Person: YAYLI, MUSTAFA ÖZGÜR
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YAYLI
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MUSTAFA ÖZGÜR
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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; Bursa Uludağ Üniversitesi/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; Bursa Uludağ Üniversitesi/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 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; Bursa Uludağ Üniversitesi/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 Nonlocal strain gradient approach for axial vibration analysis of arbitrary restrained nanorod(Springer, 2022-11-01) Uzun, Büşra; Civalek, Ömer; Yaylı, Mustafa Özgür; UZUN, BÜŞRA; YAYLI, MUSTAFA ÖZGÜR; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0002-7636-7170; AAJ-6390-2021; ABE-6914-2020Axial free vibration analysis of small size-dependent nanorod subjected to deformable restrained boundary conditions is carried out in the present work. Unlike previous works, the formulation is rewritten without resorting to any un-deformable boundary conditions neither clamped ends with Navier approximation nor considering nanorod as a compact form without any discontinuities, and the boundary conditions are assumed to be gradually deformable in the axial direction. Within the framework of Fourier sine series and Stokes' transformation, an eigenvalue problem is constructed to obtain the axial vibration frequencies. In addition, the higher-order elasticity model contains a material scale parameter considering the prominence of strain gradient stress field and a nonlocal coefficient considering the prominence of nonlocal elastic stress field. The validity of the presented procedure is checked by comparing the obtained results by giving proper values to elastic spring parameters, and good agreement is achieved. Numerical results and graphical representation are presented to demonstrate the applicability of the presented eigenvalue solution to examine the free axial response of nanorods with arbitrary boundary conditions. Effects of small-scale parameters on the dynamic response of nanorods are discussed in detail.Publication Buckling analysis of nanobeams with deformable boundaries via doublet mechanics(Springer, 2021-09-07) Civalek, Ömer; Uzun, Büşra; Yaylı, Mustafa Özgür; UZUN, BÜŞRA; YAYLI, MUSTAFA ÖZGÜR; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0002-7636-7170; 0000-0003-2231-170X; AAJ-6390-2021; ABE-6914-2020Buckling analysis of nanobeams with deformable boundary conditions is researched within the framework of doublet mechanics. This theory is an alternative nanomechanics theory for continuum modeling of the granular micromaterials. Doublet mechanics theory takes into consideration the small size parameter due to dealing with also granular nanosized structures. In many studies, rigid supporting conditions are explored in the nanomechanical analysis of beams. Even though the supporting conditions are accepted as undeformable, it is not possible to provide the desired rigidity in practice. A few studies have been conducted to explore the effects of deformable boundaries. In the present work, Fourier sine series as well as Stokes' transformation are utilized to attain the eigenvalue formulation and eigenvector characteristics of the problem. The combination of these two methods is a new approach in applied mechanics; at the same time, it is planned to create a bridge between rigid and deformable boundary conditions. By solving various examples, the accuracy of the proposed method has been tested and an excellent agreement has been achieved with the literature. In addition, the effect of the springs in the boundaries on the critical buckling load has been examined and given in a series of graphs.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; Bursa Uludağ Üniversitesi/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 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; Bursa Uludağ Üniversitesi/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 Finite element formulation for nano-scaled beam elements(Wiley, 2021-12-02) Civalek, Ömer; Uzun, Buşra; Yaylı, Mustafa Özgür; YAYLI, MUSTAFA ÖZGÜR; UZUN, BÜŞRA; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0003-1907-9479; 0000-0003-2231-170X; ABE-6914-2020; AAJ-6390-2021In the present study, size-dependent buckling and free vibration behaviors of single-walled boron nitride nanotube (SWBNNT) are performed in conjunction with various size-dependent elasticity theories. Modified couple stress theory (MCST) and Eringen's nonlocal elasticity theory are used for size-dependent models of SWBNNT. Also, the buckling loads and frequencies are obtained by using local theory to emphasize the effects and differences of these size-dependent theories. Consequently, three different elasticity theories (two non-classical and one classical) are utilized to achieve the detailed buckling and vibration analyses of SWBNNT. In this study, the buckling loads and frequencies of SWBNNTs are obtained via presented finite element formulation. In the finite element procedures based on two different size-dependent elasticity theories, matrices containing the small size parameter are derived. With these matrices containing the small size parameters, eigenvalue problems for buckling and free vibration analyses are formed. The buckling loads and frequency values of the SWBNNTs under the size effect are obtained. The influences of the dimensionless nonlocal parameter, dimensionless material length scale parameter, length-to-diameter ratio and boundary conditions on nanotube's buckling and vibration characteristics are investigated. In addition to these influences, the rotary inertia effect neglected in many other studies is also examined.Publication Comparison of blunt and sharp needles for transforaminal epidural steroid injections(Kare Publ, 2012-04-01) Özcan, Ulaş; Şahin, Şükran; Gurbet, Alp; GURBET, ALP; Çelebi, Sureyya; Türker, Gürkan; TÜRKER, YUNUS GÜRKAN; Özgür, Mustafa; YAYLI, MUSTAFA ÖZGÜR; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Anestezi ve Reanimasyon Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Algoloji Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Anestezi ve Reanimasyon Anabilim Dalı.; 0000-0002-6503-8232; 0000-0002-3019-581X; AAI-6642-2021; A-7994-2018Objectives: The aim of this study was to compare the sharp and blunt needles in order to determine the incidence of complications during transforaminal anterior epidural steroid injections.Methods: In this retrospective study, 185 cases that undergo transforaminal epidural steroid injection with sharp or blunt needles were evaluated between June 2004 and December 2008. Patients age, sex, diagnosis, needle type (sharp or blunt), volume of local anesthetic and steroid injected, complications (paresthesia, dural puncture, bleeding, paralysis, intravascular penetration, headache, local back pain, temporary motor loss in lower extremities) was recorded.Results: 3 cases in blunt needle group and 8 cases in sharp needle group showed paresthesia during the procedure. The difference was not found to be significant among the groups. Vascular penetration was observed in 2 cases in blunt and 13 cases in sharp needle group and the difference between groups was statistically significant (p<0.001). Dural puncture and headache incidence were not significant when the two groups are compared. The local back pain at the injection site had a higher incidence in the blunt needle group.Conclusion: When using the blunt needles, vascular penetration and paresthesia were less during transforaminal epidural steroid injections. Therefore blunt needles seem to be more advantageous.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; Bursa Uludağ Üniversitesi/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.