Now showing 1 - 15 of 15
ItemInfluence de la Poudre de Granit sur le Comportement Mécanique et Rhéologique du Béton Autoplaçant(2019-10-22) Rahmani, Farida; Haddad, Ouerdia; Kaci, SalahDans cette étude, nous montrons que l’ajout de poudre de granit (déchet de matériau de construction très finement broyé) en substitution partielle du ciment portland (nécessaire à la composition et à la formulation du composite de béton auto-plaçant) conserve bien les caractéristiques mécaniques et rhéologiques, aussi bien à l’état frais qu’à l’état durci, de ce composite. Cette substitution partielle permet à la fois de réaliser un gain de ciment (gain d’argent), de réduire la teneur en dioxyde de carbone généré lors de la fabrication du ciment portland (respect de l’environnement) et de mettre en valeur le déchet de récupération (moindre coût). ItemVISCOUS FINGERING IN FIVE-SPOT IMMISCIBLE DISPLACEMENT(Applications of Computer Algebra- ACA 2019 Montréal, Canada July 16-20, 2019, Ecole de Technologie Supérieure, 2019-07-16) Djebouri, Hassane; Zouaoui, Salah; Mohammedi, Kamal; Bilek, AliThe work, presented in this paper, is a numerical study that deals with the phenomenon of viscous fingering in a five-point geometry that is considered a good model of oil fields. In order to investigate the effect of the presence of the fractures and their distribution in the porous medium, three different cases are considered in this study. We considered a porous medium fully saturated with oil. Water is injected through an injection well to push this oil to a production well. The interface of the two fluids is visualized as a function of time. The flow equations are solved using the finite volume method (FVM). ItemVALURİNG BY RECYCLİNG OF POLYMERİC WASTE RECOVERED FROM ELECTRONİC AND ELECTRİCAL EQUİPMENT OUT OF ORDER(5TH INTERNAIONAL CONFERENCE ON ADVANCES IN MECHANICAL ENGINEERING ISTANBUL, 2019-12-17) Mohellebi, Mouloud; DJEDDI, FadhilaThe purpose of this study is the recovery and recycling of polymeric waste from electrical and electronics equipment out of service (WEEE) and stored in the open of environment. The high consumption of these equipments and the practice by some manufacturers of the planned obsolescence make this waste take a worrying extent in the degradation of the environment. The addition of the ABS polymer to this waste makes it possible to reintroduce them into the cycle of the production of raw materials by recycling. we proceeded by adding Acrylonitrile Butadiene Styrene (ABS) at 20, 40, 50, 60 and 80% to the WEEE Matix. The waste is washed and crushed beforehand and the ABS is used in the virgin state. The mixing was done first cold by placing the various constituents in a cylinder in random rotation, then hot extrusion. The preparation of the test samples was carried out without additives or compatibilizers by injection process after grinding of the extrusion product. The mechanical characterization of the samples showed that the introduction of WEEE in the ABS matrix generates small variations in the modulus of elasticity. The maximum elastic stress increases by 27% for the mixture (50%WEEE/50% ABS). Resilience also increases with the concentration of ABS in the WEEE matrix and reaches 90% for the mixtures (50%WEEE/50% ABS). Finally, we proceeded to the observation and readings of the fracture facies by scanning electron microscopy (SEM). ItemMesoscopic Defects of Forming and Induced properties on the Impact of a Composite Glass/Polyester(2019-12-30) Kacimi, Bachir; Teklal, Fatiha; Djebbar, ArezkiForming processes induce residual deformations on the reinforcement and sometimes lead to mesoscopic defects, which are more recurrent than macroscopic defects during the manufacture of complex structural parts. This work contributes to the experimental study of the effect of mesoscopic buckles defect and shear deformation of the reinforcement, which result from forming, on the low velocity impact behavior of a composite laminate. The material studied is a glass/polyester composite with three layers of mat and one layer of taffeta fabric. To assess the properties induced on the final composite, plates with different amplitudes of calibrated defects and deformations were manufactured. First, the healthy material, which serves as a reference, was subjected to three levels of impact energy to observe the evolution of its behavior and damage mechanisms. Results of the impact tests and observations performed on the materials with calibrated defects identified a negative effect of buckling on elastic parameters and revealed greater damage relative to the healthy material. The reinforcement shear had a beneficial effect on the impact properties of the laminate, which was attributed to the increase in local fiber density. ItemMicromechanics of Stress Transfer across the Interface fiber-matrix bonding(2019-12-30) Teklal, Fatiha; Kacimi, Bachir; Djebbar, ArezkiThe study and application of composite materials are a truly interdisciplinary endeavor that has been enriched by contributions from chemistry, physics, materials science, mechanics and manufacturing engineering. The understanding of the interface (or interphase) in composites is the central point of this interdisciplinary effort. From the early development of composite materials of various nature, the optimization of the interface has been of major importance. While there are many reference books available on composite materials, few of them deal specifically with the science and mechanics of the interface of fiber reinforced composites. Even more important, the ideas linking the properties of composites to the interface structure are still emerging. A number of experimental techniques have been devised to measure the mechanical properties of the fiber-matrix and laminar interfaces in composites. A number of analytical solutions have been proposed in order to better understand the stress transfer mechanism across the interfaces between the fiber and the matrix. In our study, we need a direct characterization of the interface; the micromechanical tests we are addressing seem to meet this objective and we chose to use two complementary tests simultaneously. The microindentation test that can be applied to real composites,and the drop test, preferred to the pull-out because of the theoretical possibility of studying systems with high adhesion (which is a priori the case with our systems). These two tests are complementary because of the principle of the model specimen used for both the first "compression indentation" and the second whose fiber is subjected to tensile stress called the drop test. Comparing the results obtained by the two methods can therefore be rewarding. ItemCracking Propagation in Concrete Bloc Exposed to Cryogenic Temperature(2019-12-30) L.DAHMANI; L.BOUCHELILIn order to investigate the cracking propagation in the concrete bloc exposed to low temperature, The ANSYS finite element code has been employed for performing a sequential, non linear, transient thermal-structural analysis, taking into account the thermal dependent properties of the concrete as thermal conductivity and specific heat. Temperature distribution data of thermal analysis is required in the coupled field analysis finally to obtain and analyze thermal stresses. An original concept based on three dimensional stress states of the integrations points in each finite element is described. The global relative crack density (GRCD) is suggested to denote the cracking state of the entire concrete bloc, which may serve as an appropriate index to evaluate the overall deterioration level of the structure. ItemEvolution des propriétés mécanique des BHP au Laitier Renforcés par un Fibrage Métallique Mixte(2019-12-17) BOUTIBA, Aldjia; CHAID, Rabah; MOLEZ, LaurentLes bétons de hautes performances (BHP) acquièrent des résistances mécaniques allant de 20 à 30 MPa à 24heures, ce qui permet d’augmenter la productivité et de réduire les délais de réalisation sur les chantiers. Aussi, avec les BHP, il est possible de construire avec moins de coffrage, moins de béton à mettre en place et moins d’armatures qu’avec un béton ordinaire. L’ajout des fibres métalliques a un effet plus efficace dans les matrices à hautes résistances, en augmentant à la fois la charge ultime et la ductilité, grâce à la bonne adhérence entre les fibres et la matrice du béton. Le but de cette étude, est de définir l’effet d'un fibrage mixte sur les propriétés mécaniques des bétons de haute performance avec ajout de laitier de haut fourneau. Les résultats obtenus montrent que l’ajout de laitier granulé ultrafin et des fibres a entraîné une amélioration relative des performances mécaniques. ItemSeismic performance of reinforced concrete frames structure based on Plastic rotation(2019-12-30) KAHIL, Amar; MEZIANI, Faroudja; KHELIL, NacimThe principal objective of this study, is the evaluation of the seismic performance of reinforced concrete frame structures, taking into account of the behavior laws, reflecting the real behavior of materials, using CASTEM2000 software. A finite element model used is based in modified Takeda model with Timoshenko elements for columns and beams. This model is validated on a Vecchio experimental reinforced concrete (RC) frame model. Then, a study focused on the behavior of a RC frame with three-level and three-story in order to visualize the positioning the plastic hinge (plastic rotation), determined from the curvature distribution along the elements. The results obtained show that the beams of the 1st and 2nd level developed a very large plastic rotations, or these rotations exceed the values corresponding to CP (Collapse prevention with cp CP= 0.02 rad), against those developed at the 3rd level, are between IO and LS (Immediate occupancy and life Safety with IO = 0.005 rad and rad LS = 0.01 respectively), so the beams of first and second levels submit a very significant damage. ItemNumerical investigation of the jacketing method of the reinforced concrete column(2019-12-30) S. Boukais; A. Nekmouche; N.Khelil; A. KezmaneThe first intent of this study is to develop a finite element model that can predict correctly the behavior of the reinforced concrete column. As second aim is to use the finite element model to investigate and evaluate the effect of the strengthening method by jacketing of the reinforced concrete column, by considering different interface contact between the old and the new concrete. ItemCOMPARATİVE STUDY OF THE MECHANİCAL BEHAVİOUR OF THE ABS POLYMER: İNJECTİON PRESS-3D PRİNTİNG(2019-12-17) F. Djeddi; M. MohellebiPlastic processing techniques depend on the nature of the polymers and on the destination of the finished products. To improve the productivity of plastics and their performance, the industrial world has given great importance to the evolution of these transformation techniques. Our work is a comparative study of the mechanical behavior of a polymer (ABS) in two different processing techniques: press injection and 3D printing. Plastic injection uses the thermoplastic properties of the polymer, to inject it softened into a mold, in order to create a footprint of it. This technique provides the best quality for productions of large and very large series.3D printing, also called additive manufacturing or direct digital manufacturing, allows making an object by creating a numerical model and printing it in three dimensions. It opens a wide range of technical possibilities with important economic stakes. Used mainly for prototyping, its potential applications are now of interest to many sectors of activity: aeronautics, automobile, medical, .... The melt flew index of the ABS used is 22.32 g / 10 min, the mode of transformation chosen, which is the injection, is in agreement with our material. The mechanical behavior of test pieces made by the two processes is different. The stress and strain characteristics are significantly higher in the conventional injection process than in the case of 3D printing. The values of modulus of elasticity and maximum stress decrease significantly in the 3D printing process. Micrographs obtained by optical microscope and scanning electron microscope observations (MEB) of fracture facies during tensile test show a big difference in the cohesion of the material between the two processes. The results obtained show that the transformation mode has a direct influence on the mechanical characteristics of the polymer. The mechanical characteristics required of the finished product impose the mode of transformation of the polymer.. ItemTemporal analysis of the performance of a RC storage tank considering the corrosion(2019-07-01) Bouzelha, Karima; Amazouz, Lynda; Miloudi, Nassima; Hammoum, HocineThe reinforced concrete (RC) water storage tanks are hydraulic structures that occupy a special place among civil engineering structures. Under the effect of hydrostatic and hydrodynamic loads, their walls undergo horizontal tensile stresses which are absorbed by horizontal reinforcements. Moreover, these structures are subjected to high aggressive atmospheric conditions that expose their walls to a risk of harmful corrosion. This dangerous phenomenon leads to the reduction of their steel reinforcement sections and consequently to the loss of their resistance and function. In this paper, we are interested in the performance analysis of RC storage tanks, taking into account the phenomenon of corrosion of strained reinforcements, considering the environments of different aggressiveness rates. Westergaard method is applied to evaluate the hydrodynamic pressure on the wall. A corrosion model is performed in order to determine the evolution in time of the reinforcement section for different environments considered. Several parameters influencing the corrosion are considered, such as the concrete cover of steel reinforcement and the concentration of chlorides ions. ItemStructural reliability of elevated water reservoirs under wind loading(2019-07-01) Hammoum, Hocine; Bouzelha, Karima; Sellamb, Youcef; Haddadb, LounesIn the field of civil engineering, concrete water storage tanks are considered as hydraulic structures occupying a special place among other structures. The location of these tanks is based on hydraulic considerations related to the desired service pressure for subscribers whose solution is obtained by a compromise with the topographical constraints. In southern Algeria and the highlands; in order to ensure adequate pressure in the drinking water supply networks, the tanks are then elevated to high heights, which puts them under significant stress during windstorms and sandstorms conditions that are frequent in the South Algerian. As the severe weather conditions due to high winds are common, the elevated water storage tanks are designed to withstand to winds speeds included between 25 and 31 m/s according to the Algerian Wind Code. Given the uncertain and randomness of this phenomenon, the classical deterministic calculations of the engineer become limited since they do not integrate the notion of failure probability of the structure. In this study, a probabilistic approach based on Monte Carlo simulations is used to analyze the reliability of elevated water tanks submitted to hazard storm of wind loading. The limit state functions are related to the ultimate and serviceability limit states of the concrete elevated tank under wind analysis. This reliability approach, takes into account mainly two parameters which are the wind speed and the concrete compressive strength considered as random variable. Fragility curves depending on wind zones are obtained, where they demonstrate the dominant failure modes that can cause the structural failure. ItemTowards the numerical simulation of fluid/solid particles flow inside a pipe(2019-07-16) Zouaoui, Salah; Djebouri, Hassane; Ferhat, Brahim; Mohammedi, Kamal; Bilek, AliThe modeling of moving solid particles in fluid flow has been the focus of many studies and has succeeded to attract sufficient attention by researchers. However, commonly used modeling approaches such as discrete element modeling (DEM) and direct numerical simulations (DNS) lack simplicity and have been computationally intensive . The aim of this paper is to develop a new approach to simulate solid transport in an incompressible Newtonian fluid flow. This method is based on the Finite element method with penalization of the deformation tensor . The fluid behavior is governed by the Navier-Stokes equations within the investigation domain. To take into account collisions, we present an algorithm which allows us to handle contacts between rigid particles [3, 4]. In this paper, 2D simulation fluid/particles flow is performed; some preliminary results are presented. ItemInfluence de la Poudre de Granit sur le Comportement Mécanique et Rhéologique du Béton Autoplaçant(23/10/2019) Kaci, Salah; Rahmani, Farida; Haddad, OuerdiaDans cette étude, nous montrons que l’ajout de poudre de granit (déchet de matériau de construction très finement broyé) en substitution partielle du ciment portland (nécessaire à la composition et à la formulation du composite de béton auto-plaçant) conserve bien les caractéristiques mécaniques et rhéologiques, aussi bien à l’état frais qu’à l’état durci, de ce composite. Cette substitution partielle permet à la fois de réaliser un gain de ciment (gain d’argent), de réduire la teneur en dioxyde de carbone généré lors de la fabrication du ciment portland (respect de l’environnement) et de mettre en valeur le déchet de récupération (moindre coût). ItemVISCOUS FINGERING IN FIVE-SPOT IMMISCIBLE DISPLACEMENT(16/07/2019) Djebouri, Hassane; Zouaoui, Salah; Mohammedi, Kamal; Bilek, AliThe work, presented in this paper, is a numerical study that deals with the phenomenon of viscous fingering in a five-point geometry that is considered a good model of oil fields. In order to investigate the effect of the presence of the fractures and their distribution in the porous medium, three different cases are considered in this study. We considered a porous medium fully saturated with oil. Water is injected through an injection well to push this oil to a production well. The interface of the two fluids is visualized as a function of time. The flow equations are solved using the finite volume method (FVM).