Browsing by Author "Aguib, Salah"

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Analysis of buckling stability behavior of hybrid plate using Ritz approach and numerical simulation
(Elsevier, 2021) Aguib, Salah; Chikh, N.; Kobzili, L.; Djedid, T.; Nour, A.; Meloussi, Mounir
In this article, we studied the instability phenomenon of plate buckling made of steel (E36-S355), and magnetorheological elastomer subject to compression loading. The study of the magnetic field intensity influence on the buckling instability of compressed hybrid plates is done by a mathematical development using the Ritz approach and by a numerical simulation under the Abaqus software. The obtained results show clearly that we can control the instabilities of the adaptive smart plate’s behavior by the magnetic field, and the orientation angle of pseudo-fibers formed by the iron particles; depending on the variation of the angle direction of the magnetic field
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
Classifying Surface Fault in Steel Strips Using a Customized NasNet-Mobile CNN and Small Dataset
(ESRGroups, 2024) Kateb, Yousra; Khebli, Abdelmalek; Meglouli, Hocine; Aguib, Salah; Khelifi-Touhami, Mohamed Salah
Steel metal is an important product in ferrous manufacturing, and the manufacturing process has to be improved so that hot-rolled strip flaws may be correctly identified. Machine-learning- based automated visual inspection (AVI) systems have been created, however they lack crucial components, such as inadequate RAM, resulting in complexity and sluggish implementation. Long execution times also result in delays or incompleteness. A scarcity of faulty samples further complicates steel defect diagnosis due to the disparity between non-defective and defective pictures. To overcome these difficulties, a deep CNN model is built using the pre- trained NasNet-Mobile backbone architecture. The model, which uses 26 times less data than other papers' datasets, recognizes steel surface pictures with six faults with 99.30% accuracy, outperforming previous methods. This study is beneficial for surface fault classification when the sample size is small, the software is less effective, or time is limited. Avoiding these issues will improve safety and end product quality in the steel industry, saving time and money
Dynamic Analysis of the Non-Linear Behavior of a Composite Sandwich Beam with a Magnetorheological Elastomer Core
(2016) Chikh, N.; Nour, Abdelkader; Aguib, Salah; Tawfiq, I.
This work deals with the active control of the vibrations of mechanical structures incorporating magnetorheological elastomer. The damping coefficient and shear modulus of the elastomer increase when exposed to a magnetic field. Compared with the vibration control where the elastomer is permanently exposed to a magnetic field, the control of this process through time reduces vibrations more effectively. The experimental study for the vibrations of a sandwich beam filled with an elastomer is conducted, followed by a numerical study using the Abaqus code. The vibration damping is found to be dependent on the loading rate of micro-size ferromagnetic particles in the elastomer
Dynamic behavior analysis of a magnetorheological elastomer sandwich plate
(Elsevier, 2014) Aguib, Salah; Nour, Abdelkader; Zahloul, H.; Bossis, G.; Chevalier, Y.; Lançon, P.
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
Experimental analysis of the tensile behavior of a hybrid composite beam with adjustable mechanical properties
(Springer, 2022) Aguib, Salah; Chikh, Noureddine; Settet, Ahmed tidjani; Nour, A.; Meloussi, Mounir; Djedid, T.
Magnetorheological elastomer beam samples were tested in uniaxial tension in magnetic fields of different intensities up to the final rupture. The samples deformed nonlinearly. Their maximum elongation reached 70% and the tensile strength increased by 120% with growing intensity of magnetic field applied
Experimental analysis of the thermal effect of the magneto-mechanical behavior of viscoelastic elastomer
(2019) Tourab, Mohamed; Aguib, Salah
This paper is devoted to an experimental of the thermal effect of the magnetomechanical behavior of elastomer; the latter is loaded with 25% of ferromagnetic particles of micrometric size; developed under the action of a magnetic field. The characterization of the rheological properties and the interaction between the micron size ferromagnetic particles as a function of the intensity of the magnetic field are studied under the effect of different temperatures. The results obtained clearly show the high energy dissipation properties of the composite, accentuated by the structure modified under the thermal effect, which gives properties of viscoelastic structures that can be adjusted as a function of the intensity of the magnetic field
Experimental characterization of microcomposite magnetorheological elastomer
(2021) Rouabah, Salah; Aguib, Salah; Hadji, Mohamed; Kobzili, Lallia
This work presents an analysis experimental of dynamic properties of microcomposite magnetorheological elastomer (MMRE) by a dynamic mechanical analyzer (DMA). The charge of magnetized iron particles is 30% of the total volume. A dynamic mechanical analysis DMA was carried out, in the scanning mode of the amplitude of shear strain, and for magnetic field densities varying from 0mT to 325mT. The storage modulus G’ and the loss modulus G’’, of the elastomer decrease, when the amplitude of the strain increases. This trend is more pronounced under a higher magnetic flux density (250mT and 325mT). In the presence of the magnetic field, the level of these two dynamic moduli and of the damping increases considerably, passing from one value to another of the applied external magnetic field. As a result, the MR effect of MRE elastomers has increased significantly with increasing magnetic flux density
Forced transverse vibration of composite sandwich beam with magnetorheological elastomer core
(Springer, 2016) Aguib, Salah; Nour, Abdelkader; Djedid, Toufik; Bossis, Georges; Chikh, Noureddine
Identification des propriétés dynamiques et simulation du comportement vibratoire des plaques en matériaux composites adaptatifs
(2014) Aguib, Salah
Le travail réalisé constitue une contribution à la détermination de la réponse vibratoire non linéaire des plaques sandwichs en élastomère magnétorhéologique et se compose de quatre chapitres ; un premier chapitre bibliographique est consacré à introduire le développement des matériaux composites, les matériaux composites sandwichs, les élastomères et les élastomères chargés, le comportement et les modèles des matériaux viscoélastiques. En fin du chapitre, nous mettons l'accent sur les matériaux et les structures en élastomère magnétorhéologique. Dans le deuxième chapitre, nous présentons un rappel de la théorie des matériaux sandwichs et faisons un modèle mathématique des plaques sandwichs soumises à un champ magnétique afin de bien définir les équations régissent le comportement dynamique de ces matériaux. Dans le troisième chapitre, on a développé une approche numérique de résolution en utilisant la méthode de Ritz avec une formulation énergétique. Un code du calcul numérique a été élaboré en langage Matlab pour déterminer les propriétés amortissantes de la plaque sandwich. Des simulations numériques par la méthode des éléments finis sous le code de calcul Abaqus ont été menées et validées, pour montrer la simplicité, la généricité, l'efficacité et les performances de ce code quelle que soit la dépendance en fréquence du modèle viscoélastique. Dans le quatrième chapitre, une identification expérimentale des propriétés en cisaillement d'un élastomère chargé par 30% de microparticules de fer à 100 Hz, est présentée en premier lieu. Par la suite, une analyse expérimentale de la réponse vibratoire en amplitude des trois plaques ayant un élastomère chargé par 20%, 30% et 40% de microparticules de fer soumises à une excitation harmonique par une force magnétique. Afin d'évaluer l'effet du champ magnétique sur la réponse des plaques, nous avons exposé ces dernières à un champ magnétique variable. Les résultats trouvés sont comparés à ceux calculés par l'approche numérique et le modèle FEM sous Abaqus
Jet instability of suspensions of different shaped particles exhibiting discontinuous shear thickening
(Society of Rheology, 2022) Meloussi, Mounir; Schaub, S.; Ciffreo, A.; Aguib, Salah; Kuzhir, P.
This work is devoted to the detailed study of jet instability occurring in concentrated aqueous mixtures of calcium carbonate (CC) isotropic-shaped particles and rigid polyamide (PA) fibers. These mixtures exhibit very sharp discontinuous shear thickening (DST). The jets were subjected to a free fall under gravitational stretching at a constant flow rate. In the absence of PA fibers, we observed relatively strong lateral oscillations occurring for jet lengths L ≳ 6 cm and accompanied by small periodic undulations of the jet diameter. Two-dimensional Direct Fourier Transform analysis reveals approximately linear dispersion relations for propagation of lateral oscillations and diameter undulations with similar wave speeds ∼ 1 m / s. This instability is ascribed to complex rheological behavior in an extensional flow above the DST transition. Theoretical modeling reveals abrupt jumps of the tensile stress along the jet likely leading to fluctuation of longitudinal and transverse velocity fields within the jet perceived through jet diameter and centerline undulations. The addition of PA fibers to CC suspension damps lateral oscillations but favors ruptures along the jet. This is tentatively explained by the interplay between growing lower and decreasing upper DST threshold stresses with increasing fiber volume fraction φ f along with the thinning of the jet diameter down to the size of fiber flocs. Quantitatively, the stabilizing effect of PA fibers is manifested through an abrupt decrease in the lateral drift amplitude at φ f ≳ 0.75 vol %
Jets of discontinuously shear thickening suspension
(2020) Meloussi, Mounir; Kuzhir, Pavel; Aguib, Salah
In the present work, jets of discontinuously shear thickening (DST) suspension emerging from a vertical pipe have been experimentally studied. The suspension flows through the pipe under gravity at nearly constant flow rate and the stress field in the jet is mostly extensional with the stress levels governed by gravitational forces. The dynamics of the jet was recorded with a high-speed camera at 300 fps, then the recorded videos were discretized into pictures and carefully analyzed with a written and executed program in MATLAB, based on image processing. The suspension is a concentrated mixture of calcium carbonate (CC) microparticles dispersed in water at 68% volume fraction with addition of different concentrations of polyamide (PA) microfibers of 700μm x 15 μm in size. The CC suspension solely exhibits strong DST behavior characterized by a viscosity divergence above a critical stress. At a given flow rate, depending on the jet length (distance between the pipe outlet and a point where the jet hits the experimental table), different behaviors are observed varying between stable viscous thread to coiling instability and elastic instabilities with periodic rupturing of the jet ascribed to achievement of the critical stress of the DST onset under extensional deformations. Addition of fibers mainly stabilizes the jets and this effect is still not fully understood and perhaps depends on the flow-induced orientation of fibers under extensional flow, increasing extensional viscosity. In this communication we will discuss in detail different regimes and present experimental correlations between the fiber concentration and dynamic parameters of the jet instability (wavelengths, lateral oscillation amplitudes, etc.)
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 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.
Mechanical Properties of Alfa, Sisal, and Hybrid Alfa/Sisal Fiber Satin Cloth Reinforced Epoxy
(Springer Nature, 2024) Baali, Besma R.; Gherbi, Mohammed Tahar; Nour, Abdelkader; Casimir, J.B.; Saci, Rachid; Aguib, Salah; Attia, Nourhane; Aribi, Chouaib
The mechanical behavior of composites, made of an epoxy resin matrix reinforced by 30 and 40% of a satin cloth from long Alfa, sisal and hybrid Alfa/sisal fibers was studied. The fibers are obtained by extraction with elimination of binders such as pectins and lignin. For each type of fibers, appropriate and optimal chemical and thermal treatments were conducted within NaOH solution, to enhance both the fiber surface quality and the interfacial bonding between fibers and matrix. Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and chemical decomposition of treated and untreated fibers lead to prove the treatment efficiency. The thermogravimetric (TGA) and differential thermogravimetric (DTG) analyses showed better thermal stability. Differential scanning calorimetry (DSC) made it possible to quantify the enthalpy changes which showed an increase in the amount of heat as a function of the increase in weight fraction of natural fibers. The endothermic reaction of the composites studied containing 30 wt% fiber reinforcement was less than that containing 40 wt% fiber reinforcement. The composite materials were produced by vacuum assisted resin transfer molding (VARTM) method due to hydrophilic nature of the fibers. The results of static tests were compared to those of pure epoxy resin. It showed a significant increase for 40 wt% woven A1lfa/epoxy of about 333, 113, and 81% in tension, 3-points bending and compression tests respectively. SEM morphology analysis revealed good interfacial adhesion between the treated fibers and the matrix.
Numerical simulation and experimental analysis of magneto-mechanical behavior of anti-seismic active sandwich structure
(Extrica, 2019) Zerrouni, Nassim; Aguib, Salah; Grine, Ali; Chikh, Noureddine
This work focuses on the quasi-static behavior study for simply supported sandwich beams with aluminum faces and magnetorheological elastomer core subjected to three points bending subjected to a magneto-mechanical loading by numerical and experimental investigations. The mechanical properties of the magnetorheological elastomer core are measured experimentally and the mechanical behavior of the MRE was identified by the generalized Maxwell rheological model. Depending upon the adjustable properties of the beam, energy dissipation is by core shear. A systematic series of experiments and finite elements simulations have been performed in order to assess the static behavior of the beam. The results obtained show a significant influence of the magnetic field intensity on the flexural displacement of the beam.
Numerical simulation of the nonlinear static behavior of composite sandwich beams with a magnetorheological elastomer core
(Elsevier, 2016) Aguib, Salah; Nour, Abdelkader; Benkoussas, B.; Tawfiq, I.; Djedid, T.; Chikh, N.
Polycopié de cours support de cours en mecanismes industriels et transmission de puissance
(Université M’Hamad Bougara de Boumerdes : Faculté de Technologie Département de Génie Mécanique, 2022) Aguib, Salah