier, S.; Duchene, Laurent ULg et al

in Oñate, E.; Owen, D. R. J. (Eds.) Computational plasticity X. Fundamentals and applications (2009, September)

This study consists in the modelling of shear tests performed on pure titanium using a polycrystalline model. Numerical and experimental results are presented.

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See detailThe Role of Void Evolution on the bendability of Steel Sheets
Ben Bettaieb, Mohamed ULg; Lemoine, Xavier; Duchene, Laurent ULg et al

in Oñate, E.; Owen, D. R. J. (Eds.) Computational plasticity X. Fundamentals and applications (2009, September)

In the present contribution, an advanced Gurson model is developed and implemented in the Lagamine finite element code[1. This model is used to simulate the bending process and to predict the bendability ... [more ▼]

In the present contribution, an advanced Gurson model is developed and implemented in the Lagamine finite element code[1. This model is used to simulate the bending process and to predict the bendability of the studied sheet. [less ▲]

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See detailEvaluation of different advanced finite element concepts for detailed stress analysis of laminated composite structures
Rah, K.; Van Paepegem, W.; Habraken, Anne ULg et al

in International Journal of Material Forming (2009), volume 2(Supplément 1), 943-947

Despite their high specific stiffness and strength, laminated composite materials, e.g. fibre-reinforced plastic plies stacked at different fibre orientations, are susceptible to damage. Damage can be ... [more ▼]

Despite their high specific stiffness and strength, laminated composite materials, e.g. fibre-reinforced plastic plies stacked at different fibre orientations, are susceptible to damage. Damage can be divided into interalaminar damage and interlaminar damage. Delamination is a typical kind of interlaminar damage which occurs in laminated composite materials, often accompanied with intralaminar damage, and may lead to a catastrophic structural collapse. The first and most crucial step in the prediction of failure of Laminated Composite Structures (LCS) is to accurately determine the stresses, particularly the three transverse stress components, also called the interlaminar stresses. It is proposed in the present paper that the integration of a displacement based solid-shell formulation and partial-hybrid stress formulation will lead to an accurate and robust solid-shell element, suitable for the efficient and detailed interlaminar stress calculation. [less ▲]

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See detailCrystal plasticity prediction of Lankford coefficient using the MULTISITE model: influence of the critical resolved shear stresses
Hammami, Walid ULg; Delannay, Laurent; Duchene, Laurent ULg et al

in International Journal of Material Forming (2009, August), 2(Supplément 1), 65-68

The MULTISITE model [1] is based on polycrystalline plasticity and the underlying hypotheses of the model are (i) that the deformation of each grain is significantly influenced by the interaction with a ... [more ▼]

The MULTISITE model [1] is based on polycrystalline plasticity and the underlying hypotheses of the model are (i) that the deformation of each grain is significantly influenced by the interaction with a limited number of adjacent grains, and (ii) that local strains deviate from their macroscopic average according to specific “relaxation modes”. The LAMEL model [2] is reformulated into the more general elastic-viscoplastic MULTISITE model permitting various relaxation modes. This model has been validated for cubic materials but hexagonal close-packed (HCP) crystals usually demonstrate larger anisotropy than cubic crystals. The model was used to simulate uniaxial tensile tests performed on rolled sheets made of Ti-6Al-4V. The Lankford coefficients (r) calculated in various directions in the plane of the sheet were analysed. In this study, different grain interaction hypotheses were tested. Besides, it appeared that the value of the critical resolved shear stresses (CRSS) of the different slip system families of the HCP metal had significant effects on the results. Their influence as well as the influence of the strain rate sensitivity parameter was examined. [less ▲]

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See detailInterests and limitations of nanoindentation for bulk multiphase material identification: Application to the β phase of Ti-5553
Gerday, Anne-Françoise ULg; Ben Bettaieb, Mohamed ULg; Duchene, Laurent ULg et al

in Acta Materialia (2009), (57), 5186-5195

This paper focuses on the numerical modeling of nanoindentation tests. The first goal of this study is to collect essential material parameters and boundary conditions from the literature and to complete ... [more ▼]

This paper focuses on the numerical modeling of nanoindentation tests. The first goal of this study is to collect essential material parameters and boundary conditions from the literature and to complete the data required to accurately model nanoindentation tests. The second goal of this study consists in validating the material parameters identified from macroscopic tensile tests of the body-centered cubic b phase of Ti-5553, a new generation of titanium alloy. This validation is performed looking at experimental and numerical nanoindentation curves obtained for different grain orientations. [less ▲]

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See detailMultiaxial fatigue damage modelling at Macro scale of Ti6AL4V alloy
Marmi, Abdeljalil ULg; Habraken, Anne ULg; Duchene, Laurent ULg

in International Journal of Fatigue (2009), 31

The Lemaitre and Chaboche fatigue model is investigated in order to predict the fatigue life of tensile samples with and without notches, defining different stress concentration fields. Elastoplastic FE ... [more ▼]

The Lemaitre and Chaboche fatigue model is investigated in order to predict the fatigue life of tensile samples with and without notches, defining different stress concentration fields. Elastoplastic FE simulations based on anisotropic yield locus description were carried out in order to obtain the stress and strain distributions near the notch root. The Lemaitre and Chaboche fatigue model was applied using the point method (local approach) and the gradient method (non-local approach). [less ▲]

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See detailValidation d'un calcul thermique métallurgique
El Bartali, Ahmed ULg; Zhang, Lihong ULg; Studer, Léo ULg et al

in Appolaire, B.; Arbab Chirani, S.; Calloch, S. (Eds.) et al Mécanique et mécanismes des changements de phases (2009)

Les sollicitations thermomécaniques en général, et les traitements thermiques en particulier, constituent un mode de sollicitation rencontré fréquemment dans le milieu industriel. Pour répondre aux ... [more ▼]

Les sollicitations thermomécaniques en général, et les traitements thermiques en particulier, constituent un mode de sollicitation rencontré fréquemment dans le milieu industriel. Pour répondre aux besoins industriels, réduire les coûts et augmenter les cadences de fabrication, éviter les fissurations et les endommagements après le traitement thermique, la simulation numérique est un outil précieux. De fait, dans un procédé de traitement thermique, il y a des aspects thermiques, métallurgiques et mécaniques. Pour effectuer une simulation numérique complète, il faut établir des modèles pour ces différents aspects et identifier leurs paramètres respectifs. En particulier pour l’aspect métallurgique, il faut connaitre la cinétique de transformation du matériau étudié. Cette cinétique est donnée par les courbes de transformations isothermes (TTT, pour Time, Temperature, Transform) ou par les courbes de transformations en refroidissement continu (CCT, pour Continus Cooling Transformation). Ce papier présente une validation du modèle de Kirkaldy (Kirkaldy et al., 1979) pour définir un diagramme TTT et une validation limitée à l’aspect thermique métallurgique d’un modèle éléments finis thermomécanique métallurgique (Habraken et Bourdouxhe, 1992) qui permet de calculer un diagramme CCT à partir de la donnée du diagramme TTT. Les cas de 2 aciers sont considérés, un acier carbone-manganèse et un acier fortement allié. [less ▲]

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See detailModeling the Vertical Spincasting of Large Bimetallic Rolling Mill Rolls
Studer, Léo ULg; Detrembleur, Sylvain ULg; Dewals, Benjamin ULg et al

in Ambrosio, J. (Ed.) Proceedings of the 7th EUROMECH Solid Mechanics Conference (2009)

In order to take into account the dynamic effects of molten metal during solidification, a methodology is presented to interface a metal solidification solver (coupled thermal mechanical metallurgical ... [more ▼]

In order to take into account the dynamic effects of molten metal during solidification, a methodology is presented to interface a metal solidification solver (coupled thermal mechanical metallurgical finite elements solver) with a specifically developed flow dynamics solver. (flow dynamics and thermics finite volume solver) The numerical set of tools is designed to be used for the simulation of bimetallic hot rolling mill rolls vertical spincasting. Modeling the industrial process for these products imply certain specifications on the numerical methods used, mainly due to the size of the geometrical domain, low Rossby & Ekman numbers, and a high Reynolds number. [less ▲]

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See detailStudy of the formability of steels
Ben Bettaieb, Mohamed ULg; Lemoine, X.; Duchene, Laurent ULg et al

in Proceedings of the International ESAFORM Conference 2009 (2009)

In the present contribution, a new advanced Gurson model [1] is developed. This new model is an extension of the initial one, to the plastic anisotropy and the mixed (isotropic+ kinematic) hardening of ... [more ▼]

In the present contribution, a new advanced Gurson model [1] is developed. This new model is an extension of the initial one, to the plastic anisotropy and the mixed (isotropic+ kinematic) hardening of the fully dense matrix. The nucleation and the growth phases are considered by integrating the empirical laws developed by Bouaziz et al. [2] in this new model. These laws, identified on the basis of X-ray microtomography results, display the triaxiality effect on the nucleation and the growth of cavities. This advanced Gurson model is implemented into a finite element code by using an implicit-explicit integration scheme. FE simulations study the behavior of a sample submitted to tensile test and assess the influence of nucleation and growth laws on the formability of this sample. [less ▲]

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See detailModelling compression tests on aluminium produced by equal channel angular extrusion
Poortmans, Stijn; Duchene, Laurent ULg; Habraken, Anne ULg et al

in Acta Materialia (2009)

The main objective of this paper was to characterize the mechanical properties of commercial purity aluminium AA1050 after being submitted to the equal channel angular extrusion (ECAE) process ... [more ▼]

The main objective of this paper was to characterize the mechanical properties of commercial purity aluminium AA1050 after being submitted to the equal channel angular extrusion (ECAE) process. Compression tests on cylindrical samples extracted from ECAE material are extensively described. The influence of ECAE conditions (number of passes, route, etc.) on the mechanical response is assessed. The extraction of the material behaviour from the experimental results is not straightforward because of inhomogeneities occurring during the test. Therefore, an inverse modelling with the finite element method was used to obtain accurate material parameters by optimization. It appeared that an accurate material yield locus (based on texture analysis) is necessary in order to reproduce the anisotropic behaviour of the ECAE material. On the other hand, its hardening behaviour during compression tests was satisfactorily represented by an elastic (near) perfectly plastic model. [less ▲]

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See detailAnalytical formulation for actual mechanical properties of stainless steel structural members
Rossi, Barbara ULg; Degée, Hervé ULg; Habraken, Anne ULg

in Steel Research International (2008), 79(2), 265-272

One of the fastest growing market segments for stainless steel is its use for cold-formed profiled structural members. It is wellknown that the forming process is likely to significantly enhance the ... [more ▼]

One of the fastest growing market segments for stainless steel is its use for cold-formed profiled structural members. It is wellknown that the forming process is likely to significantly enhance the mechanical properties of the profile by strainhardening. This leads to increased resistance compared to a resistance assessment based on nominal properties, even if this effect is partly counterbalanced by the introduction of residual stresses. It is thus necessary to be able to accurately determine its actual mechanical properties. For this purpose, experimental data and theoretical investigations aiming at determining the material behaviour of coldformed stainless steel profiles including the effects of the forming process are reported in this paper. [less ▲]

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See detailMulti-Step toolpath approach to overcome forming limitations in single point incremental forming
Verbert, J.; Belkassem, B.; Henrard, Christophe ULg et al

in Boisse, P. (Ed.) Proceedings of the 11th International ESAFORM Conference on Material Forming (2008)

Although Incremental Forming offers distinct advantages over traditional forming processes, such as short lead times and low setup costs, the process still has some drawbacks. Besides the obtainable ... [more ▼]

Although Incremental Forming offers distinct advantages over traditional forming processes, such as short lead times and low setup costs, the process still has some drawbacks. Besides the obtainable accuracy, one of the main challenges of the process are the process limits. Many workpiece geometries cannot be manufactured due to the fact that the maximum wall angle that can be formed is limited for a certain sheet material and thickness to a given angle. Different solutions to this approach have been proposed and this paper further investigates one of those solutions, the multi step approach for single point incremental forming. Experiments were performed and compared with simulations to better understand the phenomena underlying the improved process performance. [less ▲]

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See detailAdaptive remeshing for incremental forming simulation
Lequesne, Cédric ULg; Henrard, Christophe ULg; Bouffioux, Chantal ULg et al

in Pavel, H. (Ed.) Proceedings of the 7th International Conference and Workshop on Numerical Simulation od 3D Sheet Metal Forming Processes (NUMISHEET 2008) (2008)

Incremental forming of aluminium sheets has been modelled by finite element simulations. However the computation time was prohibitive because the tool deforms every part of the sheet and the mesh along ... [more ▼]

Incremental forming of aluminium sheets has been modelled by finite element simulations. However the computation time was prohibitive because the tool deforms every part of the sheet and the mesh along the tool path must be very fine. Therefore, an adaptive remeshing method has been developed. The elements that are close to the tool are divided into smaller elements in order to have a fine mesh where high deformations occur. Consequently, some new nodes become inconsistent with the non-refined neighbouring elements. To overcome that problem, their displacements are constrained, i.e. dependent on their master nodes displacements. The data concerning these new nodes and elements are stored in a linked list, which is a fundamental data structure. It consists of a sequence of cells, each containing data fields and a pointer towards the next cell. The goal of this article is to explain the developments performed in the finite element code, to validate the adaptive remeshing technique and to measure its efficiency using the line test simulation. During this test, which is a simple incremental forming test, a clamped sheet is deformed by a spherical tool moving along a linear path. [less ▲]

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See detailComparison of the tests chosen for material parameter identification to predict single point incremental forming forces
Bouffioux, Chantal ULg; Henrard, Christophe ULg; Eyckens, P. et al

in Asnafi, Nader (Ed.) Proceedings of the International Conference of International Deep Drawing Research Group (IDDRG 2008) (2008)

Single Point Incremental Forming is a sheet forming process that uses a smooth-ended tool following a specific tool path and thus eliminates the need for dedicated die sets. Using this method, the ... [more ▼]

Single Point Incremental Forming is a sheet forming process that uses a smooth-ended tool following a specific tool path and thus eliminates the need for dedicated die sets. Using this method, the material can reach a very high deformation level. A wide variety of shapes can be obtained without specific and costly equipment. To be able to optimize the process, a model and its material parameters are required. The inverse method has been used to provide material data by modeling experiments directly performed on a SPIF set-up and comparing them to the experimental measurements. The tests chosen for this study can generate heterogeneous stress and strain fields. They are performed with the production machine itself and are appropriate for the inverse method since their simulation times are not too high. [less ▲]

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See detailMultiscale finite element study of Ti-555
Habraken, Anne ULg; Gerday, Anne-Françoise ULg; Duchene, Laurent ULg

in Akhtar S. Khan; Babak Farrokh; Baig, M. (Eds.) et al Proceedings of the 14th International Symposium on Plasticity & Its Current Applications, Mechanics & Mechanisms of Finite Plastic Deformation (2008)

The material parameters of the 2 phases Ti-555 alloy have to be extracted in order to perform simulations on representative microscopic cells and guide the optimization of the alloy. The identification of ... [more ▼]

The material parameters of the 2 phases Ti-555 alloy have to be extracted in order to perform simulations on representative microscopic cells and guide the optimization of the alloy. The identification of the flow parameters of the BCC β-phase is discussed, using macroscopic and microscopic constitutive laws. The validation is performed, comparing experimental and numerical tensile tests obtained for different strain rates. [less ▲]

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