Liste des Mémoires de Master

Nombre total de résultats :77
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Détermination expérimentalement et numériquement des paramètres de rupture à l'aide de la technique de corrélation d'image digitales DIC et l'analyse FEM

M.S.Nasri  (2021)
Mémoire de Master

For the purpose of determining the critical fracture parameters of materials such as the critical energy restitution rate GIc, the stress intensity factor KIc, the maximum fracture load and the critical crack opening CTOD where δc numerous approaches are used in the literature. One of the approaches is based on experimental tests assisted by numerical methods such as Digital Images Correlation DIC and FEM finite element analysis. A FEM finite element analysis under a computation code (ABAQUS) allows to simulate the rupture tests, through numerical models in elasticity or elasto-plasticity allows to extract the values of the different components of the displacement and deformation field, the latter are confronted with the same parameters obtained experimentally. And finally, the calculation of the energy restitution rate and the stress intensity factor as well as the critical opening of the CTOD cracks. Voir les détails

Mots clés : Critical failure parameter, The critical energy release rate GIc, The stress intensity factor KIc, The maximum breaking load

Réalisation d'un système de navigation d’un quadricoptère piloté par carte Raspberry Pi

Mémoire de Master

This thesis is devoted to the realization of a navigation system specific to the quadricopter based on the Raspberry Pi 3 B development board. The latter must acquire and process in real time the information from the MPU6050 and GPS sensors, integrate scenes captured by a Pi camera integrated with the system produced, command and control the quadcopter remotely via a joystick and a smartphone. The results obtained by the sensors and the camera to be displayed on the smartphone, which represents the ground station. Voir les détails

Mots clés : UAV, quadricopter, navigation system, Raspberry Pi 3B, MPU6050, GPS, real time, Pi camera, joystick, smartphone.


M. BENTTOUMI  (2020)
Mémoire de Master

Aluminum has very low mechanical properties. To significantly increase them, we actedon three main modifying factors of the microstructure. Addition to aluminum of a very lowdensity element including 13% silicon which facilitates the flowability of the metal, gravitysand molding and structural hardening treatments.Al-Si alloys are highly indicated by their lightness, their high tensile and corrosionresistance. The study focuses on the influence of maturation on the evolution of the elasticproperties determined by the tensile and ultrasound tests of the Al-13% mass eutectic alloy. Iffor six states: raw casting noted - F and maturation in 6h steps noted - M0h, M6h, M12h,M18h and M24h. The parts produced from this alloy are part of the components used invarious projects by SNVI Rouïba and Electro-Industries de Fréha (covers, pump casing,motor pistons, etc.).All the results of the mechanical and structural properties gathered in Part III of our thesisshow us that we should recommend for the molding of parts whatever the series: the grossreference state designated - F. Voir les détails

Mots clés : Al-Si, sand, ripening, mechanical properties

Conception et réalisation d’un système de contrôle non destructif par courant de Foucault pulsé

B. GHOBCHI Younes  (2020)
Mémoire de Master

The conventional EC method is used for near-surface defects finding [5] [48] [12] [2]. On the other hand, and in order to control great depths, pulsed eddy currents are used [35] [48] [12] [2]. Through this project we aim to realize an analogue-digital PEC-NDT system, interfaced by a microcomputer. A set of experiments is carried out in order to prove the sensitivity of the designed system towards some parameters [2], where the determined mechanical properties are compared with the results obtained in order to in order to confirm some hypotheses [32]. Voir les détails

Mots clés : cnd, Instrumentation, Courants de Foucault pulsés

Caractérisation et modélisation numérique d’un composite époxy/Alfa.

A. MOUHOUB  (2020)
Mémoire de Master

Nowdays, natural fiber composites are increasingly getting great interest on an industrial scale. This undeniable success is linked to the intrinsic properties of natural fibers reinforcements and to their ecological character. Our study consists in characterizing the mechanical properties in tensile, bending and ultrasonic as well as morphological characterization by optical and scanning electron microscopy in order to evaluate their aptitude to replace synthetic fiber composites. The material to be characterized is composed of an epoxy matrix reinforced with 20% in weight Alfa short fibers. Numerical modeling using the finite element method allowed us to predict the Young's modulus of our randomly reinforced biocomposites. The ANSYS modeling software was used to generate the 3D representative elementary volume and to calculate the Young's modulus of the composite. The experimental results recorded are close to those obtained by numerical modeling. The latter remains therefore the goal to reach. Voir les détails

Mots clés : natural fibers, Alfa fibers, biocomposites, mechanical characterization, numerical modeling, ecology

Etude mécanique et microstructurale des soudures des alliages d'aluminium soudées par friction

Mémoire de Master

This work is related to the study of the friction welding process. This type of welding has many applications in different branches of industry. This process has many advantages. First, the very high quality assemblies can be made. In addition, this process is much faster than any other conventional processes. Furthermore, it can be completely automated so that constant quality is guaranteed. The aim of this study is the optimization of the parameters of friction welding: (by varying the friction time [s] and the rotational speed [rpm], forging time [s] and the friction pressure and forging [MPa] remain constant). An experimental procedure was used to obtain a welded junction (alu-alu), the alloy used is Al 6013-T8. We used several characterization methods, simple but effective and suitable for this kind of research work; such as microstructural characterization by optical microscope and mechanical characterization namely microhardness and tensile testing. We observed that the microstructure has three zones (TMAZ, HAZ and MDZ), The microhardness profile has a certain homogeneity and the tensile tests have shown that the tensile strength, elongation and elastic limit increase with increased friction time. In general, the mechanical properties are influenced by the overall effect of the metallographic structure of the weld. The latter is closely linked to the process parameters. Voir les détails

Mots clés : Friction welding, 6013-T8 alloy, Welded joint, mechanical properties, microstructure, Microhardness

Caractérisation des paramètres de fissuration en mode d'ouverture par corrélation d'images et éléments finis d’un alliage d’aluminium 2xxx

Mémoire de Master

In this work, a problem of fracture and crack resistance is studied, the 2000 aluminum alloy series available in market is chosen, in this context of fracture mechanics the structural durability and integrity of materials is investigated. Couple techniques are used, an experimental characterization assisted by the digital image correlation technique and finite elements based numerical simulations, the aim is to study the mechanical behavior in presence of cracks and determine the fracture toughness. Making use of theoretical notions, analytical formulas, experimental tests coupled by the recent digital image correlation technique and numerical simulations constitute an efficient protocol to characterize materials to resist against cracks. At the end of our work, the study was done to know the crack propagation in opening mode (mode I) and the stress evolution on the crack paths by the X-FEM extended finite element method. Voir les détails

Mots clés : failure in mode 1, stress intensity factor (SIF), Cracking, Correlation of digital images (CDI), FEM finite elements, Abaqus, Integral J, Extended finite element method (XFEM)

Segmentation des images radiographiques

I. karmal, A. Henniche  (2020)
Mémoire de Master

Image segmentation is an important step in any image analysis process. The subject has already been tackled by multiple approaches. These approaches are based on various tools such as mathematical morphology, wavelet decomposition, active contours; some are based on the detection of contours and others on the identification of regions. Each of these classes of methods has its advantages and disadvantages. In this dissertation, we present the different segmentation approaches and we choose a hybrid method for segmenting chest X-ray images composed of two algorithms. One is the FCM as an initial contour for the other segmentation method LEVEL SET which is a variant of the deformable models based on the active contour method, we injecting the images resulting from this segmentation process into a convolutional neural network (CNN) in order to classify them according to the pathological state. Therefore the aim of our work is the implementation of a model for segmentation and classification of medical X-ray images to assist doctors in the detection of pulmonary pathologies. Voir les détails

Mots clés : image segmentation, chest X-ray image, Active contour, FCM, Level set, classification, CNN

Comportement mécanique et métallurgique des jonctions hétérogènes soudées par friction rotative

Mémoire de Master

Rotational friction welding is a solid state welding process, which has seen spectacular development in various industries. It offers the possibility of producing very high quality solder joints in an extremely short time. The objective of this work is to improve the operating parameters of this process by changing the friction time (periods) and fixing the other parameters namely the speed of rotation [round per minute], the forging time [s], the friction and forging pressure [MPa]. The major problem with the disimmilar assembly of aluminum and stainless steel alloys is the low mechanical strength in the welded joint, due to the formation of certain unwanted inter-metal compounds during welding. An experimental procedure was used to obtain an Al6013-T8 /304L stainless steel welded joint with and without copper insertion. Different characterization methods were used namely x-ray diffraction, optical microscopy, HV microhardness and tensile testing. The Al6013-T8 side microstructure reveals the formation of two zones, the HAZ and the TMAZ at the center of the junction, unlike 304L stainless steel, which has not undergone any mechanical deformation. The microhardness of Al6013-T8 increased in the vicinity of the junction, and tensile testing revealed that the mechanical characteristics of the joints increase with increasing friction time. Voir les détails

Mots clés : Rotational friction welding, the speed of rotation, the forging time

Mise en œuvre de l’essai de fatigue sur des alliages d’aluminium

S. BENRABAH  (2020)
Mémoire de Master

The problem of fatigue of structures is commonly present in all sectors of the maritime, aeronautical, and mechanical and many other industries. In order to fully understand this harmful phenomenon, tests of different types of stresses are carried out at the laboratory level. This requires a good mastery of the test protocol. The analysis of the results obtained by these tests allows to study the behavior of the material. Our study consists in the implementation and the determination of the operating conditions of a uniaxial fatigue test with two types of specimens made of aluminum alloys of different thicknesses are tested. A tensile test is carried out to determine the mechanical behavior of the specimens and to have the necessary parameters to carry out a fatigue test, a metallographic study to characterize the specimens before carrying out the fatigue test. All the results obtained from the test are in the form of curves and a hysteresis loop. Voir les détails

Mots clés : Fatigue test, fatigue of aluminum, aluminum’s alloys