Publications Scientifiques
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Item Damage crack growth detection of composite pipeline using NDT(Université M'Hamed Bougara Boumerdes : Faculté de Technologie : Département Génie Mécanique, 2021) Brihmat, Chahira; Lecheb, Samir; Chellil, A.; Safi, B.; Kebir, H.; Mechakra, H.; Tablit, B.Item Assessment of the aggressive agents' penetration into concrete by non-destructive techniques(Emerald Publishing Limited, 2022) Khial, Nassima; Chaid, RabahPurpose: Around the world, many structures are affected by pathological reactions between the concrete and the surrounding environment in which these structures are designed, these pathologies lead to compromise their serviceability. In this context, this paper aims to study the durability of concrete in different environments with non-destructive techniques, by studying its contamination by the aggressive agents’ penetration. And this, by evaluation of the influence of the durability indicator that is the absorption by immersion, on the mechanical properties (compressive strength, modulus of elasticity and damage), of specimens having undergone immersion/drying cycles, in different aggressive media (water, seawater and acids: sulfuric and acetic with a concentration of 5%). Design/methodology/approach: Concrete specimens were manufactured in the laboratory, and then underwent immersion/drying cycles, in parallel, the weight gain of the specimens was carried out in the wet state after immersion and in the dry state after drying, and the ultrasonic speeds were also taken in a dry state. The results showed a decrease in the mechanical properties studied, namely, the compressive strength as well as the elastic properties (modulus of elasticity, damage) as a function of the increase in absorption, and that the weakest properties are those of test specimens submerged in water. Findings: Non-destructive tests have shown that the parameters examined increase with the immersion/drying cycles, up to the fourth cycle. Beyond that, they drop gradually, and this is valid for four environments. This decline is due to the degradation of cement pastes exposed to water, seawater and acid attacks. This is explained by the greater or lesser dissolution of all the major elements making up the cementitious matrix (CSH, Ca(OH)2, CaO, SiO2, C3S, C2S, C3A, C2S) depending on the nature and concentration of the chemical substances evacuated. The results showed that the highest absorption rate and damage are those recorded for the specimen immersed in water, followed by that of the specimens immersed in acids, followed by that of the specimen immersed in sea water. The highest compressive strength and stiffness are those of the specimen immersed in sea water, followed by that immersed in acids, then in water. Originality/value: The work developed aimed to study the durability of concrete, by addressing the study of the coupling absorption – mechanical characteristics of concrete, in different aggressive media (water, seawater and acids), to seek a relationship between these parameters. The tests provided are non-destructive tests, which consist of taking measures that do not damage the concrete. They allow indirect measurements of the mechanical properties of concrete as well as the monitoring of their evolution over time. They also allow having certain accuracy, because the measurements are taken at the same placeItem 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, HocineIn 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.Item Identification of vibratory characteristics to the damage of a composite plate(2018) Grabi, Massinissa; Chellil, A.; Lecheb, Samir; Mechakra, H.; Nour, A.; Andrianarison, O.tThe objective of this work is to study the damage behavior of composite structures by examining the influence on fatigue resistance. The finite element model of the plate will allow to analyze the vibratory behavior, to identify the stress, to study the influence of the dynamic loads on the natural frequencies of the plate in bending and torsion and will show the influence of the orientation of the Composite fiber macros on the rigidity of the plate and finally calculate the stability of the plate. The various damage mechanisms associated with these materials will also be presented with particular attention to delamination and cracking. This work will then focus on different technologies to improve the mechanical properties of these composite materials.Item Damage Modelling in Thermoplastic Laminates Reinforced with Steel and Glass Fibres under Quasi-Static Indentation Loading at Low-Velocity(Sage journals, 2019) Mahdad, M'Hamed; Ait Saada, Aicha; Belaidi, IdirThis paper deals with experimental and numerical investigations of the composites damages with ductile and fragile reinforcement under quasi-static indentation loading. The main goal of the work is to increase the post-damage residual strength and ductility of thermoplastic composite. Two types of composite laminates with polypropylene (PP) matrix are tested: glass fibre laminate (GFPP) and steel fine wire mesh laminate (SWPP). The specimens are [0° 90°]2s stacking sequence and prepared by using a compression moulding technique. Quasi-static indentation tests were performed with two distinct penetration scales under low velocity (1.2 mm/min). The diameter of the hemispherical indenter is 16 mm. The failure mechanisms of composite layers were examined by the field emission scanning electron microscope (SEM). The results show that the failure mode of SWPP laminates is principally dominated by the plastic deformation component. In contrast, the GFPP laminate exhibits a fragile behaviour which is related to the fragile failure of glass fibres. In addition, the SEM shows that matrix cracking, fibre breakage, debonding and fibre pull out are the major damages observed around the indentation area. A model based on the combined use of plasticity, damage and fracture, was developed and applied to simulate quasi-static indentation behaviour and predict the resulting damageItem Seismic vulnerability analysis of rc buildings : case study of Ibn Khaldoun area in Boumerdes city, Algeria(2021) Lazzali, FarahThis study focuses on empirical assessment of vulnerability and fragility curves of existing reinforced concrete (RC) buildings in Ibn Khaldoun area of Boumerdes city (Algeria). In this area, existing RC buildings experienced significant damage during the 2003 Boumerdes earthquake. Currently, the area includes existing non-damaged buildings, strengthened buildings and new RC buildings constructed in place of those demolished. The proposed seismic vulnerability assessment method combines the GNDT (Gruppo Nazionale per la Difesa dai Terremoti) II level method and the macroseismic method by means of correlation between the peak ground acceleration PGA and the macroseismic intensity I. For this purpose, data was collected by investigating buildings within the area. Structural and non-structural building characteristics were identified and statistical analysis was performed. Resulting vulnerability curves obtained using the macroseismic method were expressed as a function of macroseismic intensity and the vulnerability index obtained using the GNDT II level method. Fragility curves, obtained by using correlation between the peak ground acceleration PGA and the macroseismic intensity I, showed that the highest probability to reach or exceed a very heavy damage grade is obtained for the highest values of I and vulnerability index V.Item Seismic vulnerability of algerian reinforced concrete houses(Techno-Press, 2013) Lazzali, FarahItem Comparative behavior under compression of concrete columns repaired by fiber reinforced polymer (FRP) jacketing and ultra high-performance fiber reinforced concrete (UHPFRC)(Taylor & Francis, 2014) Rabehi, B.; Ghernouti, Y.; Li, Alex; Boumchedda, K.Item Analyze and modelingofdamage behavior of a C0.12%Mn1.02%Si0.29% HLE steel solicited in selected physicochemical medium(Mohammed Premier University, 2015) Belahcene, B.; Benmoussat, A.; Mansri, A.; Doghmane, Mohamed ZinelabidineThe influence of environment and physical parameters on C0.12%Mn1.02%Si0.29% HLE steel steel corrosion damage behaviour in NaCl solutions was studied using weight loss, pH evolution at 300k to 370k, electro-exchanges, and passivity. Herein, the results show that the corrosion rate changes versus type of thermal treatment and cooling fluid, solution concentration, shape, size and cooling speed of the samples. The resolution of Nernst equation proves that the increase in temperature has a direct effect on hydrogen potential of the solution, current and corrosion potential of the metal. Moreover, the inhibition efficiency was determined by theoretical calculation using mechanical molecular and semi-empirical method. These results guided us to conclude that the inhibitor, which has low electronegativity than C0.12%Mn1.02%Si0.29% Steel has good efficiencyItem Vulnerability index of algiers reinforced concrete buildings(2013) Lazzali, Farah; Farsi, Mohamed N.