Hakan Ersoy | Akdeniz Üniversitesi (original) (raw)

Papers by Hakan Ersoy

Research paper thumbnail of Design sensitivity analyses of structures based on singular value decomposition

Bu çalışmada, lineer cebirin araçlarından olan Tekil Değerlere Ayrıştırma “TD... more Bu çalışmada, lineer cebirin araçlarından olan Tekil Değerlere Ayrıştırma “TDA” (Singular Value Decomposition, SVD) metodu, yapısal sistemlerin tasarım duyarlılığı analizlerine uygulanarak TDA'ya dayalı duyarlılık analizi yöntemi geliştirilmiştir. Bir yapısal sistemin tekil değerlerinin şekillendirilmesi, aynı zamanda sistem cevabının belirlenmesi anlamına gelmektedir. Buradan hareketle, geliştirilen TDA'ya dayalı duyarlılık analizi yöntemi ile mevcut klasik tasarım duyarlılığı metodlarının statik, dinamik analizler, çoklu yükleme hali ve yapısal gürbüzlük gibi alanlarda karşılaştırmaları yapılmış ve yöntemin performansı sayısal örnekler üzerinde denenmiştir. Yöntemin belli alanlarda klasik metodlara göre daha fazla bilgi açığa çıkarmasının yanı sıra, hesaplamalı alanda işlemci süresi ve hafıza kullanımında büyük avantajlara sahip olduğu görülmektedi...

Research paper thumbnail of Strength-Based Design Analysis of a Damaged Engine Mounting Bracket Designed for a Commercial Electric Vehicle

Journal of Failure Analysis and Prevention, 2021

This study describes a strength-based design analysis protocol by means of finite element analysi... more This study describes a strength-based design analysis protocol by means of finite element analysis (FEA) for a damaged engine mounting bracket in a converted electric vehicle. The mounting bracket considered in the study is a product specifically designed and manufactured for a converted electric vehicle and failed during conventional operation of the vehicle. Thus, design improvement/revision (redesign) on the bracket geometry was investigated. In this context, to prevent such undesired failures, strength-based design features such as deformation behaviour and stress distribution under projected loads on the bracket should be properly described; however, an accurate description of these features of the bracket may become a complex experimental problem to be solved by designers. This study described redesign of the strength-based design features of the engine mounting bracket through finite element analysis under torsional loading generated by the electric engine that was determined to be the reason for the failure and thus the motivation to realise a safer design. Visual and numerical results obtained from the simulation revealed a clear understanding of the failure behaviour of the bracket and therefore enabled an informed approach to the redesign stage. The initial FEA of the part design mapped the damage regions on the part geometry and indicated the stress magnitudes that were more than the material's stress limits. The comparison of the failure plots and numerical data obtained from this initial FEA and physically damaged part was consistent. This concluded that the FEA satisfactorily exhibited the deformation behaviour and the main reason for the failure was insufficient geometry thickness and notch effect against predefined loading conditions. Therefore, the main design improvement was realised on these geometric features. Subsequently, the final FEA highlighted that the redesign would enable safe operation. This work contributes to further research into usage of numerical method-based deformation simulation studies for the mounting elements used in customised electric vehicles.

Research paper thumbnail of Free Vibration of Annular Plates by Discrete Singular Convolution and Differential Quadrature Methods

Applied and Computational Mechanics, 2016

Plates and shells are significant structural components in many engineering and industrial applic... more Plates and shells are significant structural components in many engineering and industrial applications. In this study, the free vibration analysis of annular plates is investigated. To this aim, two different numerical methods including the differential quadrature and the discrete singular convolution methods are performedfor numerical simulations. Moreover, the Frequency values are obtained via these two methods and finally, the performance of these methods is investigated.

Research paper thumbnail of Solution of Moore–Gibson–Thompson Equation of an Unbounded Medium with a Cylindrical Hole

Mathematics, 2021

In the current article, in the presence of thermal and diffusion processes, the equations governi... more In the current article, in the presence of thermal and diffusion processes, the equations governing elastic materials through thermodiffusion are obtained. The Moore–Gibson–Thompson (MGT) equation modifies and defines the equations for thermal conduction and mass diffusion that occur in solids. This modification is based on adding heat and diffusion relaxation times in the Green–Naghdi Type III (GN-III) models. In an unbounded medium with a cylindrical hole, the built model has been applied to examine the influence of the coupling between temperature and mass diffusion and responses. At constant concentration as well as intermittent and decaying varying heat, the surrounding cavity surface is traction-free and is filled slowly. Laplace transform and Laplace inversion techniques are applied to obtain the solutions of the studied field variables. In order to explore thermal diffusion analysis and find closed solutions, a suitable numerical approximation technique has been used. Compar...

Research paper thumbnail of Derivation of nonlocal FEM formulation for thermo-elastic Timoshenko beams on elastic matrix

Composite Structures, 2021

Abstract Free thermal vibration analysis of nanobeams surrounded by an elastic matrix is examined... more Abstract Free thermal vibration analysis of nanobeams surrounded by an elastic matrix is examined via nonlocal elasticity and Timoshenko beam theories in this article. Elastic matrix is formulated with a two-parameter elastic foundation modelled by combining Winkler and Pasternak assumptions. The equation of motion for free vibration is reached via Hamilton’s principle and solved by analytical method (separation of variable). However, since the separation of variable cannot be applied for boundary conditions other than simply supported nanobeams, a weighted residue-based finite element formulation is developed. Within the scope of numerical results, firstly, it is understood from the comparisons given for nondimensional frequencies that the nonlocal finite element formulation has a high accuracy and then, using this formulation, nondimensional frequencies of nanobeams with different boundary conditions are computed under different parameters. Additionally, the detailed discussions of the numerical results are presented. Finally, by giving some general results, the effect of size dependency and environmental factors on the dynamic behavior of nanobeams is expressed.

Research paper thumbnail of Free vibration analysis of symmetric laminated composite plates by FSDT and radial basis functions

Computer Methods in Applied Mechanics and Engineering, 2005

In this study, free vibration of laminated skew plates was investigated. Discrete singular convol... more In this study, free vibration of laminated skew plates was investigated. Discrete singular convolution (DSC) method is used for numerical solution of vibration problems. The straight-sided quadrilateral domain is mapped into a square domain in the computational space using a four-node element by using the geometric transformation. Typical results are presented for different geometric parameters and boundary conditions. It is concluded from the results that the skew angle have considerable influence on the variations of the frequencies with fibre orientation angle and number of layers in the laminate. The results obtained by DSC method are compared with those obtained by analytical and numerical approaches. It is shown that reasonable accurate results are obtained. Present work also indicates that the method of DSC is a promising and potential approach for computational mechanics.

Research paper thumbnail of Free vibration analysis of rectangular membranes with variable density using the discrete singular convolution approach

Membranes are widely used in various engineering applications such as the design stage of microph... more Membranes are widely used in various engineering applications such as the design stage of microphones, pumps, pressure regulators, and other acoustical applications. This paper investigates the numerical aspects for free vibration analysis of homogeneous and nonhomogeneous rectangular and square membranes. The method of discrete singular convolution is employed. The results are obtained for different density case and aspect ratios. Numerical results are presented and compared with that available in the literature. The results show that the regularized Shannon delta kernel based discrete singular convolution algorithm produces accurate frequency values.

Research paper thumbnail of Utilizing Piezo Acoustic Sensors for the Identification of Surface Roughness and Textures

Sensors

This study examines surface roughness measurements via piezo acoustic disks and appropriate signa... more This study examines surface roughness measurements via piezo acoustic disks and appropriate signal processing. Surface roughness is one characteristic of surface texture that can have various irregularities inherent to manufacturing methods. The surface roughness parameters and corresponding surface profiles are acquired by a stylus profilometer. Simultaneously, elastic waves propagated along metal surfaces caused by the friction of a diamond tip are obtained in the form of raw sound via piezo acoustic disks. Frequency spectrum analysis showed apparent correlations between the traditionally obtained measurement parameters and the piezo acoustic measurement data. Thus, it is concluded that acoustic friction measurement shows promising results as a novel measurement method for the surface roughness states of certain materials.

Research paper thumbnail of Tekil değerlerin ayrıştırılması (TDA) yöntemi ile duyarlılık analizi

Bu calismada, lineer cebirin araclarindan olan Tekil Degerlere Ayristirma “TDA” (Singular Value D... more Bu calismada, lineer cebirin araclarindan olan Tekil Degerlere Ayristirma “TDA” (Singular Value Decomposition, SVD) metodu, yapisal sistemlerin tasarim duyarliligi analizlerine uygulanarak TDA'ya dayali duyarlilik analizi yontemi gelistirilmistir. Bir yapisal sistemin tekil degerlerinin sekillendirilmesi, ayni zamanda sistem cevabinin belirlenmesi anlamina gelmektedir. Buradan hareketle, gelistirilen TDA'ya dayali duyarlilik analizi yontemi ile mevcut klasik tasarim duyarliligi metodlarinin statik, dinamik analizler, coklu yukleme hali ve yapisal gurbuzluk gibi alanlarda karsilastirmalari yapilmis ve yontemin performansi sayisal ornekler uzerinde denenmistir. Yontemin belli alanlarda klasik metodlara gore daha fazla bilgi aciga cikarmasinin yani sira, hesaplamali alanda islemci suresi ve hafiza kullaniminda buyuk avantajlara sahip oldugu gorulmektedir. Anahtar Kelimeler : Tasarim duyarlilik analizi, tekil degerler, tekil degerlere ayristirma, en kotu yukleme hali, yapisal gu...

Research paper thumbnail of Dynamic Analysis of a Fiber-Reinforced Composite Beam under a Moving Load by the Ritz Method

Mathematics

This paper presents the dynamic responses of a fiber-reinforced composite beam under a moving loa... more This paper presents the dynamic responses of a fiber-reinforced composite beam under a moving load. The Timoshenko beam theory was employed to analyze the kinematics of the composite beam. The constitutive equations for motion were obtained by utilizing the Lagrange procedure. The Ritz method with polynomial functions was employed to solve the resulting equations in conjunction with the Newmark average acceleration method (NAAM). The influence of fiber orientation angle, volume fraction, and velocity of the moving load on the dynamic responses of the fiber-reinforced nonhomogeneous beam is presented and discussed.

Research paper thumbnail of Vibration analysis of graphene sheets using membrane model

Pamukkale University Journal of Engineering Sciences

Bu çalışmada grafen tabakaların membran gibi modellenerek serbest titreşim analizleri yapılmıştır... more Bu çalışmada grafen tabakaların membran gibi modellenerek serbest titreşim analizleri yapılmıştır. Membranlar eğilmeye ya da burkulmaya karşı rijitliği olmayan ince plaklardır. Yanal güçleri eksenel ve merkezi kesme kuvvetleri ile taşırlar. Böyle yük taşımaları, aşırı incelikleri ve moment taşıma kapasitelerinin ihmal edilebilir olmasından dolayı gergin kablo ağlarına benzetilebilirler. Grafen tabakalar dikdörtgen ve kare geometriye sahip olmak üzere değişik boyutlarda modellenmiştir. Elde edilen denklemin çözümünde hem ayrık tekil konvolüsyon yöntemi ve hem de analitik yöntem kullanılmıştır. Literatürde bulunan plak modeli ile ilk defa yapılan membran modelinin sonuçları karşılaştırılmıştır. Bulunan değerler grafik ve tablo halinde sunulmuştur. In this present study vibration analysis of graphene sheets have been carried out by modeling as membrane model. Membranes are thin plates without the stiffness against bending and buckling. They carry lateral forces with axial and central shear forces. This specification, its extreme thinness and negligible moment capacity of membranes can be likened to the tense cable network. Graphene sheets are modeled in square and rectangular geometry. The resulting equation have been solved both analytically and the method of discrete singular convolution. The firstly obtained membrane results have been compared with results obtained by plate models in the literature. Results are given in graphics and tables.

Research paper thumbnail of Frequency analysis of moderately thick uniform isotropic annular plates by discrete singular convolution method

Structural Engineering and Mechanics

Research paper thumbnail of Free vibration of circular and annular membranes with varying density by the method of discrete singular convolution

Structural Engineering and Mechanics

Research paper thumbnail of Differential quadrature method for frequency analysis of membranes having irregular domains using an eight-node curvilinear element

Smart Structures and Systems

Research paper thumbnail of Small size and rotary inertia effects on the natural frequencies of carbon nanotubes

Curved and Layered Structures

In the present paper, rotary inertia and small size effects on the free vibration response of sin... more In the present paper, rotary inertia and small size effects on the free vibration response of single-walled carbon nanotubes are examined. The equations in motion and associated boundary conditions are obtained by using Hamilton’s principle on the basis of modified couple stress and Rayleigh beam theories. The size effect is taken into account by modified couple stress theory while the rotary inertia effect is considered by Rayleigh beam theory. The resulting equations are analytically solved by implementing Navier’s solution technique for pinned-pinned carbon nanotubes. Influences of slenderness ratio, length scale parameter and rotary inertia on the natural frequencies of single-walled carbon nanotubes are studied in detail.

Research paper thumbnail of The effects of thickness on frequency values for rotating circular shells

International Journal Of Engineering & Applied Sciences

The aim of the present paper is to investigate effect of thickness on frequency. For this, free v... more The aim of the present paper is to investigate effect of thickness on frequency. For this, free vibration analysis of circular shells is made via ANSYS and numerical method. Discrete singular convolution (DSC) and differential quadrature methods have been proposed for numerical solution of vibration problem. The formulations are based on the Love's first approximation shell. The performance of the present methodology is also discussed.

Research paper thumbnail of Frequencies of FGM shells and annular plates by the methods of discrete singular convolution and differential quadrature methods

Research paper thumbnail of Free vibration analysis of annular sector plates via conical shell equations

Curved and Layered Structures

In this paper, free vibration analysis of annular sector plates has been presented via conical sh... more In this paper, free vibration analysis of annular sector plates has been presented via conical shell equations. By using the first-order shear deformation theory (FSDT) equation of motion of conical shell is obtained. The method of discrete singular convolution (DSC) and method differential quadrature (DQ) are used for solution of the vibration problem of annular plates for some special value of semi-vertex angle via conical shell equation. The obtained numerical results based on the two numerical approaches for annular sector plates compare well with the results available in the literature. The effects of some geometric parameters, grid numbers and types of the grid distribution have been discussed for curved plates.

Research paper thumbnail of Dynamic Behaviors of a Two-Cylinder Four-Stroke

Gazi University Journal of Science, 2012

Research paper thumbnail of Analysis of shear deformable laminated composite trapezoidal plates

Materials and Design, Sep 1, 2009

This paper presents the discrete singular convolution (DSC) method for the free vibration analysi... more This paper presents the discrete singular convolution (DSC) method for the free vibration analysis of laminated trapezoidal plates. The plate formulation is based on first-order shear deformation theory (FSDT). The straight-sided trapezoidal domain is mapped into a square domain in the computational space using a four-node element by using the geometric transformation. The frequency parameters are obtained for symmetric angle-ply and cross-ply laminated trapezoidal plate. The accuracy of the present method is demonstrated by comparing with numerical and analytical solutions available in the literature.

Research paper thumbnail of Design sensitivity analyses of structures based on singular value decomposition

Bu çalışmada, lineer cebirin araçlarından olan Tekil Değerlere Ayrıştırma “TD... more Bu çalışmada, lineer cebirin araçlarından olan Tekil Değerlere Ayrıştırma “TDA” (Singular Value Decomposition, SVD) metodu, yapısal sistemlerin tasarım duyarlılığı analizlerine uygulanarak TDA'ya dayalı duyarlılık analizi yöntemi geliştirilmiştir. Bir yapısal sistemin tekil değerlerinin şekillendirilmesi, aynı zamanda sistem cevabının belirlenmesi anlamına gelmektedir. Buradan hareketle, geliştirilen TDA'ya dayalı duyarlılık analizi yöntemi ile mevcut klasik tasarım duyarlılığı metodlarının statik, dinamik analizler, çoklu yükleme hali ve yapısal gürbüzlük gibi alanlarda karşılaştırmaları yapılmış ve yöntemin performansı sayısal örnekler üzerinde denenmiştir. Yöntemin belli alanlarda klasik metodlara göre daha fazla bilgi açığa çıkarmasının yanı sıra, hesaplamalı alanda işlemci süresi ve hafıza kullanımında büyük avantajlara sahip olduğu görülmektedi...

Research paper thumbnail of Strength-Based Design Analysis of a Damaged Engine Mounting Bracket Designed for a Commercial Electric Vehicle

Journal of Failure Analysis and Prevention, 2021

This study describes a strength-based design analysis protocol by means of finite element analysi... more This study describes a strength-based design analysis protocol by means of finite element analysis (FEA) for a damaged engine mounting bracket in a converted electric vehicle. The mounting bracket considered in the study is a product specifically designed and manufactured for a converted electric vehicle and failed during conventional operation of the vehicle. Thus, design improvement/revision (redesign) on the bracket geometry was investigated. In this context, to prevent such undesired failures, strength-based design features such as deformation behaviour and stress distribution under projected loads on the bracket should be properly described; however, an accurate description of these features of the bracket may become a complex experimental problem to be solved by designers. This study described redesign of the strength-based design features of the engine mounting bracket through finite element analysis under torsional loading generated by the electric engine that was determined to be the reason for the failure and thus the motivation to realise a safer design. Visual and numerical results obtained from the simulation revealed a clear understanding of the failure behaviour of the bracket and therefore enabled an informed approach to the redesign stage. The initial FEA of the part design mapped the damage regions on the part geometry and indicated the stress magnitudes that were more than the material's stress limits. The comparison of the failure plots and numerical data obtained from this initial FEA and physically damaged part was consistent. This concluded that the FEA satisfactorily exhibited the deformation behaviour and the main reason for the failure was insufficient geometry thickness and notch effect against predefined loading conditions. Therefore, the main design improvement was realised on these geometric features. Subsequently, the final FEA highlighted that the redesign would enable safe operation. This work contributes to further research into usage of numerical method-based deformation simulation studies for the mounting elements used in customised electric vehicles.

Research paper thumbnail of Free Vibration of Annular Plates by Discrete Singular Convolution and Differential Quadrature Methods

Applied and Computational Mechanics, 2016

Plates and shells are significant structural components in many engineering and industrial applic... more Plates and shells are significant structural components in many engineering and industrial applications. In this study, the free vibration analysis of annular plates is investigated. To this aim, two different numerical methods including the differential quadrature and the discrete singular convolution methods are performedfor numerical simulations. Moreover, the Frequency values are obtained via these two methods and finally, the performance of these methods is investigated.

Research paper thumbnail of Solution of Moore–Gibson–Thompson Equation of an Unbounded Medium with a Cylindrical Hole

Mathematics, 2021

In the current article, in the presence of thermal and diffusion processes, the equations governi... more In the current article, in the presence of thermal and diffusion processes, the equations governing elastic materials through thermodiffusion are obtained. The Moore–Gibson–Thompson (MGT) equation modifies and defines the equations for thermal conduction and mass diffusion that occur in solids. This modification is based on adding heat and diffusion relaxation times in the Green–Naghdi Type III (GN-III) models. In an unbounded medium with a cylindrical hole, the built model has been applied to examine the influence of the coupling between temperature and mass diffusion and responses. At constant concentration as well as intermittent and decaying varying heat, the surrounding cavity surface is traction-free and is filled slowly. Laplace transform and Laplace inversion techniques are applied to obtain the solutions of the studied field variables. In order to explore thermal diffusion analysis and find closed solutions, a suitable numerical approximation technique has been used. Compar...

Research paper thumbnail of Derivation of nonlocal FEM formulation for thermo-elastic Timoshenko beams on elastic matrix

Composite Structures, 2021

Abstract Free thermal vibration analysis of nanobeams surrounded by an elastic matrix is examined... more Abstract Free thermal vibration analysis of nanobeams surrounded by an elastic matrix is examined via nonlocal elasticity and Timoshenko beam theories in this article. Elastic matrix is formulated with a two-parameter elastic foundation modelled by combining Winkler and Pasternak assumptions. The equation of motion for free vibration is reached via Hamilton’s principle and solved by analytical method (separation of variable). However, since the separation of variable cannot be applied for boundary conditions other than simply supported nanobeams, a weighted residue-based finite element formulation is developed. Within the scope of numerical results, firstly, it is understood from the comparisons given for nondimensional frequencies that the nonlocal finite element formulation has a high accuracy and then, using this formulation, nondimensional frequencies of nanobeams with different boundary conditions are computed under different parameters. Additionally, the detailed discussions of the numerical results are presented. Finally, by giving some general results, the effect of size dependency and environmental factors on the dynamic behavior of nanobeams is expressed.

Research paper thumbnail of Free vibration analysis of symmetric laminated composite plates by FSDT and radial basis functions

Computer Methods in Applied Mechanics and Engineering, 2005

In this study, free vibration of laminated skew plates was investigated. Discrete singular convol... more In this study, free vibration of laminated skew plates was investigated. Discrete singular convolution (DSC) method is used for numerical solution of vibration problems. The straight-sided quadrilateral domain is mapped into a square domain in the computational space using a four-node element by using the geometric transformation. Typical results are presented for different geometric parameters and boundary conditions. It is concluded from the results that the skew angle have considerable influence on the variations of the frequencies with fibre orientation angle and number of layers in the laminate. The results obtained by DSC method are compared with those obtained by analytical and numerical approaches. It is shown that reasonable accurate results are obtained. Present work also indicates that the method of DSC is a promising and potential approach for computational mechanics.

Research paper thumbnail of Free vibration analysis of rectangular membranes with variable density using the discrete singular convolution approach

Membranes are widely used in various engineering applications such as the design stage of microph... more Membranes are widely used in various engineering applications such as the design stage of microphones, pumps, pressure regulators, and other acoustical applications. This paper investigates the numerical aspects for free vibration analysis of homogeneous and nonhomogeneous rectangular and square membranes. The method of discrete singular convolution is employed. The results are obtained for different density case and aspect ratios. Numerical results are presented and compared with that available in the literature. The results show that the regularized Shannon delta kernel based discrete singular convolution algorithm produces accurate frequency values.

Research paper thumbnail of Utilizing Piezo Acoustic Sensors for the Identification of Surface Roughness and Textures

Sensors

This study examines surface roughness measurements via piezo acoustic disks and appropriate signa... more This study examines surface roughness measurements via piezo acoustic disks and appropriate signal processing. Surface roughness is one characteristic of surface texture that can have various irregularities inherent to manufacturing methods. The surface roughness parameters and corresponding surface profiles are acquired by a stylus profilometer. Simultaneously, elastic waves propagated along metal surfaces caused by the friction of a diamond tip are obtained in the form of raw sound via piezo acoustic disks. Frequency spectrum analysis showed apparent correlations between the traditionally obtained measurement parameters and the piezo acoustic measurement data. Thus, it is concluded that acoustic friction measurement shows promising results as a novel measurement method for the surface roughness states of certain materials.

Research paper thumbnail of Tekil değerlerin ayrıştırılması (TDA) yöntemi ile duyarlılık analizi

Bu calismada, lineer cebirin araclarindan olan Tekil Degerlere Ayristirma “TDA” (Singular Value D... more Bu calismada, lineer cebirin araclarindan olan Tekil Degerlere Ayristirma “TDA” (Singular Value Decomposition, SVD) metodu, yapisal sistemlerin tasarim duyarliligi analizlerine uygulanarak TDA'ya dayali duyarlilik analizi yontemi gelistirilmistir. Bir yapisal sistemin tekil degerlerinin sekillendirilmesi, ayni zamanda sistem cevabinin belirlenmesi anlamina gelmektedir. Buradan hareketle, gelistirilen TDA'ya dayali duyarlilik analizi yontemi ile mevcut klasik tasarim duyarliligi metodlarinin statik, dinamik analizler, coklu yukleme hali ve yapisal gurbuzluk gibi alanlarda karsilastirmalari yapilmis ve yontemin performansi sayisal ornekler uzerinde denenmistir. Yontemin belli alanlarda klasik metodlara gore daha fazla bilgi aciga cikarmasinin yani sira, hesaplamali alanda islemci suresi ve hafiza kullaniminda buyuk avantajlara sahip oldugu gorulmektedir. Anahtar Kelimeler : Tasarim duyarlilik analizi, tekil degerler, tekil degerlere ayristirma, en kotu yukleme hali, yapisal gu...

Research paper thumbnail of Dynamic Analysis of a Fiber-Reinforced Composite Beam under a Moving Load by the Ritz Method

Mathematics

This paper presents the dynamic responses of a fiber-reinforced composite beam under a moving loa... more This paper presents the dynamic responses of a fiber-reinforced composite beam under a moving load. The Timoshenko beam theory was employed to analyze the kinematics of the composite beam. The constitutive equations for motion were obtained by utilizing the Lagrange procedure. The Ritz method with polynomial functions was employed to solve the resulting equations in conjunction with the Newmark average acceleration method (NAAM). The influence of fiber orientation angle, volume fraction, and velocity of the moving load on the dynamic responses of the fiber-reinforced nonhomogeneous beam is presented and discussed.

Research paper thumbnail of Vibration analysis of graphene sheets using membrane model

Pamukkale University Journal of Engineering Sciences

Bu çalışmada grafen tabakaların membran gibi modellenerek serbest titreşim analizleri yapılmıştır... more Bu çalışmada grafen tabakaların membran gibi modellenerek serbest titreşim analizleri yapılmıştır. Membranlar eğilmeye ya da burkulmaya karşı rijitliği olmayan ince plaklardır. Yanal güçleri eksenel ve merkezi kesme kuvvetleri ile taşırlar. Böyle yük taşımaları, aşırı incelikleri ve moment taşıma kapasitelerinin ihmal edilebilir olmasından dolayı gergin kablo ağlarına benzetilebilirler. Grafen tabakalar dikdörtgen ve kare geometriye sahip olmak üzere değişik boyutlarda modellenmiştir. Elde edilen denklemin çözümünde hem ayrık tekil konvolüsyon yöntemi ve hem de analitik yöntem kullanılmıştır. Literatürde bulunan plak modeli ile ilk defa yapılan membran modelinin sonuçları karşılaştırılmıştır. Bulunan değerler grafik ve tablo halinde sunulmuştur. In this present study vibration analysis of graphene sheets have been carried out by modeling as membrane model. Membranes are thin plates without the stiffness against bending and buckling. They carry lateral forces with axial and central shear forces. This specification, its extreme thinness and negligible moment capacity of membranes can be likened to the tense cable network. Graphene sheets are modeled in square and rectangular geometry. The resulting equation have been solved both analytically and the method of discrete singular convolution. The firstly obtained membrane results have been compared with results obtained by plate models in the literature. Results are given in graphics and tables.

Research paper thumbnail of Frequency analysis of moderately thick uniform isotropic annular plates by discrete singular convolution method

Structural Engineering and Mechanics

Research paper thumbnail of Free vibration of circular and annular membranes with varying density by the method of discrete singular convolution

Structural Engineering and Mechanics

Research paper thumbnail of Differential quadrature method for frequency analysis of membranes having irregular domains using an eight-node curvilinear element

Smart Structures and Systems

Research paper thumbnail of Small size and rotary inertia effects on the natural frequencies of carbon nanotubes

Curved and Layered Structures

In the present paper, rotary inertia and small size effects on the free vibration response of sin... more In the present paper, rotary inertia and small size effects on the free vibration response of single-walled carbon nanotubes are examined. The equations in motion and associated boundary conditions are obtained by using Hamilton’s principle on the basis of modified couple stress and Rayleigh beam theories. The size effect is taken into account by modified couple stress theory while the rotary inertia effect is considered by Rayleigh beam theory. The resulting equations are analytically solved by implementing Navier’s solution technique for pinned-pinned carbon nanotubes. Influences of slenderness ratio, length scale parameter and rotary inertia on the natural frequencies of single-walled carbon nanotubes are studied in detail.

Research paper thumbnail of The effects of thickness on frequency values for rotating circular shells

International Journal Of Engineering & Applied Sciences

The aim of the present paper is to investigate effect of thickness on frequency. For this, free v... more The aim of the present paper is to investigate effect of thickness on frequency. For this, free vibration analysis of circular shells is made via ANSYS and numerical method. Discrete singular convolution (DSC) and differential quadrature methods have been proposed for numerical solution of vibration problem. The formulations are based on the Love's first approximation shell. The performance of the present methodology is also discussed.

Research paper thumbnail of Frequencies of FGM shells and annular plates by the methods of discrete singular convolution and differential quadrature methods

Research paper thumbnail of Free vibration analysis of annular sector plates via conical shell equations

Curved and Layered Structures

In this paper, free vibration analysis of annular sector plates has been presented via conical sh... more In this paper, free vibration analysis of annular sector plates has been presented via conical shell equations. By using the first-order shear deformation theory (FSDT) equation of motion of conical shell is obtained. The method of discrete singular convolution (DSC) and method differential quadrature (DQ) are used for solution of the vibration problem of annular plates for some special value of semi-vertex angle via conical shell equation. The obtained numerical results based on the two numerical approaches for annular sector plates compare well with the results available in the literature. The effects of some geometric parameters, grid numbers and types of the grid distribution have been discussed for curved plates.

Research paper thumbnail of Dynamic Behaviors of a Two-Cylinder Four-Stroke

Gazi University Journal of Science, 2012

Research paper thumbnail of Analysis of shear deformable laminated composite trapezoidal plates

Materials and Design, Sep 1, 2009

This paper presents the discrete singular convolution (DSC) method for the free vibration analysi... more This paper presents the discrete singular convolution (DSC) method for the free vibration analysis of laminated trapezoidal plates. The plate formulation is based on first-order shear deformation theory (FSDT). The straight-sided trapezoidal domain is mapped into a square domain in the computational space using a four-node element by using the geometric transformation. The frequency parameters are obtained for symmetric angle-ply and cross-ply laminated trapezoidal plate. The accuracy of the present method is demonstrated by comparing with numerical and analytical solutions available in the literature.