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See detailNumerical simulation of shock-absorber devices for crashworthiness : explicit vs implicit formulation
Ponthot, Jean-Philippe ULg; Graillet, D.

in 32nd ISATA, International Symposium on Automotive Technology and Automation, special session on Automotive Crashworthiness, paper 99 SF004 (1999, June)

Detailed reference viewed: 30 (1 ULg)
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See detailNumerical Simulation of Springback in Sheet Metal Forming
Ponthot, Jean-Philippe ULg; Papeleux, Luc ULg; GOHY, S. et al

in Proceedings of ECCOMAS 2000/COMPLAS VI, European Congress on Computational Methods in Applied Sciences and Engineering (2000)

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See detailNumerical Simulation of Springback in Sheet Metal Forming Using Linear Shell Elements
Papeleux, Luc ULg; Ponthot, Jean-Philippe ULg; GOHY, S. et al

in Proceedings of IASS-IACM 2000, Fourth International Colloquium on Computation of Shell and Spatial Structure (2000)

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See detailNumerical Simulation of Springback in Sheet Metal Forming Using Shell Elements
Papeleux, Luc ULg; GOHY, S.; COLLARD, X. et al

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

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See detailNumerical simulation of springback using enhanced assumed strain elements
Bui, Q. V.; Papeleux, Luc ULg; Ponthot, Jean-Philippe ULg

in Journal of Materials Processing Technology (2004), 153(1), 314-318

The quality of springback prediction for a sheet metal forming process depends on a precise estimate of the elasto-plastic stress distribution throughout the metal sheet. The use of low-order conventional ... [more ▼]

The quality of springback prediction for a sheet metal forming process depends on a precise estimate of the elasto-plastic stress distribution throughout the metal sheet. The use of low-order conventional finite elements may be, without any proper treatment, responsible for low quality prediction because of volumetric and shear lockings. In this study, the enhanced assumed strain technique will be exploited for locking removal. The quality of the numerical simulation is evaluated through a comparison with other popular techniques like selective and uniform reduced integration. In contrast to the latter, and thanks to a full numerical integration scheme, the enhanced assumed strain element is very efficient in accurately capturing the development of plastic flow. This enables a reliable prediction of springback even with a rather coarse mesh. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailNumerical simulation of Springback using enhanced assumed strain elements
BUI, Q. V.; Papeleux, Luc ULg; Ponthot, Jean-Philippe ULg

in Proceedings of AMPT 2003, Advances in Materials and Processing Technologies (2003)

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See detailNumerical Simulation of Stationary Roll Forming using ALE formalism
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Oñate, E.; Owen, D. R. J.; Peric, D. (Eds.) et al Computational Plasticity XI - Fundamentals and Applications (2011, September)

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See detailNumerical simulation of T-bend of multilayer coated metal sheet using solid-shell element
Ben Bettaieb, Amine ULg; Tuninetti Vásquez, Victor ULg; Duchene, Laurent ULg

in Steel Research International (2012)

The main aim of this paper is to model the T-bend test performed on multilayer coated metal sheets in order to measure the coating flexibility. Because of important uses of polymer coatings in many ... [more ▼]

The main aim of this paper is to model the T-bend test performed on multilayer coated metal sheets in order to measure the coating flexibility. Because of important uses of polymer coatings in many industrial applications and higher requirement on the quality of products, an accurate modeling of the T-bend process is therefore essential. During the modeling with the finite element method, the large thickness ratio between the different layers is likely to produce elements with an unfavorable aspect ratio. Therefore, to avoid obtaining inaccurate results linked to the shape of the elements, solid-shell elements are used in this study. These elements are based on the Enhanced Assumed Strain (EAS) technique and the Assumed Natural Strain (ANS) technique. These techniques permit to avoid locking problems even in very bad conditions (nearly incompressible materials, very thin elements conducting to large aspect ratios, distorted element geometry…). The EAS technique artificially introduces additional degrees of freedom (DOFs) to the element. They permit to increase the flexibility of the element which is very efficient for several locking issues. On the other hand, the ANS technique modifies the interpolation scheme for particular strain components. The ANS technique proved to eliminate the transverse shear locking from the element in bending dominated situations. Besides, a numerical integration scheme dedicated to Solid-Shell elements was implemented. It uses a user-defined number of integration points along the thickness direction, which permits to increase the element accuracy with a mesh containing a reduced number of elements along the thickness direction. The results obtained from numerical simulations are compared with some analytical results in order to check the strain predicted in the coated layer by FEM. This information helps to investigate the coating layer ductility in the real process. [less ▲]

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See detailNumerical simulation of the electrical characteristics of CIGS/CdS/ZnO solar cell heterostructures
Amand, Julien ULg; Nguyen, Ngoc Duy ULg

Poster (2013, December 03)

The electrical characteristics of CIGS-based solar cell heterostructure have been simulated by numerically solving the basic semiconductor equations by means of a finite differences method based on a ... [more ▼]

The electrical characteristics of CIGS-based solar cell heterostructure have been simulated by numerically solving the basic semiconductor equations by means of a finite differences method based on a Scharfetter-Gummel discretization scheme. The electric potential, electric field, carrier concentrations, current densities and recombination rates are obtained as function of the space coordinate and the bias voltage. Starting with the analysis of a single absorber layer structure sandwiched between two metal electrodes, we subsequently studied the properties of the CIGS/ZnO pn heterojunction and the influence of the buffer layer thickness in the CIGS/CdS/ZnO on the cell electrical response. A special focus was also given to the influence of grain boundaries in the bulk of CIGS depending on the defects nature and concentration. Electrical measurements including admittance spectroscopy were performed on samples for comparison to be further lead. Motivations This research is part of the project IQuaReS (Innovative in-line Quality control for Renewable Solar solutions) that aims to develop an in-line quality control tool for manufactured CIGS-based solar cells, based on electrical and optoelectrical, preferably non-invasive measurement methods. Exploratory simulations aim to isolate signature patterns that could be sought in experimental measurements . [less ▲]

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See detailNumerical simulation of the electrical characteristics of CIGS/CdS/ZnO solar cell heterostructures
Amand, Julien ULg; Nguyen, Ngoc Duy ULg

Poster (2013, September 17)

The electrical characteristics of CIGS-based solar cell heterostructure have been simulated by numerically solving the basic semiconductor equations by means of a finite differences method based on a ... [more ▼]

The electrical characteristics of CIGS-based solar cell heterostructure have been simulated by numerically solving the basic semiconductor equations by means of a finite differences method based on a Scharfetter-Gummel discretization scheme. The electric potential, electric field, carrier concentrations, current densities and recombination rates are obtained as function of the space coordinate and the bias voltage. Starting with the analysis of a single absorber layer structure sandwiched between two metal electrodes, we subsequently studied the properties of the CIGS/ZnO pn heterojunction and the influence of the buffer layer thickness in the CIGS/CdS/ZnO on the cell electrical response. A special focus was also given to the influence of grain boundaries in the bulk of CIGS depending on the defects nature and concentration. [less ▲]

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See detailNumerical simulation of the fluid-structure interaction between air blast waves and free-standing plates
Kambouchev, Nayden; Noels, Ludovic ULg; Radovitzky, Raúl

in Computers & Structures (2007), 85(nov-14 Sp. Iss. SI), 923931

A numerical method is used to compute the flow field corresponding to blast waves of different incident profiles propagating in air and impinging on free-standing plates. The method is suitable for the ... [more ▼]

A numerical method is used to compute the flow field corresponding to blast waves of different incident profiles propagating in air and impinging on free-standing plates. The method is suitable for the consideration of compressibility effects in the fluid and their influence on the plate dynamics. The history of the pressure experienced by the plate is extracted from numerical simulations for arbitrary blast strengths and plate masses and used to infer the impulse per unit area transmitted to the plate. The numerical results complement some recent analytical solutions in the intermediate range of plate masses and arbitrary blast intensities where exact solutions are not available. The resulting beneficial effect of the fluid-structure interaction (FSI) in reducing transmitted impulse in the presence of compressibility effects is discussed. In particular, it is shown that in order to take advantage of the impulse reduction provided by the FSI effect, large plate displacements are required which, in effect, may limit the practical applicability of exploiting FSI effects in the design of blast-mitigating systems. (C) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailNumerical simulation of the magnetization of high-temperature superconductors: a 3D finite element method using a single time-step iteration
Lousberg, Grégory ULg; Ausloos, Marcel ULg; Geuzaine, Christophe ULg et al

in Superconductor Science and Technology (2009), 22

In this paper, we report progress towards a 3D finite element model for the magnetization of a high-temperature superconductor (HTS): we suggest a method that takes into account a power law conductivity ... [more ▼]

In this paper, we report progress towards a 3D finite element model for the magnetization of a high-temperature superconductor (HTS): we suggest a method that takes into account a power law conductivity and demagnetization effects, while neglecting the effects associated with currents that are not perpendicular to the local magnetic induction. We consider samples that are subjected to a uniform magnetic field varying linearly with time. Their magnetization is calculated by means of a weak formulation in the magnetostatic approximation of the Maxwell equations (A–φ formulation). An implicit method is used for the temporal resolution (backward Euler scheme) and is solved with the open source solver GetDP. Fixed point iterations are used to deal with the power law conductivity of HTS. The finite element formulation is validated for an HTS tube with large n value by comparing with results obtained with other well-established methods. We show that carrying out the calculations with a single time-step (as opposed to many small time-steps) produces results with excellent accuracy in a drastically reduced simulation time. The numerical method is extended to the study of the trapped magnetization of cylinders that are drilled with different arrays of columnar holes arranged parallel to the cylinder axis. [less ▲]

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See detailNumerical simulation of the Roll forming of thin-walled sections and evaluation of corner strength enhancement
Rossi, Barbara ULg; Degée, Hervé ULg; Boman, Romain ULg

in Finite Elements in Analysis & Design (2013), 72

Cold roll forming modifies the mechanical properties of thin-walled profiles by strain hardening. The understanding of this phenomenon, which is rather good for profiles made of traditional construction ... [more ▼]

Cold roll forming modifies the mechanical properties of thin-walled profiles by strain hardening. The understanding of this phenomenon, which is rather good for profiles made of traditional construction steel, is mandatory for assessing the member resistance. Less information is however available for profiles made of materials exhibiting a pronounced degree of nonlinearity of the stress-strain curve such as high-strength and stainless steels. Current codes generally encounter difficulties for modelling this fabrication process because of the size of industrial mills. Indeed, accurate modelling of the continuous cold roll forming process using finite elements requires a huge number of elements leading to excessive CPU times. Therefore, modellers usually reduce the geometry of the formed sheet or increase the size of the finite elements, inducing a loss of accuracy in the results. In this work, the finite element software METAFOR is used to model cold roll forming of channel profiles made of high-strength and stainless steels. The numerical results, expressed in terms of corner strength enhancement versus radius–to–thickness ratio, are compared against an existing predictive model. [less ▲]

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See detailNumerical simulation of the solidification of a beam blank in the mould
Hubsch, P.; Bourdouxhe, M.; Pascon, Frédéric ULg et al

in Proceedings of the 4th European Continuous Casting Conference (2002)

The stability of the casting process and the wear of the mould as well as the quality of the product depend strongly on the mould design. This is particularly true when considering the production of beam ... [more ▼]

The stability of the casting process and the wear of the mould as well as the quality of the product depend strongly on the mould design. This is particularly true when considering the production of beam blanks. If the mould is too tight, thermal contraction can generate considerable contact forces between the product and the mould on the inner surfaces of the flanges. If it is not tight enough, the thermal coupling between the mould and the beam blank is not sufficient to allow the solidification of a skin of the required thickness upon exit from the mould. A finite element model was developed to assist in the mould design. This model takes both the thermal and mechanical interaction between the mould and the product into account. The effect of solidification is implicitly included in the (thermal) finite element formulation while the ferro-static pressure is applied by the means of a specially developed element. The model was applied to a medium gage beam blank cast at ProfilARBED Differdange. The skin thickness as well as the localisation of the wear of the mould predicted by the model are in good agreement with observations made in industrial practice. [less ▲]

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See detailNumerical Simulation of the Steam-tube Rotatory Dryer for the Desulfurization Gypsum
Zhang, Zongyu; Zhao, Hongming; Xin, Zhaoxiang et al

in Shandong Chemical Industry (2010), 39(8), 46-49

According to the preliminary testand analysis of the heat transferprocess in rotary tube dryer, used the granularmultiphase model to predictmoving of gypsum particles, solid concentration field, velocity ... [more ▼]

According to the preliminary testand analysis of the heat transferprocess in rotary tube dryer, used the granularmultiphase model to predictmoving of gypsum particles, solid concentration field, velocity field and temperature field in rotary tube dryer. Compared with the experimental results showed that this model was suitable for engineering accuracy, could change the rotary tube dryer engineering design and structure optimization for reference. [less ▲]

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See detailNumerical simulation of tissue differentiation around loaded implants in a bone chamber
Geris, Liesbet ULg; Vander Sloten, Jos

in In Proceedings of the Mini-Symposium Biomécanique de l'appareil locomoteur (2004)

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See detailNumerical simulation of tissue differentiation around loaded titanium implants in a bone chamber.
Geris, Liesbet ULg; Andreykiv, A.; Van Oosterwyck, H. et al

in Journal of Biomechanics (2004), 37(5), 763-9

The application of a bone chamber provides a controlled environment for the study of tissue differentiation and bone adaptation. The influence of different mechanical and biological factors on the ... [more ▼]

The application of a bone chamber provides a controlled environment for the study of tissue differentiation and bone adaptation. The influence of different mechanical and biological factors on the processes can be measured experimentally. The goal of the present work is to numerically model the process of peri-implant tissue differentiation inside a bone chamber, placed in a rabbit tibia. 2D and 3D models were created of the tissue inside the chamber. A number of loading conditions, corresponding to those applied in the rabbit experiments, were simulated. Fluid velocity and maximal distortional strain were considered as the stimuli that guide the differentiation process of mesenchymal cells into fibroblasts, chondrocytes and osteoblasts. Mesenchymal cells migrate through the chamber from the perforations in the chamber wall. This process is modelled by the diffusion equation. The predicted tissue phenotypes as well as the process of tissue ingrowth into the chamber show a qualitative agreement with the results of the rabbit experiments. Due to the limited number of animal experiments (four) and the observed inter-animal differences, no quantitative comparison could be made. These results however are a strong indication of the feasibility of the implemented theory to predict the mechano-regulation of the differentiation process inside the bone chamber. [less ▲]

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See detailNumerical Simulation of Transient Unconfined Seepage Problems
Charlier, Robert ULg; Radu, Jean-Pol ULg; Dassargues, Alain ULg

in Proceedings of the International Conference on Computer Methods and Water Resources - Volume 1: Groundwater and aquifer modelling (1988, June)

Detailed reference viewed: 48 (15 ULg)