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Etude des Propriétés Mécaniques et de la Ténacité du Polyéthylène Haute Densité Destiné au Revêtement des Pipelines de Gaz

Zelmati Djamel (2005)
Mémoire de magister

Pour bien étudier l’influence de la morphologie des matériaux polymères sur la variabilité  des propriétés mécaniques et de la rupture, nous avons pu déterminer la ténacité à l’amorçage au mode I des PEHD destinés aux revêtement des pipelines gaz, en utilisant des corrélations qui permettent d’obtenir la ténacité à partir des critères en termes de contraintes et des critères énergétiques.   L’étude montre l’influence de l’épaisseur de la couche de revêtement ainsi que la vitesse de chargement sur la variabilité des propriétés mécaniques, et qu’il est possible de mesurer expérimentalement le facteur d’intensité de contrainte en état de contrainte plane  égale à 0.954 , on se basant sur des courbes d’évolution de la contrainte ultime en fonction d’un coefficient englobant la géométrie de l’éprouvette et la longueur de la fissure, ainsi que la mesure expérimentale de la ténacité représentée par  égale 87.95 KJ/m2 , observée par des essais de traction sur les éprouvettes parallélépipèdes d’épaisseur 1mm présentant des longueurs d’entailles différents. Voir les détails

Mots clés : matériau polymère, PEHD, ténacité, facteur d'intensité de contraintes, intégrale J

Study of The Reliability of A Composite Used In The Knee Prosthesis

L. Alimi, M. Boulkra, N. Sassane, S. Boukhezar, M. HASSANI, K. Bedoud, K. BEY  (2019)
Publication

In orthopedic surgery, the effectiveness of the implants used, such as hip and knee prostheses, depends mainly on their geometries and the type of loading to which they are subjected. In this work a probabilistic approach is chosen to study the reliability of a composite structure used in the manufacture of knee prostheses. The purpose of integrating reliability concepts is to consider uncertainty in several aspects including loading and material properties. The reliability index β is an excellent indication of durability and safety for given operating conditions. β is obtained using failure probability and a mechanical model. The critical stress intensity factor (Kc) is adopted as a criterion to the maximum limit of a numerically calculated KI. The results presented are discussed according to the length of the crack (a), and the limit load used. Voir les détails

Mots clés : Reliability analysis, critical stress intensity factor, crack length, load, reliability index

Experimental study of chemically aged HDPE pipe material in toluene-methanol mixture and distilled water

Latifa ALIMI, Kamel CHAOUI, Nacira Hamlaoui, and Khouloud Bedoud  (2019)
Publication

Studying the aging phenomenon of plastic pipes presents simultaneously an economic achievement and a technical challenge for water and natural gas transportation systems. Ver y often, they are exposed to aggressive environmental agents such as UV rays, ambient oxygen, acids, bases and some other so lvents, altering the material microstructure, its physical and chemical properties. The high density polyethylene (HDPE) material degradation and loss of performance are usually the consequence of unwanted changes in mechanical behaviors leading to lower resistance. In this s tudy, we examine the effects of distilled water (DW) and a mixture of toluene-methanol (TM) in contact with an HDPE pipe. Morphological properties such as crystallinity and oxidation induction time (OIT) are in vestigated using DSC method. Tensile tests and thermal analysis show that the TM mixture is much more absorbed by the resin as compared to DW. An increase in crystallinity is observed as established from literature for other organic solutions. Finally, the study gives an idea about property variances and their evolution as a function of the pipe thickness which c an be used as an estimation of the structural heterogeneity of the product. Voir les détails

Mots clés : Pipe; HDPE; Aging; Distilled Water; Toluene-Methanol Mixture; Crystallinity; OIT

Elaboration et caractérisation des couches minces de NiFe élaborées par électrodéposition 

LAKHDARI Delloula (En préparation)
Thèse de doctorat

L’étude des matériaux magnétique à l’état massif ou sous différentes géométries n’a cessé de croitre. L’arrivée de nouveaux procédés de fabrication a permis l’apparition des couches minces, des couches ultra minces et des nano-structures (tel que les nano-vibres a base  des polymeres ). Les propriétés de ces matériaux font toujours l’objet d’études approfondies et ont apporté de nombreuses applications. L’enjeu principal de ces recherches repose sur la miniaturisation et la rapidité de ces dispositifs de stockage des données liées au magnétisme.Le permalloy ou Ni80Fe20 (Py) est l’un des rares matériaux ou il y a eu une continuité entre état de l’art historique des matériaux ferromagnétiques doux massifs et celui des couches minces. De plus, cet alliage bénéficie en couche mince de techniques d’élaboration doubles : par voie chimique (électrolyse) et par voie physique (dépôt en phase vapeur), ce qui en fait la couche  mince ferromagnétique de loin la plus utilisée aujourd’hui dans les laboratoires et dans l’industrie. L’élaboration des couches minces par la méthode de l’électrodéposition est une bonne alternative aux voix physiques. En effet, l’électrodéposition est une technique peu couteuse et facile à mettre en œuvre. Dans ce sujet de thèse, nous nous intéressons à l’étude des propriétés physiques des couches minces de permalloy élaborées par électrodéposition sur des substrats semi-conducteurs et sur des nanostructures Si.  Dans ce sujet de thèse l’étudiante aura à effectuer les taches suivantes : -          Elaboration de couches minces Py par électrodéposition sur des substrats ITO et FTO.-          Caractérisation structurale et microstructurale des couches minces Py et étude de l’influence du type de substrat (ITO et FTO) sur la croissance cristalline et la morphologie.-          Caractérisation magnétique par magnétométrie à échantillon vibrant et par spectrométrie Mössbauer du 57Fe.  -          Elaboration des nanostructures de Silicium. -          Electrodéposition des couches minces de riche en nickel sur des nanostructures à base de polymère et de Si.-          Caractérisation structurale, microstructurale et magnétiques des couches minces de Py électro-déposées sur des nanostructures à base de polymère et de Si.-          Application de ces nanostructures dans le domaine biotechnologie ; capteur de glucose ; capteur anti bactérie.    Voir les détails

Mots clés : electrodeposition, Nickel, Fer, alliage, glucose, Nonostructure

Feedback linearization control based particle swarm optimization for maximum power point tracking of wind turbine equipped by PMSG connected to the grid

Youcef Soufi, Sami KAHLA, Mohcene Bechouat  (2016)
Publication

The main problem regarding wind power systems is the major discrepancy between the irregular character of the primary source (wind speed is a random, strongly non-stationary process) and the exigent demands regarding the electrical energy quality. This paper presents a feedback linearization controller based particle swarm optimization for maximum power point tracking of wind turbine equipped by PMSG connected to the grid, the proposed method which aims at maximizing the power captured by WECS. In order to drive the system to the optimal operating point using the selection of the controller parameters with particle swarm optimization. The obtained simulation results with a variable wind profile show an adequate dynamic of the conversion system using the proposed approach. Voir les détails

Mots clés : Wind turbine, Maximum Power Point Tracking, Feedback linearization control, Particle Swarm Optimization (PSO), Wind Energy Conversion System (WECS)

Particle swarm optimization based sliding mode control of variable speed wind energy conversion system

Youcef Soufi, Sami KAHLA, Mohcene Bechouat  (2016)
Publication

This paper proposes a particle swarm optimization based sliding mode control of squirrel cage induction generator of a variable speed wind energy conversion system. The key feature of sliding mode control is a wisely chosen sliding surface which allows the turbine to operate more or less close to the optimal regimes characteristic. Optimal control parameters which are the convergence speed to the sliding-mode, the slope of the surface and the switching component amplitude of SMC are determined using particle swarm optimization approach. The simulation results prove the viability of the proposed control structure. Voir les détails

Mots clés : Squirrel Cage Induction Generator (SCIG), Wind Energy Conversion System (WECS), Sliding Mode Control (SMC), Particle Swarm Optimization (PSO)

Particle Swarm Optimization Backstepping Controller for a Grid-Connected PV/Wind Hybrid System.

Mohcene Bechouat, Moussa Sedraoui, Youcef Soufi, Laatra Yousfi, Abdelhalim Borni, Sami KAHLA  (2017)
Publication

The current paper investigates Backstepping controller using Particle Swarm Optimization for Photovoltaic "PV"/Wind hybrid system. The tested system was connected to the grid by three-phase inverter commissioned to address current depending on the grid parameters and still deliver its reactive power to zero. Backstepping control is a recursive methodology that uses Lyapunov function which can ensure the system stability. The best selection of Lyapunov function gains values should give a good result. In most of the literatures, the choice was based on the expertise of the studied system using hurwitzienne method considered as heuristic choice. The aim of this work is to propose an optimization using a powerful method commonly called Particle Swarm Optimization "PSO" able to calculate the gains values depending on the grid parameters by minimizing a selected criterion. The simulation results show that the PSO Backstepping controller gives good results shown in the current injected to grid with a small harmonic distortion despite climate change in the wind speed and the irradiation, which also shows the robustness of the applied control. Voir les détails

Mots clés : PV/Wind Grid-Connected, MPPT, Backstepping Controller, PSO, Matlab/Simulink

Fuzzy-PSO controller design for maximum power point tracking in photovoltaic system

Youcef Soufi, Mohcene Bechouat, Sami KAHLA  (2017)
Publication

Photovoltaic power generation system becomes increasingly important, highly attractive as a clean and renewable energy sources, widely used today in many applications. Recently, researchers have strongly promoted the use of solar energy as a viable source of energy due to its advantages and which it can be integrated into local and regional power supplies. The P–V curve of photovoltaic system exhibits multiple peaks under various conditions of functioning and changes in meteorological conditions which reduces the effectiveness of conventional maximum power point tracking (MPPT) methods and the Particle swarm optimization (PSO) algorithm is considered to be highly efficient for the solution of complicated problems.In this paper, the application of this approach based MPPT algorithm for Photovoltaic power generation system operating under variable conditions is proposed to optimize and to design an intelligent controller comparing to conventional one. PSO Approaches is considered to select and generate an optimal duty cycle which varies with photovoltaic parameters in order to extract the maximum Power. Simulation results show that the proposed approach can track the maximum power point faster and can improve the performance of the system compared to the conventional method. Voir les détails

Mots clés : Particle Swarm Optimization (PSO), photovoltaic System, Boost, PWM, MPPT, FLC

Maximum Power Point Tracking of Wind Energy Conversion System Using Multi-objective grey wolf optimization of Fuzzy-Sliding Mode Controller

Sami KAHLA, Youcef Soufi, Moussa Sedraoui, Mohcene Bechouat  (2017)
Publication

Ongoing electricity demand and the increasing growth of population have become necessary to provide alternative and clean sources of energy. Wind energy is one of the most important sustainable energies but the irregular characters of the primary source, which is characterized by a random wind speed variation, makes the process of control is difficult in order to maximize the power. This paper presents a multi objective grey wolf optimization (MOGWO) of fuzzy sliding mode controller in order to maximize the power captured by wind turbine; meanwhile, the mechanical loads are alleviated for variable speed wind energy conversion system (VS-WECS); firstly, Fuzzy logic theory based sliding mode control is developed by collecting the sliding surface data to reduce the chattering effect caused by the SMC, then the Grey Wolf Optimization is introduced to solve multi-objectives functions of WECS which are extracting the maximum power and alleviation the mechanical loads in order to find the optimal parameters of Fuzzy-Sliding mode controller to drive the conversion system to the optimal operating point. The obtained results are compared with those given by Sliding mode controller and Fuzzy-Sliding mode controller in which our proposed method can ensure a better dynamic behavior of the WECS. Voir les détails

Mots clés : Wind Energy Conversion System WECS, Maximum Power Point Tracking MPTT, Sliding mode control, fuzzy logic control, MO-GWO

Particle Swarm Optimization Based Maximum Power Point Tracking Algorithm for Photovoltaic Energy Conversion System

Youcef Soufi, Moheene Bechouat, Sami KAHLA  (2018)
Publication

In order to extract the maximum power from PV system, the maximum power point tracking (MPPT) method is one of the most popular and widely used and it has always been applied in photovoltaic energy conversion system. However, this method exhibits fluctuations among the maximum power point (MPP) due to the nature of unpredicted and changes of the environmental parameters. Therefore, it is significant to include an intelligent controller that can track the maximum peak regardless of parameters variations such as: irradiation and temperature. This paper describes the design and development of particle swarm optimization (PSO) based maximum power point tracking (MPPT) algorithm for photovoltaic energy conversion system. The proposed MPPT is simple, flexible, accurate and efficient in maximum photovoltaic power tracking. In this work, MATLAB/Simulink simulation package is used to simulate the performance of the proposed MPPT algorithm. The performance of the proposed PSO algorithm is evaluated by comparing it with the conventional P&O method in terms of tracking speed and accuracy. The simulation results demonstrate that the tracking capability of the PSO algorithm is more efficient, comparing to the traditional one, particularly under parameters variation conditions. Voir les détails

Mots clés : Photovoltaic systems, Maximum Power Point Tracking (MPPT), Particle Swarm Optimization (PSO), perturb and observe (P&O)