Designing of a new seismic base isolation system

The design of a new base isolation system is proposed in this research with the objective that the system does not transmit any force to the structure under horizontal loading. The structure must remain operational and steady. Before investigating the dynamics problem of the base isolation system, the isolator components of the model can be solved analytically using different approaches. In order to calculate the deformation of any element of the isolator due to a compressive vertical load, the analysis focuses on the primary instability region to determine all deformations parameters which can lead to frictions coefficients. This region is located at the interaction contact point between the elements. The design is based on the contact point developed by different approaches. In the present study, the mathematical analysis methods by using formulations can calculate the different dimensions and deformations of the elements of the system and which are verified using ANSYS finite element analysis.  After ensuring the adequate dimensions of the different parts of the isolator system from the analysis, the system can be applied on the structure. This technique can reduce significantly the displacements and accelerations at the underground level with a new seismic isolation system, which it is an uncoupled system between the structure and the underground

Designing of a new seismic base isolation system

The design of a new base isolation system is proposed in this research with the objective that the system does not transmit any force to the structure under horizontal loading. The structure must remain operational and steady. Before investigating the dynamics problem of the base isolation system, the isolator components of the model can be solved analytically using different approaches. In order to calculate the deformation of any element of the isolator due to a compressive vertical load, the analysis focuses on the primary instability region to determine all deformations parameters which can lead to frictions coefficients. This region is located at the interaction contact point between the elements. The design is based on the contact point developed by different approaches. In the present study, the mathematical analysis methods by using formulations can calculate the different dimensions and deformations of the elements of the system and which are verified using ANSYS finite element analysis.  After ensuring the adequate dimensions of the different parts of the isolator system from the analysis, the system can be applied on the structure. This technique can reduce significantly the displacements and accelerations at the underground level with a new seismic isolation system, which it is an uncoupled system between the structure and the underground

Contraste sociolinguistique, dynamique socioculturelle et variation dialectale, Cas de deux familles d’Adrar installées à Tlemcen

Sociolinguistic Contrast between the North and the South of Algeria – Sociocultural Dynamics and Dialectal Variations, Case of Two Families from Adrar settled in Tlemcen ABSTRACT: The Maghreb countries are known for their linguistic diversity due to ethnic mixing and the different waves of migration brought by Islamic conquests and colonial constraints. Today, each city and each region bears within them, to different degrees, the marks of this history which is rather combined in the plural. This contribution focuses on the correlation between social mobility and dialectal variety to justify certain phenomena such as transculturalism and bidialectism cause of phonetic distortions and semantic changes. An investigation is proposed to validate these phenomena. RÉSUMÉ : Les pays du Maghreb sont connus pour leurs diversités linguistiques dues au brassage ethnique et aux différentes vagues migratoires apportées par les conquêtes islamiques et les invasions coloniales. Aujourd’hui, chaque ville et chaque région porte en elles, à des degrés différents, les marques de cette histoire qui se conjugue plutôt au pluriel. Cette contribution s’intéresse à la corrélation entre mobilité sociale et variété dialectale pour justifier certains phénomènes tels que la transculturation et le bidialectisme, causes de distorsions phonétiques et de changements sémantiques. Une enquête de terrain est proposée pour analyser et comprendre ces phénomènes  

Optimisation et simulation du rotomoulage réactif

Le rotomoulage réactif est un procédé de fabrication de pièces creuses en polymère où la synthèse du matériau intervient pendant la mise en œuvre. Cette méthode présente plusieurs avantages comparée à la méthode traditionnelle utilisant des poudres thermoplastiques : réduction du temps de cycle, utilisation possible de matériaux techniques, et baisse de la consommation d'énergie et du coût des matières premières. Cependant le rotomoulage réactif est plus complexe à mettre en œuvre car la polymérisation provoque un changement important et rapide de la viscosité. Une des solutions pour optimiser ce procédé est de simuler l'écoulement du système réactif pendant la mise en œuvre.Pour ce travail nous avons utilisé un polyuréthane thermodurcissable. Des analyses thermiques et rhéologiques ont permis d'étudier les phénomènes de gélification et de vitrification du matériau et le diagramme Temps-Température-Transformation a été établi. Le comportement rhéocinétique du système a également été modélisé.Le procédé a été simulé en utilisant un code de calcul basé sur la méthode Smoothed Particle Hydrodynamics (SPH). Ce code a été développé par notre équipe et plusieurs améliorations ont été apportées au cours de cette étude. Pour effectuer des simulations plus réalistes en utilisant un plus grand nombre de particules, la première amélioration a consisté à accélérer la résolution des calculs. Ensuite l'évolution de la viscosité a été prise en compte grâce à l'utilisation d'un modèle rhéocinétique et une nouvelle condition limite a été développée pour simuler l'adhésion du polymère sur la paroi du moule. Les modifications nécessaires à la simulation d'écoulements 3D ont également été apportées au code SPH.Reactive rotational molding is a process to manufacture hollow plastic parts where synthesis occurs during the shaping. This method has several advantages compared to traditional rotomolding using thermoplastic powders: shorter cycle time, possible use of high performance materials, and decrease of energy consumption and raw materials costs. However reactive rotational molding is more complex to implement mainly because of the important and quick change of viscosity occurring during polymerization. One of the solutions to optimize this process is to simulate the reactive system flow during processing.In this work we used thermoset polyurethane as reactive system. Thanks to thermal and rheological analysis, gelation and vitrification phenomena were studied and Time-Temperature-Transformation diagram was established. Material chemiorheological behavior was also modeled.The process has been simulated using a solver based on Smoothed Particle Hydrodynamics (SPH) method. This solver was developed in our research team and several improvements have been added during this study. To be able to simulate realistic flows with a high number of particles, the first improvement was to accelerate the resolution of calculations. Then the change of viscosity has been taken into account using a chemiorheological model and a new boundary condition was developed to simulate adhesion of polymer on the mold wall. To be able to simulate 3D flows, the needed modifications have been also added to the SPH solver.PARIS-Arts et Métiers (751132303) / SudocSudocFranceF

Coupling of inverse method and cuckoo search algorithm for multiobjective optimization design of an axial flow pump

This work describes the application of a multiobjective cuckoo search method for turbomachinery design optimization of an axial pump. Maximization of the total efficiency and minimization of the required net positive suction head of the pump are the two objective functions considered for the optimization problem. The optimization process is carried out on a range of imposed volumetric flow rates, with taking into account at each discretized radius between the hub and tip of the rotor: the profile camber, rotor wall thickness, angular deviation, and the solidity, regarded as geometrical constraints and nominal flow rate as mechanical constraint. Two strategies are proposed in order to solve the problem. In the first one, three forms of mono-objective model with two variables, total efficiency and net positive suction head, are considered. In the second one, a multiobjective model with nondominated sorting scheme is adopted. A comparative evaluation of results obtained from the proposed approach with those of a reference machine and genetic algorithm allowed us to validate the present work

Efficiency of bio- and socio-inspired optimization algorithms for axial turbomachinery design

Turbomachinery design is a complex problem which requires a lot of experience. The procedure may be speed up by the development of new numerical tools and optimization techniques. The latter rely on the parameterization of the geometry, a model to assess the performance of a given geometry and the definition of an objective functions and constraints to compare solutions. In order to improve the reference machine performance, two formulations including the off-design have been developed. The first one is the maximization of the total nominal efficiency. The second one consists to maximize the operation area under the efficiency curve. In this paper five optimization methods have been assessed for axial pump design: Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Cuckoo Search (CS), Teaching Learning Based Optimization (TLBO) and Sequential Linear Programming (SLP). Four non-intrusive methods and the latter intrusive. Given an identical design point and set of constraints, each method proposed an optimized geometry. Their computing time, the optimized geometry and its performances (flow rate, head (H), efficiency (η), net pressure suction head (NPSH) and power) are compared. Although all methods would converge to similar results and geometry, it is not the case when increasing the range and number of constraints. The discrepancy in geometries and the variety of results are presented and discussed. The computational fluid dynamics (CFD) is used to validate the reference and optimized machines performances in two main formulations. The most adapted approach is compared with some existing approaches in literature

LEÓN, JOSÉ CLAUDIO DE Y SRA. [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Contribution à la modélisation aéroacoustique des ventilateurs centrifuges à grande vitesse

L'étude porte sur la modélisation numérique du comportement aérodynamique et acoustique des ventilateurs centrifuges à grande vitesse opérant en régime subsonique. Des travaux expérimentaux ont permis la validation des résultats théoriques et la conception de nouveaux prototypes optimaux d'un point de vu acoustique. L'approche théorique utilisée pour la simulation du champ aérodynamique dans le ventilateur centrifuge est basée sur la résolution des équations de Navier-Stokes moyennées instationnaires couplée à des modèles de fermeture en un point. Deux configurations, avec et sans prise en compte du jeu axial entre la roue et le flasque avant, ont été testées sur un banc d'essais normalisé ISO5801. Cette comparaison a permis la validation de la modélisation numérique d'une part et la mise en évidence de l'importance de la prise en compte du jeu axial d'autre part. Une modélisation du bruit du ventilateur centrifuge à la fréquence de passage de pales et à ses harmoniques a été réalisée. Celle-ci est basée sur le formalisme de Ffowcs Williams et Hawkings en champ lointain acoustique et géométrique. La non-compacité des sources a été prise en compte ainsi que le caractère instationnaire de la répartition des charges sur les profils. Les résultats aéroacoustiques obtenus ont été comparés aux mesures expérimentales. Sur la base des résultats de l'étude aérodynamique et acoustique complétés par une étude paramétrique des caractéristiques géométriques du ventilateur centrifuge de référence, de nouveaux prototypes de diffuseurs et de roues ont été proposés.The study relates to the numerical modeling of the aerodynamic and acoustic behaviour of high speed centrifugal fans operating in subsonic modes. Experimental work allowed the validation of the theoretical results and the design of new optimal prototypes. The theoretical approach used for the numerical simulation of the aerodynamic field in the centrifugal fan is based on the resolution of the unsteady RANS equations. Two configurations, with and without taking into account of the axial gap between the impeller and the casing, were tested on a standardized ISO5801 test bench. This comparison allowed the validation of numerical modeling and focuses the importance of the taking into account of the axial gap. A modeling of the centrifugal fan noise at the blade passing frequency (BPF) and its harmonics was performed. The aeroacoustic modeling is based on the Ffowcs Williams and Hawkings formalism in acoustical and geometrical far field. The non-compactness of the sources was taken into account as well as the unsteady character of the acting force partitions on the blades. The so obtained aeroacoustic results were compared with experimental measurements. On the basis of result of the aerodynamic and acoustic study supplemented by a parametric study of the geometrical characteristics of the centrifugal fan, new prototypes of diffusers and impellers were designed.PARIS-Arts et Métiers (751132303) / SudocSudocFranceF

Vers une approche interculturelle dans le processus d’enseignement/apprentissage du FLE

Cet article s’inscrit dans une approche interculturelle. Il se propose d’expliquer et de cerner avec précision l’acception que pourrait recouvrir l’adjectif « interculturel » notamment dans le domaine d’enseignement du FLE. Il insiste aussi sur la place de la compétence interculturelle dans le processus d’enseignement/apprentissage des langues étrangères. L’objectif majeur de notre article est de montrer comment, dans un cours de langue, la compétence interculturelle contribue à rapprocher les deux cultures ; cible/source et incite à l’ouverture sur l’autre lors d’acquisition des compétences culturelles. Abstract This article is part of an intercultural approach. He intends to explain and define precisely the meaning that the term "intercultural" could cover, particularly in the teaching of FLE. He also insisted on the place of intercultural competence in the teaching of foreign languages. The main objective of our article is to show how, in a language course, intercultural competence contributes to bringing the two cultures closer together; target / source and encourages openness to others when acquiring cultural skills.

Aeroacoustic noise prediction for SRM

6 pagesInternational audienceHigh speed motors produce an important aeroacoustic noise which restrains their field of use. In this paper we focus on an adaptation of some aeroacoustic studies in the case of a single phase SRM whose rotation rate is between 25,000 and 45,000 rpm under low rotational Mach number (M<0.15). This paper aims to build an aeroacoustic noise prediction procedure dedicated to electrical motors