Yazar "Fantuzzi, Nicholas" seçeneğine göre listele

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    Influences of elastic foundations on the nonlinear free vibration of composite shells containing carbon nanotubes within shear deformation theory
    (ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND, 2022) Avey, Mahmure; Fantuzzi, Nicholas; Sofiyev, Abdullah H.; Kuruoğlu, Nuri
    In this work, the solution of nonlinear free vibration problem of composite shells structures containing carbon nanotubes (CNTs) resting on elastic soils within shear deformation theory (ST) is presented. After modeling the mechanical properties of nanocomposite shell structures containing CNTs and elastic soils, the basic relations, and governing equations of double curved shell structures within the ST are established considering the geometric nonlinearity. The frequencies of nonlinear and linear free vibrations and their ratios for inhomogeneous nanocomposite structures on the soils within the ST are obtained using perturbation method for the first time. After checking the methodology of the research, the effects of soils, nonlinearity, shear strains and patterns of CNT on the frequency-amplitude dependence of nanocomposite shell structures for various geometric parameters are carried out.
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    Modeling and Solution of Large Amplitude Vibration Problem of Construction Elements Made of Nanocomposites Using Shear Deformation Theory
    (MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND, 2021) Deniz, Ali; Fantuzzi, Nicholas; Sofiyev, Abdullah H.; Kuruoğlu, Nuri
    The main purpose of the study is to investigate the vibration behaviors of carbon nanotube (CNT) patterned double-curved construction elements using the shear deformation theory (SDT). After the visual and mathematical models of CNT patterned double-curved construction elements are created, the large amplitude stress–strain relationships and basic dynamic equations are derived using the first order shear deformation theory (FSDT). Then, using the Galerkin method, the problem is reduced to the nonlinear vibration of nanocomposite continuous systems with quadratic and cubic nonlinearities. Applying the Grigolyuk method to the obtained nonlinear differential equation, largeamplitude frequency-amplitude dependence is obtained. The expressions for nonlinear frequencies of homogenous and inhomogeneous nanocomposite construction members such as plates, panels, spherical and hyperbolic-paraboloid (hypar) shells in the framework of FSDT are found in special cases. The accuracy of the results of the current study has been confirmed by comparing them with the reliable results reported in the literature. Original analyses are carried out to examine the effects of nonlinearity, CNT patterns and volume fraction changes on frequencies in the framework of shear deformation and classical shell theories.
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    Nonlinear vibration of multilayer shell-type structural elements with double curvature consisting of CNT patterned layers within different theories
    (ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND, 2021) Avey, Mahmure; Fantuzzi, Nicholas; Sofiyev, Abdullah H.; Kuruoğlu, Nuri
    In this article, the nonlinear vibration of moderately thick multilayer shell?type structural elements with double curvature consisting of carbon nanotube (CNT) patterned layers is investigated within different shell theories. The first order shear deformation theory has been generalized on the motion for moderately thick multilayer shell?type structural elements with double curvature consisting of CNT patterned layers for the first time. Then, by applying Galerkin and semi?inverse perturbation methods to motion equations, and the frequency? amplitude relationship is obtained. From these formulas, the expressions for nonlinear frequencies of multilayer spherical and hyperbolic?paraboloid shells, rectangular plate and cylindrical panels patterned by CNTs within shear deformation and classical shell theories are obtained in special cases. The reliability of obtained results is verified by comparison with other results reported in the literature. The effects of transverse shear strains, volume fraction, sequence and number of nanocomposite layers on nonlinear frequency are discussed in detail.
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    Primary resonance of double-curved nanocomposite shells using nonlinear theory and multi-scales method: Modeling and analytical solution
    (PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND, 2021) Avey, Mahmure; Sofiyev, Abdullah H.; Fantuzzi, Nicholas; Kuruoğlu, Nuri
    In this article, the forced vibration of double-curved nanocomposite shells under a time dependent excitation is studied using nonlinear shell theory and multi-scales method in primary resonance. The nanocomposite representative volume element consists of two phases, including carbon nanotube (CNT) and matrix. By generalizing the Ambartsumyan’s first order shear deformation shell theory (FSDT) to the heterogeneous nanocomposite shells, the nonlinear partial differential equations are derived. Then, the problem is reduced to the nonlinear forced vibration of damped nanocomposite shells with quadratic and cubic nonlinearities. For the occurrence of the primary resonance, the damping, nonlinearity, and excitation terms in the disturbance circuit are reduced to the same order. Applying the multi-scales method to nonlinear ordinary differential equation, nonlinear frequency–amplitude dependence in primary resonance is obtained.