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Peer Reviewed
See detailNumerical Simulations and Experimental Investigations of the Semi-Solid Metal Processing of Steels
Rassili, A.; Geuzaine, Christophe ULg; Legros, Willy ULg et al

in Proceedings of the 7th International Conference on Semi-Solid Processing of Alloys and Composites, S2P 2002 (2002)

Detailed reference viewed: 19 (0 ULg)
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See detailThe Numerical Simulations and Physical Model of Pipeline under Wave Action
Li; Lai; Chen et al

in Pacific/Asia Offshore Mechanics Symposium, PACOMS 96, Edited by ISOPE (1996, October)

Detailed reference viewed: 22 (1 ULg)
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See detailNumerical simulations in support of fire resistance tests
Franssen, Jean-Marc ULg

Conference given outside the academic context (2013)

This paper presesnts how non linear numerical simulations can be used as a tool to support experimental tests made to determine the fire resistance of building structures. Numerical simulations have been ... [more ▼]

This paper presesnts how non linear numerical simulations can be used as a tool to support experimental tests made to determine the fire resistance of building structures. Numerical simulations have been made to calculate precisely the flexibility of the loading frame, to verify that no undesirable failure mode can develop in a test to be performed, to choose the load to be applied in order to obtain a desired failure temperature and to estimate the influence of observed non uniform temperature distribution. [less ▲]

Detailed reference viewed: 22 (2 ULg)
See detailNumerical simulations o the wind of magnetic massive star HD191612
ud-Doula, Asif; Nazé, Yaël ULg

Diverse speeche and writing (2010)

Detailed reference viewed: 8 (0 ULg)
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See detailNumerical Simulations of Asperity Crushing - Application to Cold Rolling
Carretta, Yves ULg; Legrand, Nicolas; Laugier, Maxime et al

in Proceedings of ESAFORM : Belfast, 27-29th april 2011 (2011)

Asperity flattening has a huge influence on friction and wear in metal forming processes. Nevertheless, phenomena that occur at the microscopic scale are still not well understood. Since no experiments ... [more ▼]

Asperity flattening has a huge influence on friction and wear in metal forming processes. Nevertheless, phenomena that occur at the microscopic scale are still not well understood. Since no experiments can be easily performed in real forming conditions, numerical models are essential to achieve a better knowledge of what happens in these contact regions. In this paper, two finite elements models are presented. The first one represents the flattening of a serrated asperity field in plane strain conditions. The results are compared to the experiments conducted by Sutcliffe [1]. The second one is a tri-dimensional asperity model flattened by a rigid plane. The boundary conditions applied to this model correspond to the ones encountered in a real cold rolling case. The results are compared to the relative contact area computed by a strip rolling model using the analytical laws proposed by Wilson & Sheu [2] and Marsault [3]. [less ▲]

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See detailNumerical simulations of asperity crushing using boundary conditions encountered in cold-rolling
Carretta, Yves ULg; Boman, Romain ULg; Legrand, Nicolas et al

in Key Engineering Materials [=KEM] (2013), 554-557

Asperity flattening has a huge influence on friction and wear in metal forming processes. Nevertheless, phenomena that occur at the microscopic scale are still not well understood. Since no experiment can ... [more ▼]

Asperity flattening has a huge influence on friction and wear in metal forming processes. Nevertheless, phenomena that occur at the microscopic scale are still not well understood. Since no experiment can be easily performed in real forming conditions, numerical models are essential to achieve a better knowledge of what happens in these contact regions. In this paper, two finite elements models are presented. The first one represents the flattening of a serrated asperity field in plane-strain conditions. The results are compared to the experiments published by Sutcliffe [1]. The second one is a tri-dimensional asperity model flattened by a rigid plane. The boundary conditions applied to this model correspond to the ones encountered in a real cold-rolling case. The results are compared to the relative contact area computed by a strip rolling model using the analytical laws proposed by Wilson & Sheu [2] and Marsault [3]. [less ▲]

Detailed reference viewed: 62 (35 ULg)
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See detailNumerical simulations of brittle and elasto-plastic fracture for thin structures subjected to dynamic loadings
Becker, Gauthier ULg

Doctoral thesis (2012)

The main purpose of this thesis is the development of a framework to model fracture initiation and propagation in thin bodies. This is achieved by the combination of two original models. On one hand ... [more ▼]

The main purpose of this thesis is the development of a framework to model fracture initiation and propagation in thin bodies. This is achieved by the combination of two original models. On one hand, (full) discontinuous Galerkin formulations of Euler-Bernoulli beams as well as Kirchhoff-Love shells are established. These formulations allow modeling a thin structure with discontinuous elements, the continuity being ensured weakly by addition of interface terms. The first advantage of the recourse to a discontinuous method is an easy insertion of cohesive elements during the simulation without a modification of the mesh topology. In fact with a continuous method, the insertion of the cohesive elements at the beginning of the simulation leads to numerical issues and their insertion at onset of fracture requires a complex implementation to duplicate the nodes. By contrast, as interface elements are naturally present in a discontinuous formulation their substitution at fracture initiation is straightforward. The second advantage of the discontinuous Galerkin formulation is a simple parallel implementation obtained in this work by exploiting, the discontinuity of the mesh in an original manner. Finally, last advantage of the recourse to a discontinuous Galerkin method for thin bodies is to obtain a one field formulation. In fact, the C1 continuity is ensured weakly by interface terms without considering rotational degrees of freedom. On the other hand, the through-the-thickness crack propagation is complicated by the implicit thickness model inherent to thin bodies formulations. Therefore we suggest an original cohesive model based on reduced tresses. Our model combines the different reduced stresses in such a way that the expected amount of energy is released during the crack process leading to a model which respects the energetic balance whatever the applied loadings. The efficiency of the obtained framework is demonstrated through the simulation of several benchmarks whose results are in agreement with numerical and experimental data coming from the literature. Furthermore, the versatility of our framework is shown by simulating 2 very different fracture phenomena: the crack propagation for elastic as well as for elasto-plastic behavior and the fragmentation of brittle materials. This demonstrates that our framework is a powerful tool to study dynamics crack phenomena in thin structure problems involving a large number of degrees of freedom. [less ▲]

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Peer Reviewed
See detailNumerical simulations of fire resistance tests on steel and composite structural elements or frames
Schleich, Jean-Baptiste; Dotreppe, Jean-Claude ULg; Franssen, Jean-Marc ULg

in First International Symposium on Fire Safety Science (1986)

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See detailNumerical simulations of seasonal and interannual variability of the Black Sea thermohaline circulation
Stanev, Emil; Beckers, Jean-Marie ULg

in Journal of Marine Systems (1999), 22(4), 241-267

The Black Sea general circulation is simulated by a primitive equation model with active free surface. The forcing is seasonally variable and is based on available climatic data. The model reproduces the ... [more ▼]

The Black Sea general circulation is simulated by a primitive equation model with active free surface. The forcing is seasonally variable and is based on available climatic data. The model reproduces the main features of the Black Sea circulation, including the river discharge effects on the mean sea level and the Bosphorus outflow. Model results show that the simulated sea surface elevation increases in spring over the whole sea, reaching a maximum in the Danube delta area. In the same region, a minimum is observed in winter. The amplitude of the seasonal oscillations (about 8-12 cm over the whole basin) is of the same order of magnitude as the maximum horizontal variations (about 15-18 cm between the coastal areas and the basin interior). This strong signal formed mostly by river discharges, along with the seasonal variability in the other forcing functions and the local dynamics creates a well-pronounced interannual variability. The performance of the model in simulating the seasonal and interannual variability is critically analyzed, with a special attention on the cold intermediate water formation and the circulation in the upper 150 m. The simulations demonstrate that the source of intermediate waters is on the shelf, and that the water mass in the core of cold intermediate layer changes with time as a response to the periodic forcing at sea surface. This type of variability is characterized by pronounced interannual changes, proving that important differences could exist between water mass structure in different years, even when using identical atmospheric forcings each year. (C) 1999 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailNumerical simulations of the sound propagation in non rectilinear streets
Billon, Alexis ULg; Picaut, Judicaël; Valeau, Vincent et al

Conference (2009, October)

At high frequencies, the sound propagation can be approximated by the propagation of sound particles which are reflected and absorbed at the boundaries. This propagation follows then a transport process ... [more ▼]

At high frequencies, the sound propagation can be approximated by the propagation of sound particles which are reflected and absorbed at the boundaries. This propagation follows then a transport process. In urban canyons, this transport process can be reduced to a diffusion process. The resultant model allows one to obtain the spatial distribution of the acoustical energy in a street in a few seconds using a classical finite elements program. This diffusion model has been previously validated in rectilinear streets for different geometrical and acoustical parameters. In this paper, more complex geometries such as varying cross-sections, bents and streets crossings are dealt with. As the diffusion model only models the reverberated sound field, diffraction effects on the direct sound field at streets corners are added. The obtained results are then compared to scale model experiments. [less ▲]

Detailed reference viewed: 41 (3 ULg)
See detailNumerical simulations of the wind of magnetic massive star HD191612
ud-Doula, A.; Nazé, Yaël ULg

Poster (2010)

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See detailNUMERICAL SIMULATIONS OF THIXOFORMING PROCESSES: DEVELOPMENT AND COMPARISON OF SEVERAL SEMI-SOLID CONSTITUTIVE LAWS
Koeune, Roxane ULg; Ponthot, Jean-Philippe ULg

(2011)

ABSTRACT This paper deals with the development, and the comparison, of several constitutive laws in the frame of the simulation of thixoforming processes. The comparison is based on the simulation of a ... [more ▼]

ABSTRACT This paper deals with the development, and the comparison, of several constitutive laws in the frame of the simulation of thixoforming processes. The comparison is based on the simulation of a simple academic test that is well representative of the thixotropic behavior: a simple shear test, with shear-rate step-up and step-down. [less ▲]

Detailed reference viewed: 55 (8 ULg)
Peer Reviewed
See detailNumerical simulations of tissue ingrowth and differentiation around a loaded titanium implant in a bone chamber
Van Oosterwyck, Hans; Geris, Liesbet ULg; Vander Sloten, Jos et al

in Proceedings of the symposium on integrated systems in dental healthcare (2003)

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See detailNumerical simulations of torsional flutter oscillations of a bluff body: Energy issues, GraSMech poster session
Andrianne, Thomas ULg; Dimitriadis, Grigorios ULg

Poster (2012, May)

The possibility of harvesting energy from aeroelastic phenomena is assessed through numerical simulations. The unsteady aerodynamics around an aeroelastic structure are modeled using the Discrete Vortex ... [more ▼]

The possibility of harvesting energy from aeroelastic phenomena is assessed through numerical simulations. The unsteady aerodynamics around an aeroelastic structure are modeled using the Discrete Vortex Method (DVM). The Torsional Flutter oscillations of a rectangular cylinder are studied in this work. The phenomenon is characterized by Limit Cycle Oscillations (LCOs) around the pitch axis of the rectangle. The complete bifurcation behaviour is investigated numerically and compared to wind tunnel measurements for validation. The energy issues are investigated in terms of the sensibility of the energy output to variations in the structural damping. [less ▲]

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See detailA Numerical Simulator for VITRUV
Lebouquin, J.-B.; Herwats, Emilie ULg; Carvalho, M.-I. et al

in Richichi, A.; Delplancke, F.; Paresce, F. (Eds.) et al The Power of Optical/IR Interferometry: Recent Scientific Results and 2nd Generation Instrumentation (2008)

VITRUVsim is a numerical tool with as much as possible physics included. Inputs are the source parameters (flux, morphology, position...) and outputs are sequences of observed fringes and/or reduced ... [more ▼]

VITRUVsim is a numerical tool with as much as possible physics included. Inputs are the source parameters (flux, morphology, position...) and outputs are sequences of observed fringes and/or reduced visibilities. VITRUVsim is written in a portable and free language. [less ▲]

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See detailNumerical solution of DAEs in flexible multibody dynamics using Lie group time integrators
Bruls, Olivier ULg; Cardona, Alberto; Arnold, Martin

in Proceedings of the First Joint International Conference on Multibody System Dynamics (2010, May)

This paper studies a family of Lie group time integrators for the simulation of flexible multibody systems. The method provides an elegant solution to the rotation parameterization problem and, as an ... [more ▼]

This paper studies a family of Lie group time integrators for the simulation of flexible multibody systems. The method provides an elegant solution to the rotation parameterization problem and, as an extension of the classical generalized-alpha method for dynamic systems, it can deal with constrained equations of motion. Here, second-order accuracy of the Lie group method is demonstrated for constrained problems. The convergence analysis explicitly accounts for the nonlinear geometric structure of the Lie group. The performance is illustrated on two critical benchmarks of rigid and flexible systems with large rotation amplitudes. Second-order accuracy is evidenced in both of them. The remarkable simplicity of the new algorithms opens some interesting perspectives for real-time applications, model-based control and optimization of multibody systems. [less ▲]

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See detailNumerical solution of DAEs in flexible multibody dynamics with applications in control and mechatronics
Bruls, Olivier ULg

Scientific conference (2010, October 21)

Detailed reference viewed: 17 (0 ULg)
See detailNumerical solution of the transfer of diffuse radiation in spherically symmetric emission nebulas
Manfroid, Jean ULg

in Bulletin de la Société Royale des Sciences de Liège (1975), 44

The equation of transfer of the diffuse radiation in a spherically symmetric nebula is transformed following a method proposed by Chandrasekhar. Numerical equations are obtained in terms of finite ... [more ▼]

The equation of transfer of the diffuse radiation in a spherically symmetric nebula is transformed following a method proposed by Chandrasekhar. Numerical equations are obtained in terms of finite differences, and a resolution scheme is given. [less ▲]

Detailed reference viewed: 11 (0 ULg)
Peer Reviewed
See detailNumerical solutions on non steady-state conditions of lubrication in internal combustion engine bearing
NELIS, M.; Bozet, Jean-Luc ULg

in Proc. 6th International Congress on Tribology (1994), 4

Detailed reference viewed: 7 (0 ULg)
Peer Reviewed
See detailNumerical study of coupling between optical fibers
Guenneau, S.; Nicolet, A.; Zolla, F. et al

in Proceedings of the 5th International Workshop on Electric and Magnetic Fields, EMF 2000 (2000)

Detailed reference viewed: 2 (0 ULg)