Yazar "Avey, Mahmure" seçeneğine göre listele

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    Analytical Solution of Stability Problem of Nanocomposite Cylindrical Shells under Combined Loadings in Thermal Environments
    (MDPI, 2023) Avey, Mahmure; Fantuzzi, Nicholas; Sofiyev, Abdullah H.
    The mathematical modeling of the stability problem of nanocomposite cylindrical shells is one of the applications of partial differential equations (PDEs). In this study, the stability behavior of inhomogeneous nanocomposite cylindrical shells (INH-NCCSs), under combined axial compression and hydrostatic pressure in the thermal environment, is investigated by means of the first-order shear deformation theory (FSDT). The nanocomposite material is modeled as homogeneous and heterogeneous and is based on a carbon nanotube (CNT)-reinforced polymer with the linear variation of the mechanical properties throughout the thickness. In the heterogeneous case, the mechanical properties are modeled as the linear function of the thickness coordinate. The basic equations are derived as partial differential equations and solved in a closed form, using the Galerkin procedure, to determine the critical combined loads for the selected structure in thermal environments. To test the reliability of the proposed formulation, comparisons with the results obtained by finite element and numerical methods in the literature are accompanied by a systematic study aimed at testing the sensitivity of the design response to the loading parameters, CNT models, and thermal environment.
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    The Application of the Modified Lindstedt-Poincaré Method to Solve the Nonlinear Vibration Problem of Exponentially Graded Laminated Plates on Elastic Foundations
    (MDPI, 2024) Avey, Mahmure; Tornabene, Francesco; Aslanova, Nigar Mahar; Sofiyev, Abdullah H.
    The solution of the nonlinear (NL) vibration problem of the interaction of laminated plates made of exponentially graded orthotropic layers (EGOLs) with elastic foundations within the Kirchhoff–Love theory (KLT) is developed using the modified Lindstedt–Poincaré method for the first time. Young’s modulus and the material density of the orthotropic layers of laminated plates are assumed to vary exponentially in the direction of thickness, and Poisson’s ratio is assumed to be constant. The governing equations are derived as equations of motion and compatibility using the stress–strain relationship within the framework of KLT and von Karman-type nonlinear theory. NL partial differential equations are reduced to NL ordinary differential equations by the Galerkin method and solved by using the modified Lindstedt–Poincaré method to obtain unique amplitude-dependent expressions for the NL frequency. The proposed solution is validated by comparing the results for laminated plates consisting of exponentially graded orthotropic layers with the results for laminated homogeneous orthotropic plates. Finally, a series of examples are presented to illustrate numerical results on the nonlinear frequency of rectangular plates composed of homogeneous and exponentially graded layers. The effects of the exponential change in the material gradient in the layers, the arrangement and number of the layers, the elastic foundations, the plate aspect ratio and the nonlinearity of the frequency are investigated.
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    Influences of elastic foundations and thermal environments on the thermoelastic buckling of nanocomposite truncated conical shells
    (Springer, 2022) Avey, Mahmure; Sofiyev A.H.; Kuruoglu N.
    In this study, the combined effects of two-parameter elastic foundation and thermal environment on the buckling behaviors of carbon nanotube (CNT) patterned composite conical shells in the framework of the shear deformation theory (SDT) are investigated. It is assumed that the nanocomposite conical shell is freely supported at its ends and that the material properties are temperature dependent. The derivation of fundamental equations of CNT-patterned truncated conical shells on elastic foundations is based on the Donnell shell theory. The Galerkin method is applied to the basic equations to find the expressions for the critical temperature (CT) and axial buckling loads of CNT-patterned truncated conical shells on elastic foundations and in thermal environments. In the presence of elastic foundations and thermal environments, it is estimated how the effects of CNT patterns, the volume fractions, and the characteristics of conical shells on the buckling load within SDT change by comparing them with the classical shell theory (CST).
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    On the solution of thermal buckling problem of moderately thick laminated conical shells containing carbon nanotube originating layers
    (MDPI, 2022) Avey, Mahmure; Fantuzzi, Nicholas; Sofiyev, Abdullah
    This study presents the solution for the thermal buckling problem of moderately thick laminated conical shells consisting of carbon nanotube (CNT) originating layers. It is assumed that the laminated truncated-conical shell is subjected to uniform temperature rise. The Donnell-type shell theory is used to derive the governing equations, and the Galerkin method is used to find the expression for the buckling temperature in the framework of shear deformation theories (STs). Different transverse shear stress functions, such as the parabolic transverse shear stress (Par-TSS), cosine-hyperbolic shear stress (Cos-Hyp-TSS), and uniform shear stress (U-TSS) functions are used in the analysis part. After validation of the formulation with respect to the existing literature, several parametric studies are carried out to investigate the influences of CNT patterns, number and arrangement of the layers on the uniform buckling temperature (UBT) using various transverse shear stress functions, and classical shell theory (CT).