References of "Gerday, Anne-Françoise"
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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 ▲]

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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 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 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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See detailComparisons of FEM approaches modelling the metal plastic behaviour
Habraken, Anne ULg; Gerday, Anne-Françoise ULg; Diouf, B. et al

in Cueto, Elías; Chinesta, Francisco (Eds.) Proceedings of the 10th ESAFORM Conference on Material Forming (2007)

Simple phenomenological laws (e.g. classical Hill 1948 quadratic law) are compared to more complex laws based on crystal plasticity through various numerical simulations: mechanical tests of ECAE ... [more ▼]

Simple phenomenological laws (e.g. classical Hill 1948 quadratic law) are compared to more complex laws based on crystal plasticity through various numerical simulations: mechanical tests of ECAE materials, nanoindentation of titanium alloys and copper, and large strain torsion of copper bars. Taking into consideration the complexity of the investigated processes, the numerical results present rather good agreements with experimental observations. [less ▲]

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See detailInverse modelling of nanoindentation tests to identify Ti-555 behaviour
Gerday, Anne-Françoise ULg; Clement, N.; Jacques, P. J. et al

in Proceedings of the 11th world conference on titanium (2007)

Nanoindentation is commonly used to probe local plastic properties of materials [1-4]. From these nanoindentation tests, finite element (FE) modeling is currently used to identify material data. The ... [more ▼]

Nanoindentation is commonly used to probe local plastic properties of materials [1-4]. From these nanoindentation tests, finite element (FE) modeling is currently used to identify material data. The general ambition of this research is to extract the material parameters representative of the response of a new generation of Ti alloy, called Ti-555, in order to perform simulations on representative microscopic cells and guide the optimization of the alloy. In this paper, the identification of the flow parameters of the -phase of this alloy, using a microscopic crystal plasticity-based constitutive law is described. The nanoindentation tests are performed using a pyramidal Berkovich diamond indenter and the different slip systems of the b.c.c. -phase are supposed to be activated with identical critical shear stresses. The FE nanoindentation force-displacement curves obtained with the microscopic constitutive law are compared to the experimental ones. The influence of the orientation of the grains is also analysed. A previous sensivity analysis on different parameters with different constitutive laws and materials has shown a great influence of different parameters on the nanoindentation results but almost no influence of other parameters [5-6]. [less ▲]

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See detailFinite element simulations of nanoindentation in beta metastable Ti alloys
Gerday, Anne-Françoise ULg; Clement, N.; Jacques, P. J. et al

in Juster, Neal; Rosochowski, Andrzej (Eds.) Proceedings of the 9th International ESAFORM Conference on Material Forming (2006)

Nanoindentation is a versatile tool to probe local plastic properties of materials. Finite element (FE) modelling is currently used to identify material data from nanoindentation tests [1-4]. The general ... [more ▼]

Nanoindentation is a versatile tool to probe local plastic properties of materials. Finite element (FE) modelling is currently used to identify material data from nanoindentation tests [1-4]. The general ambition of this research is to extract the material parameters describing the response of a new Ti alloy, called Ti-555, in order to perform simulations on representative microscopic cells and guide the optimisation of this alloy. In this paper, the first steps of the identification of the macroscopic flow parameters of the β-phase are described. The nanoindentation tests using a pyramidal Berkovich diamond indenter are performed in the β-phase. The FEM results with different parameters of an isotropic and anisotropic elasto-plastic (EP) constitutive law are analyzed and the predicted shapes are compared to the final shape of the indented material. The FE results very much depend on physical model choices, and cannot rely on an automatic identification approach. [less ▲]

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See detailAxes rotation during simple shear test: Measurement and predictions
Lelotte, Thomas; Gerday, Anne-Françoise ULg; Flores, Paulo et al

in Oñate, E.; Owen, D. R. J. (Eds.) Proceedings of the VIII International Conference on Computational Plasticity (COMPLAS VIII) (2005)

For a simple shear test, the finite element (FE) local frame, that stays orthogonal, does not follow the anisotropic material frame. To study this effect, FE simulations have been compared with ... [more ▼]

For a simple shear test, the finite element (FE) local frame, that stays orthogonal, does not follow the anisotropic material frame. To study this effect, FE simulations have been compared with experimental results (optical and texture measurements) and it was shown that it is necessary to take into account the effect of texture updating for local axes rotation. [less ▲]

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See detailModeling of the fatigue cracks in welded beam-to-column connection of steel moment frame buildings submitted to earthquake
Lequesne, Cédric ULg; Gerday, Anne-Françoise ULg; Plumier, André ULg et al

in Aliabadi, M. H.; Planas, J.; Buchholz, F.-G. (Eds.) et al Proceedings of the 4th International Conference on Fracture and Damage Mechanics (2005)

Fatigue cracks in welded connections of steel moment frame buildings submitted to earthquakes are studied. The connections of beams with thick flanges designed to resist to seismic phenomena by plastic ... [more ▼]

Fatigue cracks in welded connections of steel moment frame buildings submitted to earthquakes are studied. The connections of beams with thick flanges designed to resist to seismic phenomena by plastic dissipation are presented. The structural components, the materials and the crack mechanics are described. To predict the crack initiation, the knowledge of residual internal stresses, generated by the welding process, is required. So these stresses are assessed by a FEM thermo-mechanical analysis. The potential sites of crack locations are detected by using an FEM model of the connection with the continuum damage model of Lemaître and Chaboche. After these FEM analyses, new meshes with specific elements located at the potential crack locations are defined. A cohesive zone law is used to model the crack propagation. This model describes the crack growth by analyzing the energy released by the generation of the new surfaces and damage micro-phenomena behind the crack tip. A constitutive tension-separation law computes this energy. In these cases of low cycle fatigue, the damage and the cyclic loading conditions are taken into account. [less ▲]

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