Yazar "Fantuzzi N." seçeneğine göre listele

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    Analytical solution of stability and vibration problem of clamped cylindrical shells containing functionally graded layers within shear deformation theory
    (Elsevier, 2022) Sofiyev A.H.; Fantuzzi N.
    The aim of the study is to present a new approach to the analytical solution of the vibration and stability problem of clamped sandwich cylindrical shells (SCSs) covered by functionally graded (FG) coatings under an axial compressive load in the framework of shear deformation theory (ST). After modeling the micro and macro mechanical properties of FG coated SCSs with various configurations, the constitutive relations and basic equations are derived depending on the stress, deflection and two angles of rotation functions using modified Donnell type theory. An attempt is made to analytically solve the fundamental differential equations for SCSs covered by FG coatings using novel approximation functions satisfying the clamped boundary conditions. Three different shear stress functions (SSFs) such as parabolic shear stress function (Par-SSF), cosine-hyperbolic shear stress function (Cos-Hyp-SSF) and uniform shear stress function (USSF) are used in the analysis. After confirming the accuracy of the obtained results, the influences of coating profiles, volume fractions and layer arrangement variations on the critical parameters for three different transverse shear stress functions are investigated in detail.
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    Buckling behavior of multilayer cylindrical shells composed of functionally graded nanocomposite layers under lateral pressure in thermal environments
    (Elsevier, 2023) Avey M; Fantuzzi N.; Sofiyev A.H.; Zamanov A.D.; Hasanov Y.N.; Schnack E.
    In this study, the stability behavior of multilayer cylindrical shells made of functionally graded nanocomposite layers (FG-NCLs) subjected to the lateral pressure in thermal environments is investigated. It is postulated that nanocomposite layers forming layered cylindrical shells are made of single-walled carbon nanotube (SWCNT)- reinforced polymers that have four types of profiles based on the uniform and linear distributions of mechanical properties. The material properties of SWCNTs are assumed to be dependent on location as well as temperature and are obtained from molecular dynamics simulations. The governing equations are derived as partial differ ential equations within shear deformation theory (SDT) and solved in a closed form, using the Galerkin pro cedure, to determine the lateral critical pressure (LCP) in thermal environments. The numerical representations relate to the buckling behavior of multilayer cylindrical shells made of functionally graded nanocomposite layers under the uniform lateral pressure for different CNT patterns and temperatures within SDT and Kirchhoff-Love theory (KLT).
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    Thermoelastic stability of CNT patterned conical shells under thermal loading in the framework of shear deformation theory
    (Taylor and Francis Ltd., 2022) Avey M.; Fantuzzi N.; Sofiyev A.H.
    This study presents the thermoelastic stability of carbon nanotube (CNT) patterned composite conical shells in the framework of shear deformation theory (ST). The study includes two different boundary value problems. As the material properties are independent of temperature, the truncated conical shell is assumed to be under thermal load, and when the material properties are temperature dependent, the conical shell is assumed to be under axial compressive load. The modified Donnell-type shell theory is used to derive the basic equations for CNT patterned truncated conical shells. The Galerkin method is applied to the basic equations to find the critical temperature and critical axial load expressions of CNT patterned composite truncated conical shells in the framework of ST. The effect of changes in CNT patterns, volume fraction, radius-to-thickness and length-to-thickness ratios, as well as the half-peak angle on critical parameters within the ST, are estimated by comparison with classical shell theory (CT).
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    Vibration of laminated functionally graded nanocomposite structures considering the transverse shear stresses and rotary inertia
    (Elsevier Ltd, 2022) Avey M.; Fantuzzi N.; Sofiyev A.H.
    The aim of this study is to determine the fundamental frequencies of laminated double-curved nanocomposite structures considering transverse shear stresses (TSSs) and rotary inertia (RI). The basic equations of laminated double-curved structures composed of CNT patterned layers based on the Donnell type shell theory are derived within TSSs and considering RI. By applying the Galerkin technique, the fundamental equations are transformed into frequency-dependent sixth-order algebraic equations, and this equation is solved numerically to find the fundamental frequency for laminated double curved structures consisting of CNT patterned layers considering TSSs and RI. In addition, when the rotary inertia is neglected, analytical expressions for frequencies are obtained in the framework of shear deformation theory (ST) and classical theory (CT). Finally, the influences of the volume fraction, CNT patterns, array of nanocomposite layers, TSSs and RI on the fundamental frequency are examined.