Publications Scientifiques

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    Relationship between structural and mechanical properties of polyethylene matrix nanocomposites
    (Faculty of Engineering, Khon Kaen University, 2024) Rahmaoui, Fath Eddine Zakaria; Belaidi, Idir
    This study examined the impact of incorporating graphene nanoplatelets (GnP) into high-density polyethylene (PE) to create nanocomposites, with and without a compatibiliser. We specifically focused on the impact of structural crystallinity on the mechanical properties of the nanocomposites. These nanocomposites exhibited a much higher Young's modulus compared with pure PE. Specifically, the Young’s modulus increased exponentially with the addition of a compatibiliser and linearly without it. One explanation for this exponential rise in Young's modulus is that the crystal's compacted polymer chain structure improved its stiffness, facilitating effective load transfer. Additionally, a poor distribution of GnP in the nanocomposites with a filler content of 0.5 and 1 wt.%, both with and without a compatibiliser, led to a decreased stress and strain at break. However, at higher filler contents, well-distributed GnP play a key role in enhancing stress and strain at break.
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    A review of emulsion flows, their characterization and their modeling in pumps
    (Institution of Chemical Engineers, 2024) Achour, Lila; Specklin, Mathieu; Asuaje, Miguel; Kouidri, Smaine; Belaidi, Idir
    In the engineering field, emulsions and liquid–liquid two-phase flows within centrifugal pumps are generally unwanted as emulsions will have negative effects on pump operation. Besides, emulsions are usually formed when the oil and water phases are brought together in a process called emulsification, which is enhanced by high shear rates. This topic has been extensively researched over the past decades, with sophisticated theories regarding the phenomena involved in emulsions formation and characterization in pumps. Besides, given the complexity of the physics governing emulsions, studies on their modeling within pumps, based on empirical correlations or computational fluid dynamics models, are insufficient and remain limited. This review aims to provide a complete overview of investigations on liquid–liquid flow in centrifugal pumps. Characteristics of these mixtures, such as stability, phase inversion, droplet size distribution and rheological behavior, are discussed. Current approaches and techniques for analyzing pump performance handling emulsion and two-phase liquid–liquid flow are reviewed thoroughly. The limitations of the existing models are studied, and potential future developments are proposed.
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    Prediction of the peak load and absorbed energy of dynamic brittle fracture using an improved artificial neural network
    (Elsevier, 2022) Oulad Brahim, Abdelmoumin; Belaidi, Idir; Fahem, Noureddine; Khatir, Samir; Mirjalili, Seyedali Jamal; Abdel Wahab, Magd M.
    In this paper, a robust technique is presented to predict the peak load and crack initiation energy of dynamic brittle fracture in X70 steel pipes using an improved artificial neural network (IANN). The main objective is to investigate the behaviour of API X70 steel based on two experimental tests, namely Drop Weight Tear Test (DWTT) and the Charpy V-notch impact (CVN), for steel pipe specimens. The mechanical properties in the brittle fracture behaviour of API X70 steel pipes are predicted utilizing numerical approaches with different crack lengths. Next, to simulate the impact of API X70 steel pipes at lower temperatures through a numerical approach, a cohesive approach using the extended Finite Element Method (XFEM) is used. The data obtained are used as input for the proposed IANN using Balancing Composite Motion Optimization (BCMO), Particle Swarm Optimization (PSO) and Jaya optimization algorithms, to predict the peak load values and crack initiation energy of dynamic brittle fractures in API X70 steel with different crack lengths. The results show the effectiveness of ANN-PSO and ANN-BCMO based on the convergence of the results and the accuracy of the prediction of the peak load and crack initiation energy.
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    A new methodology to predict the sequence of GFRP layers using machine learning and JAYA algorithm
    (Elsevier, 2023) Fahem, Noureddine; Belaidi, Idir; Oulad Brahim, Abdelmoumin; Capozucca, Roberto; Thanh, Cuong Le; Khatir, Samir; Abdel Wahab, Magd M.
    In this paper, the best stacking sequence using experimental tests of GFRP composites is investigated. The main objective of this work is to determine the main specification of GFRP composite material, which is represented by its physics-mechanical properties, weight, and cost, before performing a series of experimental tests based on various stacking sequences. Our methodology is divided into three stages. The first stage is characterized by extracting the bending data from mechanical tests of some GFRP composites. In the second stage, the validated numerical model is used to simulate numerous cases of stacking sequences. In the last stage, the extracted data is used to determine the parameters for different stacking sequences using an inverse technique based on ANN and JAYA algorithm. The results provide a good prediction of parameters as well as a good orientation to make decisions on the best GFRP stacking sequence to be used, according to the required specifications of the manufacturer.
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    A reduced-order method with PGD for the analysis of dynamically loaded journal bearing
    (2022) Megdoud, Abdelhak; Manser, Belkacem; Belaidi, Idir; Bakir, Farid; Khelladi, Sofiane
    Machine component design has become a prominent topic for researchers in recent years. The analysis of bearing systems has received considerable attention in order to avoid detrimental contact. Among the most important studies in this area are the transient problems of journal bearings, which are usually performed by coupling the Reynolds equation with the motion equations. Many techniques have been presented in the literature and are still being explored to ensure the accurate findings and efficient solution prediction of unsteady state Reynolds equation. In this paper, the Proper Generalized Decomposition (PGD) approach is expanded for the analysis of the lubricant behavior of dynamically loaded journal bearing considering Swift-Stieber boundary conditions. The PGD model is applied in this problem, seeking the approximate solution in its separated form of the partial differential Reynolds equation at each time step during the load applied cycle employing the alternating direction strategy. Compared to the classical resolution, the PGD solution has a considerably low computational cost. To verify the accuracy and efficiency of this approach, three cases have been considered, infinitely short, infinitely long and finite journal bearings under the dynamic load. The results of the suggested methodology when compared to the full discretized model (FDM) show that, the new scheme is more efficient, converges quickly, and gives the accurate solutions with a very low CPU time consumption.
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    A reduced-order method with PGD for the analysis of mis- aligned journal bearing
    (2021) Megdoud, Abdelhak; Manser, Belkacem; Belaidi, Idir; Bakir, Farid; Khelladi, Sofiane
    n recent years, machine component design has been a major con- cern for researchers. Emphasis has been placed especially on the analysis of bearing systems in order to avoid detrimental contact. The shaft misalignment is one of the most problems that affects directly the operating conditions of these components. In this context, the present study proposes a reduced-order method "Proper Generalized Decomposition" (PGD) using the separation tech- nique through the alternating direction strategy to solve the modified Reynolds equation, taking into account the presence of misalignment in the shafting sys- tem. The solution shows the representation of two types of misalignment ge- ometry, especially axial and twisting. A comparison of the results between the proposed approach and the classical method, through several benchmark ex- amples, made it possible to highlight that the new scheme is more efficient, converges quickly and provides accurate solutions, with a very low CPU time expenditure.
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    Numerical study of the performance loss of a centrifugal pump carrying emulsion
    (2021) Achour, Lila; Mathieu, Specklin; Belaidi, Idir; Kouidri, Smaine
    The performance and hydrodynamic behavior of cen- trifugal pumps when handling two-phase liquid-liquid flow and emulsion remain relatively unexplored, al- though they are of fundamental importance in optimiz- ing the operating conditions of these pumps. Hence, this study aims at investigating the performance degra- dation of a centrifugal pump under emulsion flow by combined means of analytical and computational fluid dynamic (CFD) models. The analytical approach is based on internal energy loss equations while the CFD approach models the emulsion as a continuous and ho- mogeneous single-phase fluid exhibiting shear thinning behavior. The results give a good insight into the per- formance degradation of such a system, especially at the best efficiency point (BEP).
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    Towards an accurate aerodynamic performance analysis methodology of Cross-Flow fans
    (MDPI, 2022) Himeur, Rania Majda; Khelladi, Sofiane; Ait Chikh, Mohamed Abdessamad; Vanaei, Hamid Reza; Belaidi, Idir; Bakir, Farid
    Cross-flow fans (CFFs) have become increasingly popular in recent years. This is due to their use in several domains such as air conditioning and aircraft propulsion. They also show their utility in the ventilation system of hybrid electric cars. Their high efficiency and performance significantly rely on the design parameters. Up to now, there is no general approach that predicts the CFFs’ performance. This work describes a new methodology that helps deduce the performance of CFFs in turbomachinery, using both analytical modeling and experimental data. Two different loss models are detailed and compared to determine the performance–pressure curves of this type of fan. The efficiency evaluation is achieved by realizing a multidisciplinary study, computational fluid dynamics (CFD) simulations, and an optimization algorithm combined to explore the internal flow field and obtain additional information about the eccentric vortex, to finally obtain the ultimate formulation of the Eck/Laing CFF efficiency, which is validated by the experimental results with good agreement. This approach can be an efficient tool to speed up the cross-flow fans’ design cycle and to predict their global performance
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    Optimisation multi-objectif de la structure d'une machine d'usinage agile de type delta linéaire
    (Université Mouloud Mammeri de Tizi-Ouzou, 2018) Mansouri, Khaled; Belaidi, Idir; Atia, Abdelmalek
    La conception d’architectures innovantes de machines agiles dédiées à l'usinage à très grande vitesse (UTGV) nécessite la mise en œuvre de modèles analytiques et numériques pour l’optimisation du comportement cinématique, statique et dynamique de la machine, avec prise en considération des déformations élastiques et leur compensation au niveau de la commande de la machine. Dans le contexte d’une optimisation multi-objectif, il s’agit dans une première partie d’identifier les paramètres et variables inhérents à chaque élément constitutif d’une machine de type robot DELTA, dont le but d’optimiser les éléments essentiels de sa structure. Ceci nécessite une formulation du problème multi- objectif en exprimant les fonctions objectifs, les contraintes et les espaces de recherche correspondants, ainsi que la résolution du problème par l’utilisation de méthodes et outils mathématiques performants (Algorithmes génétique...).
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    Experimental and numerical evaluation of Quasi-Static Indentation behaviour of laminates with polypropylene matrix
    (Polish Society of Composite Materials, 2021) Mahdad, M'Hamed; Benidir, Adel; Belaidi, Idir
    This paper presents an analysis of the damage process of composite laminates subjected to low-velocity quasi-static indentation (QSI) load. The laminates were prepared using the compression moulding technique. The composites were made from orthotropic layers with E-glass or steel fibres and a polypropylene matrix. The quasi-static indentation tests were carried out at three levels of indentation energy under low-velocity. The experimental results reveal that using steel fibres increases the perforation threshold, which alludes to the importance of the fibre type in delineating damage regions. In contrast, the evolution of the damage and the perforation resistance of glass fibre reinforced laminates is somewhat different. A numerical model based on a finite element program was developed to understand the mechanisms of damage evolution in the laminates. It in-volves implementing the Matzenmiller-Lubliner-Taylor (MLT) damage model. A comparison between the experimental and numerical results was also made