Browsing by Author "Djedid, Toufik"

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Analysis of the dynamic behavior of magnetorheological elastomer composite : elaboration and identification of rheological properties
(2018) Nedjar, Ali; Aguib, Salah; Djedid, Toufik; Nour, Abdelkader; Settet, Ahmed; Tourab, Mohamed
Dynamic characterization of the magnetomechanical properties of off axis anisotropic magnetorheological elastomer
(De Gruyter Open, 2022) Bendjeddou, Walid; Aguib, Salah; Chikh, Noureddine; Nour, Abdelkader; Djedid, Toufik; Kobzili, Lallia; Meloussi, Mounir
The use of magnetorheological elastomers in the mechanical and acoustic fields, by the automotive, aeronautical, and building industries, is currently developing strongly and rapidly. The perfect understanding of the capacity of smart insulation based on the absorption of the vibratory waves by magnetorheological elastomers materials passes by the knowledge of their dynamic mechanical behavior. In this present work, we have characterized the dynamic mechanical properties of the magnetorheological elastomer off axes anisotropy by the inclination, of different angles (15°, 30°, and 45°), of the pseudo-fibers of the iron particles formed by the application of a magnetic field at different intensities using an optimal loading rate of 30%. The rubber specimens were prepared by mixing micron-sized iron particles dispersed in room temperature vulcanized (RTV) silicone rubber by solution mixing. The experimental results obtained show a clear dependence of the effect of inclusion of ferromagnetic chains on the magnetomechanical properties. It is observed that the mechanical properties are better when applying a magnetic field of 0.6 T with an angle of inclination of 45°. The improvements added in this work could be useful in several industrial applications, such as automotive, aeronautic through adaptive control of damping and vibration level
Effects of the geometrical parameters of the core on the mechanical behavior of sandwich honeycomb panel
(2019) SETTET, Tidjani Ahmed; Aguib, Salah; Djedid, Toufik; Chikh, Noureddine; Chellil, Ahmed
The present work is the study of mechanical behavior due to variation of the geometrical parameters in the core of the sandwich honeycomb panel. This study has allowed us to increase or decrease the strains and stresses of the panel, in changing the angle of alveolus, as explained and described below. In taking into consideration the results obtained previously to improve the mechanical properties and increase the adhesion of different parts of the panel, without changing the adhesive, we have conceived two new models, in increasing the contact surfaces in boundary of each part of the panel and giving a conical hexagonal shape in his corp
Etude d'une aube de turbine en fonction de la statique et du choc dynamique
(Université M'Hamed Bougara Boumerdès : Faculté de Technologie, 2025) Djedid, Toufik; Nour, Abdelkader(Directeur de thèse)
Dans ce travail, les propriétés mécaniques statiques et d'impact des matériaux composites de différents renforts ont été étudiés. En premier lieu, deux variétés de composites sandwichs (Carbone-Alfa/Epoxy et Kevlar-Alfa/Epoxy), élaborés d'une matrice de résine époxy renforcée par une fraction volumique de 40wt. % de tissu de fibres longues d'Alfa, ont été proposées pour la fabrication de pales de turbines éoliennes. Un traitement alcalin et thermique a été réalisé pour améliorer la liaison interfaciale entre le tissu Alfa et la matrice. La spectroscopie infrarouge à transformée de Fourier (FTIR), la microscopie électronique à balayage (MEB) et l'analyse de la décomposition chimique des fibres Alfa ont montré l'efficacité de ce traitement alcalin avec une augmentation de la cellulose et une bonne adhésion interfaciale entre les fibres traitées et la matrice. En deuxième lieu, une structure sandwiche en élastomère magnétorhéologique à cœur en nid d'abeille a été élaborée dont les propriétés mécaniques peuvent être modulées en fonction des conditions d'exploitation (pression, vitesse). Dans ce but, une structure en nid d'abeille a été étudiée expérimentalement, avec et sans application du champ magnétique, et enfin, une analyse numérique de la structure a été faite par la MEF sous le code de calcul Abaqus et les résultats ont été comparés et discutés
Evaluation des risques liés aux travaux de maintenance préventive sur les équipements statiques
(Université M’Hamed Bougara Boumerdes : Faculté de Technologie, 2020) Si Salah, Mahdi Housseyn; Djedid, Toufik; Djedid, Toufik(Promoteur)
Toute activité humaine comporte une part de risque et d’incertitude, plus précisément quand il s’agit d’industrie complexe le but primordial de la majorité des entreprises est de diminuer le nombre d’accident de travail. Donc on opte sur l’évaluation des risques potentiels au poste de travail et de maladie de travail avant leur survenue de préférence tout cela en faisant des études et en tirant les bonnes conclusions
Forced transverse vibration of composite sandwich beam with magnetorheological elastomer core
(Springer, 2016) Aguib, Salah; Nour, Abdelkader; Djedid, Toufik; Bossis, Georges; Chikh, Noureddine
Identification et modélisation des contraintes cycliques du couple d'engrenages : cas de la boite de transmission principale
(2008) Djedid, Toufik
On traite dans ce mémoire la modélisation des contraintes sur les engrenages spiroconiques par application de la méthode des éléments finis. Pour ce faire, on a tout d’abord adopté le modèle de simulation de l’opération de taillage de la firme Gleason, développé par le russe Litvin L.Faydor, dans le but de déterminer la géométrie de ce type d’engrenage. Ce modèle repose sur les paramètres et réglages machine appliqués lors du processus de taillage, et les dimensions générales du couple d’engrenages à réaliser. En deuxième lieu, on a appliqué le modèle de simulation du contact entre le couple de dents spiroconiques, appelé Tooth Contact Analysis (TCA) et développé par Gleason System dans sa complexité. Ce modèle prend en considération tous es paramètres cités ci dessus en plus des défauts fonctionnels possibles sur les arbres concourants du couple d’engrenages. Avec ces deux approches, nous avons pu analyser les états de contraintes du couple de dents en contact, en introduisant plusieurs cas de défauts d’alignement
Measurements and identification of smart magnetomechanical elastomer composite materials properties in shear mode
(Institute of Physics Publishing, 2019) Nedjar, Ali; Aguib, Salah; Djedid, Toufik; Nour, Abdelkader; Meloussi, Mounir
Magnetorheological elastomer composite materials (MRE) are a new class of intelligent active materials composed of ferromagnetic particles, of micrometric size, dispersed in a silicone elastomer matrix, which exhibit variable stiffness and damping properties which are modifiable under the application of an external magnetic field. Currently, these devices are primarily used in automotive and building applications, but they can easily be adapted to meet the requirements of aerospace applications. The development process and experimental characterization needed to evaluate the active control performance of this material have been made. This is done by characterizing the mechanical properties as a function of the magnetic field, as a function of the excitation frequency and as a function of the different percentage of ferromagnetic particles loading. An example of application of this material in aeronautics is also presented
Mechanical Performances of Honeycomb Structures Reinforced by a Magnetorheological Elastomer Material: Experimental and Numerical Approaches
(2024) Djedid, Toufik; Nour, A.; Aguib, S.; Chikh, N.; Settet, A.T.; Khebli, A.; Kobzili, L.; Boudjana, Abderzak; Tourab, M.
In this article, the performance of mechanical resistance against failure of mechanical structures under bending load was studied by the use of a hybrid sandwich composite (Magnetorheo- logical Elastomer (MRE) - Honeycomb). Accordingly, a series of four-point bending mechanical tests were carried out. In addition, a comparison of the force-deflection responses, the values of the maxi- mum forces supported by each sample before damage were determined. Through the additional effect of the MRE core, the hybrid sandwich composite samples presented the best performances in terms of energy absorption-dissipation, and thanks to the effect of the honeycomb part, the Hybrid sandwich composite samples presented the best performance in terms of mechanical strength. To validate the performance of these developed hybrid structures, the numerical results are compared with the corre- sponding experimental results.
Mechanical properties and low-velocity impact analysis of camel hair and hybrid camel hair/flax fibre-reinforced epoxy
(Springer, 2024) Bencheikh, Amir; Nour, Abdelkader; Casimir, Jean B.; Aguib, Salah; Gherbi, Mohammed T.; Attia, Nourhane; Djedid, Toufik; Baali, Besma. R.; Aribi, Chouaib
Composite plates structures are subjected to many damage problems under low-velocity impacts such delamination and matrix cracking, in order to know the importance of hybridisation on improving mechanical properties. This study explores the low-velocity impact behaviour of two composites: one reinforced with camel hair fibre/epoxy (CHF/Epoxy) and the other with a hybrid of camel hair and flax fibres camel hair fibre–flax fibre/epoxy (CHF-Flax/Epoxy). Static tests (tensile, compression, and bending) were conducted to characterise the mechanical properties of the composites. Impact tests were performed using a drop weight impact machine at three energy levels (3, 7, and 20 J). Particularly, the hybrid composite plate (camel hair fibre/epoxy) exhibited superior mechanical properties in static tests, leading to enhanced impact resistance compared to the composite plate (camel hair fibre/epoxy). Additionally, a numerical study was conducted using a 3D finite elements model. The Hashin criteria and the progressive damage model were used to predict intralaminar damage, and surface-based cohesive behaviour with quadratic stress failure criteria was used to predict delamination. The progressive damage model was coded and its implementation is conducted with a user-defined material subroutine (VUMAT) for Abaqus/Explicit. The damage mechanism and energy dissipation were observed at each energy level. Matrix cracking occurred first, followed by delamination. The 3D damage model was able to simulate the damage initiation and damage evolution until failure. The results of the model showed good agreement with experimental results in term of force, displacement and energy dissipation curves.
Vibration control of a hydrostatic bearing using magnetorheological elastomer shell bearing
(JVE International, 2018) Chikh, Noureddine; Aguib, Salah; Djedid, Toufik; Nour, Abdelkader; Tawfiq, Imad
In rotating machines, random movements or sliding movements of the rotor in its housing can produce undesirable phenomena for some parts. To solve this problem, a new hydrostatic bearing with an intelligent magnetorheological elastomer sell bearing has been designed to control the undesirable vibrations of rigid rotors. The different effects of the influence parameters on the vibratory behavior of the sell bearing are calculated numerically using Abaqus software, and the results found are encouraging