References of "Habraken, Anne"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailNumerical simulation of DP steel damage using a physically-based GTN model
Fansi, Joseph; Habraken, Anne ULg; Balan, Tudor et al

Poster (2012)

Poster describing the identification and use of Gurson model on DP Steel

Detailed reference viewed: 36 (17 ULg)
Full Text
Peer Reviewed
See detailApplication of an Advanced GTN Model
Fansi, Joseph; Habraken, Anne ULg; Balan, Tudor et al

Conference (2012)

The present contribution consists of implementing an advanced GTN damage model as a "User Material subroutine" in the Abaqus FE code. This damage model is based on specific nucleation and growth laws.This ... [more ▼]

The present contribution consists of implementing an advanced GTN damage model as a "User Material subroutine" in the Abaqus FE code. This damage model is based on specific nucleation and growth laws.This model is applied to the prediction of the damage evolution and the stress state in notched specimens made of dual phase steel. By comparing numerical predictions with experimental results based on high-resolution X-ray absorption tomography, the numericalapproach was improved and validated [less ▲]

Detailed reference viewed: 51 (18 ULg)
Full Text
Peer Reviewed
See detailFinite element analysis of the free surface effects on the mechanical behavior of thin nickel polycrystals
Keller, Clément ULg; Hug, eric; Habraken, Anne ULg et al

in International Journal of Plasticity (2012), 29

The miniaturization of metallic samples has been proved to deeply affect their mechanical properties leading to a softening or a hardening effect depending on the order of the dimension reduction. The ... [more ▼]

The miniaturization of metallic samples has been proved to deeply affect their mechanical properties leading to a softening or a hardening effect depending on the order of the dimension reduction. The objective of this work is to provide new numerical results which explain the softening mechanisms on the mechanical behavior for nickel polycrystals which have been experimentally characterized by the authors in a previous published paper (Keller et al., 2011). Based on a strain gradient crystalline plasticity model identified for nickel, simulations of tensile tests were performed for samples with different thicknesses and grain sizes. The simulations correctly reproduce the softening effect linked to a decrease in the thickness and in the number of grains across the thickness. The analysis of the plasticity mechanisms shows that the softening is due to surface effects which are discussed in terms of grain orientations, dislocation mean free path and long-range back-stress. The model also predicts a hardening mechanism for further dimension reduction if the samples have only grain boundaries perpendicular to the tensile direction. In this case, the modification of the mechanical behavior is due to strain gradients formation. [less ▲]

Detailed reference viewed: 82 (30 ULg)
Full Text
Peer Reviewed
See detailCompression test for metal characterization using digital image correlation and inverse modeling
Tuninetti Vásquez, Victor ULg; Gilles, Gaëtan ULg; Péron-Lührs, Vincent ULg et al

in Procedia IUTAM (2012)

In the case of sheet metal characterization, compression tests at normal direction of the sheet can be done by means of the layer compression test. Circular cylinder specimens are commonly used for ... [more ▼]

In the case of sheet metal characterization, compression tests at normal direction of the sheet can be done by means of the layer compression test. Circular cylinder specimens are commonly used for compression test but the complicated layer alignment is time consuming and may induce a wrong anisotropy characterization. This final goal explains the interest of working on elliptic shape. In this article, an elliptical cylinder specimen is proposed and tested for bulk Titanium alloy. Full-field optical technique (3D Digital Image Correlation) is used for displacement measurements by means of three camera systems (Limess), which allows out-of-plane displacement/strain fields on around 300° of the specimen. The use of this technique easily provides accurate barreling profile used to compute Coulomb friction coefficient by using inverse method. [less ▲]

Detailed reference viewed: 129 (57 ULg)
Full Text
Peer Reviewed
See detailExperimental and numerical study of an AlMgSc sheet formed by an incremental process
Bouffioux, Chantal ULg; Lequesne, Cédric ULg; Vanhove, H. et al

in Journal of Materials Processing Technology (2011), 211(11), 1684-1693

A recently developed AlMgSc alloy is studied since this material, which is well adapted to the aeronautic domain, is poorly known. The first objective is to reach a better knowledge of this alloy to ... [more ▼]

A recently developed AlMgSc alloy is studied since this material, which is well adapted to the aeronautic domain, is poorly known. The first objective is to reach a better knowledge of this alloy to provide the missing useful information to the aeronautic industry and to help research institutes who want to simulate sheet forming processes by Finite Element (FE) simulations. A set of experimental tests has been performed on the as-received sheets, material laws have been chosen and the corresponding material parameters have been adjusted to correctly describe the material behaviour. The second objective is to study the applicability of the Single Point Incremental Forming process (SPIF) on this material. Truncated cones with different geometries were formed and the maximum forming angle was determined. A numerical model was developed and proved to be able to predict both the force evolution during the process and the final geometrical shape. Moreover, the model helps reaching a better understanding of the process. The characterisation method described in this research and applied on the AlMgSc alloy can be extended to other alloys. In addition, the numerical simplified model, able to accurately describe the SPIF process with a reduced computation time, can be used to study more complex geometries. [less ▲]

Detailed reference viewed: 70 (27 ULg)
Full Text
Peer Reviewed
See detailPhenomenological and crystal plasticity approaches to describe the mechanical behaviour of Ti6Al4V titanium alloy
Hammami, Walid ULg; Gilles, Gaëtan ULg; Habraken, Anne ULg et al

in International Journal of Material Forming (2011), 4(2), 205-2015

This paper presents a multiscale study of the quasi-static behaviour of a Ti6Al4V titanium alloy sheet. Tensile and compressive tests were carried out on specimens along several orientations from the ... [more ▼]

This paper presents a multiscale study of the quasi-static behaviour of a Ti6Al4V titanium alloy sheet. Tensile and compressive tests were carried out on specimens along several orientations from the rolling direction in order to characterise the material anisotropy. In parallel, X-Ray diffraction texture measurements were performed before and after deformation in tension. A phenomenological model (CPB06exn) and a multiscale crystal plasticity model (Multisite) were investigated to describe the mechanical behaviour of the tested material. The identification of the material parameters provides good predictions of the plastic anisotropy using both tensile and compressive data. The crystal plasticity model is in good agreement with the experiments in tension but it was observed that some improvements should be done to take into account the tension-compression asymmetry displayed by the material. Moreover both models lead to a good prediction of the Lankford’s coefficients and yield strength. [less ▲]

Detailed reference viewed: 90 (39 ULg)
Full Text
Peer Reviewed
See detailNumerical modeling of damage evolution of DP steels on the basis of X-ray tomography measurements
Ben Bettaieb, Mohamed ULg; Lemoine, Xavier; Bouaziz, O. et al

in Mechanics of Materials (2011), 43(3), 139-156

In order to couple the damage evolution and the stress state of DP steel grades, a new advanced GTN (Gurson-Tvergaard-Needleman) model was developed and implemented into a finite element code. This model ... [more ▼]

In order to couple the damage evolution and the stress state of DP steel grades, a new advanced GTN (Gurson-Tvergaard-Needleman) model was developed and implemented into a finite element code. This model is an extension of the original one. It takes into account the plastic anisotropy and the mixed (isotropic+ kinematic) hardening of the matrix. Two different methods to compute the void volume fraction were developed and used within the constitutive equations. The first method is new and allows the accurate modeling of the observations of damage initiation and growth in DP steels measured using high-resolution X-ray absorption tomography (Bouaziz et al., 2008; Maire et al., 2008). The second method is classic and assumes the additive decomposition of the total void volume fraction into a nucleation and a growth part. A parametric study is carried out to assess the effect of the kinematic hardening on some mechanical parameters such as the equivalent plastic strain, the triaxiality and the porosity. The numerical predictions are favorably compared to the experimental results. [less ▲]

Detailed reference viewed: 82 (29 ULg)
Full Text
Peer Reviewed
See detailTi6A14V Anisotropy and Texture Evolution Predictions Using Multisite and Self Consistent Crystal Plasticity Models
Hammami, Walid ULg; Tirry, Wim; Coghe, Frederick et al

in Proceedings of the 12th World conference on Titanium (2011)

Detailed reference viewed: 67 (33 ULg)
Full Text
Peer Reviewed
See detailNew Solid-Shell Finite Element Based on EAS and ANS Concepts for Sheet Metal Forming
Ben Bettaieb, Amine ULg; Duchene, Laurent ULg; Zhang, Lihong ULg et al

in AIP Conference Proceedings (2011), 1383

Detailed reference viewed: 83 (22 ULg)
Full Text
Peer Reviewed
See detailMaterial behavior of the hexagonal alpha phase of a titanium alloy identified from nanoindentation tests
Gerday, Anne-Françoise ULg; Ben Bettaieb, Mohamed ULg; Duchene, Laurent ULg et al

in European Journal of Mechanics A : Solids (2011), 30

This article focuses on the numerical modeling of nanoindentation tests performed on the hexagonal a phase of Ti-5553 alloy in order to identify its mechanical behavior. The main goal consists in ... [more ▼]

This article focuses on the numerical modeling of nanoindentation tests performed on the hexagonal a phase of Ti-5553 alloy in order to identify its mechanical behavior. The main goal consists in determining the relative strength of the slip modes in the a phase of Ti-5553. This work was performed using an elastoviscoplastic crystal plasticity-based constitutive law. The difficulties in determining the slip systems that can be activated and their corresponding critical resolved shear stresses (CRSS) are discussed. Numerical predictions are compared to experimental nanoindentation curves. [less ▲]

Detailed reference viewed: 83 (19 ULg)
Full Text
Peer Reviewed
See detailNotched Specimens Fracture Prediction with an Advanced GTN Model
Fansi Tchonko, Joseph ULg; Ben Bettaieb, Mohamed ULg; Balan, Tudor et al

in Key Engineering Materials [=KEM] (2011), 488-489

Detailed reference viewed: 38 (8 ULg)
Full Text
Peer Reviewed
See detailA partial hybrid stress solid-shell element for the analysis of laminated composites
Rah, Kamran; Van Paepegem, Wim; Habraken, Anne ULg et al

in Computer Methods in Applied Mechanics and Engineerinrg (2011), 200(49-52), 35263539

In this paper a low order partial hybrid stress solid-shell element based on the composite energy functional for the analysis of laminated composite structures is presented. This solid-shell element has ... [more ▼]

In this paper a low order partial hybrid stress solid-shell element based on the composite energy functional for the analysis of laminated composite structures is presented. This solid-shell element has eight nodes with only displacement degrees of freedoms, and three-dimensional constitutive models can be directly employed in the present formulation without any additional treatment. The assumed interlaminar stress field provides very accurate interlaminar stress calculation through the element thickness. These elements can be stacked on top of each other to model multilayer structures, fulfilling the interlaminar stress continuity at the interlayer surfaces and zero traction conditions on the top and bottom surfaces of the laminate. The present solid-shell does not show the transverse shear, trapezoidal and thickness locking phenomenon. [less ▲]

Detailed reference viewed: 16 (1 ULg)
Full Text
Peer Reviewed
See detailForming forces in single point incremental forming: prediction by finite element simulations, validation and sensitivity
Henrard, Christophe; Bouffioux, Chantal ULg; Eyckens, P. et al

in Computational Mechanics (2011), 47

The aim of this article is to study the accuracy of finite element simulations in predicting the tool force occurring during the single point incremental forming (SPIF) process. The forming of two cones ... [more ▼]

The aim of this article is to study the accuracy of finite element simulations in predicting the tool force occurring during the single point incremental forming (SPIF) process. The forming of two cones in soft aluminum was studied with two finite element (FE) codes and several constitutive laws (an elastic–plastic law coupled with various hardening models). The parameters of these laws were identified using several combinations of a tensile test, shear tests, and an inverse modeling approach taking into account a test similar to the incremental forming process. Comparisons between measured and predicted force values are performed. This article shows that three factors have an influence on force prediction: the type of finite element, the constitutive law and the identification procedure for the material parameters. In addition, it confirms that a detailed description of the behavior occurring across the thickness of the metal sheet is crucial for an accurate force prediction by FE simulations, even though a simple analytical formula could provide an otherwise acceptable answer. [less ▲]

Detailed reference viewed: 106 (30 ULg)
Full Text
Peer Reviewed
See detailStrain Evolution in the Single Point Incremental Forming Process: Digital Image Correlation Measurement and Finite Element Prediction
Eyckens, P.; Belkassem, B.; Henrard, Christophe et al

in International Journal of Material Forming (2011)

Incremental Sheet Forming (ISF) is a relatively new class of sheet forming processes that allow the manufacture of complex geometries based on computer-controlled forming tools in replacement (at least ... [more ▼]

Incremental Sheet Forming (ISF) is a relatively new class of sheet forming processes that allow the manufacture of complex geometries based on computer-controlled forming tools in replacement (at least partially) of dedicated tooling. This paper studies the straining behaviour in the Single Point Incremental Forming (SPIF) variant (in which no dedicated tooling at all is required), both on experimental basis using Digital Image Correlation (DIC) and on numerical basis by the Finite Element (FE) method. The aim of the paper is to increase understanding of the deformation mechanisms inherent to SPIF, which is an important issue for the understanding of the high formability observed in this process and also for future strategies to improve the geometrical accuracy. Two distinct large-strain FE formulations, based on shell and first-order reduced integration brick elements, are used to model the sheet during the SPIF processing into the form of a truncated cone. The prediction of the surface strains on the outer surface of the cone is compared to experimentally obtained strains using the DIC technique. It is emphasised that the strain history as calculated from the DIC displacement field depends on the scale of the strain definition. On the modelling side, it is shown that the mesh density in the FE models plays a similar role on the surface strain predictions. A good qualitative agreement has been obtained for the surface strain components. One significant exception has however been found, which concerns the circumferential strain evolution directly under the forming tool. The qualitative discrepancy is explained through a mechanism of through-thickness shear in the experiment, which is not fully captured by the present FE modelling since it shows a bending-dominant accommodation mechanism. The effect of different material constitutive behaviours on strain prediction has also been investigated, the parameters of which were determined by inverse modelling using a specially designed sheet forming test. Isotropic and anisotropic yield criteria are considered, combined with either isotropic or kinematic hardening. The adopted constitutive law has only a limited influence on the surface strains. Finally, the experimental surface strain evolution is compared between two cones with different forming parameters. It is concluded that the way the plastic zone under the forming tool accommodates the moving tool (i.e. by through-thickness shear or rather by bending) depends on the process parameters. The identification of the most determining forming parameter that controls the relative importance of either mechanism is an interesting topic for future research. [less ▲]

Detailed reference viewed: 114 (18 ULg)
Full Text
Peer Reviewed
See detailTowards the Prediction of Damage Of Peritectic Steels During Continuous Casting Process
Keller, Clément ULg; Schwartz, Renée; Bobadilla, Manuel et al

in AIP Conference Proceedings (2011), 1353

In the Continuous Casting process, products are sometimes rejected or called defective due to the presence of transversal cracks. This type of macroscopic damage is expected to be due to a ductility loss ... [more ▼]

In the Continuous Casting process, products are sometimes rejected or called defective due to the presence of transversal cracks. This type of macroscopic damage is expected to be due to a ductility loss during cooling in the bending and unbending areas of the CC line. In order to study this damage, a 2D model has been developed to predict at the mesoscopic level the intergranular crack event taking into account the creep and diffusion of voids. Already validated for a microalloyed steel, the model is identified and used in this study to predict the crack formation for three different grades of peritectic steels. Results show encouraging predictions of the damage. [less ▲]

Detailed reference viewed: 72 (33 ULg)
Full Text
Peer Reviewed
See detailA finite element analysis of the bending and the bendability of metallic sheets
Ben Bettaieb, Mohamed ULg; Lemoine, Xavier; Bouaziz, O. et al

in International Journal of Material Forming (2011), 4(3), 283-297

The main objective of this paper is to study the bendability of metallic sheets by using the finite element method. In this aim, two variants of an advanced Gurson-Tvergaard-Needleman model [1, 2] are ... [more ▼]

The main objective of this paper is to study the bendability of metallic sheets by using the finite element method. In this aim, two variants of an advanced Gurson-Tvergaard-Needleman model [1, 2] are implemented in the home made FE code LAGAMINE [3, 4] and coupled with the Thomason model to predict the coalescence of voids. This advanced model is an extension of the original one to take into account of the plastic anisotropy and the mixed (isotropic + kinematic) hardening of the matrix. The difference between the two variants is related to the modeling of the damage evolution. As the advanced model is used to study the bending process, its yield function is slightly modified in order to take into account the loadings with negative triaxiality ratios. These present implementations are used to simulate the pure bending process and to predict the bendability of dual phase (DP) steel. The combined effect of an initial geometrical imperfection and damage evolution on the bendability is also studied. [less ▲]

Detailed reference viewed: 46 (14 ULg)
Full Text
Peer Reviewed
See detailOn the numerical integration of an advanced Gurson model
Ben Bettaieb, Mohamed ULg; Lemoine, Xavier; Duchene, Laurent ULg et al

in International Journal for Numerical Methods in Engineering (2011), 85(8), 1049-1072

This article is focused on a new extended version of Gurson's model (J. Eng. Mater. Technol. 1977; 99:2–15), its numerical integration scheme and its consistent tangent matrix being within an FE code ... [more ▼]

This article is focused on a new extended version of Gurson's model (J. Eng. Mater. Technol. 1977; 99:2–15), its numerical integration scheme and its consistent tangent matrix being within an FE code. First, this new advanced Gurson model is proposed, which is an extension of the original to take into account plastic anisotropy and mixed (isotropic+kinematic) hardening. In this paper, only the growth phase of cavities is considered (the nucleation of new voids is ignored). Second, a new numerical algorithm for the integration of this new Gurson model is presented. The algorithm is implicit in all variables and is unconditionally stable. This algorithm is generic and could be used for other anisotropic yield functions and other hardening laws. Third, the consistent tangent matrix is computed in an explicit way by exact linearization of the constitutive equations. To check its efficiency and robustness, the proposed integration algorithm is compared, under some simplified assumptions and choices, with the algorithms of Aravas (Int. J. Numer. Meth. Engng 1987; 24:1395–1416) and Kojic (Int. J. Numer. Meth. Engng 2002; 53(12):2701–2720). The performance of the developed consistent modulus, compared to other techniques for the computation of the tangent matrix is assessed. The paper ends with numerical simulations of tensile tests on homogeneous and notched specimens. [less ▲]

Detailed reference viewed: 91 (32 ULg)
Full Text
Peer Reviewed
See detailExperimental characterization and elasto-plastic modeling of the quasi-static mechanical response of TA-6 V at room temperature
Gilles, Gaëtan ULg; Hammami, Walid ULg; Libertiaux, Vincent ULg et al

in International Journal of Solids & Structures (2011), 48(9), 12771289

The paper presents an experimental study of the quasi-static deformation behavior of a TA-6V in sheet form. To quantify the plastic anisotropy and the tension-compression asymmetry of this material at ... [more ▼]

The paper presents an experimental study of the quasi-static deformation behavior of a TA-6V in sheet form. To quantify the plastic anisotropy and the tension-compression asymmetry of this material at room temperature, monotonic tensile and compressive tests were carried out on specimens cut out along several orientations in the plane of the sheet. It was observed that although the tensile flow stress anisotropy is very mild, the Lankford coefficients’ anisotropy is very pronounced. To describe the observed mechanical response an elastic/plastic approach was used. Yielding was described using a family of yield criteria that account for strength differential effects and allow an improved description of the anisotropy and its evolution through multiple linear transformations. Comparisons between uniaxial monotonic data and FE simulations using the model show a very good agreement. [less ▲]

Detailed reference viewed: 81 (54 ULg)
Peer Reviewed
See detailInvestigation of the Efficiency of the Ti555 Compared with TA6V Alloy in the Case of an Aeronautic Application
Ben Bettaieb, Mohamed ULg; Van Hoof, T.; Zhang, Lihong ULg et al

in Proceedings of the 12th World Conference on Titanium (2011)

Detailed reference viewed: 26 (1 ULg)