Publications Internationales

Permanent URI for this collectionhttps://dspace.univ-boumerdes.dz/handle/123456789/13

Browse

Author: search.filters.author.Nebab, MokhtarSubject: search.filters.subject.Free vibration

Search Results

Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    Warping and porosity effects on the mechanical response of FG-Beams on non-homogeneous foundations via a Quasi-3D HSDT
    (Techno-Press, 2024) Nebab, Mokhtar; Atmane, Hassen Ait; Bennai, Riadh; Dahmane, Mouloud
    This paper suggests an analytical approach to investigate the free vibration and stability of functionally graded (FG) beams with both perfect and imperfect characteristics using a quasi-3D higher-order shear deformation theory (HSDT) with stretching effect. The study specifically focuses on FG beams resting on variable elastic foundations. In contrast to other shear deformation theories, this particular theory employs only four unknown functions instead of five. Moreover, this theory satisfies the boundary conditions of zero tension on the beam surfaces and facilitates hyperbolic distributions of transverse shear stresses without the necessity of shear correction factors. The elastic medium in consideration assumes the presence of two parameters, specifically Winkler-Pasternak foundations. The Winkler parameter exhibits variable variations in the longitudinal direction, including linear, parabolic, sinusoidal, cosine, exponential, and uniform, while the Pasternak parameter remains constant. The effective material characteristics of the functionally graded (FG) beam are assumed to follow a straightforward power-law distribution along the thickness direction. Additionally, the investigation of porosity includes the consideration of four different types of porosity distribution patterns, allowing for a comprehensive examination of its influence on the behavior of the beam. Using the virtual work principle, equations of motion are derived and solved analytically using Navier's method for simply supported FG beams. The accuracy is verified through comparisons with literature results. Parametric studies explore the impact of different parameters on free vibration and buckling behavior, demonstrating the theory's correctness and simplicity.
  • No Thumbnail Available
    Item
    An enhanced quasi-3D HSDT for free vibration analysis of porous FG-CNT beams on a new concept of orthotropic VE-foundations
    (Taylor & Francis, 2024) Djilali Djebbour, Kenza; Nebab, Mokhtar; Ait Atmane, Hassen; Alghanmi, Rabab A.; Hadji, Lazreg; Bennai, Riadh
    The original primary objective of this study is to conduct a comprehensive investigation into the free vibration behavior of beams with porosity, reinforced by carbon nanotubes (CNTs). These beams are supported by an arbitrary orthotropic variable elastic foundation (AOVEF). The focus lies on understanding how the presence of porosity and CNT reinforcement, coupled with the complex support provided by the AOVEF, influences the vibration characteristics of the beams. In addition, we intend to examine the impact of a number of micromechanical models on the vibration properties of these beams. Four carbon nanotube variables are introduced to symbolize several CNT variations. CNTs’ mechanical properties are examined through a variety of micromechanical models. Shear deformation effects are considered into account in the framework of higher-order shear deformation (HSDT) beam theory. The equations of motion are constructed using Hamilton’s concept and the equation system for the FG-CNT beam with supported ends is solved via the Navier methodology. A new approach in elastic foundation modeling is the Arbitrarily Orthotropic Variable Elastic (AOP-VE) foundation. It builds on the Winkler layer concept but introduces the idea of a variable response along the length of the beam foundation. Unlike the Winkler-Pasternak model, AOP-VE allows for control over the directional properties of the Pasternak foundation. The study looks into multiple aspects, involving various distribution kinds of CNTs, the impact of Winkler and Pasternak factors, mode values, side-to-length ratio, porosity, and angle variation. The results indicate that these parameters have a major effect on the inherent vibration features of FG-CNT beams. The study results in various novel findings that improve the understanding of the subject topic and set a standard for future studies.
  • No Thumbnail Available
    Item
    Fundamental frequencies of cracked FGM beams with influence of porosity and Winkler/Pasternak/Kerr foundation support using a new quasi-3D HSDT
    (Taylor & Francis, 2023) Nebab, Mokhtar; Dahmane, Mouloud; Belqassim, Ayache; Ait Atmane, Hassen; Bernard, Fabrice; Benadouda, Mourad; Bennai, Riadh; Hadji, Lazreg
    In this study, we have introduced, for the first time, a novel integral quasi-3D higher-order shear deformation theory (HSDT) employing a third-order shape function. This approach is employed to analyze the free vibration characteristics of a cracked porous functionally graded material (FGM) beam supported on a three-parameter elastic foundation (Winkler/Pasternak/Kerr). This new Quasi HSDT introduces a stretching effect that surpasses the capabilities of FSDT and other HDST. The employed shape function satisfies the conditions of shear stress nullity at both the higher and lower facets without the need for correction factors. The study incorporates a mathematical model representing Winkler/Pasternak/Kerr foundation types into the Hamiltonian to derive the equations of motion. The FGM beam studied in this paper is assumed to be composed of materials with a distribution that varies according to a power law along its height. Our results are compared with previous studies and we reinforce our findings with a parametric study assessing the impact of crack attributes on the natural frequencies of the FG plate. This study presents an advanced integral quasi-3D HSDT, applied for the first time, to analyze the behavior of FG beams resting on a three-parameter foundation.
  • No Thumbnail Available
    Item
    Dynamic characteristics analysis of functionally graded cracked beams resting on viscoelastic medium using a new quasi-3D HSDT
    (Taylor & Francis, 2024) Kehli, Ahmed; Nebab, Mokhtar; Bennai, Riadh; Ait Atmane, Hassen; Dahmane, Mouloud
    In this study, a new four-unknown quasi-3D shear deformation theory is proposed for studying the vibration responses of functionally graded (FG) beams containing open-edge cracks resting on three-parameter viscoelastic foundations (VEFs). The number of unknowns and governing equations in the current theory has been reduced, making it easier to use. Even less than conventional theories, this theory includes indeterminate integral variables and contains only four unknowns where no shear correction factor is used. The study is conducted with an eye toward a three-parameter foundation that takes into account the effects of the elastic medium’s damping coefficient, the Pasternak coefficient, and the Winkler coefficient. The material characteristics of the FG beams are considered to vary in the thickness direction via a power law distribution as a function of the volume fractions of the constituents. The system of differential equations governing the free vibration behavior of FG beams is derived by Hamilton’s principle. To satisfy the foundation conditions, the Navier method is used to obtain the analytical solutions of the dynamic response of cracked FG beams resting on viscoelastic foundations. Comparison of the results of the current theory with other results and with data available in the literature demonstrates its accuracy. A detailed parametric study is presented to show the impact of material properties, slenderness ratio, foundation type and foundation damping coefficient, crack depth, and location on the natural frequencies of cracked FG beams resting on VEFs.