Publications Scientifiques

Permanent URI for this communityhttps://dspace.univ-boumerdes.dz/handle/123456789/10

Browse

Subject: search.filters.subject.Finite element method

Search Results

Now showing 1 - 8 of 8
  • No Thumbnail Available
    Item
    Experimental and numerical study of the effect of the presence of a geometric discontinuity of variable shape on the tensile strength of an epoxy polymer
    (Sciendo, 2023) Saada, Khalissa; Amroune, Salah; Zaoui, Moussa; Houari, Amin; Madani, Kouider; Hachaichi, Amina
    The presence of geometric discontinuity in a material reduces considerably its resistance to mechanical stresses, therefore reducing the service life of materials. The analysis of structural behaviour in the presence of geometric discontinuities is important to ensure the proper use, especially if it is regarding a material of weak mechanical properties such as a polymer. The objective of the present work is to analyse the effect of the notch presence of variable geometric shapes on the tensile strength of epoxy-type polymer specimens. A series of tensile tests were carried out on standardised specimens, taking into account the presence or absence of a notch. Each series of tests contains five specimens. Two notch shapes were considered: circular (hole) and elliptical. The experimental results in terms of stress-strain clearly show that the presence of notches reduces considerably the resistance of the material, where the maximum stress for the undamaged specimen was 41.22 MPa and the lowest stress for the elliptical-notched specimen was 11.21 MPa. A numerical analysis by the extended finite element method (XFEM) was undertaken on the same geometric models; in addition, the results in stress-strain form were validated with the experimental results. A remarkable improvement was obtained (generally an error within 0.06%) for strain, maximum stress, Young's modulus and elongation values. An exponential decrease was noted in the stress, strain, and Young's modulus in the presence of a notch in the material
  • No Thumbnail Available
    Item
    Axisymmetric frictionless contact between an elastic layer thickness and a circular base under a rigid punch
    (SAGE, 2023) Guerrache, Fadila; Boutoutaou, Hamid; Hachemi, Madjid
    The study presented in this work deals with analytical methods for an axisymmetric problem of an elastic layer partially reposing on a rigid circular base, and is indented along the upper surface with a rigid punch. The contact between the medium and the base is smooth. This boundary value problem is transformed into a system of dual integral equations. In contrast to the classical approach consisting in resolving the corresponding Fredholm equation of the second kind, the latter equations are obtained from an infinite algebraic system of simultaneous equations, where the particular case (Formula presented.) is verified. The results of this system are also obtained numerically. The normal displacement, normal stress, and the stress singularity factor are given analytically and shown graphically with discussion. By comparison with those predicted by the finite element method, the accuracy of the numerical method is approved
  • No Thumbnail Available
    Item
    Dynamic failure analysis and lifetime estimation of Tool-string in rotary drilling system under Torsional-Axial coupled vibrations
    (Elsevier, 2022) Kessai, Idir; Benammar, Samir; Doghmane, M.Z.
    Failure analysis and lifetime assessment of drilling systems are very important to reduce maintenance costs. Of all the failure modes, coupled vibration due to the stick–slip phenomenon is the most common problem that can affect rotary drilling systems. The main objective of this study is to estimate the number of cycles before failure (useful life) of the lower part of rotary drilling system toolstring under axial and torsional vibrations. To achieve this goal, a complete procedure based on different methods and approaches, such as: finite element method (FEM), rainflow counting method (RFM), Goodman approach (GA), S-N diagram and Miner’s rule, has been proposed. To this end, the FEM has been used to determine the loading cycles (equivalent stress); whereas, the number of stress cycles in the loading cycle diagram has been counted using RFM. The GA has been used to select the main cycles that can cause failure on the toolstring and to calculate their amplitudes. Then, S-N diagram has been used to determine the number of cycles to failure of the toolstring. Finally, Miner’s rule has been applied to find the approximate time to failure of the drilling system. Regarding the estimation of the toolstring lifetime, the results obtained have shown a good agreement with real data recorded in an oil field in Algeria
  • No Thumbnail Available
    Item
    A damage identification technique for beam-like and truss structures based on FRF and Bat Algorithm
    (Elsevier, 2018) Zenzen, Roumaissa; Belaidi, Idir; Khatir, Samir; Wahabc, MagdAbdel
    In this paper, a Structural Health Monitoring (SHM) technique for damage identification in beam-like and truss structures using Frequency Response Function (FRF) data coupled with optimization techniques is presented. Genetic Algorithm (GA) and Bat Algorithm (BA) are used to estimate the location and severity of damage. The damage in the structures is simulated by reduction in rigidity of specific members. Both optimization techniques are coupled with modelled structures using Finite Element Method (FEM). The approach is based on minimizing an objective function by comparing measured and calculated FRFs. The results show that better accuracy is obtained using BA than using GA in terms of precision and computational time. Furthermore, it is found that the proposed approach provides faster solution than other approaches in the literature.
  • No Thumbnail Available
    Item
    Dynamic eccentricity fault diagnosis in induction motors using finite element method and experimental tests
    (Inder Science Online, 2017) Bouzida, Ahcene; Abdelli, Radia; Touhami, Omar; Aibeche, Abderrazak
    This paper presents the dynamic eccentricity (DE) in the squirrel cage induction machine obtained by the simulation using finite element method (FEM) and the experimental tests. Motor current signature analysis (MCSA) through the power spectral density (PSD) is used to monitor the low frequency components related to the rotor faults. In order to generalise the study, a comparison was performed between faulty machines and healthy, under different load conditions. The experimental tests show the encountered difficulties in the detection of the dynamic eccentricity under various load conditions because the spectral representation shows the existence of low frequency components for the healthy case, which are superimposed with the indicator components. These low frequency components offer an alternative way to the monitoring of eccentricity air-gap when the load is balanced
  • No Thumbnail Available
    Item
    Pipelines corrosion due to the electromagnetic pollution caused by the high voltage power lines
    (2016) Ouadah, M'hamed; Touhami, Omar; Ibtiouen, R.; Bouzida, Ahcene; Bouyegh, Saida; Allou, Djilali; Haddad, Ahmed
  • No Thumbnail Available
    Item
    Dynamic eccentricity fault diagnosis in induction motors using finite element method and experimental tests
    (Inderscience, 2017) Bouzida, Ahcene; Abdelli, Radia; Touhami, Omar; Aibeche, Abderrazak
  • No Thumbnail Available
    Item