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Génie mécanique

Nombre total de résultats : 130
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Improvement of surface finish by ball burnishing:approach by fractal dimension

M. BOUREBIA, L. Laouar, H. Hamadache & S. Dominiak (2016)
Publication

The surface roughness significantly affects the quality of parts and their functional properties suchas contact surface, as well as coating adhesion. The machined surface quality is evaluated byarithmetic deviation Ra which does not suffice to describe the surface irregularities. In order toapprehend these deficiencies a new technique based on fractal geometry was introduced. Toapply this concept an experimental work was carried out to characterise surface quality byfractal dimension ‘D’. The operations of burnishing ball were performed according to plans ofexperiments of ‘Box–Behnken’, an optimal regime was obtained and a mathematical model wascleared for predicting the fractal dimension ‘D’ as a function of treatment regime parameters.Furthermore, the application of optimal regime under several passes ‘i’ has enabled to examinethe evolution of ‘D’. The results confirm that fractal dimension ‘D’ has impact on surface qualityand tribological parameters.Voir les détails

Mots clés : roughness, fractal dimension, Burnishing process, Designs of experiments

Evaluation of surface quality by Fractal Dimension and VolumeParameters

Mounira Bourebia, Hichem Bounezour, Lakhdar Laouar, Hamid Hamadache (2016)
Publication

This study aims, the evaluation of the surface quality by the fractal dimension "D" and volume settings (Vmp,Vmc, Vvv). Experimental work was conducted by process of surface mechanical treatment; in this case ballburnishing was applied on a commercial aluminum alloy material. Three parameters of regime were considered:"burnishing feed f", "burnishing force Py" and "burnishing ball diameter Db". Mathematical models wereidentified using the plans of multifactorial experiments "Box-Behnken" for prediction of fractal dimension "D"and volume parameters. Experimental and simulation results have enabled to show than the large diameter ballunder low loads and medium feed speeds, favors the elimination of peaks and reduction of fractal dimensionwhence quality improvement of surface.Voir les détails

Mots clés : burnishing, volume parameters, fractal dimension, experimental designs

Influence of manufacturing process on wear resistance Of grinding balls

BOUREBIA.MOUNIRA, BOUHAMLA Khedidja, MAOUCHE Hichem, Gherbi Amel, Chaour Mouhamed, Laouar.Lakhder (2017)
Communication

Abstract The grinding balls are widely used in cement works, they are often manufactured by the molding process, but the problem faced by major cement plants in Algeria is that these balls wear out quickly and broken. The objective of this work is to test wear resistance of grinding balls made by molding and grinding balls produced by forging. The tests of characterization of samples will be made thus that wear tests. The results indicate that grinding balls made by forging resist longer than molded balls by fact this method offers by fiber-forming phenomenon a solid texture which allows increases service life, wear resistance and impact strength.Voir les détails

Mots clés : Grinding ball, forging, molding, texture, wear

INFLUENCE OF MECHANICAL PARAMETERS ON THE TRIBOLOGICAL AND THERMAL BEHAVIORS OF STEEL-COMPOSITE CARBONE/CARBONE COUPLE

Abdeldjalil BENFOUGHAL, Khaled BOUBENDIRA, Nasira SASSANE, Mohamed BOULKRA, Skander Boukhezar, Noureddine BOUGHDIR, Nihel HAMZAOUI (2016)
Communication

The tribological and thermal behavior of dry sliding contact steel composite carbone/carbone and steel-organic matrix composites are studied according to the parameters normal load, sliding speed, friction coefficient and test time. In the case of automotive braking, using a mathematical model, the surface temperature of contact was determined. Four normal forces, four sliding speeds and four friction coefficients were applied in this study. These parameters have a significant influence on the variation of average contact temperature. The results illustrate the evolution of the contact temperature according to the braking time.Voir les détails

Mots clés : Temperature, friction, steel, composite, Disc, Trim.

Contribution à l’étude du comportement du composite verre/polypropylène par la technique de nano-indentation instrumentée

A. Mokhtari, N. TALA IGHIL, A.Brick Chaouche, K. Bettahar (2016)
Communication

Le comportement des composites à matrice polypropylène a été étudié à l’échelle locale par la nano-indentation. Les essais de nano-indentations ont été réalisés sur les différents constituants du composite (matrice, fibre et interface) et des simulations numériques ont été menées au moyen du code de calcul éléments finis Abaqus/Explicit. Les résultats montrent que le comportement des constituants est élastique à faible charge. Lorsque la charge est importante, il y’a apparition de nombreuses zones d’endommagement au niveau de la fibre de verre et à l’interface pp/verre. Les résultats de la simulation sont comparés aux résultats expérimentaux obtenus.Voir les détails

Mots clés : matériaux composites, Matrice thermoplastique, essai de nano-indentation, échelle locale

Study of Composite with Metallic Matrix WC/W2C–20W–20Ni Realized by Spontaneous Infiltration ofthe Bronze Alloy Cu–30Mn–3P

Mokrane Gousmine, Djamel Miroud, Mohamed Farid Benlamnouar, Boualeme Demri, Abderrahmane YOUNES (2016)
Publication

The improved performance and duration of an impregnated tool for the mineral drilling requires thoroughunderstanding of the mechanisms involved in the consolidation of powder mixtures in the liquid phasesintering cycle (FPL). The elements used for the manufacture of the active parts of these tools are usuallymade from mixtures of loose powders based on WC/W–Ni. The spontaneous infiltration process is themost appropriate method offers a big possibility of shapes due to molding. It lets to have considerabledensity of the metal matrix composite (MMC) constituting the active head and increase its resistance toerosion and abrasion. This work consists to develop a metal matrix composite which can constitute theactive part of a drilling tool impregnated by the infiltration of industrial process SILP (Sintering byInfiltration of an appropriate mixture of Loose Powders). The mixture of loose powders (WC/W2C–W–Ni)is infiltrated under hydrogen by a manganese bronze (Cu–30Mn–3P) and then characterized by DTA,optical microscopy, SEM coupled with EDS, HRA hardness and micro-hardness Hv0.1.Voir les détails

Mots clés : Applied Mechanics, Behavior of Materials, Engineering Systems

Modélisation du comportement et de l’endommagement des composites à matrice thermoplastique

Ahcene MOKHTARI  (2016)
Thèse de doctorat

Ce travail est dédié à l’étude d’une approche avancée basée sur la modélisation du comportement et de l’endommagement des composites à matrice thermoplastique sous chargement de traction, de cisaillement et de compression. En particulier, nous nous sommes intéressés à l’étude de l’endommagement couplé à la rupture des composites à matrice polypropylène renforcés de tissus en jute. L’augmentation de l’utilisation de ces composites dans l’industrie automobile et de sports requiert le développement de modèles constitutifs fiables pour prédire leurs réponses sous des conditions de chargement complexes. Actuellement, les modèles disponibles n’incluent pas le comportement non-linéarité et les instabilités des structures. Ce travail focalise sur le développement d’un modèle d’endommagement tenant en compte des non-linéarités matérielle et géométrique des ces composites. Ce modèle considère tous les dommages dans le plan : endommagement provoqué par la fissuration de la matrice ainsi que ceux dus à la rupture des tissus en jute dans les directions longitudinale et transversale. L’analyse de la propagation de l’endommagement, basée sur un vaste ensemble des résultats expérimentaux, combine différents modèles de la mécanique de l’endommagement afin de développer un modèle pour ces composites à matrice thermoplastique, dont la réponse des composites est gouvernée par un couplage entre l’endommagement et la rupture. Le modèle développé dépend des seuils d’endommagement, de flambage et de rupture des composites tissés provoqués par l’évolution de l’endommagement. Ce modèle est implémenté dans un logiciel d’élément fini (ABAQUS/Explicit) en utilisant la subroutine VUMAT. Les résultats des simulations présentés dans ce travail démontrent que le modèle développé peut prédire correctement la réponse statique obtenue par les mesures expérimentales. Les résultats des simulations, pour les post-flambages et les grandes déformations sont également bien prédits.Voir les détails

Mots clés : Matrice thermoplastique, endommagement, modelisation

Heat source modeling of keyhole Laser Welding process: Models analysis

A. MASMOUDI, M. AISSANI, M. BOUKRAA, A. ZITOUNI, T. REDDAH (2016)
Communication

Laser welding is widely used in several industrial applications for the development of different structures such as in aeronautic, nuclear field…etc. It is characterized by high weld speed, low energy entering into the assembled metals and small affected zone, indeed particular accuracy. Heat transfer is one of the complex phenomena occurring during laser welding operation, which aims for the material properties at higher temperatures. This paper focuses on analysis of laser beam heat source models of deep penetration laser welding (keyhole). The various models describing this heat source of power distribution developed, using heat flux, are presented. In literature, most of works focus the attention on the models of the laser-material interaction, so that allows to obtain the temperature distribution during the laser welding. Finally, the main methods used in modelling and numerical simulation of laser welding are discussed and illustrated with some case studies, showing the most efficient model.Voir les détails

Mots clés : Laser welding, keyhole, modeling, heat source, laser-material interaction

Rolling Bearing Fault Diagnosis Based on Improved Complete Ensemble Empirical Mode Decomposition

I. Attoui, N. Fergani, B. Oudjani, A. Deliou (2016)
Communication

In order to rolling bearing fault diagnosis using vibration signal analysis, this paper presents a new procedure based on the Improved Complete Ensemble Empirical Mode Decomposition ICEMD. In this procedure, firstly, in order to calculate the feature vector, we propose the use a combination of the Improved Complete Ensemble Empirical Mode Decomposition ICEMD and Entropy techniques for determining the entropy values for each one of the five first intrinsic mode functions (IMFs) of the ICEMD. Lastly, using the calculated feature vector, the Adaptive-Network-based Fuzzy Inference System ANFIS algorithm is used as a classifier system. In the experimental step, twelve different health bearing conditions were introduced to provide that the proposed approach can be an effective and efficient method for processing bearing fault signals.Voir les détails

Mots clés : vibration signals analysis; processing bearing fault signals; ANFIS algorithm, improved CEEMDAN

Detection Of Defects In The Materials By Using The Heat Equation.

S.Boulkroune, M.Chaour, A.boudiaf, S.Benchiheub (2016)
Communication

We propose a numerical study of heat transfer whose objective is to detect defects in a solid material in the presence of the fault, and see how the fault influences the transfer of heat by the the variation in temperature in a solid material. The finite difference method has been used to solve the governing equations. The numerical simulations were made for a wide range of thermal conductivity numbers ( ), and the temperature of the walls in order to determine a correlation that connects the temperature according to the thermal conductivity for different materials.Voir les détails

Mots clés : detect defects, Finite difference method, solid material