Publications Internationales

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Now showing 1 - 9 of 9
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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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    Seismic vulnerability analysis of rc buildings : case study of Ibn Khaldoun area in Boumerdes city, Algeria
    (2021) Lazzali, Farah
    This 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.
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    Seismic vulnerability of algerian reinforced concrete houses
    (Techno-Press, 2013) Lazzali, Farah
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    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 Zinelabidine
    The 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 efficiency
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    Seismic risk and damage prediction : case of the buildings in constantine city (Algeria)
    (Springer, 2014) Boukri, Mehdi; Naboussi Farsi, Mohammed; Mebarki, Ahmed; Belazougui, Mohamed; Amellal, Omar; Mezazigh, Brahim; Guessoum, Nabila; Bourenane, Hamid; Benhamouche, Azzedine
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    Modelling damage of composite laminates with different stacking sequences
    (2013) Benbelaid, S.; Bezzazi, B.; Bezazi, A.
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    Modeling damage of the hydrogen enhanced localized plasticity in stress corrosion cracking
    (2010) Benbelaid, S.; Belouchrani, M. A.; Assoul, Y.; Bezzazi, B.
    Stress corrosion cracking is an important and complex mode of failure in high-performance structural metals operating in deleterious environments, due to metallurgical, mechanical, and electrochemical factors. Depending on the material/solution system, the stress corrosion cracking mechanism may involve a combination of hydrogen embrittlement (HE) and anodic dissolution. In this article, a numerical model for predicting the mechanical behavior of hydrogen-induced damage in stress corrosion cracking is described. The methodology of modeling used in this study is based on the thermodynamics of continuum solids and elastoplastic damage. This model is based on a stress corrosion mechanism that occurs through the simultaneous interaction of hydrogen and plasticity. This mechanism is also called hydrogen-enhanced localized plasticity, which is a viable mechanism for hydrogen embrittlement. The model is applied to the fatigue damage problems of nuclear reactor pipe, and the results are compared with published fatigue life data obtained experimentally
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    Flexural fatigue behavior of cross-ply laminates.An experimental approach
    (2003) Bezazi, A.; El-Mahi, A.; Berthelot, J. M.; Bezzazi, B.
    Within an experimental approach we describe the mechanical behavior of different resin-epoxy laminates reinforced with cross-ply Kevlar and glass fibers under conditions of static and cyclic three-point bending. In static tests, we consider the effect of stacking sequence, the thickness of 90°-oriented layers, reinforcement type on the mechanical behavior of laminates under loading and on realization of various damage modes leading to rupture. Cyclic loading studies have been performed in two steps. In the first stage, we inquire into the dependence of the behavior and durability of four glass fiber-reinforced laminate-types on the stacking sequence; the second stage is devoted to studying the dependence of cyclic strength and fatigue behavior of laminates on the reinforcement type. Fatigue tests are carried out in load-control regime for glass and hybrid (Kevlar + glass) fiber laminates. Fatigue curves are constructed in coordinates “stress – number of cycles until fracture” from the criteria corresponding to a drop in stiffness by 5 and 10%. Analysis of the results obtained permits evaluation of the effect of the stacking sequence and the reinforcement type on the behavior of cross-ply laminates in cyclic loading. The presence of Kevlar fibers accounts for nonlinear behavior of laminates in static tests and for low cyclic strength in fatigue tests under three-point bending