References of "Boman, Romain"
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See detailNumerical Simulation of Cold Roll Forming Process
Bui, Quoc Viet; Papeleux, Luc ULg; Boman, Romain ULg et al

in Banabic, Dorel (Ed.) Proceedings of the 8th ESAFORM Conference on Material Forming (2005, April)

Cold roll-forming process of a U profile is modelled and simulated. The simulation is based on a 3D finite element analysis with the help of the home made Metafor code. The prediction on dimensions and ... [more ▼]

Cold roll-forming process of a U profile is modelled and simulated. The simulation is based on a 3D finite element analysis with the help of the home made Metafor code. The prediction on dimensions and deformed shape of the cold roll-formed sheet is in good agreement with the experimental results. Parametric study on roll forming parameters, such as the yield limit and the hardening property of materials, and the distance between stations is performed. [less ▲]

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See detailNumerical simulation of tribological devices used as a set of benchmarks for comparing contact algorithms
Chabrand, Patrick; Dubois, Frédéric; Graillet, Denis et al

in Finite Elements in Analysis & Design (2005), 41(6), 637-665

The aim of the present study was to carry out a numerical comparison of different frictional contact algorithms. Therefore three different contact algorithms (Lemke, penalty and Augmented Lagrangian) have ... [more ▼]

The aim of the present study was to carry out a numerical comparison of different frictional contact algorithms. Therefore three different contact algorithms (Lemke, penalty and Augmented Lagrangian) have been implemented into two. finite element codes. The correct implementation and behavior of these contact algorithms has been investigated by modeling four different tribological devices. It is shown that all these different methodologies lead to extremely similar results. Besides these four applications have been carefully described and detailed in such a way that the presented tests can be reproduced. The authors wish that they could serve as a benchmark set in order to allow comparison with other finite element software including frictional contact capabilities. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailArchitecture de Metafor - code EF orienté objet
Boman, Romain ULg

Scientific conference (2005, February)

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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 detailCompléments de C++
Boman, Romain ULg

Scientific conference (2003, November)

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See detailHuman-Visual-System-Based Fusion of Multimodality 3D Neuroimagery using Brain-Shift-Compensating Finite-Element-Based Deformable Models
Verly, Jacques ULg; Vigneron, Lara; Petitjean, Nicolas et al

in Proceedings of SPIE (2003, February), 5029

Our goal is to fuse multimodality imagery to enhance image-guided neurosurgery. Images that need to be fused must be registered. Registration becomes a challenge when the imaged object deforms between the ... [more ▼]

Our goal is to fuse multimodality imagery to enhance image-guided neurosurgery. Images that need to be fused must be registered. Registration becomes a challenge when the imaged object deforms between the times the images to be fused are taken. This is the case when “brain-shift” occurs. We begin by describing our strategy for nonrigid registration via finite-element methods. Then, we independently discuss an image fusion strategy based on a model of the human visual system. We illustrate the operation of many components of the registration system and the operation of the fusion system. [less ▲]

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See detailSimulation of metal forming processes : Numerical aspects of contact and friction
Boman, Romain ULg

Scientific conference (2003, January)

During this presentation, two numerical methods for managing contact in large stresses/strains problems are described: the Lagrange Multipliers method (available in Cast3M - FE code used in LaCaN) and the ... [more ▼]

During this presentation, two numerical methods for managing contact in large stresses/strains problems are described: the Lagrange Multipliers method (available in Cast3M - FE code used in LaCaN) and the penalty method (available in Metafor - FE code used at LTAS-MCT - University of Liège). Contact algorithms can be divided into three steps. The first one - the contact search - is purely geometric and answers the question: which nodes are currently in contact. Main problems and their solutions are discussed. The computation of the normal force is the second step. Non-penetration conditions are applied on the contact nodes. Finally, during the third step, a tangent force due to friction is applied when the nodes are sticking or sliding. Methods are compared in details in the case of metal forming processes. The penalty method seems to be more efficient when a large number of contact nodes are involved during the simulation. The system to be solved is smaller, the convergence is faster and curved analytical surfaces can be easily used for the tools. However, a good penalty coefficient can sometimes be hard to find. As a conclusion, numerical examples coming from Metafor are presented including skin-pass simulation, hydroforming of a tube and blade loss in a aeronautic engine. [less ▲]

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See detailNumerical Simulation of Lubricated Contact in Rolling Processes
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Journal of Materials Processing Technology (2002), 125-126

In this paper, the lubrication problem in numerical simulation of rolling process is presented. In this case, the recent and complex model of Marsault for the solution of the mixed lubrication regime has ... [more ▼]

In this paper, the lubrication problem in numerical simulation of rolling process is presented. In this case, the recent and complex model of Marsault for the solution of the mixed lubrication regime has been implemented and tested. This model requires the use of the finite difference method to work properly. We will discuss the advantages and the difficulties encountered when trying to solve the same problem with the finite element method in a general frame. Finally, a finite element formulation for the solution of the time-dependent Reynolds' equation coupled with the deformation of the workpiece is proposed. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailNumerical Simulation of Lubricated Contact between Solids in Metal Forming Processes using the Arbitrary Lagrangian Eulerian Formulation
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Simulation of Material Processing: Theory, Methods and Application: Proceedings of the 7th International Conference NUMIFORM 2001 (2001, June)

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See detailArbitrary Lagrangian Eulerian Method for the Simulation of Lubricated Contact between Solids in Metal Forming Processes
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Pietryk, Maciej; Kusiak, Jan; Majta, Janusz (Eds.) et al Metal Forming 2000 (2000, September)

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See detailALE Methods for Determining Stationary Solutions Metal Forming Processes
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Oñate, E.; Bugeda, G.; Suárez, B. (Eds.) Proceedings of ECCOMAS 2000/COMPLAS VI, European Congress on Computational Methods in Applied Sciences and Engineering (2000, September)

In this paper, two efficient convection algorithms are briefly presented in order to update the values stored at the Gauss point during the Eulerian step of an Arbitrary Lagrangian Eulerian computation in ... [more ▼]

In this paper, two efficient convection algorithms are briefly presented in order to update the values stored at the Gauss point 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. Two applications are presented : a cold rolling simulation and a drawbead simulation. [less ▲]

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See detailALE Update Procedures for Stationary Solutions of Metal Forming Processes
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Proceedings of the 5th National Belgian Congress on Theoretical and Applied Mechanics (2000, May)

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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 ▲]

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See detailEléments Finis de Lubrification pour la Prise en Compte du Frottement dans la Simulation de Processus de Formage des Matériaux
Boman, Romain ULg

in Chabrand, Patrick; Jean, Michel; Raous, Michel (Eds.) Colloque National Mécamat 2000 (2000, January)

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See detailA Quasi-Coulomb Model for Frictional Contact Interfaces
Garcìa Garino, C.; Ponthot, Jean-Philippe ULg; Boman, Romain ULg et al

in MECOM'99 - Proceedings of the 6th Argentine Congress on Computational Mechanics (1999, September)

Frictional contact interfaces have to be modeled in practice when industrial problems such as metal forming operations, crashworthiness, and so on, have to be simulated. Usually a Coulomb model is used in ... [more ▼]

Frictional contact interfaces have to be modeled in practice when industrial problems such as metal forming operations, crashworthiness, and so on, have to be simulated. Usually a Coulomb model is used in order to describe the constitutive law for the frictional case. Following a standard plasticity approach to Coulomb law a non-symmetric tangent operator is found, and so a non-symmetric solver has to be used in order to take full advantage of consistent operators. With respect to symmetric ones, these non-symmetric operators lead to prohibitive computational times. However, in practice different schemes have been proposed in order to recover the symmetric operator, and consequently, use a symmetric solver. In this work an alternative approach based on an idea due to Garcia Garino and Oliver [33] is defined in order to avoid to deal with non-symmetric solvers and thus save a large amount of computational time, which renders the computational simulation more attractive to industry. Applications to metal forming simulations and crashworthiness analysis are envisaged. [less ▲]

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

in ECCM’99, European Conference on Computational Mechanics (1999, August)

In this paper, the lubrication problem in numerical simulation of forming processes is presented. In the case of the rolling process, the recent and complex model of Marsault for the solution of the mixed ... [more ▼]

In this paper, the lubrication problem in numerical simulation of forming processes is presented. In the case of the rolling process, the recent and complex model of Marsault for the solution of the mixed lubrication regime has been implemented and tested. This model needs the use of the finite difference method to work properly. We will discuss the advantages and the difficulties encountered when trying to solve the same problem with the finite element method in a general frame. Finally, a finite element formulation for the solution of the time dependant Reynolds’ equation coupled with the deformation of the workpiece is proposed. [less ▲]

Detailed reference viewed: 75 (15 ULg)