Publications Internationales
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Item Using a supperficially treated 2024 aluminum alloy drill pipe to delay failure during dynamic loading(Elsevier, 2019) Belkacem, Lallia; Abdelbaki, Noureddine; Otegui, Jose Luis; Gaceb, Mohamed; Bettayeb, MouradFor many years, a critical factor while drilling deep wells in Algeria oil fields has been the fatigue loads in drill strings used in high tortuosity sections. One solution is the use of drill pipes made of alternative lighter materials instead of conventional steel. A thorough study of superficially (ST) treated 2024 aluminum alloy joined to steel drill pipes in crooked well trajectories is presented in this article. This work discusses several limiting loads exerted on the drill pipes that affect the drilling operation such as axial, twisting and bending forces, which lead to combined cyclic loads. This study is aimed to determine whether it is possible to extend the drilling operation by joining ST 2024 aluminum alloy drill pipes into the drilling string, without losing drilling stability or reliability. It is established that the ST 2024 aluminum alloy drill pipe exerts significant influence on the allowable combined load, but affects to a larger extent the critical load at which loss of drilling string stability occurs, along with improved resistance to wear and corrosion, even at high temperatureItem Analysis of the bauschinger effect on a multilayer helicopter blade by XFEM simulation(Elsevier, 2017) Nour, Abdelkader; Gherbi, Mohamed Tahar; Tawfiq, ImadItem Establishment of data base and a classification of defects in the metal of pipes according to their severity(Elsevier, 2012) Bettayeb, M.; Bouali, E.; Abdelbaki, Noureddine; Gaceb, M.Given the distances between areas of production and consumption of hydrocarbons, transport by pipeline is the most competitive means. These pipelines made of metal pipes can contain several types of defects of different origins. These defects can lead to pipeline failures that may have serious consequences resulting in ecological or financial disasters. The causes of these failures can be of various kinds. To assess the integrity and study the ageing of hydrocarbons transport pipelines is a current problem in the world which must be solved. The degraded state of thousands of kilometers of pipeline in the world requires the elaboration of rehabilitation by repair or replacement programs of sections in poor condition. If on one hand rehabilitation operations do improve the safety of hydrocarbons transport pipelines and prolong their remaining life, they are very expensive on the other. Therefore they must be carried out according to a previously well established plan, which determines the priority given. This priority must be defined by a multi-criteria evaluation, which also includes the criterion of severity of the defects located in the pipes metal according to the result of previous inspections of the pipelines towards the importance and the integrity of each section of the pipe.In this context the elaboration of a database and a classification of the defects in the metal of the hydrocarbons transportation pipes according to their severity are essential in this studyItem Quasi-static mechanical characterization and fatigue of a composite laminates(2014) Belkacemi, C.; Bezzazi, B.This present work focuses on the quasi- static mechanical characterization and or fatigue of a composite materials (laminate) jute/polyester manufactured under vacuum and with stacking sequences of 0/ 90. The obtained results of tensile tests on the laminate, showed a similar behavior on two levels: a linear portion up to 20 MPa and a nonlinear portion to rupture at 47 MPa σ max , followed by elongation of 2.08 % with a break elongation up to 2.50 %. Also, it was noted that increasing the temperature of the samples (5-6 ° C ) when the fatigue test remains in ISO 13003 , which requires a temperature increase of less than 10 ° C. the results of fatigue test showed also that with a loading of 50% of the maximum load reached more than one million cycle, the more load is increasing the cycle numbers of decreasesItem Mechanical characterizations of composite material with short Alfa fibers reinforcement(Elsevier, 2015) Mechakra, Hamza; Nour, Abdelkader; Lecheb, Samir; Chellil, AhmedItem 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