Article
Mechanics
Keivan Kiani, Krzysztof Kamil Zur
Summary: In this study, suitable surface energy-nonlocal-integral and differential models were reported for investigating the mechanical behavior of a nanosystem consisting of double parallel nanorods with defects. By evaluating nonlocal-surface energy-based modes and implementing the Galerkin method, the capabilities of capturing the natural frequencies of the defected nanosystem were revealed. The roles of nonlocality, surface energy, nanorod characteristics, defect properties, and elastic interface layer constant on free vibration were explained.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Multidisciplinary
Mehdi Simyari, Seyed Amirhosein Hosseini
Summary: In this study, the torsional vibration analysis of small-scaled rods is investigated using Eringen's nonlocal theory. The equations of motion and boundary conditions are derived using the Hamilton principle. Nonlocal elasticity theory based on Eringen's model is employed to describe the size-dependent behavior. Galerkin's analytical method is utilized for solving the equations of motion. The study focuses on the time-dependent torsional vibration of an elliptical nanorod with clamped-clamped end supports under linear and harmonic external torques.
APPLIED MATHEMATICAL MODELLING
(2023)
Article
Materials Science, Multidisciplinary
Shahin Behdad, Mahmood Fakher, Shahrokh Hosseini-Hashemi
Summary: The study demonstrates that using two-phase local/nonlocal elasticity theory is more suitable for analyzing the dynamic stability and damping vibration of Timoshenko nanobeams subjected to an axial load, compared to the fully nonlocal elasticity theory. This approach allows for studying the size-dependent vibration and stability under various boundary conditions.
MECHANICS OF MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Mehmet N. Balci
Summary: This study investigated the longitudinal vibration of a nanorod embedded in viscoelastic medium using nonlocal strain gradient theory. Results showed that the material length scale parameter has an influence on modal frequencies, while elastic and damping parameters have significant impacts on modal frequencies and damping ratios.
ADVANCES IN NANO RESEARCH
(2022)
Article
Engineering, Multidisciplinary
Francesco Paolo Pinnola, Marzia Sara Vaccaro, Raffaele Barretta, Francesco Marotti de Sciarra
Summary: The bending behavior of systems of straight elastic beams at different scales is investigated using stress-driven nonlocal continuum mechanics, and an effective computational methodology is developed to accurately account for long-range interactions.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2021)
Article
Engineering, Civil
Abbas Assadi, Hossein Najaf, Mostafa Nazemizadeh
Summary: This paper investigates size-dependent vibration of single-crystalline nanoplates with cubic anisotropy using the generalized differential quadrature method. The results show that size scale parameters have different effects on vibration depending on material orientation and boundary conditions. In particular, the natural frequency of FCC materials decreases as the nanoplate rotates from [100] to [110] axis.
THIN-WALLED STRUCTURES
(2022)
Article
Chemistry, Physical
Omer Civalek, Busra Uzun, Mustafa Ozgur Yayli
Summary: An efficient eigenvalue algorithm is developed for the axial vibration analysis of embedded short-fiber-reinforced micro-/nano-composite rods under arbitrary boundary conditions. The algorithm considers the size effect using nonlocal elasticity theory and simulates deformable boundary conditions with elastic springs. It also presents a new system of linear equations to determine the reinforcing effect of restrained nano-/micro-rods.
Article
Engineering, Mechanical
Busra Uzun, Ugur Kafkas, Babur Deliktas, Mustafa Ozgur Yayli
Summary: This study investigates the size-dependent free axial vibration of a nanorod made of porous material using nonlocal elasticity theory and Bishop rod theory. The frequencies of the porous Bishop nanorod under various parameters are obtained and the effects of these parameters are discussed.
JOURNAL OF VIBRATION ENGINEERING & TECHNOLOGIES
(2023)
Article
Engineering, Mechanical
Jianshi Fang, Bo Yin, Xiaopeng Zhang, Bin Yang
Summary: This study investigates the free vibration of rotating functionally graded nanobeams based on nonlocal elasticity theory, considering the thickness-wise material gradient variation of the nanobeam. By introducing a second-order axial shortening term, the governing equations of motion for the rotating nanobeams are derived and solved through the Galerkin method. Results show that rotating nanobeams with high angular velocity may have larger fundamental frequencies compared to stationary nanobeams, and demonstrate axial stretching-transverse bending coupled vibration characteristics.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Mechanical
Busra Uzun, Omer Civalek, Mustafa Ozgur Yayli
Summary: This study presents an analysis of axial free vibration of small size-dependent nanorods subjected to deformable restrained boundary conditions. The formulation is rewritten without using any undeformable boundary conditions and considers gradually deformable boundary conditions. The eigenvalue problem is constructed using Fourier sine series and Stokes' transformation, and higher-order elasticity model is employed to consider strain gradient stress field and nonlocal elastic stress field. The validity of the procedure is verified through numerical results and the effects of small-scale parameters on the dynamic response of nanorods are discussed.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2022)
Article
Construction & Building Technology
Mahsa Najafi, Isa Ahmadi
Summary: A nonlocal Layerwise theory is proposed for free vibration analysis of nanobeams resting on an elastic foundation, considering small-scale effects and predicting more accurate results. Effects of nonlocal parameter, Pasternak shear coefficient, Winkler spring coefficient, and boundary conditions on the vibration of nanobeams are studied. The theory can be applied to analyze the mechanical behavior of various nanostructures with different loading and boundary conditions.
STEEL AND COMPOSITE STRUCTURES
(2021)
Article
Mathematics, Applied
Aurora Angela Pisano, Paolo Fuschi, Castrenze Polizzotto
Summary: Eringen's fully nonlocal elasticity model leads to ill-posed boundary-value problems and boundary effects, but an enhanced model with a regularizing non-homogeneous local phase provides well-posed boundary-value problems without paradoxes. The enhanced model applied to beam bending is equivalent to a sixth order differential equation with variable coefficients and predicts softening size effects consistently. The influence of the length scale parameter on the beam's response is highlighted, showing a wave pattern in the response function delta(lambda) as the parameter increases.
ZAMM-ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND MECHANIK
(2021)
Article
Engineering, Multidisciplinary
Zhu XiaoWu, Li Li
Summary: This study demonstrates how both cross-sectional nonlocal interactions and axial nonlocality affect the tensile behaviors of nanobars. When the length-to-height ratio is small, nonlocal interactions become significant, while in slender bars, the main nonlocal effect stems from the nonlocal cross-sectional effect. Overcoming the ill-posed problem of pure nonlocal integral elasticity can be achieved by employing both pure nonlocal integral elasticity and surface elasticity.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2021)
Article
Mechanics
Pejman Ayoubi, Habib Ahmadi
Summary: For the first time, the mixed local/nonlocal elasticity theory is used to study the free axisymmetric vibration of an annular single-layer graphene sheet. The imperfections on the sheet are considered as centric perforations. Dynamic equilibrium equations are derived and solved analytically. The influence of mixture parameter, nonlocal parameter, and imperfection radius on the natural frequency is examined and it is found that increasing the mixture parameter leads to an increase in the natural frequency.
Article
Mathematics, Applied
Yongfang Wei, Zhanbing Bai
Summary: This paper studies a class of superlinear damped vibration equations with nonlocal boundary conditions on time scales by using the calculus of variations. The variational structure is established in an appropriate Sobolev's space, and the existence of infinitely many large energy solutions is proved.
NONLINEAR ANALYSIS-MODELLING AND CONTROL
(2022)
Article
Mechanics
Omer Civalek, Shahriar Dastjerdi, Bekir Akgoz
Summary: This article investigates the free vibration and buckling behaviors of CNT-reinforced cross-ply laminated composite plates using FSDT and DSC methods. Parametric study is conducted to analyze the effects of various factors on frequencies and buckling loads.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2022)
Article
Materials Science, Multidisciplinary
Mohammad Amin Shahmohammadi, Sayed Mohamad Mirfatah, Hamzeh Salehipour, Fatemeh Azhari, Omer Civalek
Summary: This article investigates the dynamic instability of hybrid fiber/nanocomposite-reinforced toroidal shells, achieving a semi-analytical solution through the approximation of Fourier series and Galerkin method. By comparing the results and performing a parametric study, the accuracy and effects of geometrical and mechanical specifications on the dynamic instability are evaluated.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2023)
Article
Engineering, Multidisciplinary
Shahriar Dastjerdi, Amin Alibakhshi, Bekir Akgoz, Omer Civalek
Summary: This paper applies a semi-analytical polynomial method (SAPM) to solve the mechanical governing equations of nano-sized spherical functionally graded structures. The SAPM is based on polynomial functions and assumes the spherical coordinate system. The results obtained are compared with those in other articles to examine the accuracy of the solution method.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Engineering, Multidisciplinary
Mohammad Amin Shahmohammadi, Sayed Mohamad Mirfatah, Hamzeh Salehipour, Omer Civalek
Summary: The objective of this paper is to evaluate the geometrically nonlinear and size-dependent response of shallow sandwich curved micro-panels. The governing equations are developed using modified couple stress theory based on the first-order shear deformation theory. The equations are analytically solved using the Galerkin method and numerically solved using the forth-order Runge-Kutta method. The accuracy of the method is validated and the effects of various properties on the forced vibration of the micro-panels are evaluated through a parametric study.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Engineering, Aerospace
Sayed Mohamad Mirfatah, Saman Tayebikhorami, Mohammad Amin Shahmohammadi, Hamzeh Salehipour, Omer Civalek
Summary: This paper investigates the geometric nonlinear dynamic behavior of shallow sandwich panels made of nanocomposite enriched face-sheets and auxetic honeycomb core with negative Poisson's ratio. An analytical approach based on the Galerkin method is used to solve the governing nonlinear differential equations, resulting in a closed form equation of motion solved by the fourth-order Runge-Kutta method. The proposed method is verified and shown to yield results with less than 2% error compared to previously published papers. Numerical studies show that the proposed method allows for efficient nonlinear dynamic analysis of the panels.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Civil
Emad Sobhani, Amir R. Masoodi, Omer Civalek, Amir Reza Ahmadi-Pari
Summary: This article investigates the frequencies of tangential waves in Functionally Graded (FG) sandwich Merged Hemispherical-Cylindrical Shells (MHCS) with free-damped vibration characteristics. The three-layered MHCS contains Functionally Graded Material (FGM) with functional variation along the thickness. The mechanical features of the materials are determined using Equivalent Single Layer (ESL) and Rule of Mixture (RM). Eight sandwich types are examined, assuming flexible merging and support conditions. The article utilizes Donnell's hypothesis and Hamilton's scheme to acquire the kinetic differential equations and applies the Generalized Differential Quadrature Method (GDQM) to discretize the equations and determine the tangential wave frequencies.
ENGINEERING STRUCTURES
(2023)
Article
Mathematics, Applied
Omer Civalek, Busra Uzun, Mustafa Ozgur Yayli
Summary: This paper proposes a finite element model to investigate the size-dependent vibrational responses of guide-supported imperfect functionally graded nonlocal beams embedded in an elastic foundation. The nonlocal finite element solution considers nonlocal effect, power-law distribution function, sigmoid distribution function, even and uneven porosity models, elastic foundation parameter, and guide support condition for vibration analysis of imperfect FG nanobeams. Tables and figures are used to show the frequency values of perfect/imperfect FG power-law and sigmoid nanobeams obtained by using a nonlocal FE method.
ZAMM-ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND MECHANIK
(2023)
Article
Mathematics, Applied
Ahmed E. Abouelregal, Bekir Akgoz, Omer Civalek
Summary: The objective of this work is to improve a generalized thermoelastic heat transport framework, which is compatible with observable physical processes and allows speed reduction of heat waves within the solid. The proposed model can be used to derive alternative thermoelasticity models as special cases. The influence of Hall current on magneto-thermoelastic couplings in an infinite conducting viscoelastic medium with a cylindrical cavity under a strong magnetic field is also considered.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2023)
Article
Engineering, Civil
Sayed Mohamad Mirfatah, Mohammad Amin Shahmohammadi, Hamzeh Salehipour, Omer Civalek
Summary: The aim of this paper is to study the size-dependent geometrical nonlinear static characteristics of curved panels enriched by nano-additives incorporating thermal effects. The size-dependency is considered by developing the basic equations based on the modified couple stresses theory (MCST). An analytical approach based on the Galerkin method is used to find the response of the achieved set of nonlinear differential equations and obtain a closed-form pressure-deflection relationship representing the nonlinear equilibrium path of the curved micropanels. The closed-form relationship is examined and a parametric numerical study is conducted to investigate the effects of material length-scale parameter (MLSP) and the characteristics of geometry and material on the geometrical nonlinear path of equilibrium.
ENGINEERING STRUCTURES
(2023)
Article
Engineering, Multidisciplinary
Omer Civalek, Busra Uzun, Mustafa Ozgur Yayli
Summary: In this work, the nonlinear stability behaviors of saturated porous nanobeams embedded in an elastic foundation are investigated. The restrained nanobeam is modeled using geometric nonlinear equations and the constitutive law of saturation. Three patterns for saturation along the thickness of the nanobeam are considered. The effects of saturation and nonlinearity on buckling loads are studied, and the nonlinear results are validated.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Engineering, Multidisciplinary
Shahriar Dastjerdi, Omer Civalek, Mohammad Malikan, Bekir Akgoz
Summary: This research focuses on analyzing rotating truncated conical baskets reinforced by carbon nanotubes around two independent axes. A time-dependent analysis is used to extract the nonlinear dynamic governing equations for the structure. Carbon nanotubes are used to reinforce the conical basket, with different distributions impacting the mechanical properties. The resistance of a novel two-axis rotating conical basket as a centrifuge device is investigated at various rotational velocities. The results show that reinforcing the basket with carbon nanotubes increases its resistance against deformation caused by rotation.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Mechanics
Shahriar Dastjerdi, Mohammad Malikan, Bekir Akgoz, Omer Civalek, Victor A. Eremeyev
Summary: The research simulates the motion of the Earth's layers caused by internal pressures using an efficient mathematical model. By considering the Earth's rotation, the model provides more accurate results regarding the shape and displacement of the internal layers and tectonic plates. It also solves the fully nonlinear and dynamic differential equations using a semi-analytical polynomial method, which is an innovative and efficient approach.
JOURNAL OF APPLIED AND COMPUTATIONAL MECHANICS
(2023)
Article
Multidisciplinary Sciences
O. Ragb, Mohamed Salah, M. S. Matbuly, H. Ersoy, O. Civalek
Summary: In this study, polynomial, discrete singular convolution, and sinc quadrature techniques were utilized to derive accurate and efficient numerical solutions for reaction-diffusion equations. Three models were presented and reduced to nonlinear ordinary differential equations using different quadrature schemes. The Runge-Kutta fourth-order method was employed to solve these equations, and MATLAB program was used for computation. Comparisons and statistical errors showed the ease of implementation and efficiency of the new methods. Parametric analysis demonstrated the influence of diffusion and reaction parameters on the solution.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2023)
Article
Mechanics
Busra Uzun, Omer Civalek, Mustafa Ozgur Yayli
Summary: This study presents a vibration analysis of functionally graded nano-sized beams resting on an elastic foundation using a finite element method. The beams are modeled based on Euler-Bernoulli beam theory and Eringen's nonlocal elasticity theory under various boundary conditions. The material properties of the beams vary across the thickness direction. The paper emphasizes the use of shape functions and Eringen's nonlocal elasticity theory to establish stiffness matrices and mass matrices for free vibration analysis. Several numerical examples are provided to investigate the effects of different parameters on frequencies.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Engineering, Multidisciplinary
Tohya Kanahama, Motohiro Sato
Summary: This study theoretically explains the effect of initial deflection and initial slope on self-buckling characteristics of heavy columns and proposes a formula characterizing the self-buckling problem. The results show that the greatest height is proportional to the 2/3 power of radius, and the formula can potentially predict the height of tree-like natural structures.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
Aps Selvadurai, Alexander P. Suvorov
Summary: This paper examines the torsion of a solid cylinder made of a fluid-saturated porous medium with a hyperelastic porous skeleton. It analyzes the mechanics of the twisted cylinder in both short-term and long-term behaviors, using numerical solutions and the ABAQUSTM finite element code.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
S. Kanaun
Summary: This study focuses on spherical radially transverse isotropic heterogeneous inclusions in homogeneous isotropic conductive host media. The volume integral equation for the field in the medium with an isolated inclusion subjected to a constant external field is solved using Mellin-transform technique. The method allows revealing tensor structure of the solution with precision to one scalar function of radial coordinate. The study also investigates the influence of neutral inclusions and conductivity coefficients on the effective conductivity of the composite material.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
Marinos Kattis, Vassilis Tsitsos, Vassilis Karatzaferis
Summary: The proposed model utilizes continuum mechanics to describe the mechanical behavior of a weakened interface between materials with microstructure, simulating the weakened interface using a surface elastic medium adhering on either side with bulk elastic continua. The model is able to investigate the effect of a weakened interface on stress concentration around inhomogeneities embedded in an unbounded matrix of Cosserat materials.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
Shixiang Zhao, Yu. V. Petrov, Yuyi Zhang, G. A. Volkov, Zejian Xu, Fenglei Huang
Summary: This paper theoretically studies the thermal softening related to stress relaxation using the incubation time approach and examines the temperature-time correspondence. The developed relaxation model of plasticity (RP model) is analyzed and compared with other constitutive models and artificial neural networks. The advantages and disadvantages of different models are discussed, and the differences between the ANN model and other constitutive models are examined.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
Ivan I. Argatov, Federico J. Sabina
Summary: This study models a seismic metabarrier as a cluster of single-degree-of-freedom resonator units and considers the scattering effects on pulsed Rayleigh waves caused by the vertical displacements of the resonators and the normal contact forces. The variation of the amplitude reduction factor due to the model parameters variation is studied in detail.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
