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See detailA Numerical Study of Fiber Glass Drawing Process
Chouffart, Quentin ULg; Terrapon, Vincent ULg

Scientific conference (2012, October 19)

The industrial glass fiber process is very sensitive to disturbances as they can lead to fibers break during the extrusion step. To identify and better characterize the relevant underlying physics and the ... [more ▼]

The industrial glass fiber process is very sensitive to disturbances as they can lead to fibers break during the extrusion step. To identify and better characterize the relevant underlying physics and the possible causes of fiber break, the glass behavior from the die exit to the winder is investigated numerically. In a first step, simulations of the glass fiber extrusion process are performed where the fluid is considered Newtonian. The full Navier-Stokes equations including the energy equation for the temperature are solved with a finite-element method. The solution is then compared to previous results from the literature. In a second step, we conducted a sensitivity analysis of the key process variables, such as glass height above the tip, viscosity and flow rate at the tip exit, winder velocity... Additionally, the importance of an accurate physical representation of the heat transfers, i.e., conduction within the fiber, radiation of the fiber, and convection around the fiber, is investigated. This model shows very good agreement with cases from the literature. It was found that bushing temperature and fiber environment have a significant impact on forming fiber shape. This demonstrates that numerical simulations can provide a useful tool to adjust the process operating window. [less ▲]

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See detailNumerical study of shear band instability and effect of cavitation on the response of a specimen under undrained biaxial loading
Sieffert, Yannick; Buzzi, Olivier; Collin, Frédéric ULg

in International Journal of Solids and Structures (2014), 51(9), 16861696

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See detailNumerical study of the fatigue crack in welded beam-to-column connection using cohesive zone model
Lequesne, Cédric ULg; Plumier, André ULg; Degée, Hervé ULg et al

in Proceedings of the International Conference on Fracture and Damage Mechanics V (2006)

The fatigue behaviour of the welded beam-to-column connections of steel moment resisting frame in seismic area must be evaluated. The cohesive zone model is an efficient solution to study such connections ... [more ▼]

The fatigue behaviour of the welded beam-to-column connections of steel moment resisting frame in seismic area must be evaluated. The cohesive zone model is an efficient solution to study such connections by finite elements. It respects the energetic conservation and avoids numerical issues. A three-dimensional cohesive zone model element has been implemented in the home made finite element code Lagamine [1]. It is coupled with the fatigue continuum damage model of Lemaître and Chaboche [2]. The cohesive parameters are identified by the inverse method applied on a three points bending test modelling. [less ▲]

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See detailA numerical study of the influence of the dirunal cycle on the surface energy and water budgets
Delire, Christine; Gérard, Jean-Claude ULg

in Journal of Geophysical Research (1995), 100

Global models including atmospheric, oceanic, and biogeochemical processes are needed for the study of possible environmental changes, but they require efficient approximations of physical processes in ... [more ▼]

Global models including atmospheric, oceanic, and biogeochemical processes are needed for the study of possible environmental changes, but they require efficient approximations of physical processes in order to reduce the computing time. The need to resolve the dirunal cycle when treating such problems is questionable. The Interaction Soil Biosphere Atmosphere (ISBA) model describing soil-vegetation-atmosphere interactions is used to analyze the importance of the dirunal cycle on the surface energy and water budjets. Stand-alone simulations are first performed using the Hydrologic Atmospheric Pilot EXperiment-MOdélisation du BILan HYdrique (HAPEX-MOBILHY) and Amazonian Region Micrometeorological Experiment (ARME) data sets to assess the need of an explicit dirunal variation of the atmospheric forcing for different sites. As a reference, the run is forced by measured values of atmospheric variables and radiative fluxes. As a test, ISBA is run forced by the 24-hour means of these atmospheric and radiative forcings. The surface and deep water content, the total evaporation, and the net radiation flux are correctly evaluated without the diurnal cycle. In contrast, the interception reservoir is highly overestimated. The model is then coupled with a one-dimensional atmospheic model in which, as test, the solar flux at the top of the atmosphere is replaced by a daily constant mean insolation. The superficial soil moisture content and the total evapotranspiration flux are correctly estimated. The surface temperature and the sensible heat flux are not satisfactorily predicted. Thus it appears that neglecting the diurnal cycle is adequate when considering the hydrologic balance of the surface but not the surface temperature. [less ▲]

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See detailNumerical Study of the Shielding properties of Macroscopic Hybrid Ferromagnetic/Superconductor Hollow Cylinders
Lousberg, Grégory ULg; Fagnard, Jean-François ULg; Ausloos, Marcel ULg et al

in IEEE Transactions on Applied Superconductivity (2010), 20(1), 33

We study the magnetic shielding properties of hybrid ferromagnetic/superconductor (F/S) structures consisting of two coaxial cylinders, with one of each material.We use an axisymmetric finite-element ... [more ▼]

We study the magnetic shielding properties of hybrid ferromagnetic/superconductor (F/S) structures consisting of two coaxial cylinders, with one of each material.We use an axisymmetric finite-element model in which the electrical properties of the superconducting tube are modeled by a nonlinear E-J power law with a magnetic-field-dependent critical current density whereas the magnetic properties of the ferromagnetic material take saturation into account. We study and compare the penetration of a uniform axial magnetic field in two cases: 1) a ferromagnetic tube placed inside a larger superconducting tube (Ferro-In configuration) and 2) a ferromagnetic tube placed outside the superconducting one (Ferro-Out configuration). In both cases, we assess how the ferromagnetic tube improves the shielding properties of the sole superconducting tube. The influence of the geometrical parameters of the ferromagnetic tube is also studied: It is shown that, upon an optimal choice of the geometrical parameters, the range of magnetic fields that are efficiently shielded by the hightemperature superconductor tube alone can be increased by a factor of up to 7 (2) in a Ferro-Out (Ferro-In) configuration. The optimal configuration uses a 1020 carbon steel with a thickness of 2 mm and a height that is half that of the superconducting cylinder (80 mm). [less ▲]

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See detailNumerical study of the thermo-hydro-mechanical behavior of GMZ bentonite
Chen, L.; Wang, J.; Liu, Y. et al

Conference (2012, October)

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See detailNumerical study to identify the material parameters of a damage model
Schwartz, Renée ULg; Castagne, Sylvie; Habraken, Anne ULg

in Computer Methods in Materials Science (2007), 7(2), 237-242

In the continuous casting (CC) process, transversal cracks happen. This type of macroscopic damage is due to the process loading in the bending and unbending area of the CC line. In order to study this ... [more ▼]

In the continuous casting (CC) process, transversal cracks happen. This type of macroscopic damage is due to the process loading in the bending and unbending area of the CC line. In order to study this damage, a 2D model was developed. It simulates the intergranular crack at the mesoscopic level. Already validated for a microalloyed steel with C level < 0.1 wt%, this model must be extended to peritectic and stainless steels. The first step is to identify the model parameters for these grades. The type and the quantity of hot tensile tests required to identify a single set of parameters for the damage law must be determined. So, simulations of hot tensile tests of notched samples are needed. The computed stress and strain histories are applied on the representative mesoscopic cell and the moment of rupture is determined in function of the input parameters. Thanks to inverse modelling, the parameters of the damage law are adapted in order to get one single set of parameters with only two different geometries of notch. [less ▲]

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See detailNumerical Techniques for Fast Multilook ScanSAR
Cantraine, Guy; Dendal, Didier; Barbier, Christian ULg et al

in SPIE (Ed.) Proceeding SPIE (1995)

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See detailNumerical thermo-hydro-mechanical modeling of compacted bentonite inChina-mock-up testfor deep geological disposal
Chen, L; Wang, J; Liu, Y et al

in Journal of Rock Mechanics and geotechnical engineering (2012), 4(2), 183-192

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See detailNumerical tools for assessing reservoir sedimentation and sediment management
Dewals, Benjamin ULg

Conference (2007, July 27)

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See detailNumerical tools for dam break risk assessment: validation and application to a large complex of dams
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Hewlett, Henry (Ed.) Improvements in reservoir construction, operation and maintenance (2006)

The present paper first describes briefly the hydrodynamic model WOLF 2D. Secondly, the simulation of the Malpasset dam break enables to highlight the effectiveness of WOLF 2D. Lastly, the model is ... [more ▼]

The present paper first describes briefly the hydrodynamic model WOLF 2D. Secondly, the simulation of the Malpasset dam break enables to highlight the effectiveness of WOLF 2D. Lastly, the model is applied to simulate the flood generated by the hypothetic collapse of a large concrete dam, which would induce three dam breaks in cascade. [less ▲]

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See detailNumerical tools for the optimization of hydroelectric power stations in cascade
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Dick, Erik; Hogge, Michel; Van Keer, Roger (Eds.) Proceedings of the 3rd Internationale Conference on Advanced Computational Methods in Engineering (2005)

The numerical optimization process of the system of hydroelectric power stations installed on a 60 km long section of the rivers Amblève and Warche in Belgium is presented in detail. The river network is ... [more ▼]

The numerical optimization process of the system of hydroelectric power stations installed on a 60 km long section of the rivers Amblève and Warche in Belgium is presented in detail. The river network is modelled in quasi-2D using real natural topographic data on almost 1,100 finite volumes. In a first step, the hydrological balance is closed using a numerical solver and roughness coefficients are calibrated from water level and discharge field measurements. Secondly, the hydroelectric production is maximised by an automatic calibration of the parameters of the hydrograph released in the network at the upstream dam. This approach leads to a substantial gain in hydroelectric production, brings significant financial benefits and deals with all management and security criteria of the river network. [less ▲]

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See detailNumerical validation of an improved proposal to the Eurocode 3 for lateral-torsional buckling of steel beams subjected to fire
Vila Real, P. M. M.; Lopes, N.; Simoes da Silva, L. et al

in Vila Real, P. M. M. (Ed.) Proceedings of the 4th International workshop Structures in Fire (2006)

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See detailNumerical, analytical and experimental investigations on the response of steel and composite buildings further the loss of a column
Jaspart, Jean-Pierre ULg; Demonceau, Jean-François ULg; Luu, Nguyen Nam Hai ULg

in Proceedings of the Colloquium on structural design of constructions subjected to exceptional or accidental actions (2008)

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. Accord-ing to Eurocodes and some ... [more ▼]

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. Accord-ing to Eurocodes and some different other national design codes, the structural integrity of civil engineering constructions should be ensured through appropriate measures but, in most of the cases, no precise practical guidelines on how to achieve this goal are provided. A European RFCS project entitled “Robust structures by joint ductility” has been set up in 2004, for three years, with the aim to provide requirements and practical guidelines ensuring the structural integrity of steel and composite structures under exceptional events through an appropriate robustness. In particular, one substructure test simulating the loss of a column in a composite building has been performed at Liège University. Present paper describes ana-lytical, numerical and experimental investigations carried out at Liège University as part of this European project. [less ▲]

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See detailA NUMERICAL-SIMULATION OF CLIMATE CHANGES DURING THE OBLIQUITY CYCLE ON MARS
François, Louis ULg; WALKER, J. C. G.; KUHN, W. R.

in Journal of Geophysical Research (1990), 95(B9), 14761-14778

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See detailA numerically efficient data analysis method with error map generation
Rixen, M.; Beckers, Jean-Marie ULg; Brankart, J. M. et al

in Ocean Modelling (2000), 2

The variational inverse model (VIM) for data analysis was already shown to be statistically equivalent to objective analysis (OA) provided the covariance function for the OA and the VIM reproducing kernel ... [more ▼]

The variational inverse model (VIM) for data analysis was already shown to be statistically equivalent to objective analysis (OA) provided the covariance function for the OA and the VIM reproducing kernel are identical. The VIM, however does not allow a direct derivation of the error field associated with the analysis. The purpose of the paper is to extend the one to one correspondance between the two analysis shemes by proposing a heuristic statistical error expression for the VIM. The numerical efficiency on analysis and error map generation of both methods is compared on quasi-synoptic and climatological data sets. It is shown that the VIM analysis and error map generation offers interesting numerical skills in both case studies. [less ▲]

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See detailNumérique ? Vous avez dit numérique ?
Tomasovic, Dick ULg

Speech (2006)

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See detailLa numérisation des Archives Photographiques de Papyrologie Littéraire du CEDOPAL
Marganne, Marie-Hélène ULg

in Frosen, J.; Purola, T.; Salmenkivi, E. (Eds.) Proceedings of the 24. Congress of Papyrology. Helsinki, 1-7 August 2004 (2007)

The file and the Database Mertens-Pack3 of the CEDOPAL of the University of Liège (Belgium) complement each other with a unique collection to the world, begun more than forty years ago with the Professor ... [more ▼]

The file and the Database Mertens-Pack3 of the CEDOPAL of the University of Liège (Belgium) complement each other with a unique collection to the world, begun more than forty years ago with the Professor Paul Mertens, and ceaselessly enriched, more than 8000 photos of literary papyri, in black and white for the greater part, accompanied with their archives, that is, essentially, the enormous exchanged correspondence, since the sixties, between the CEDOPAL and the conservators of papyri. To perpetuate its collection of reproductions and give it more easily to the international scientific community, the CEDOPAL began since July, 2003, by means of a " Grant 2003 " of the International Association of Papyrologues, to digitize every photography of papyrus and to archive these images in a specialized database, which also includes informations from archival documents. [less ▲]

Detailed reference viewed: 80 (8 ULg)