Browsing by Author "Dahmane, Mouloud"

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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.
Elastic wave propagation and dynamic response of multidirectional FG beams under varying thermal conditions
(Taylor and Francis, 2025) Bourouis, Mohammed El Amin; Dahmane, Mouloud; Nebab, Mokhtar; Benadouda, Mourad; Ait Atmane, Hassen; Bennai, Riadh
The present research proposes an in-depth analysis of wave propagation in simply supported functional gradient (FG) porous beams subjected to complex thermal environments. The novelty of this study lies in the consideration of a thermal distribution applied unidirectionally (1D), bidirectionally (2D), and tridirectionally (3D) through the thickness, thickness and width, and then the thickness, width and length of the beam, respectively. Thermal loads dependent on and independent of mechanical properties are introduced to simulate realistic service conditions, enabling better anticipation of the dynamic response of FGM structures in thermally unstable environments. The power law function is intended to change the structure’s mechanical and physical characteristics as its thickness, width, and length increases. By applying Hamilton’s principle, the governing equations for elastic wave propagation under thermal loading are rigorously established. The problem is formulated as an eigenvalue system in order to derive the analytical dispersion relation in the unidirectional, bidirectional, and tridirectionally cases. The effects of temperature distribution types, wave propagation numbers, and volume fraction distributions on the wavpropagation dynamic of an imperfect functionally graded beam are subjected to extensive considerations
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.
Investigation of the behavior of an RC beam strengthened by external bonding of a porous P-FGM and E-FGM plate in terms of interface stresses
(Techno Press, 2023) Sadoun, Zahira; Bennai, Riadh; Nebab, Mokhtar; Dahmane, Mouloud; Atmane, Hassen Ait
During the design phase, it is crucial to determine the interface stresses between the reinforcing plate and the concrete base in order to predict plate end separation failures. In this work, a simple theoretical study of interface shear stresses in beams reinforced with P-FGM and E-FGM plates subjected to an arbitrarily positioned point load, or two symmetrical point loads, was presented using the linear elastic theory. The presence of pores in the reinforcing plate distributed in several forms was also taken into account. For this purpose, we analyze the effects of porosity and its distribution shape on the interracial normal and shear stresses of an FGM beam reinforced with an FRP plate under different types of load. Comparisons of the proposed model with existing analytical solutions in the literature confirm the feasibility and accuracy of this new approach. The influence of different parameters on the interfacial behavior of reinforced concrete beams reinforced with functionally graded porous plates is further examined in this parametric study using the proposed model. From the results obtained in this study, we can say that interface stress is significantly affected by several factors, including the pores present in the reinforcing plate and their distribution shape. Additionally, we can conclude from this study that reinforcement systems with composite plates are very effective in improving the flexural response of reinforced RC beams.
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.