Yazar "Ozbey, Mehmet Bugra" seçeneğine göre listele

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    Damped forced vibration of functionally graded porous sandwich plate
    (Taylor & Francis Inc, 2025) Ozbey, Mehmet Bugra; Calim, Faruk Firat
    This study investigates the dynamic response of functionally graded (FG) porous viscoelastic sandwich plates with various porosity distributions under dynamic loading, an area that remains underexplored in existing literature. The plate considered in the analysis consists of a homogeneous ceramic core layer and upper and lower layers made of functionally graded porous material. The plate's displacements are described utilizing higher order shear deformation theory (HSDT). The motion's equations are derived utilizing Hamilton's principle and analytically solved through Navier approach. To streamline the solution process, displacements obtained in Laplace domain are converted back to the time domain utilizing Durbin's approach. A key novelty of this study lies in the incorporation of viscoelastic material properties, which are represented utilizing linear standard viscoelastic model. A computational code is developed in Mathematica to carry out the analyses. The developed code is verified by conducting FG porous sandwich plates' free vibration analysis and validating the results through comparison with studies in literature. Following this, a detailed parametric investigation is carried out by applying dynamic distributed loads to FG porous viscoelastic sandwich plate with various porosity distributions. Damped forced vibration analyses are carried out, examining the influences of viscoelastic damping ratios, porosity and porosity distributions, layer characteristics, and FG material gradations on the plate's displacement-time response and maximum displacements.
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    Damped response of porous functionally graded viscoelastic cylindrical shells
    (Taylor & Francis Inc, 2024) Calim, Faruk Firat; Ozbey, Mehmet Bugra
    In this article, the behavior of viscoelastic porous functionally graded (FG) shells regarding the free and damped forced vibration analysis is investigated. The differential equations are derived by using higher order shear deformation theory. Using Hamilton's principle and the energy method, the equations of motion are obtained and solved using Navier's method. The damping effect is implemented into the analysis by means of Kelvin and linear standard viscoelastic models. With the correspondence principle, the transition from elastic material properties to viscoelastic material properties is achieved. First, a free vibration analysis is performed to verify the accuracy of the developed algorithm and obtained results are compared with the existing studies in the literature. Afterwards, a parametric study considering two different viscoelasticity models is performed. In the first parametric example, damped forced vibration analysis is performed for simply supported FG cylindrical shell using linear standard viscoelastic model as the viscoelastic model. Then, damped forced analysis is performed using Kelvin viscoelastic model for simply supported FG cylindrical shell. Analyses are performed in Laplace domain. The obtained results are transferred to time domain using Durbin's inverse Laplace transform method. The displacement graphs are given for the damped forced vibration examples. In the performed parametric studies, the effects of various porosity coefficients, ratios of instantaneous value, retardation times of the relaxation function and damping ratios on the analysis are investigated.
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    Dynamic Analysis of Functionally Graded Carbon Nanotube-Reinforced Composite Viscoelastic Shells
    (Springer Heidelberg, 2025) Calim, Faruk Firat; Ozbey, Mehmet Bugra
    PurposeIn this study, functionally graded carbon nanotube reinforced composite viscoelastic shells' dynamic behaviour is investigated. The use of carbon nanotubes enhances material properties such as strength, stiffness, and thermal resistance, enabling tailored performance. By leveraging metals' high strength and ceramics' thermal and corrosion resistance, functionally graded materials eliminate interface issues through continuous property variation. Traditional forced vibration analysis often neglects internal damping impacts, leadings to inaccuracies in mechanical response prediction. To overcome this limitation, Kelvin viscoelastic model is employed.MethodsThe strain and stress distribution shape function is employed to determine the displacement field, while a higher-order shear deformation theory is employed for these shape functions. The motion 's equations are obtained via Hamilton's principle in Laplace domain. Furthermore, viscoelasticity of the material is taken into account by employing Kelvin's viscoelastic model for the solid bodies. The displacements calculated in Laplace domain are converted to time domain by using Durbin's modified inverse Laplace transform technique.ResultsThe developed method's validity is verified through free vibration analysis. Additionally, a comprehensive parametric study is carried out, encompassing both free and forced vibration analyses. The study investigates the impacts of various geometric properties, carbon nanotube distributions, material gradation, and viscoelastic material characteristics on fundamental frequencies and displacements.ConclusionThis study provides insights into the dynamic behaviour of functionally graded carbon nanotube reinforced composite viscoelastic shells.
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    Dynamic analysis of viscoelastic FGM shells with porosities on elastic foundation
    (Techno-Press, 2024) Calim, Mehmet Halil; Capar, Omer Faruk; Ozbey, Mehmet Bugra; Cuma, Yavuz Cetin
    This study investigates free and damped vibration behaviours of porous functionally graded shells supported by Winkler-Pasternak foundation, considering different geometries. Utilizing a higher-order shear deformation theory, the displacement field is determined. The equations of motion are formulated using Hamilton's principle, and the solutions are obtained Navier's method employing double Fourier series. Parametric studies regarding the effects of porosity, material distribution, elastic foundation, shell geometry and damping are carried out. Results are given in tabular and graphical form for the free and forced vibration analyses, respectively.
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    Dynamic analysis of viscoelastic functionally graded nanoplate
    (Taylor & Francis Inc, 2025) Ozbey, Mehmet Bugra; Calim, Faruk Firat
    In this article, the dynamic behavior of nanoplates under time-dependent load is investigated, focusing on functionally graded viscoelastic materials and nanoscale effects. Eringen's nonlocal elasticity theory is utilized to examine mechanical response of the nanoplate. Hamilton's principle is utilized to derive the equations of motion, taking into account both kinetic and potential energy aspects. The obtained complex partial differential equations are then solved employing Navier method and provides an efficient way to obtain analytical solutions. The study initially performed a free vibration analysis for functionally graded nanoplate, comparing the obtained results with those available in the literature to validate the developed method. Following this validation, a parametric analysis was conducted to examine the influence of both nonlocal parameter, which accounts for nanoscale effects, and power law exponent governing material gradation on free vibration behavior of functionally graded nanoplate. Finally, as the original contribution of this study, a damped forced vibration analysis was carried out within the scope of the parametric study, investigating the effects of power law exponents, viscoelastic parameters, nonlocal parameters, and various geometric properties on functionally graded viscoelastic nanoplates' the displacement-time relationship and maximum displacements.
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    Dynamic analysis of viscoelastic porous functionally graded plates resting on elastic foundation
    (Techno-Press, 2024) Capar, oemer Faruk; Calim, Mehmet Halil; Ozbey, Mehmet Bugra; Cuma, Yavuz Cetin
    In this study, free and forced vibration behaviour of viscoelastic porous functionally graded (VPFG) plates resting on elastic foundations are investigated. Differential equations are obtained via higher order shear deformation theory. Equations of motion are obtained through energy formulations and Hamilton's principle. Navier's method based on double Fourier series is employed for the solution. Damping effect is implemented into the analysis by means of Kelvin and linear standard viscoelastic models. Viscoelastic material properties are used instead of elastic properties by means of the correspondence principle. Displacements of the plates are determined in Laplace domain and transformed into time domain by using Durbin's Modified Inverse Laplace transform method. The proposed algorithm's accuracy is validated through free and damped vibration analyses on VPFG plate, with results compared to existing studies in the literature. The study examines the influence of viscoelastic damping parameters, porosity volume fraction indexes, foundation characteristics, porosity distribution patterns and material property variations on the damped forced vibration response.
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    Free and forced vibration analysis of FG-CNTRC viscoelastic plate using high shear deformation theory
    (Techno-Press, 2024) Ozbey, Mehmet Bugra; Cuma, Yavuz Cetin; Deneme, Ibrahim Ozgur; Calim, Faruk Firat
    This paper investigates the dynamic behavior of a simply supported viscoelastic plate made of functionally graded carbon nanotube reinforced composite under dynamic loading. Carbon nanotubes are distributed in 5 different shapes: U, V, A, O and X, depending on the shape they form through the thickness of the plate. The displacement fields are derived in the Laplace domain using a higher -order shear deformation theory. Equations of motion are obtained through the application of the energy method and Hamilton's principle. The resulting equations of motion are solved using Navier's method. Transforming the Laplace domain displacements into the time domain involves Durbin's modified inverse Laplace transform. To validate the accuracy of the developed algorithm, a free vibration analysis is conducted for simply supported plate made of functionally graded carbon nanotube reinforced composite and compared against existing literature. Subsequently, a parametric forced vibration analysis considers the influence of various parameters: volume fractions of carbon nanotubes, their distributions, and ratios of instantaneous value to retardation time in the relaxation function, using a linear standard viscoelastic model. In the forced vibration analysis, the dynamic distributed load applied to functionally graded carbon nanotube reinforced composite viscoelastic plate is obtained in terms of double trigonometric series. The study culminates in an examination of maximum displacement, exploring the effects of different carbon nanotube distributions, volume fractions, and ratios of instantaneous value to retardation times in the relaxation function on the amplitudes of maximum displacements.
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    Thermal vibration analysis of viscoelastic functionally graded porous plate
    (Taylor & Francis Inc, 2025) Ozbey, Mehmet Bugra; Calim, Faruk Firat
    This study examines the dynamic response of functionally graded (FG) porous viscoelastic plate under thermal conditions. The material characteristics vary depending on thickness, porosity, power law index, and temperature. Motion's equations are derived utilizing Hamilton principle and solved analytically through Navier method. The damping effect is incorporated through Kelvin viscoelastic model, offering a realistic representation of time-dependent material behavior. The developed method's validity is confirmed by comparing free vibration analysis under thermal effects with established results in the literature. As part of parametric study, free vibration analysis under thermal loading is performed, examining the variation of dimensionless fundamental frequencies with thermal loads, temperature rise types, porosity coefficients, and power law index. Also, under dynamic loads, displacement-time response and maximum displacement of the plate are evaluated for different porosity properties, material gradation transitions, thermal effects, and viscoelastic material properties. The novelty of this study primarily stems from investigating damped forced vibration behavior of FG porous plates under thermal loading by incorporating viscoelastic material model. In addition, the use of a higher-order shear deformation theory (HSDT) and the concurrent investigation of the effects of porosity, material gradation, thermal loading, and damping make the study stand out among related works.
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    Vibration analysis of viscoelastic functionally graded porous nanoshell
    (Techno-Press, 2025) Ozbey, Mehmet Bugra; Calim, Faruk Firat
    This paper presents dynamic analyses for nanoscale shells with various geometries, utilizing linear standard viscoelastic material properties and functionally graded porous materials. The displacements in Cartesian coordinates for FG porous nanoshell are formulated utilizing a stress and strain shape function based on higher order shear deformation theory, which has been previously employed in the literature. The motion's equations are derived through Hamilton principle, incorporating energy expressions of the system. The forces and moments in motion's equations are expressed with nonlocal terms based on Eringen's nonlocal elasticity theory. Navier method, which allows analytical solutions for simply supported conditions, is employed in the analysis. For the dynamic analysis, dynamic distributed load applied to nanoshell is represented as a trigonometric series. To facilitate the solution, displacements are obtained in Laplace domain and subsequently transformed back into time domain. Material properties in the analysis are represented employing linear standard viscoelastic model. In this context, a computational method is developed utilizing Mathematica, and its accuracy is validated by performing a free vibration analysis. The obtained natural frequencies are compared with values from previous studies in the literature to demonstrate the model's reliability. Subsequently, a series of forced vibration analyses are conducted under dynamic distributed loading as part of parametric study on functionally graded porous viscoelastic nanoshell. The influences of different geometries, geometric properties, nanoscale characteristics, material variations, linear standard viscoelastic coefficients, porosity distributions, and porosity on displacements are investigated.
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    Vibration and damping analysis of functionally graded shells
    (Springer, 2024) Cuma, Yavuz Cetin; Ozbey, Mehmet Bugra; Calim, Faruk Firat
    In this study, dynamic behaviour of viscoelastic functionally graded shells under time-varying load is investigated. Displacement field is obtained by using higher order shear deformation theory. Equations of motion are obtained in Laplace domain by using the energy method. The equations of motion are solved by the Navier's method. Results are transferred to time domain by implementing Durbin's inverse Laplace algorithm. A parametric study of the damped forced vibration of functionally graded shells considering the effects of shell geometry, rate of material variation, the principal radii of curvature, viscoelastic parameters is carried out. Damping behaviour is investigated via linear standard viscoelastic model. Accuracy of the results are verified by comparison with the literature results.