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See detailCoupled computations of highly erosive flows with WOLF software
Dewals, Benjamin ULiege; Archambeau, Pierre ULiege; Erpicum, Sébastien ULiege et al

in Proc. 5th Int. Conference on Hydro-Science & -Engineering (ICHE) (2002)

Detailed reference viewed: 14 (6 ULiège)
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See detailCoupled electro-mechanics simulation methodology of the dynamic pull-in in micro-systems
Rochus, Véronique ULiege; Rixen, Daniel J.; Golinval, Jean-Claude ULiege

in Sensor Letters (2006), 4(2), 206-213

The aim of this paper is to deal with multi-physics simulation of micro-electro-mechanical systems (MEMS) based on an advanced numerical methodology. MEMS are very small devices in which electric as well ... [more ▼]

The aim of this paper is to deal with multi-physics simulation of micro-electro-mechanical systems (MEMS) based on an advanced numerical methodology. MEMS are very small devices in which electric as well as mechanical and fluid phenomena appear and interact. Because of their microscopic scale, strong coupling effects arise between the different physical fields, and some forces, which were negligible at macroscopic scale, have to be taken into account. In order to accurately design such micro-electro-mechanical systems, it is of primary importance to be able to handle the strong coupling between the electric and the mechanical fields. In this paper, the finite element method (FEM) is used to model the electro-mechanical interactions and to perform static and transient analyses. The application example considered here is a micro-bridge consisting of a clamped-clamped beam suspended over a substrate (the lower electrode). When a voltage is applied between the beam and the substrate, electrostatic forces appear which force the beam to bend. When the applied voltage increases, the electrostatic forces become dominant and the plates stick together. The corresponding critical voltage is called the pull-in voltage. When the dynamic behaviour of the system is taken into account, it is shown that two new parameters have to be defined: the dynamic pull-in displacement and the dynamic pull-in time. [less ▲]

Detailed reference viewed: 57 (7 ULiège)
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See detailCoupled Electro-Mechanics Simulation Methodology of the Dynamic Pull-in in Micro-Systems
Rochus, Véronique ULiege; Rixen, Daniel J.; Golinval, Jean-Claude ULiege

Conference given outside the academic context (2005)

The aim of this paper is to deal with multi-physics simulation of micro-electro-mechanical systems (MEMS) based on an advanced numerical methodology. MEMS are very small devices in which electric as well ... [more ▼]

The aim of this paper is to deal with multi-physics simulation of micro-electro-mechanical systems (MEMS) based on an advanced numerical methodology. MEMS are very small devices in which electric as well as mechanical and fluid phenomena appear and interact. Because of their microscopic scale, strong coupling effects arise between the different physical fields, and some forces, which were negligible at macroscopic scale, have to be taken into account. In order to accurately design such micro-electro-mechanical systems, it is of primary importance to be able to handle the strong coupling between the electric and the mechanical fields. In this paper, the finite element method (FEM) is used to model the electro-mechanical interactions and to perform static and transient analyses. The application example considered here is a micro-bridge consisting in a clamped-clamped beam suspended over a substrate (the lower electrode). When a voltage is applied between the beam and the substrate, electrostatic forces appear which force the beam to bend. When the applied voltage increases, the electrostatic force becomes dominant and the plates stick together. The corresponding critical voltage is called the pull-in voltage. When the dynamic behavior of the system is taken into account, it is shown that two new parameters have to be defined: the dynamic pull-in displacement and the dynamic pull-in time. [less ▲]

Detailed reference viewed: 48 (1 ULiège)
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See detailA coupled electro-thermal Discontinuous Galerkin method
Homsi, Lina ULiege; Geuzaine, Christophe ULiege; Noels, Ludovic ULiege

in Journal of Computational Physics (2017), 348

This paper presents a Discontinuous Galerkin scheme in order to solve the nonlinear elliptic partial differential equations of coupled electro-thermal problems. In this paper we discuss the fundamental ... [more ▼]

This paper presents a Discontinuous Galerkin scheme in order to solve the nonlinear elliptic partial differential equations of coupled electro-thermal problems. In this paper we discuss the fundamental equations for the transport of electricity and heat, in terms of macroscopic variables such as temperature and electric potential. A fully coupled nonlinear weak formulation for electro-thermal problems is developed based on continuum mechanics equations expressed in terms of energetically conjugated pair of fluxes and fields gradients. The weak form can thus be formulated as a Discontinuous Galerkin method. The existence and uniqueness of the weak form solution are proved. The numerical properties of the nonlinear elliptic problems i.e., consistency and stability, are demonstrated under specific conditions, i.e. use of high enough stabilization parameter and at least quadratic polynomial approximations. Moreover the prior error estimates in the H1-norm and in the L2-norm are shown to be optimal in the mesh size with the polynomial approximation degree. [less ▲]

Detailed reference viewed: 46 (14 ULiège)
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See detailA coupled electro-thermo-mechanical discontinuous Galerkin method applied on composite materials
Homsi, Lina ULiege; Noels, Ludovic ULiege

Conference (2016, September 07)

Carbon fiber reinforced polymer composites have become increasingly important due to their unique properties which are appreciated in many practical applications such as low weight, low cost, low density ... [more ▼]

Carbon fiber reinforced polymer composites have become increasingly important due to their unique properties which are appreciated in many practical applications such as low weight, low cost, low density, high mechanical characteristics. Moreover the range of their electrical conductivity can be controlled by the amount of carbon fibers. Carbon fiber reinforced polymer composites consist of at least two components, a polymer matrix (generally dielectric) and electrically conductive fillers. This combination results in multifunctional composites, both structural and conductive. The existence of the polymer matrix will avoid catastrophic failure due to fiber breaking, and the existence of the carbon fibers will enhance strength and stiffness on one hand, and will allow to a significant temperature gradient when electric current is applied on the other hand. The objective of this paper is to study the response of the carbon fiber reinforced polymer composites when an electric power is applied and to determine the effective properties. To this end governing equations describing electro-thermo-mechanical coupling in composite materials are developed and discretized using the Discontinuous Galerkin (DG) finite element method. DG methods have many advantages such as optimal convergence and local approximation properties in addition to their flexibility for mesh adaption and their straightforward use of high order polynomial approximations. A micromechanical model of unidirectional carbon fibers dispersed in a polymer matrix is formulated considering the interaction of electrical, thermal and mechanical fields It is then solved using the DG method to determine the time dependent response of the electro-thermo-mechanical coupling and quantify the variation of the fields. [less ▲]

Detailed reference viewed: 71 (11 ULiège)
See detailA coupled formulation for Thermo-Viscoplasticity at Finite Strains: Application to Hot Metal Forming
Adam, Laurent; Ponthot, Jean-Philippe ULiege

in Proceedings of the Fifth National Belgian Congress on Theoretical and Applied Mechanics (2000)

Detailed reference viewed: 78 (1 ULiège)
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See detailA coupled formulation for Thermo-Viscoplasticity at Finite Strains: Application to Hot Metal Forming
Adam, Laurent; Ponthot, Jean-Philippe ULiege

in fifth IUTAM Symposium on Creep in Structures (2001)

Detailed reference viewed: 38 (1 ULiège)
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See detailCoupled hydro-thermo-mechanical analysis of a deep radioactive waste disposal based on porous media mechanics
Passarotto, Mareva; Luison, Loris; Sanavia, Lorenzo et al

Poster (2009)

Detailed reference viewed: 115 (3 ULiège)
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See detailCoupled hydro-thermo-mechanical analysis of a deep radioactive waste disposal based on porous media mechanics
Sanavia, Lorenzo; Laloui, Lyesse; Passarotto, Mareva et al

in Int. Conf. on Computational Methods for Coupled Problems in Science and Engineering, Coupled Problems’09 (2009)

Detailed reference viewed: 30 (2 ULiège)
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See detailCoupled Hydrodynamic Ecosystem model of the Black Sea at basin scale. First results.
Grégoire, Marilaure ULiege; Beckers, Jean-Marie ULiege; Nihoul, Jacques ULiege et al

in Ozsoy, Emin; Mikaelyan, Alexander (Eds.) Sensitivity to change : Black Sea, Baltic Sea and North Sea (1997)

Detailed reference viewed: 50 (13 ULiège)
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See detailCoupled instabilities of steel box sections
Kuhlmann, U.; Detzel, A.; Degée, Hervé ULiege

in Proceddings of the 6th European Solid Mechanics Conference ESMC 2006 (2006)

Thin walled columns are subject to stability failure on local (plate buckling) and global (column buckling) level. Both buckling phenomena interact. A proposal for the use of EBC for the determination of ... [more ▼]

Thin walled columns are subject to stability failure on local (plate buckling) and global (column buckling) level. Both buckling phenomena interact. A proposal for the use of EBC for the determination of the carrying capacity of welded steel box sections is given and compared to an extensive numerical simulation study. [less ▲]

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See detailCoupled Line-Profile and Continuum Variations in EZ Canis Majoris: Implications for the Driving Mechanism of Global Wind Structures in Wolf-Rayet Winds
Morel, Thierry ULiege; St-Louis, Nicole; Moffat, Anthony F J et al

in Astrophysical Journal (1998), 498

EZ CMa is an apparently unusual Wolf-Rayet star of the nitrogen sequence that exhibits strong variations on a period of 3.77 days with coherency lasting typically about 10 cycles. We have used an ... [more ▼]

EZ CMa is an apparently unusual Wolf-Rayet star of the nitrogen sequence that exhibits strong variations on a period of 3.77 days with coherency lasting typically about 10 cycles. We have used an extensive set of optical spectroscopic observations to investigate a possible link between its line-profile and photometric continuum variability. Despite the strong epoch dependency of the variations, a persistent correlation is found between changes in the wind line profiles (N V lambda lambda 4604, 4620 in particular) and in continuum flux emanating near the stellar core. We suggest that these observations give further support to the idea that the physical conditions prevailing in the vicinity of the star's photosphere have a significant impact on the wind structure and that a spatial dependence of these conditions at the base of the outflow induces the formation of azimuthal wind structures in EZ CMa. The epoch-dependent nature of the variability could be related to long-term behavior of corotating magnetic structures, although pulsational instabilities constitute a viable alternative. [less ▲]

Detailed reference viewed: 25 (4 ULiège)
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See detailCoupled MBS-FE Applications: A New Trend in Simulation
Géradin, Michel ULiege

Conference (2013, November 26)

Detailed reference viewed: 21 (0 ULiège)
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See detailCoupled mechanical-electrostatic FE-BE analysis with FMM acceleration
V Sabariego, Ruth ULiege; Gyselinck, Johan; Dular, Patrick ULiege et al

in COMPEL (2004), 23(4), 876-884

This paper deals with the coupled mechanical-electrostatic analysis of a shunt capacitive MEMS switch. The mechanical and electrostatic parts of the problem are modelled by the FE and BE methods ... [more ▼]

This paper deals with the coupled mechanical-electrostatic analysis of a shunt capacitive MEMS switch. The mechanical and electrostatic parts of the problem are modelled by the FE and BE methods, respectively. The fast multipole method is applied to reduce the storage requirements and the computational cost of the BE electrostatic model An adaptive truncation expansion of the 3D Laplace Green function is employed The strong interaction between the mechanical and electrostatic systems is considered iteratively. [less ▲]

Detailed reference viewed: 61 (13 ULiège)
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See detailA coupled mechanobioregulatory model for the simulation of peri-implant bone formation in an in vivo bone chamber
Geris, Liesbet ULiege; Vandamme, K.; Duyck, J. et al

in Proceedings of the second thematic workshop of the European Society of Biomechanics on Finite Element modelling in Biomechanis and Mechanobiology (2007, August)

Detailed reference viewed: 15 (0 ULiège)
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See detailCoupled modeling of Excavation Damaged Zone in Boom clay: Strain localization in rock and distribution of contact pressure on the gallery’s lining
Salehnia, Fatemeh ULiege; Collin, Frédéric ULiege; Li, Xiang Ling et al

in Computers and Geotechnics (2015), 69

Around galleries excavated at depth in geological media, the creation of a damaged zone with significant irreversible deformation is generally unavoidable. In the case of a geological disposal system for ... [more ▼]

Around galleries excavated at depth in geological media, the creation of a damaged zone with significant irreversible deformation is generally unavoidable. In the case of a geological disposal system for high-level radioactive waste, the resulting change in the host rock properties in this damaged zone may potentially be important with respect to the long-term evolution and the performance of that system. In this context, predicting the extent of the so-called Excavation Damaged Zone (EDZ) and, possibly, the fractures' network topology remains a challenge. This study is aimed to simulate numerically the extension of this zone at the large scale's excavation, around the Connecting gallery (HADES URL, Mol, Belgium), in Boom clay host rock through analyzing the evolution of strain localization in shear bands mode. To realistically model the involved phenomena, the concrete lining is considered on the gallery wall highlighting its impacts on the evolution of convergence and EDZ around the gallery. The focus of the current paper is made on analyzing the coupled hydro-mechanical behavior of Boom clay host rock during and after the gallery excavation with respect to the evolution of localized shear bands around the gallery. This study is accompanied by the analysis of the contact mechanism on the interface between the clay massive and the lining. The obtained results reveal some interesting features regarding the contact phenomenon relatively to the evolution pattern of shear bands within the clay around the gallery. To assess the reliability of the proposed approach, a discussion on some in-situ observations during the gallery's construction is also performed based on which a good agreement is found between the in-situ evidence and simulated results. [less ▲]

Detailed reference viewed: 107 (29 ULiège)
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See detailCoupled modeling of global carbon cycle and climate in the Neoproterozoic: links between Rodinia breakup and major glaciations
Godderis, Yves; Donnadieu, Yannick; Dessert, Celine et al

in Comptes Rendus Geoscience (2007), 339(3-4), 212-222

A coupled climate-geochemical model of new generation (GEOCLIM) is used to investigate the possible causes of the initiation of snowball glaciations during Neoproterozoic times. This model allows the ... [more ▼]

A coupled climate-geochemical model of new generation (GEOCLIM) is used to investigate the possible causes of the initiation of snowball glaciations during Neoproterozoic times. This model allows the calculation of the partial pressure of atmospheric CO2 simultaneously with the climate at the continental surface with a rough 2D spatial resolution (10 degrees lat. x 50 degrees long.). We calculate that the breakup of the Rodinia supercontinent, starting 800 Myr ago, results in a global climatic cooling of about 8 degrees C triggered by enhanced consumption of atmospheric CO2 resulting from increased runoff over continental surfaces. This increase in runoff is driven by the opening of oceanic basins resulting in an increase of soil moisture sources close to continental masses. This climatic effect of the supercontinent breakup is particularly strong within the 800-700 Ma interval since all continents are located in the equatorial area, where temperature and runoff conditions optimize the consumption of CO2 through weathering processes. However, this effect alone is insufficient to trigger snowball. We propose that the efficient weathering of fresh basaltic surfaces that erupted during the Rodinia breakup, and were transported to the humid equatorial area through continental plate motion, contributed the necessary CO2 sink that triggered the ca. 730-Ma Sturtian glacial event. Simulations of the GEOCLIM model for the ca 580-Ma Gaskiers ice age, where all continents are centered on the South Pole, shows that no snowball glaciation can be initiated. The calculated CO2 partial pressure remains above 1000 ppmv, while a threshold of less than 80 ppmv is required to initiate a snowball glaciation. At that time, a polar configuration does not allow the onset of total glaciation. Nevertheless, a regional glaciation is simulated by the GEOCLIM when the climatic and geochemical (i.e. weathering related) effects of the Pan-African orogeny (similar to 600 Ma) are taken into account. Finally, the question of the role of the paleogeographic setting in the Marinoan snowball event (similar to 635 Ma) is still an open question, since no reliable Marinoan paleogeographic reconstruction exists due to the paucity of paleomagnetic data. [less ▲]

Detailed reference viewed: 75 (5 ULiège)