Publications Scientifiques

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    An algorithmic approach for the distribution of the blades of a gas turbine rotor
    (Editura Politechnica, 2024) Houari, Amin; Amroune, Salah; Chellil, Ahmed; Madani, Kouedar; Saada, Khalissa; Farsi, Chouki
    Our study focuses on the critical steps of balancing and maintaining the turbine rotor in electricity production companies. We aim to develop a MATLAB program for blade distribution to optimize the turbine's performance. We conducted practical tests using the BLADIS software from a major company in the field and compared it with the test data from our program. We performed three blade distribution experiments using the initial static moment values of each blade, which the MEI Company's (Sonelgaz-M'sila) electronic balance provided. Our main objective is to propose a new algorithm for turbine rotor blade distribution using a MATLAB subroutine that remains applicable during maintenance operations, including punctual blade changes. This proposed algorithm will help improve the turbine rotor's efficiency and performance. Electricity production companies to maintain their turbines and optimize energy output can use our study’s findings and algorithm. By implementing our proposed algorithm, companies can save costs and increase their energy efficiency, making them more competitive in the market.
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    Experimental Investigation Into the Tensile Strength Post-Repair on Damaged Aluminium 2024 -T3 Plates Using Hybrid Bonding/Riveting
    (Sciendo, 2024) Merah, Abdelkrim; Houari, Amin; Madani, Kouider; Belhouari, Mohamed; Amroune, Salah; Chellil, Ahmed; Yahia, Cherif Zineelabidine; Campilho, Raul D.S.G. Duarte Salgueiral Gomes
    Since the implementation of repair processes by composite patch bonding, this process has consistently demonstrated high performance across various industrial sectors, especially in the fields of aeronautics, aerospace and civil engineering. Consequently, there are situations in which the riveting process becomes the sole solution, particularly when the structure is subjected to severe mechanical or thermo-mechanical stresses, since adhesives have low mechanical strength after aging. Each method has its own set of advantages and disadvantages. The current trend is to combine these two processes to minimise their drawbacks as much as possible. The objective of this work is to present an experimental study on the repair of an aluminium plate AL2024-T3 with a central circular notch using a patch of different nature (metal or composite), under tensile loading conditions. The repair composite considered is a carbon/epoxide. The results of the tensile tests showed that the repair by the combination of the two processes improves the mechanical strength of the damaged structure. A comparison of the results of the experimental curves obtained on riveted, bonded and hybrid assemblies has been taken into consideration.
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    Evaluation of Viscoelastic Performance and Molecular Structures of Natural Rubber/NBR Blends Reinforced by Carbon Black and Nano-Silica
    (Periodica Polytechnica, 2024) Chelli, Amel; Mechakra, Hamza; Chellil, Ahmed; Tria, Djalel Eddine; Bessa, Wissam; Ikkache, Kamel; Safi, Brahim
    This study focuses on the evaluation of the dynamic mechanical properties, molecular structure, density, hardness, swelling behavior of natural rubber blends (NR) and nitrile rubber (NBR) reinforced with carbon black and/or nano-silica. An experimental work has been conducted to study of the effects of increasing NR content and incorporating nano-silica on the mechanical properties and molecular structure were studied using dynamic mechanical analysis (DMA) and Fourier transform infrared (FTIR) spectroscopy. The results show that increasing the NR content and/or incorporating nano-silica into the elastomer leads to a higher storage modulus with no significant change in the glass transition temperature. FTIR analysis indicates the compatibility of the polyblends and the presence of oxidation of the main polymer chain generated during the grinding of the rubber. Additionally, the results of the swelling study demonstrate that stronger molecular interactions occur on the surface of the nano-silica between the nitrile radicals in the NBR and the silanol (Si-OH) radicals. These findings suggest that blending NR and NBR with carbon black and/or nano-silica can improve the mechanical properties and compatibility of the resulting polyblends, with potential applications in the development of advanced elastomeric materials.
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    Experimental investigation into the tensile strength post-repair on damaged Aluminium 2024 -T3 plate using hybrid bonding/riveting
    (2024) Merah, Abdelkrim; Houari, Amine; Madani, Kouider; Belhouari, Mohamed; Amroune, Salah; Chellil, Ahmed; Yahi, Cherif Zineelabidine; R.D.S.G., Campilho
    Since the implementation of repair processes by composite patch bonding, this process has consistently demonstrated high performance across various industrial sectors, especially in the fields of aeronautics, aerospace and civil engineering. Consequently, there are situations in which the riveting process becomes the sole solution, particularly when the structure is subjected to severe mechanical or thermo-mechanical stresses, since adhesives have low mechanical strength after aging. Each method has its own set of advantages and disadvantages. The current trend is to combine these two processes to minimize their drawbacks as much as possible. The objective of this work is to present an experimental study into the repair of an aluminum plate AL2024-T3 with a central circular notch using a patch of different nature (metal or composite), under tensile loading conditions. The repair composite considered is a carbon/epoxide. The results of the tensile tests clearly showed that the repair by the combination of the two processes clearly improves the mechanical strength of the damaged structure. A comparison of the results of the experimental curves obtained on riveted, bonded, and hybrid assemblies has been taken into consideration.
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    Failure Prediction of Laminated Composites: Simulation of the Nonlinear Behavior and Progressive Damage
    (Korean Fiber Society, 2023) Bensalem, Abdelhafid; Daoui, Abdelhakim; Cheriet, Abderrahmane; Lecheb, Samir; Chellil, Ahmed; Kebir, Hocine; Aissani, Linda
    The Hashin’s criteria are useful in composite structural applications because of their simple concept and their theoretical results are relatively close to that got in the experimental parts. In the present study, in the present study, the failure of the composite laminates under static loading have been developed predicted using Hashin’s Criterion. Nonhomogeneous stresses within a structure may induce a complicated failure scenario whereby one ply at a point can initiate failure and can affect also other plies at the same point or the same ply in different neighboring points. With neglecting the possibility of interlaminar failure, only in-plane loads are considered in this state. The results showed that the failure analysis was proposed to simulate the nonlinear laminate behavior and progressive damage of selected laminates under to their ultimate strength. In our approach, the finite element analysis is performed using MATLAB software to study the effect of tensile and compressive loading on the failure of epoxy resin laminate AS4/3501-6.
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    Damage diagnostic of ball Bearing using vibration analysis
    (Université M'Hamed Bougara Boumerdes : Faculté de Technologie, 2021) Belaid, Siham; Lecheb, Samir; Chellil, Ahmed; Djellab, Amira; Mechakra, Hamza; Kebir, Hocine
    Maintenance of any machinery is very important in view of downtime of machinery. The bearing sector is one of the examples without which not single rotating machinery work, Our work is devoted first to a study of static behavior by determining the stress, strain and displacement, then dynamic behavior by determining the first four naturals frequencies. Secondly the dynamic analysis of the Bearing with defect as a function of crack size and location. Finally, the analysis of the results obtained in terms of residual parameters, allow us to draw a roadmap for the diagnosis and maintenance of bearings.
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    Book Abstract
    (Université M'Hamed Bougara Boumerdes : Faculté de Technologie :Département Génie Mécanique, 2021) Chellil, Ahmed; Yahi, Mostepha; Saidi, Mohamed
    La conférence de la Mécanique et Maintenance regroupe tous les acteurs du domaine dans un espace en ligne, a pour but principal de renforcer la communication entre la famille de l’enseignement supérieur et les industriels, rapprocher le secteur socio-économique avec les compétences académiques et l'administration publique. Notre objectif est de mettre en place un écosystème national favorable à l’investissement, par la communication entre les secteurs concernés. Aussi nous souhaitons à travers cette conférence, tracer une feuille de route qui pousse l'économie et le développement national vers le progrès.
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    Strain and Damage Assessment of Treated and Untreated Luffa Mat Composite Using Acoustic Emission and Digital Image Correlation
    (Taylor et francis, 2022) Grabi, Massinissa; Chellil, Ahmed; Habibi, Mohamed; Laperriere, Luc; Grabi, Hocine
    In this work, acoustic emission and digital image correlation were applied to three different composites reinforced with treated (2% and 5% NaOH) and untreated luffa fibers during tensile testing, to follow the evolution of the different damage modes and determine strains and Poisson’s ratio. The tensile test results showed that alkaline treatment of 5% improved Young’s modulus and tensile strength. In comparison, the 2% treatment showed the most outstanding improvements in mechanical properties. The K-means clustering methodology identified four types of damage: matrix cracking, fiber pull-out, delamination, and fiber breaking. The 5% treated composite had lower cumulative energy and hits than the untreated and 2% treated composites, implying that the T5% composite suffered less damage. The DIC results showed that the longitudinal strains found by the extensometer are very approximate to those found by DIC, this technique also allows us to find the transverse strains of the composites UT (0.324), T2% (0.295), and T5% (0.207%). It is shown that the 5% alkaline treatment leads to the decrease of Poisson’s ratio (0.2378) compared to 2% treated (0.3113) and untreated (0.3120) composites. Based on AE, DIC results, and mechanical properties, the T5% composite is the most successful.
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    Alkaline Treatment’s Effect on Mechanical Properties and Damage Assessment Through Acoustic Emission of Luffa Fiber Composite
    (Springer, 2022) Grabi, Massinissa; Chellil, Ahmed; Habibi, Mohamed; Laperriere, Luc
    Improving the mechanical properties and reduced damage of natural fiber-reinforced composites can contribute to their increased use in various fields. In this paper, an experimental study describes the effect of alkaline treatment of two different concentrations of 2 % and 5 % NaOH for one hour on the mechanical performance and damage of luffa fiber composites. Three different composites reinforced with treated and untreated luffa fibers were developed using the resin transfer molding (RTM) process. The specimens were coupled with acoustic emission during tensile tests, to monitor and evaluate damage mechanisms. The tensile test results showed that the alkaline treatment of 5 % improved tensile strength, which reached 81.08±1.48 MPa. However, the 2 % treatment improved Young’s modulus with 8.94±0.5 GPa. In comparison, T2 % and T5 % composites provided the best results for mechanical properties compared to NT composites. Four classes of damage mechanisms have been identified using the K-means clustering method, including matrix cracking, fiber pull-out, delamination, and fiber breakage. The cumulated energy and hits of the 5 % treated composite was lower than the untreated and 2 % treated, which means less damage to the T5 % specimen. Scanning electron microscopy (SEM) pictures of the tensile fractured surfaces of luffa fiber composites treated with 5 % NaOH, revealed good adhesion between the fibers and the matrix. The AE results are convincing, and they were confirmed by SEM pictures of the specimens’ fractured faces, which revealed the main causes of material failure, So, based on the AE results and mechanical properties, T5 % composite is preferable.
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    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