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Peer Reviewed
See detailFinite element simulation of cold roll-forming processes
BUI, Q. V.; Ponthot, Jean-Philippe ULg

in ACOMEN 2005 (2005)

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See detailFinite Element Simulation of Lubricated Contact in Rolling using the Arbitrary Lagrangian-Eulerian Formulation
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Computer Methods in Applied Mechanics and Engineering (2004), 193(39-41), 4323-4353

In this paper, the lubrication problem in numerical simulation of forming processes is considered. Two efficient convection algorithms are presented in order to update the value stored at the Gauss points ... [more ▼]

In this paper, the lubrication problem in numerical simulation of forming processes is considered. Two efficient convection algorithms are presented in order to update the value stored at the Gauss points during the Eulerian step of an arbitrary Lagrangian Eulerian computation in solid mechanics. They are based on the finite volume method and on the streamline upwind Petrov Galerkin method. After enumerating the difficulties encountered when trying to solve the lubrication problem with the finite element method, a generalization of the formulation introduced by Liu [Simulation of Ring Rolling Process by Arbitrary Lagrangian Eulerian Finite Element Method, vol. 20, p. 225; ASME Winter Meeting, Dallas, Tx, 1990, Int. J. Numer. Methods Engrg. 36 (1993) 855; Numerical Methods in Industrial Forming Processes, Valbonne, France, 1992, p. 731] for the thin film hydrodynamic lubrication regime is presented. This method is then applied to a strip rolling simulation, using the arbitrary Lagrangian Eulerian formalism. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailFinite element simulation of springback in sheet metal forming
Papeleux, Luc ULg; Ponthot, Jean-Philippe ULg

in Journal of Materials Processing Technology (2002), 125(Sp. Iss. SI), 785-791

Although finite element analysis (FEA) is successful in simulating complex industrial sheet forming operations, the accurate and reliable application of this technique to springback has not been widely ... [more ▼]

Although finite element analysis (FEA) is successful in simulating complex industrial sheet forming operations, the accurate and reliable application of this technique to springback has not been widely demonstrated. Several physical parameters, as well as numerical, influence this phenomenon and its numerical prediction. In this paper, we investigate the impact of these parameters on the springback appearing in a 2D U-draw bending. (C) 2002 Elsevier Science B.V. All rights reserved. [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 detailFinite Element Simulations of Simple 2-D Geometries in Slamming
Constatinescu, A.; Neme, A.; Jacques, N. et al

in Int. Conf. OMAE-2008, ASME, Estoril, Portugal, June 2008, Paper 57482 (2008, June)

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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 detailFinite element study of the effect of some local defects on the risk of transverse cracking in continuous casting of steel slabs
Pascon, Frédéric ULg; Habraken, Anne ULg

in Computer Methods in Applied Mechanics & Engineering (2007), 196

This paper introduces a numerical 2.5D model of continuous casting of steel slabs. This model is based on the finite element method and it has been applied to the study of some local defects in a ... [more ▼]

This paper introduces a numerical 2.5D model of continuous casting of steel slabs. This model is based on the finite element method and it has been applied to the study of some local defects in a continuous caster, such as partial blockage of nozzles (leading to a local reduction of secondary cooling rate), locking or misalignment of rolls. The purpose of the study was the evaluation of the effect of such defects on the risk of transverse cracking during bending and unbending operations. To do so, the simulation at macro-scale of the complete process has been first performed in standard conditions to get reference values and then each defect has been introduced. Defining two indexes (indicators) of the risk of transverse cracking, it has been possible to classify the defects in terms of risk increase, helping steel producers to focus on the most critical problems. [less ▲]

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See detailA Finite Element Subproblem Method for Position Change Conductor Systems
Dular, Patrick ULg; Krähenbühl, Laurent; Vazquez Sabariego, Ruth ULg et al

in IEEE Transactions on Magnetics (2012), 48(2), 403-406

Analyses of magnetic systems with position changes of both massive and stranded conductors are performed via a finite element sub- problem method. A complete problem is split into subproblems associated ... [more ▼]

Analyses of magnetic systems with position changes of both massive and stranded conductors are performed via a finite element sub- problem method. A complete problem is split into subproblems associated with each conductor and the magnetic regions. Each complete solution is then expressed as the sum of subproblem solutions supported by different meshes. The subproblem procedure simplifies both meshing and solving processes, with no need of remeshing, and accurately quantifies the effect of the position changes of conductors on both local fields, e.g., skin and proximity effects, and global quantities, e.g., inductances and forces. Applications covering parameterized analyses on conductor positions to moving conductor systems can benefit from the developed approach. [less ▲]

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See detailA Finite Element Subproblem Method for Position Change Conductor Systems
Dular, Patrick ULg; Krähenbühl, Laurent; V Sabariego, Ruth ULg et al

(2011, July)

Analyses of magnetic circuits with position changes of both massive and stranded conductors are performed via a finite element subproblem method. A complete problem is split into subproblems associated ... [more ▼]

Analyses of magnetic circuits with position changes of both massive and stranded conductors are performed via a finite element subproblem method. A complete problem is split into subproblems associated with each conductor and the magnetic regions. Each complete solution is then expressed as the sum of subproblem solutions supported by different meshes. The subproblem procedure simplifies both meshing and solving processes, with no need of remeshing, and accurately quantifies the effect of the position changes of conductors on both local fields, e.g. skin and proximity effects, and global quantities, e.g. inductances and forces. Applications covering parameterized analyses on conductor positions to moving conductor systems benefit from the developed approach. [less ▲]

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See detailFinite element thermo-mechanical model of continuous steel casting
Pascon, Frédéric ULg; Habraken, Anne ULg

in Kiuchi, M.; Nishimura, H.; Yanagimoto, J. (Eds.) Proceedings of the 7th International Conference on Advanced Technology of Plasticity (2002)

Problems in continuous casting of steel are numerous and have been leading producers to find ever more efficient solutions. Wa have developed a thermomechanical model of continuous casting, using a non ... [more ▼]

Problems in continuous casting of steel are numerous and have been leading producers to find ever more efficient solutions. Wa have developed a thermomechanical model of continuous casting, using a non-linear finite element code. Since a complete 3D discretization seemed impossible, the model has been based on a generalized plane strain state (2D1/2) and it includes at the same time thermal exchanges, mechanical behaviour of steel at very high temperature, the ferrostatic pressure and contact between the strand and the machine. This paper presents some results of two industrial applications. First results tend to prove the importance of some process factors (such as the mould taper) and local defects of the machine on the quality of cast products, according with observations. [less ▲]

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See detailFinite Elements for the Lubricated Contact Between Solids in Metal Forming Processes
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Acta Metallurgica Sinica (English Letters) (2000), 13(1), 319-327

In this paper, the lubrication problem in numerical simulation of forming processes is considered. After enumerating the difficulties encountered when trying to solve such a problem with the finite ... [more ▼]

In this paper, the lubrication problem in numerical simulation of forming processes is considered. After enumerating the difficulties encountered when trying to solve such a problem with the finite element method, a generalization of the formulation of Liu for the thin film hydrodynamic lubrication regime is presented. This method is then applied to a strip rolling simulation, using the Arbitrary Lagrangian Eulerian (ALE) formalism. [less ▲]

Detailed reference viewed: 26 (16 ULg)
Peer Reviewed
See detailFinite elements modeling of tunelling in jointed rocks
El Kiri, M.; Charlier, Robert ULg; Debaty, J. M.

in Proc. of the 3rd Int. Symposium NUMOGIII, Numerical Models in Geomechanics (1989, May)

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See detailFinite elements modelling of a large water table aquifer in transient conditions
Dassargues, Alain ULg; Radu, Jean-Pol ULg; Charlier, Robert ULg

in Advances in Water Resources (1988), 11(2), 58-66

A chalky aquifer located near Liege (Belgium), is recharged by infiltration through the overlying loess. Wells and collecting tunnels produce a daily flow of 60OO0m a out of this aquifer when ... [more ▼]

A chalky aquifer located near Liege (Belgium), is recharged by infiltration through the overlying loess. Wells and collecting tunnels produce a daily flow of 60OO0m a out of this aquifer when hydrogeological balances have shown that an average yield of 100 0OO m a/day should be possible. Finite element modelling has been developed to foresee the evolution of the water table to get some additional information especially about the main drainage axis. The transient flow constitutive laws are recalled in confined and unconfined aquifers. A new law is proposed to model the water table surface in transient conditions and with a fixed meshing network. Using the local flow equilibrium and the virtual power principle, the FEM formulation is set up. The time integration and the iteration technique are shortly discussed. The 3D discretization and the modelling of the entire aquifer has been realized. The problem requires about 3600 DOF and 2670 8-nodes isoparametric brick finite elements. The modelling has been quite delicate because of the geometric complexity of the different geological layers. This complexity justifies fully the use of the finite element method; there is indeed a great diversity of geological characteristics and the range of the different permeabilities is very wide. Sensitivity of the model to permeabilities and storage coefficient variations has been studied and various numerical problems have been notified. The calibration procedure is described in its main steps, and the most significant results are presented. [less ▲]

Detailed reference viewed: 52 (18 ULg)
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See detailFinite elements modelling of a large water-table in transient conditions
Dassargues, Alain ULg; Radu, Jean-Pol ULg; Charlier, Robert ULg

in Proc. of the Int. Conf. on Computers Methods and Water Resources (1988, March)

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See detailFinite orbits of language operations
Charlier, Emilie ULg

Scientific conference (2011, May)

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See detailFinite orbits of language operations
Charlier, Emilie ULg; Domaratzski, Michael; Harju, Tero et al

in Lecture Notes in Computer Science (2011), 6638

We consider a set of natural operations on languages, and prove that the orbit of any language L under the monoid generated by this set is finite and bounded, independently of L. This generalizes previous ... [more ▼]

We consider a set of natural operations on languages, and prove that the orbit of any language L under the monoid generated by this set is finite and bounded, independently of L. This generalizes previous results about complement, Kleene closure, and positive closure. [less ▲]

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See detailA finite volume based data transfer method for remeshing. Application to metal forming problems
Bussetta, Philippe ULg; Ponthot, Jean-Philippe ULg

in Proceedings of the 18th International Symposium on Plasticity & Its Current Applications (2012, January)

The resolution of many nonlinear solid mechanical problems with the Finite Elements Method requires remeshing when very large deformations occur. The remeshing operation is divided into two parts: the ... [more ▼]

The resolution of many nonlinear solid mechanical problems with the Finite Elements Method requires remeshing when very large deformations occur. The remeshing operation is divided into two parts: the generation of the new mesh and the data transfer from the old to the new mesh. In dynamic plasticity problems, two kinds of fields have to be transferred: the first is defined thanks to the nodal values and the second one is defined at the integration points. These two kinds of fields are transferred thanks to an original computation of the Data Transfer Method based on the Finite Volume Elements. This method is compared to another one using Mortar Elements to solve metal forming problems. [less ▲]

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See detailA finite volume method with conservative and consistent viscous terms discretization for three-dimensional flows
Vigneron, Didier ULg; Vaassen, Jean-Marc; Essers, Jean-André ULg

Conference given outside the academic context (2005)

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See detailA Finite Volume Spatial Discretisation for taxis-diffusion-reaction systems with axi-symmetry: application to fracture healing
Gerisch, Alf; Geris, Liesbet ULg

in Deutsch, A.; Brusch, L.; Byrne, H. (Eds.) et al Advances in Mathematical Modeling of Biological Systems (2007)

We consider the numerical simulation of a time-dependent taxis-diffusion-reaction model of fracture healing in mice using the method of lines. The partial differential equation problem has an axi ... [more ▼]

We consider the numerical simulation of a time-dependent taxis-diffusion-reaction model of fracture healing in mice using the method of lines. The partial differential equation problem has an axi-symmetric structure and this is employed to properly reduce the model to an equivalent problem in two-dimensional (2D) space leading subsequently to an efficient spatial discretisation. Special care is given to respect conservation of mass and the non-negativity of the solution. The numerical simulation results are contrasted to those obtained from a simplistic reduction of the axi-symmetric model to 2D space (at the same computational cost).We observe quantitative and qualitative differences. [less ▲]

Detailed reference viewed: 28 (0 ULg)