Sainte-Foy-lès-Lyon, France
Sainte-Foy-lès-Lyon, France

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Arous F.M.,University of Science and Technology Houari Boumediene | Mataoui A.,University of Science and Technology Houari Boumediene | Terfous A.,Laboratoire Of Genie Of La Conception | Ghenaim A.,Laboratoire Of Genie Of La Conception
Progress in Computational Fluid Dynamics | Year: 2012

A two-dimensional turbulent wall jet over a shallow cavity is studied numerically. The present paper investigates the wall jet outer layer effect on a shallow cavity flow structure. This layer is an important turbulence source which is added to that of the inner shear layer. It was found that the reattachment process seems to be accelerated in the turbulent wall jet incoming flow compared to that of the cavity in duct flow. The present study shows that the flow structure is very sensitive to the cavity depth to nozzle height ratio; the increasing of this ratio induces a reattachment length decrease. Copyright © 2012 Inderscience Enterprises Ltd.

Kuhm D.,University of Strasbourg | Kuhm D.,Laboratoire Of Genie Of La Conception | Knittel D.,University of Strasbourg | Knittel D.,Laboratoire Of Genie Of La Conception
ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis, ESDA 2012 | Year: 2012

Accumulators are used in industrial elastic web processing plant such as paper, mills, fabric, rolling mills, to permit rewind or unwind core changes while the process continues at a constant velocity. The objective is to maintain constant web line velocity and tension into and downstream the accumulator. This paper presents a summarize of nonlinear models of different classical industrial accumulator structures: one with a pneumatic actuated carriage and one with a motorized carriage. These models are derived from physical laws that describe web tension and velocity dynamics in each web span. A second part presents new accumulator structures enabling performances improvement, considering the accumulator output web tension. Finally, the last part of this paper compares, by simulations in Mat-lab/Simulink software environment and using performances criteria, the performances of optimized accumulators and classical industrial ones. Copyright © 2012 by ASME.

Kuhm D.,University of Strasbourg | Kuhm D.,CNRS Textile Mechanics and Physics Laboratory | Knittel D.,University of Strasbourg | Knittel D.,Laboratoire Of Genie Of La Conception
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2011

This paper concerns the modelling of an accumulator used in an industrial elastic web processing plant (paper, fabric, polymer, metal ...). Accumulators are used to allow unwind or rewind roll changes while the rest of the line remains at a constant web velocity. Detailed nonlinear models of industrial accumulators are first given. The first one is a pneumatic actuated accumulator, the second one is motor actuated. These models are derived from the physical relationships that describe web tension and velocity dynamics in each web span of the accumulator. In a second part, control strategies are detailed. Industrial PI controllers, tuned with evolutionary algorithm on our realistic non-linear model, are presented, allowing good robustness against mechanical parameter variations. In this part the motor actuated accumulator performances are enhanced by including a dancer. © 2011 IFAC.

Armaghan N.,CNRS Research team on Innovative Processes | Renaud J.,Laboratoire Of Genie Of La Conception
Information Sciences | Year: 2012

Industrial decision-makers often try to develop new products by reusing their past experience. Methods for obtaining feedback are available in knowledge management and produce tangible results in the industrial world. Nowadays, companies often consider employees' knowledge as an asset. This approach is a potential answer for reusing knowledge acquired through experience. The Case-Based Reasoning (CBR) methodology, based on cognitive sciences, consists in solving new problems by reusing past experience. Case-Based Reasoning is an approach to solving a new problem by remembering and adapting a previous successful similar situation to the problem at hand. Of the four activities comprising CBR - Retrieve, Reuse, Revise, and Retain-this paper deals with the "Retrieve" phase. Consequently, we suggest using the Multi-Criteria Decisions concept in problem description to search for the solution in a case-based scenario. We show that Multi-Criteria Decisions and Case-Based Reasoning are complementary. This paper proposes using knowledge acquisition as a basis for seeking solutions from non-compensatory multi-criteria decision aids such as the ELECTRE-I and ELECTRE-II methods. We also carry out a robustness analysis at the end of this paper. We describe an industrial application with wire forming machines as an illustration of our recommendation. © 2012 Elsevier Inc. All rights reserved.

Pham A.D.,Laboratoire Of Genie Of La Conception | Mouhoubi S.,Laboratoire Of Genie Of La Conception | Bonnet M.,Ecole Polytechnique - Palaiseau | Chazallon C.,Laboratoire Of Genie Of La Conception
Engineering Analysis with Boundary Elements | Year: 2012

The solution of three-dimensional elastostatic problems using the Symmetric Galerkin Boundary Element Method (SGBEM) gives rise to fully populated (albeit symmetric) matrix equations, entailing high solution times for large models. This paper is concerned with the formulation and implementation of a multi-level fast multipole SGBEM (FM-SGBEM) for elastic solid with cracks. Arbitrary geometries and boundary conditions may be considered. Numerical results on test problems involving a cube, single or multiple cracks in an unbounded medium, and a cracked cylindrical solid are presented. BEM models involving up to 10 6 BEM unknowns are considered, and the desirable predicted trends of the elastostatic FM-SGBEM, such as a O(N) complexity per iteration, are verified. © 2012 Elsevier Ltd. All rights reserved.

Dubois S.,Laboratoire Of Genie Of La Conception | Tate D.,Texas Tech University | Conrardy C.,Eurinnov | Nguyen T.A.,Concordia University at Montréal | And 2 more authors.
Journal of Integrated Design and Process Science | Year: 2012

This paper presents the results of a study designed to compare the processes followed by practitioners of three design methods: the algorithm of inventive problem solving, axiomatic design, and environment-based design. Prior literature has postulated the complementary nature of these design methods, and in some cases, has provided case studies of their mutual application on a design problem. However, prior studies have not focused on the detailed activities used in each method to examine the similarities and differences in the outputs of the activities. In this study, a series of three one-day and three three-day design exercises were conducted simultaneously by three international research groups, each focusing on one method. The objectives of this study were to examine the early stages of the design process that deal with macro activities: problem analysis, problem synthesis, and design evaluation and decision making. Several micro design activities were conducted within these, depending on the design method: clarification of requirements, gathering information on existing technologies, initial conceptualization of an assembly of technologies, the identification of system contradictions/coupling, and the solution of contradictions. The objectives of this comparative study were to establish, from observations of practitioners-rather than from a theoretical point of view-the differences and complementarities between the design methods. The problems presented to designers covered a range of design tasks that spanned multiple disciplines, multiple levels of openendedness/specificity of the task, and various levels of inventiveness required. The comparison showed the complementary nature of the design methods, highlighted their respective strengths, and suggested the outlines of an integrated method based on the main benefit of each. © 2012-Society for Design and Process Science. All rights reserved.

Nowamooz H.,University of Lorraine | Nowamooz H.,Laboratoire Of Genie Of La Conception | Gomez-Espina R.,CIEMAT | Villar M.V.,CIEMAT | Masrouri F.,Laboratoire Environnement Geomecanique and Ouvrages
Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils | Year: 2011

This paper presents an experimental study on a bentonite/silt mixture using odometers with suction controlled either by the osmotic technique or by air overpressure at two different temperatures of 20° and 60°C in a suction range between 0 and 8 M Pa. The compression curves permitted us to interpret the influence of the temperature on the different yielding surfaces. The temperature increase rigidified the samples producing a significant increase of the preconsolidation stress. We observed that the compression curves at different imposed suctions converged toward the saturated state for the high applied vertical stresses. The stress from which the compression curves follow the saturated state is called the saturation pressure (P sat). The P sat values increased with the temperature increase. © 2011 Taylor & Francis Group, London.

Nowamooz H.,Laboratoire Of Genie Of La Conception | Nowamooz H.,University of Lorraine | Arsenie M.I.,Laboratoire Of Genie Of La Conception | Arsenie M.I.,University of Lorraine | And 2 more authors.
Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils | Year: 2011

The article presents an experimental study on compacted natural sand of Missillac in France using two different suction methods: • Filter paper to measure the soil matrix suction; • Tensiometer to measure the matrix suction range between 0 and 100 kPa. All the applied techniques permit to obtain the SWRC of the compacted samples. These experimental results, beside their modelling applications, provide a good database to compare the accuracy of each applied method in a suction range very close to the saturated state. Generally, we can find a good correspondence between these curves. Additionally, the Soil Water Retention Curve (SWRC) is used to add the suction parameter in a non linear elasticity model (respectively shakedown elastoplastic model) for the finite element modelling of the resilient behaviour (respectively long term behaviour) of road pavement under traffic loading. Unfavorable moisture conditions are one of the most common mechanisms of deterioration of low traffic pavements, with unbound granular bases. © 2011 Taylor & Francis Group, London.

Ghostine R.,French National Center for Scientific Research | Mose R.,French National Center for Scientific Research | Vazquez J.,French National Center for Scientific Research | Ghenaim A.,Laboratoire Of Genie Of La Conception | Gregoire C.,CNRS Hydrology and Geochemistry Laboratory of Strasbourg
Journal of Hydraulic Engineering | Year: 2010

Classically, in open-channel networks, the flow is numerically approximated by the one-dimensional Saint Venant equations coupled with a junction model. In this study, a comparison between the one-dimensional (1D) and two-dimensional (2D) numerical simulations of subcritical flow in open-channel networks is presented and completely described allowing for a full comprehension of the modeling of water flow. For the 1D, the mathematical model used is the 1D Saint Venant equations to find the solution in branches. For junction, various models based on momentum or energy conservation have been developed to relate the flow variables at the junction. These models are of empirical nature due to certain parameters given by experimental results and moreover they often present a reduced field of validity. In contrast, for the 2D simulation, the junction is discretized into triangular cells and we simply apply the 2D Saint Venant equations, which are solved by a second-order finite-volume method. In order to give an answer to the question of luxury or necessity of the 2D approach, the 1D and 2D numerical results for steady flow are compared to existing experimental data. © 2010 ASCE.

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