References of "Ponthot, Jean-Philippe"
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See detailA trust region algorithm for automatic identification of elasto-viscoplastic model parameters in metallurgical finite element model
Jeunechamps, Pierre-Paul ULg; Walmag, Jérôme; Duysinx, Pierre ULg et al

in Steel Grips 2 (2004), Supplement Metal Forming 2004

Simulation of manufacturing processes, here metal forming, has made major progresses during the last years. The virtual simulation of the manufacturing process being now quite well established, a natural ... [more ▼]

Simulation of manufacturing processes, here metal forming, has made major progresses during the last years. The virtual simulation of the manufacturing process being now quite well established, a natural step ahead consists in trying to find automatic procedures to optimize it. Another perspective is also to take care of the influence of the manufacturing constraints upon the design, which is the long term objective of the present research project. It aims at optimizing the design subject to both service constraints (stiffness and strength) and manufacturing constraints. A preliminary stage is to be able to build high fidelity digital models. Complex models require more and more material parameters for behavior laws (e.g. material constitutive and friction laws), which have to be identified numerically from experimental data. In this material parameter identification process, three steps can be identified. At first, an experimental testing is carried out. The second step consists in building a simulation model of the experiment. Finally, the unknown model parameters are determined to match the experimental data. A standard identification procedure consists in minimizing a given norm (here the Euclidean norm) of the error between the model predictions and the experimental results. Even if the identification problem is generally quasi-unconstrained, it has the same complexity as structural optimization problems because of the highly nonlinear and implicit character of the functions, which is especially amplified by the large deformation simulation analysis. In this paper, we use an approach of elastoplastic calculation by finite elements combined with two optimization algorithms: a Levenberg-Marquardt algorithm, which is rather classical in the literature for solving identification problems (see [2]) and a trust-region one (see [1]), which is a rather novel approach at least for structural problems. The results obtained with these two methods are then compared and discussed on two test cases. The first application is an academic test case to validate the identification method. The second one, the compression of a cylinder, takes into account an actual experiment. In this application, the material is assumed to be elasto-viscoplastic and described by a Norton-Hoff behavior law and an isotropic strain hardening law. The parameters to be identified are the coefficients of the Norton-Hoff law. [less ▲]

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See detailA Consistent Dissipative Time Integration Scheme for Structural Dynamics. Application to Rotordynamics.
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

(2004)

Recently, robust implicit energy and momentum conserving algorithms have been developed in the non-linear range. In previous works, the authors extended these algorithms to hypoelasticity-based ... [more ▼]

Recently, robust implicit energy and momentum conserving algorithms have been developed in the non-linear range. In previous works, the authors extended these algorithms to hypoelasticity-based constitutive models. In this paper we introduce numerical dissipation, opening the way to more complex simulations such as blade-loss in a turbofan. [less ▲]

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See detailThermo-elasto-plastic modeling of the behaviour of metals submitted to finite strains. A coupled thermo-mechanical approach
Ponthot, Jean-Philippe ULg; Adam, L.

in Proceedings of ENIEF 2004, XIV Congress on numerical methods and their applications (2004)

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See detailModeling the elastic-plastic behavior of a rotor support structure under a large unbalance: numerical simulations
Stainier, Laurent ULg; BUI, Q. V.; Ponthot, Jean-Philippe ULg

in Proceedings of ISMA 2004, International Conference on Noise & Vibration Engineering (2004)

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See detailModeling and experimental validation of an industrial sheet metal forming process
CELENTANO, D.; GARCIA, C.; FLORES, F. et al

in Computational Mechanics, WCCM VI (2004)

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See detailThermomechanical Modeling at finite strains : updated EAS and SRI finite element formalisms
ADAM, L.; Ponthot, Jean-Philippe ULg

in Proceedings of PACAM VIII, eigth Pan American Congress of Applied Mechanics (2004)

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See detailImprovements of an iterative and staggered Approach for a Model of Mixed Lubrication in Cold Rolling
STEPHANY; Ponthot, Jean-Philippe ULg

in Proceedings of NUMIFORM 2004, The 8th International Conference on Numerical Methods in Industrial Forming Processes: Materials processing and design. Modeling, Simulation and Applications (2004)

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See detailArbitrary Lagrangian Eulerian methods
Donea, Jean; Huerta, Antonio; Ponthot, Jean-Philippe ULg et al

in Encyclopedia of Computational Mechanics (2004)

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See detailSimulation of complex impact problems with implicit time algorithms. Application to crashworthiness problems
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in Matériaux et Techniques (2004)

Recently, robust implicit energy and momentum conserving algorithms have been developed in the non-linear range. The authors extended these algorithms to hypoelasticity-based constitutive models and ... [more ▼]

Recently, robust implicit energy and momentum conserving algorithms have been developed in the non-linear range. The authors extended these algorithms to hypoelasticity-based constitutive models and introduced numerical dissipation, opening the way to more complex simulations such as blade-loss in a turbofan. [less ▲]

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See detailAdvances in the time integration of Dynamical Systems. Applications to Crashworthiness problems
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in Proceedings of the International Crashworthiness and Design Symposium 2003 (2003, December)

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See detailA coupled thermo-viscoplastic formulation at finite strains for the numerical simulation of superplastic forming
Adam, Laurent; Ponthot, Jean-Philippe ULg

in Journal of Materials Processing Technology (2003), 139

This paper deals with a thermo-elasto-viscoplastic formulation for the simulation of metal forming involving large deformations. The authors present the governing equations of the model and some ... [more ▼]

This paper deals with a thermo-elasto-viscoplastic formulation for the simulation of metal forming involving large deformations. The authors present the governing equations of the model and some applications to superplastic forming. The numerical examples illustrate the potentiality of the finite-element code METAFOR based on this formulation. (C) 2003 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailParameter identification and shape/process optimization in metal forming simulation
Kleinermann, J. P.; Ponthot, Jean-Philippe ULg

in Journal of Materials Processing Technology (2003), 139(1-3), 521-526

Nowadays, computer simulations of metal forming processes using the finite element method (FEM) have reached some level of maturity. The purpose of inverse problems is to determine the simulation input ... [more ▼]

Nowadays, computer simulations of metal forming processes using the finite element method (FEM) have reached some level of maturity. The purpose of inverse problems is to determine the simulation input data for one or more of these forming processes, leading to a desired result. The first example is called parameter identification. This consists in evaluating the material parameters for material behavior laws that would lead to the most accurate model, minimizing the difference between experimental results and the corresponding FEM simulation. The second example is initial geometry and tool shape design, consisting in determining the initial shape of the specimen and/or the shape of the forming tools, in order to provide the desired final geometry after the forming process. Both inverse problem examples can be formulated as optimization problems. In this paper, the authors propose to solve these optimization problems with different non-linear optimization methods and to compare their efficiency. (C) 2003 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailIdentification of elastoplastic model in large deformation problems
Jeunechamps, Pierre-Paul ULg; Walmag, Jérôme ULg; Delhez, Eric ULg et al

in Cinquini, Carlo (Ed.) Proceedings of the 5th World Congress of Structural and Multidisciplinary Optimization WCSMO5 (2003, May)

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the ... [more ▼]

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the classic Levenberg-Marquardt algorithm. The second one is a trust-region algorithm based on a quadratic model. The two algorithms are compared on two cases, one of them being an actual experiment. [less ▲]

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See detailOptimization of sheet metal forming processes using inverse problems methodology
KLEINERMANN, J. P.; Ponthot, Jean-Philippe ULg; Stainier, Laurent ULg

in Proceedings of COMPLAS 2003, VII International Conference on Computational Plasticity. Fundamentals and Applications (2003, April)

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See detailEfficient springback prediction based on Enhanced Assumed Strain Elements
BUI, Q. V.; Papeleux, Luc ULg; Ponthot, Jean-Philippe ULg

in Proceedings of COMPLAS 2003, VII International Conference on Computational Plasticity. Fundamentals and Applications (2003, April)

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See detailCombined implicit/explicit time integration algorithms for crashworthiness analysis and metal forming simulation
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in Proceedings of IMPLAST'2003, 8th International Symposium on Plasticity and Impact Mechanics (2003, March)

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See detailIdentification of elastoplastic model parameters in large deformation problems using gamma methods
Jeunechamps, Pierre-Paul ULg; Walmag, J.; Mathonet, V. et al

in Proceedings of the 5th World Congress on Structural and Multidisciplinary Optimization (2003)

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the ... [more ▼]

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the classic Levenberg-Marquardt algorithm. The second one is a trust-region algorithm based on a quadratic model. The two algorithms are compared on two cases, one of them being an actuel experiment. [less ▲]

Detailed reference viewed: 74 (17 ULg)