Yazar "Ozbey, Mehmet Bugra" seçeneğine göre listele

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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 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 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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    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.