Liste des communications
A Simple Efficient Finite Element for the Sandwich Plates Analysis
In this work, a numerical simulation has been considered of a sandwich composite panel subjected to a mechanical uniaxial load in order to study the buckling behaviors. In this study, we used the finite element Abaqus software and a simple efficient finite element model available in the literature [1] in order to: 1- Describe the fundamental buckling modes of a sandwich composite panel. 2- Understand the buckling behavior on this type of structure. 3- Validate the reply of the developed element on buckling behavior for the sandwich composite structure with the finite element ABAQUS software. Voir les détails
Mots clés : composite, sandwich, buckling modes, finite element
Electric Field Distribution in point-insulating barrier-Plane System using experimental and Theoretical method
The present paper deals with the influence of insulating barriers on the breakdown and the electric field distribution in the Point –insulating barrier- plane air gap system. An experimental investigation on the influence of different parameters such as gap distance between electrodes and barrier dimensions, under AC voltage, have been studied. The results show that the width and thickness of the insulating barrier effect the electric field variation which increases with increasing applied voltage. The experimental results are compared with a numerical model. Voir les détails
Mots clés : Electric field, Finite Element Method, breakdown voltage, insulating barrier, point- plane system
Analyse par spectroscopie Infrarouge à transformée de Fourier et diffraction des rayons X d’un matériau composite.
Les composites à matrice polymère sont utilisés en général comme des biomatériaux à cause de leurs constituants. Le matériau analysé est un composite à matrice en polymère renforcé par une fibre de verre utilisé comme prothèse orthopédique d’un tibia. Les résultats obtenus de diffraction des rayons X et spectroscopie Infrarouge à transformée de Fourier(FTIR) montrent la présence de la silice SiO2 et de l’alumine Al2O3 se sont parmi les constituants de la fibre de verre ainsi que la présence des molécules organiques se sont parmi les constituants de la résine polyester. Voir les détails
Mots clés : composite, Prothèse orthopédiques, DRX, FTIR.
Characterization of The Structure, Microstructure of ZnO Powder Nanostructures as Transparent Ceramic for Optical Applications
ZnO powder nanoparticles have been studied to investigate their structural and microstructural properties using X-ray diffraction (XRD)and optical microscope for examined ZnO pure powder. The ZnO powder exhibited a hexagonal crystal structure with space group p63mc of ZnO, XRD patterns of powder ZnO were obtained from the full pattern XRD using the MATCH program. For the applications of Zinc oxide as transparent ceramic for optical applications, ZnO is a potential candidate material for optics applications, which has attracted considerable attention over past decades due to its wide potential applications. Voir les détails
Mots clés : ZnO, microstructure, XRD, Optical Microscope.
RELATIONSHIP BETWEEN AE PARAMETERS AND FRACTURE OF COMPOSITE MATERIALS UNDER SOLICITATIONS
Abstract: Acoustic emission (AE) techniques have been extensively studied in concrete engineering. There has been much research in relating AE parameters, such as energy, amplitude, count number, rise time to physical properties such as crack area delaminating, pull out, break down. Our work is performed using of carbon fiber reinforced polymer to study the evolution of AE parameters under solicitations. Meanwhile the waveforms created by the failure were monitored by AE sensors attached to the concrete beam.Examination of the waveforms produced by a range of four sensors with different frequency responses reveals that the fracture depth affects the AE parameters detected during failure. Relationship between fracture area and AE parameters was examined. These results can be used to aid the quantification of damage size based on energy release from concrete structures in the field. Voir les détails
Mots clés : acoustic emission, carbon fiber, sollicitation, quantifi
Structural and Thermal Characterization of 1% Fe-doped ZnO Powder Nanostructures Prepared by Mechanical Alloying as Transparent Ceramic for Optical Applications
ZnO powder nanoparticles mechanically alloyed were doped with iron to investigate their structural and microstructural properties using X-ray diffraction (XRD) for examined 1% Fe doped ZnO. The ZnO starting pure powder exhibited a hexagonal crystal structure with space group p63mc of ZnO, however with the introduction of 1% Fe in the ZnO milled powder, the hexagonal ZnO phase remained unchanged, whereas the microstructural parameters were subject to significant variations due to the introduction of Fe atoms into the ZnO hexagonal matrix to replace oxygen ones. The size of crystallites and microstrains are found milling time dependent. For the applications of Zinc oxide, Zinc oxide (ZnO) is a potential candidate material for optics applications which has attracted considerable attention over past decades due to its wide potential applications such as ZnO photonic crystal slab ,photo catalyst, antibacterial treatment,UV absorption, light emitting diodes, photo detectors, solar cells, gas sensors and so on. Voir les détails
Mots clés : ZnO, XRD, microstructure, Optics applications
Modélisation de l’élaboration d’un biomatériau (hydroxyapatite)
Résumé / Abstract : L’hydroxyapatite (HA) Ca10 (PO4) 6 (OH) 2est élément major dans le corps humain, dans notre travail on a fait une élaboration du ce biomatériau avec la variation de six facteur nécessaire a la fabrication de ce dernier et ce la selon un plan d’expérience Plackett-Burman et ainsi on a calculé le rendement de la réaction on se basant sur un model mathématique avec l’utilisation du minitab14. Les paramètres qui ont été suivi sont : le rapport molaire Ca/P, le temps de la réaction, la vitesse d’agitation, le débit d’ajout des phosphates, la température de la réaction et la température de calcination du produit final. Ainsi, à la fin du processus, les produits solides susceptibles qui sont obtenus sont CaCl2, 2H2O, Na2HP04, 12H2O et Ca3 (PO4) 2, les autres NaCl et HCl sont éliminés avec l'eau de rinçage.Les résultats obtenus montrent que le paramètre rapport Ca/P semble être le plus important et que le produit obtenu est un mélange de phosphate tricalcique avec les réactifs initiaux de la réaction à savoir le chlorure de calcium hydraté et le di-sodium hydrogénophosphate hydraté. Cela fait en tout un mélange d’hydroxyapatite, de phosphate tricalcique et aussi des produits de départ, le chlorure de calcium et le sel de phosphate les deux hydratés. Voir les détails
Mots clés : hydroxyapatite, plan d’expérience, élaboration, Plackett-Burman, Biomatériau
Thermal analysis of aging of a matrix polymer material reinforced with a glass fiber.
The objective of this work is to evaluate the influence of temperature variation on the oxidation induction time of a fiberglass-reinforced polymeric matrix material for prosthesis of a tibia.To do this, we used the differential scanning calorimetry (DSC) technique to calculate the oxidation induction time this last one is the time needed to start the oxidation of the material in an oxygenated environment with an isotherm. And thanks to which we could determine the variation of an isotherm for different temperatures as a function of time.The experimental results obtained show that the time required to start the oxidation of the material in an oxygenated environment with an isotherm (OIT) decreases with the increase of the temperature of the sample this is confirmed by a hardness test. Voir les détails
Mots clés : thermal analysis, Polymer material, Oxidation induction time (OIT), hardness test
Comparison in Temperature evolution and Mechanical properties of an aluminium alloy welded by FSW and TIG processes
The purpose of this study is to show the potentiality of Friction Stir Welding (FSW) for joining the 2017A aluminium alloy, which is difficult to be welded by fusion techniques. A comparative study of FSW with a conventional fusion process as Tungsten Inert Gas (TIG) is made. FSW welds are made up using a specific tool mounted on a milling machine, however a single pass welding was applied to obtain a TIG joint. Thereafter, the comparison between the two processes has been made on the mechanical properties and thermal behavior. The results show that the thermal cycle peak induced by FSW process are lower than that induced by TIG process about 25%. Because the FSW does not need to melt the materials during welding. Microstructural examination revealed the grains refinement of the FSW weld joints that induce better mechanical properties (tensile tests and microhardness), higher joint efficiency (more than 80%) and good ductility compared to TIG joint. FSW process currently opens a great opportunity of application in the industrial and transport fields. Voir les détails
Mots clés : FSW, TIG, aluminum, Temperature, tensile joint efficiency, Microhardness
Contribution à la modélisation du processus de refroidissement secondaire d’acier coulée en continue
Dans l’industrie sidérurgique, la coulée continue est le procédé qui se situe entre l’élaboration d’acier et le laminage. Ce procédé a pris, depuis 30 ans, une place de plus en plus importante dans la filière de production en raison des avantages par rapport à la technique traditionnelle de coulée en lingots ; économie d’énergie et de main d’œuvre, meilleur rendement et amélioration de la qualité du produit, ainsi l’amélioration du rendement métallique de la coulée et la possibilité de couler des produits de plus faible section, directement adaptés aux laminoirs finisseurs. La coulée continue permet de transformer le métal liquide en métal solide en des formes simples, et de façon continue. Un des soucis majeurs dans l’industrie de l’acier est l’amélioration de la qualité finale du produit. Certes, le produit final présente parfois des défauts, qui sont difficiles à détecter pendant la fabrication ; la plupart du temps, ils ne sont détectés que dans les phases finales de fabrication. L’objectif de ce travail consiste à fournir un modèle numérique du refroidissement secondaire permettant de prédire l’évolution du débit de refroidissement secondaire en fonction de la vitesse de coulée dans chaque zone des nuances de l’acier. Voir les détails
Mots clés : Modélisation thermomécanique, coulée continue, refroidissement secondaire, acier, Défaut.