Person: UZUN, BÜŞRA
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UZUN
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BÜŞRA
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Publication Longitudinal vibration analysis of FG nanorod restrained with axial springs using doublet mechanics(Taylor & Francis, 2021-10-26) Civalek, Ömer; Uzun, Büsra; Yaylı, Mustafa Özgür; UZUN, BÜŞRA; YAYLI, MUSTAFA ÖZGÜR; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0002-7636-7170; 0000-0003-2231-170X; AAJ-6390-2021; ABE-6914-2020In the current paper, the free longitudinal vibration response of axially restrained functionally graded nanorods is presented for the first time based on the doublet mechanics theory. Size dependent nanorod is considered to be made of functionally graded material consist of ceramic and metal constituents. It is assumed that the material properties of the functionally graded nanorod are assumed to vary in the radial direction. The aim of this study is that to investigate the influences of various parameters such as functionally graded index, small size parameter, length of the nanorod, mode number and spring stiffness on vibration behaviors of functionally graded nanorod restrained with axial springs at both ends. For this purpose, Fourier sine series are used to define the axial deflection of the functionally graded nanorod. Then, an eigenvalue approach is established for longitudinal vibrational frequencies thanks to Stokes' transformation to deformable axial springs. Thus, the presented eigenvalue solution method is attributed to both rigid and deformable boundary conditions for the axial vibration of the functionally graded nanorod. With the help of the results obtained with the presented eigenvalue problem, it is observed that the parameters examined cause significant changes in the frequencies of the functionally graded nanorod.Publication Torsional static and free vibration analysis of noncircular short-fiber-reinforced microwires with arbitrary boundary conditions(Wiley, 2023-03-29) Civalek, Ömer; Uzun, Büşra; UZUN, BÜŞRA; Yaylı, Mustafa Özgür; YAYLI, MUSTAFA ÖZGÜR; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0003-1907-9479; 0000-0002-7636-7170; 0000-0003-2231-170X; AAJ-6390-2021; ABE-6914-2020This study investigates the free torsional vibration response of short fiber-reinforced noncircular microwires by considering the size effect. Moreover, the formulation of Eigen value problem based on forced boundary conditions that consider warping function and small-scale parameter. The composite microwire has been considered to be composed of fiber reinforced by short particle distributed along the thickness direction based on different symmetric patterns. The partial differential equation with force boundary conditions of a microwire under the general boundary conditions are presented in a matrix form and are solved analytically via the modified couple stress theory. An analytical solution is obtained for a microwire with arbitrary boundary conditions using the Fourier sine series with Stokes' transformation and effect of different parameters including warping function and elastic springs at the ends, material length scale parameter, distribution of short fibers on the free torsional frequencies are investigated.Publication Torsional and axial vibration of restrained saturated nanorods via strain gradient elasticity(Springer, 2022-12-31) Civalek, Ömer; Uzun, Büşra; UZUN, BÜŞRA; Yaylı, Mustafa Özgür; YAYLI, MUSTAFA ÖZGÜR; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0002-7636-7170; 0000-0003-1907-9479; ABE-6914-2020; HKT-5010-2023Size-dependent torsional and longitudinal free vibrations of restrained saturated porous nanorods are studied by a higher-order elasticity theory. The strain gradient elasticity model is used in this study able to overcome inconsistencies of classical elasticity model. The presented higher-order model leads to well-posed boundary value problem for arbitrary value of the small size parameter. Two elastic springs in torsional and axial directions are attached to saturated porous nanorods at two boundary points. Angular rotation and axial deflection functions based on the strain gradient elasticity model are represented by two Fourier sine series. The difference of this proposed solution is that it does not impose a limitation on the support conditions and allows the frequencies to be obtained with a single solution. Two coefficient matrices including torsional or axial effects are obtained by using Stokes' transformation and non-classical boundary conditions. Free vibration frequencies of saturated nanorods are calculated by an effective eigen-value solution strategy. It is shown clearly that elastic spring coefficients, small-scale parameter and saturation a notable impact on the dynamic response of nanorods.Publication Size-dependent nonlinear stability response of perforated nano/microbeams via fourier series(Springer, 2023-10-20) Civalek, Ömer; YAYLI, MUSTAFA ÖZGÜR; UZUN, BÜŞRA; Uzun, Büşra; UZUN, BÜŞRA; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0003-1907-9479; 0000-0002-7636-7170; 0000-0003-2231-170X; ABE-6914-2020; AAJ-6390-2021In this work, perforated and restrained nanobeams with deformable boundary conditions are modeled based on the non-local strain gradient elasticity theory with the elastic medium effect. In this approach in which the Fourier infinite series and Stokes' transformation are used together, the nanobeam is detached into parts from the two boundary points with the main part. Then using elastic force boundary conditions, a system of linear equations in terms of nonlinearity, elastic medium parameter, spring coefficients and small size effects are derived and the eigenvalue solution of these equations is also presented. The nonlinear stability of restrained nanobeam is examined and the effects of size parameters, perforation and elastic spring coefficients are studied. To reveal the accuracy and effectiveness of the offered model, several numerical applications are solved for the nonlinear stability response of restrained nanobeams with elastic medium effects. The outcomes of this method validated that the presented approach is appropriate for the stability behavior of rigid and restrained nanobeams with perforated cross section.Publication Stability analysis of arbitrary restrained nanobeam embedded in an elastic medium via nonlocal strain gradient theory(Sage Publications Ltd, 2023-04-19) Uzun, Büşra; Yaylı, Mustafa Özgür; UZUN, BÜŞRA; YAYLI, MUSTAFA ÖZGÜR; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0002-7636-7170; 0000-0003-2231-170X; AAJ-6390-2021; ABE-6914-2020A novel stability model is analytically reformulated for the nano-sized beam resting on a one-parameter elastic foundation. The stability solution is based on the nonlocal strain gradient elasticity theory. To corporate the small size effects, two small scale parameters are introduced. The six-order ordinary differential form of the buckling equation, together with two force boundary conditions, are utilized to examine the stability equation in terms of lateral deflection. The infinite terms of linear equations are discretized with the help of the Stokes' transformation and Fourier sine series. The present work can investigate the effects of elastic spring parameters at the ends, nonlocal properties, elastic medium properties, strain gradient parameter, and buckling behavior of the nanobeam. The predictions of the proposed analytical model with deformable boundary conditions are in agreement with those available in the scientific literature for the nanobeam on elastic foundation based on a closed form of solution. The presence of the deformable conditions, elastic foundation, nonlocal, and strain gradient properties change the buckling loads and buckling mode shapes.Publication An effective analytical method for buckling solutions of a restrained fgm nonlocal beam(Springer Heidelberg, 2022-03-01) Civalek, Ömer; UZUN, BÜŞRA; Uzun, Büşra; Yaylı, Mustafa Özgür; YAYLI, MUSTAFA ÖZGÜR; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0002-7636-7170; 0000-0003-2231-170X; AAJ-6390-2021; ABE-6914-2020This work studies the size-dependent stability analysis of restrained nanobeam with functionally graded material via nonlocal Euler-Bernoulli beam theory using the Fourier series. The nonlocal elasticity theory introduced by Eringen is utilized to show the size effect on the buckling response of restrained functionally graded nanobeam. In addition, buckling loads of functionally graded nanobeam are obtained by classical elasticity theory as well to highlight the size effects. The influences of various parameters such as the nonlocal parameter, rotational restraints and power-law index on the critical buckling load of the functionally graded nonlocal beam are investigated. The contribution of this paper is that it presents an efficient analytical solution for the buckling response of functionally graded nanobeam with non-rigid boundary conditions.Publication A fourier sine series solution of static and dynamic response of nano/micro-scaled fg rod under torsional effect(Techno-press, 2022-05-01) Civalek, Ömer; Yaylı, M. Özgür; YAYLI, MUSTAFA ÖZGÜR; Uzun, Büşra; UZUN, BÜŞRA; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0003-1907-9479; 0000-0002-7636-7170; 0000-0003-2231-170X; ABE-6914-2020; AAJ-6390-2021In the current work, static and free torsional vibration of functionally graded (FG) nanorods are investigated using Fourier sine series. The boundary conditions are described by the two elastic torsional springs at the ends. The distribution of functionally graded material is considered using a power-law rule. The systems of equations of the mechanical response of nanorods subjected to deformable boundary conditions are achieved by using the modified couple stress theory (MCST) and taking the effects of torsional springs into account. The idea of the study is to construct an eigen value problem involving the torsional spring parameters with small scale parameter and functionally graded index. This article investigates the size dependent free torsional vibration based on the MCST of functionally graded nano/micro rods with deformable boundary conditions using a Fourier sine series solution for the first time. The eigen value problem is constructed using the Stokes' transform to deformable boundary conditions and also the convergence and accuracy of the present methodology are discussed in various numerical examples. The small size coefficient influence on the free torsional vibration characteristics is studied from the point of different parameters for both deformable and rigid boundary conditions. It shows that the torsional vibrational response of functionally graded nanorods are effected by geometry, small size effects, boundary conditions and material composition. Furthermore, for all deformable boundary conditions in the event of nano-sized FG nanorods, the incrementing of the small size parameters leads to increas the torsional frequencies.Publication Buckling analysis of perforated nano/microbeams with deformable boundary conditions via nonlocal strain gradient elasticity(Techno-Press, 2023-10-01) Kafkas, Uğur; Ünal, Yunus; Yayli, M. Özgür; Uzun, Büşra; Ünal, Yunus; YAYLI, MUSTAFA ÖZGÜR; UZUN, BÜŞRA; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0002-7636-7170; ABE-6914-2020; JTF-6675-2023; JTS-2032-2023This work aims to present a solution for the buckling behavior of perforated nano/microbeams with deformable boundary conditions using nonlocal strain gradient theory (NLSGT). For the first time, a solution that can provide buckling loads based on the non-local and strain gradient effects of perforated nanostructures on an elastic foundation, while taking into account both deformable and rigid boundary conditions. Stokes' transformation and Fourier series are used to realize this aim and determine the buckling loads under various boundary conditions. We employ the NLSGT to account for size-dependent effects and utilize the Winkler model to formulate the elastic foundation. The buckling behavior of the perforated nano/microbeams restrained with lateral springs at both ends is studied for various parameters such as the number of holes, the length and filling ratio of the perforated beam, the internal length, the nonlocal parameter and the dimensionless foundation parameter. Our results indicate that the number of holes and filling ratio significantly affect the buckling response of perforated nano/microbeams. Increasing the filling ratio increases buckling loads, while increasing the number of holes decreases buckling loads. The effects of the non-local and internal length parameters on the buckling behavior of the perforated nano/microbeams are also discussed. These material length parameters have opposite effects on the variation of buckling loads. This study presents an effective eigenvalue solution based on Stokes' transformation and Fourier series of the restrained nano/microbeams under the effects of elastic medium, perforation parameters, deformable boundaries and nonlocal strain gradient elasticity for the first time.Publication A hardening nonlocal elasticity approach to axial vibration analysis of an arbitrarily supported fg nanorod(Springer, 2023-06-01) Civelek, Ömer; Uzun, B.; UZUN, BÜŞRA; Yaylı, Mustafa; YAYLI, MUSTAFA ÖZGÜR; Mühendislik Fakültesi; İnşaat Mühendisliği Bölümü; 0000-0002-7636-7170; 0000-0003-1907-9479; 0000-0003-2231-170X; ABE-6914-2020; AAJ-6390-2021The present work is aimed at analyzing free longitudinal vibrations of nanorods composed of a functionally graded (FG) material with deformable boundaries within a hardening nonlocal elasticity approach. For this purpose, a FG nanorod composed of the ceramic and metal constituents is considered to be elastically supported by means of axial springs at both ends. Then the analytical method based on the association of the Fourier sine series and the Stokes transformation is developed to solve the free axial vibration problem of a FG nanorod with both deformable and nondeformable boundaries. Free axial vibration of a restrained FG nanorod is first studied within hardening nonlocal elasticity. To show the validity and profitability of the proposed analytical method, the presented Fourier series method with the Stokes transformation is used for the analysis of axial vibration of a rigidly supported homogeneous nanorod by setting the appropriate spring stiffness values. The main superiority of this new approach is in its power of dealing with numerous boundary conditions to determine longitudinal vibration frequencies of FG nanorods. Using the present solution method, various numerical applications are given for different small-scale parameters, gradient index, and nanorod length.Publication Thermal vibration of perforated nanobeams with deformable boundary conditions via nonlocal strain gradient theory(Walter De Gruyter Gmbh, 2023-06-12) Kafkas, Uğur; Güçlü, Gökhan; Uzun, Büşra; UZUN, BÜŞRA; Yaylı, Mustafa Özgür; YAYLI, MUSTAFA ÖZGÜR; Mühendislik Fakültesi; 0000-0002-7636-7170; 0000-0003-2231-170X; ABE-6914-2020Due to nonlocal and strain gradient effects with rigid and deformable boundary conditions, the thermal vibration behavior of perforated nanobeams resting on a Winkler elastic foundation (WEF) is examined in this paper. The Stokes transformation and Fourier series have been used to achieve this goal and to determine the thermal vibration behavior under various boundary conditions, including deformable and non-deformable ones. The perforated nanobeams' boundary conditions are considered deformable, and the nonlocal strain gradient theory accounts for the size dependency. The problem is modeled as an eigenvalue problem. The effect of parameters such as the number of holes, elastic foundation, nonlocal and strain gradient, deformable boundaries and size on the solution is considered. The effects of various parameters, such as the length of the perforated beam, number of holes, filling ratio, thermal effect parameter, small-scale parameters and foundation parameter, on the thermal vibration behavior of the perforated nanobeam, are then illustrated using a set of numerical examples. As a result of the analysis, it was determined that the vibration frequency of the nanobeam was most affected by the changes in the dimensionless WEF parameter in the first mode and the changes in the internal length parameter when all modes were considered.