Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 109 (27 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 78 (3 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 30 (0 ULg)
Peer Reviewed
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)

Detailed reference viewed: 1 (0 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 9 (0 ULg)
Full Text
Peer Reviewed
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)
Full Text
Peer Reviewed
See detailNumerical simulation of tribological devices used as a set of benchmarks for comparing contact algorithms
Chabrand, Patrick; Dubois, Frédéric; Graillet, Denis et al

in Finite Elements in Analysis & Design (2005), 41(6), 637-665

The aim of the present study was to carry out a numerical comparison of different frictional contact algorithms. Therefore three different contact algorithms (Lemke, penalty and Augmented Lagrangian) have ... [more ▼]

The aim of the present study was to carry out a numerical comparison of different frictional contact algorithms. Therefore three different contact algorithms (Lemke, penalty and Augmented Lagrangian) have been implemented into two. finite element codes. The correct implementation and behavior of these contact algorithms has been investigated by modeling four different tribological devices. It is shown that all these different methodologies lead to extremely similar results. Besides these four applications have been carefully described and detailed in such a way that the presented tests can be reproduced. The authors wish that they could serve as a benchmark set in order to allow comparison with other finite element software including frictional contact capabilities. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 16 (5 ULg)
Full Text
Peer Reviewed
See detailNumerical simulation of two-dimensional and three-dimensional axisymmetric advection-diffusion systems with complex geometries using finite-volume methods
Ashbourn, J. M. A.; Geris, Liesbet ULg; Gerisch, A. et al

in Proceedings : Mathematical, Physical & Engineering Sciences (2010), 466(2118), 1621-1643

A finite-volume method has been developed that can deal accurately with complicated, curved boundaries for both two-dimensional and three-dimensional axisymmetric advection-diffusion systems. The ... [more ▼]

A finite-volume method has been developed that can deal accurately with complicated, curved boundaries for both two-dimensional and three-dimensional axisymmetric advection-diffusion systems. The motivation behind this is threefold. Firstly, the ability to model the correct geometry of a situation yields more accurate results. Secondly, smooth geometries eliminate corner singularities in the calculation of, for example, mechanical variables and thirdly, different geometries can be tested for experimental applications. An example illustrating each of these is given: fluid carrying a dye and rotating in an annulus, bone fracture healing in mice, and using vessels of different geometry in an ultracentrifuge. [less ▲]

Detailed reference viewed: 20 (5 ULg)
Full Text
Peer Reviewed
See detailNumerical simulation of viscoplastic and frictional heating during finite deformation of metal. Part I: Theory
Adam, Laurent; Ponthot, Jean-Philippe ULg

in Journal of Engineering Mechanics (2002), 128(11), 1215-1221

In this paper we will apply the theoretical framework developed in Part I to various metal forming processes. These numerical simulations are exposed showing the capability of the formulation to simulate ... [more ▼]

In this paper we will apply the theoretical framework developed in Part I to various metal forming processes. These numerical simulations are exposed showing the capability of the formulation to simulate finite anisothermal deformation of solids and thermal field evolution due to viscoplastic and frictional heating. [less ▲]

Detailed reference viewed: 11 (2 ULg)
Full Text
Peer Reviewed
See detailNumerical Simulation of Viscoplastic and Frictional Heating during Finite Deformation of Metal. Part II: Applications
Adam, Laurent; Ponthot, Jean-Philippe ULg

in Journal of Engineering Mechanics (2002), Vol. 128

In this paper we will apply the theoretical framework developed in Part I to various metal forming processes. These numerical simulations are exposed showing the capability of the formulation to simulate ... [more ▼]

In this paper we will apply the theoretical framework developed in Part I to various metal forming processes. These numerical simulations are exposed showing the capability of the formulation to simulate finite anisothermal deformation of solids and thermal field evolution due to viscoplastic and frictional heating. [less ▲]

Detailed reference viewed: 18 (0 ULg)
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: 20 (0 ULg)
Full Text
Peer Reviewed
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)
Full Text
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: 27 (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)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 35 (9 ULg)
Full Text
Peer Reviewed
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: 68 (37 ULg)
Full Text
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 ▲]

Detailed reference viewed: 227 (54 ULg)
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)

Detailed reference viewed: 22 (3 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 15 (2 ULg)