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plates--structural-components
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Nonlinear dynamic analysis of SWNTs conveying fluid using nonlocal continuum theory
, Article Structural Engineering and Mechanics ; Volume 66, Issue 5 , 10 June , 2018 , Pages 621-629 ; 12254568 (ISSN) ; Mousavi, T ; Bahai, H ; Sharif University of Technology
Techno Press
2018
Abstract
By employing the nonlocal continuum field theory of Eringen and Von Karman nonlinear strains, this paper presents an analytical model for linear and nonlinear dynamics analysis of single-walled carbon nanotubes (SWNTs) conveying fluid with different boundary conditions. In the linear analysis the natural frequencies and critical flow velocities of SWNTs are computed. However, in the nonlinear analysis the effect of nonlocal parameter on nonlinear dynamics of cantilevered SWNTs conveying fluid is investigated by using bifurcation diagram, phase plane and Poincare map. Numerical results confirm existence of chaos as well as a period-doubling transition to chaos. Copyright © 2018 Techno-Press,...
Investigation of shear lag effect on tension members fillet-welded connections consisting of single and double channel sections
, Article Structural Engineering and Mechanics ; Volume 74, Issue 3 , 2020 , Pages 445-455 ; Maleki, S ; Mirtaheri, M ; Nazeryan, M ; Seyed Mahdi, M. S ; Sharif University of Technology
Techno Press
2020
Abstract
Shear lag phenomenon has long been taken into consideration in various structural codes; however, the AISC provisions have not proposed any specific equation to calculate the shear lag ratio in some cases such as fillet-welded connections of front-to-front double channel sections. Moreover, those equations and formulas proposed by structural codes are based on the studies that were conducted on riveted and bolted connections, and can be applied to single channel sections whilst using them for fillet-welded double channels would be extremely conservative due to the symmetrical shape and the fact that bending moments will not develop in the gusset plate, resulting in less stress concentration....
Post-buckling analysis of geometrically imperfect nanoparticle reinforced annular sector plates under radial compression
, Article Computers and Concrete ; Volume 26, Issue 1 , 2020 , Pages 21-30 ; Forsat, M ; Mollaee, S ; Barati, M. R ; Afshari, B. M ; Hamouda, A. M. S ; Sharif University of Technology
Techno-Press
2020
Abstract
Buckling and post-buckling behaviors of geometrically imperfect annular sector plates made from nanoparticle reinforced composites have been investigated. Two types of nanoparticles are considered including graphene oxide powders (GOPs) and silicone oxide (SiO2). Nanoparticles are considered to have uniform and functionally graded distributions within the matrix and the material properties are derived using Halpin-Tsai procedure. Annular sector plate is formulated based upon thin shell theory considering geometric nonlinearity and imperfectness. After solving the governing equations via Galerkin’s technique, it is showed that the post-buckling curves of annular sector plates rely on the...
Investigation of hydroelastic effect in analysis of high-speed craft
, Article Ships and Offshore Structures ; Volume 11, Issue 1 , 2016 , Pages 16-24 ; 17445302 (ISSN) ; Seif, M. S ; Tabeshpur, M. R ; Yaakob, O ; Sharif University of Technology
Taylor and Francis Ltd
2016
Abstract
Hydroelastic effect in bottom slamming problem of high-speed craft is one of the most challenging issues in structural design. In this paper, numerical method is used to investigate the hydroelastic effect in bottom-water impact analysis of high-speed monohull craft. Slamming with two viewpoints of rigid and elastic structures (hydroelastic effect) is modelled by coupled computational fluid dynamic (CFD) and finite element method (FEM) techniques. The results showed that considering hydroelastic effect, especially in high-impact speed, reduces the structural deformations and stresses compared with quasi-statistic analysis. The effect of different parameters, such as boundary condition, plate...
Hydrodynamic performance of multiple co-axial heave plates with different diameters
, Article Ships and Offshore Structures ; Volume 15, Issue 4 , 2020 , Pages 380-392 ; Behzad, M ; Thiagarajan, K. P ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Heave plates are structural components of a floating structure whose primary purpose is to increase damping and added mass in heave or pitch direction. If multiple plates are stacked along a common axis, then the relative diameters and spacing in between are important factors affecting the performance. In the present study, hydrodynamic coefficients of single, double and triple disks are experimentally investigated in different arrangements as Uniform, Concave and Convex edge shapes. It is observed that each disk in a multiple arrangement with lower diameter ratio have better hydrodynamic performance compared to the cases with higher diameter ratio when the spacing is small compared to the...
Buckling and vibration analysis of FG-CNTRC plate subjected to thermo-mechanical load based on higher order shear deformation theory
, Article Mechanics Based Design of Structures and Machines ; Volume 50, Issue 4 , 2022 , Pages 1137-1160 ; 15397734 (ISSN) ; Karbon, M ; Eyvazian, A ; Jung, D. W ; Habibi, M ; Safarpour, M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
In the present study, based on 12-unknown higher order shear deformation theory (HSDT), buckling and vibration analysis of FG-CNTRC rectangular plate are investigated for various types of temperature distribution and boundary conditions. Implementing Hamilton’s principle, the equations of motion are derived and solved by adopting the Navier solution for the simply supported boundary conditions and DQM method for other boundary conditions. Validation is carried out by comparing the numerical results with those obtained in the open literature. Also, a detailed parametric analysis is carried out to illuminate the influence of different system parameters such as CNT distributions, CNT volume...
Differential quadrature method for nonlocal nonlinear vibration analysis of a boron nitride nanotube using sinusoidal shear deformation theory
, Article Mechanics of Advanced Materials and Structures ; Volume 23, Issue 11 , 2016 , Pages 1278-1283 ; 15376494 (ISSN) ; Sadatshojaie, A ; Fakhar, M. H ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
This article presents a nonlocal sinusoidal shear deformation beam theory (SDBT) for the nonlinear vibration of single-walled boron nitride nanotubes (SWBNNTs). The surrounding elastic medium is simulated based on nonlinear Pasternak foundation. Based on the nonlocal differential constitutive relations of Eringen, the equations of motion of the SWBNNTs are derived using Hamilton's principle. Differential quadrature method (DQM) for the nonlinear frequency is presented, and the obtained results are compared with those predicted by the nonlocal Timoshenko beam theory (TBT). The effects of nonlocal parameter, vibrational modes, length, and elastic medium on the nonlinear frequency of SWBNNTs...
Natural frequency analysis of functionally graded material truncated conical shell with lengthwise material variation based on first-order shear deformation theory
, Article Mechanics of Advanced Materials and Structures ; Volume 23, Issue 5 , 2016 , Pages 565-577 ; 15376494 (ISSN) ; Kargarnovin, M. H ; Satouri, S ; Satouri, A ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
Based on the first-order shear deformation theory, the free vibration of the functionally graded (FG) truncated conical shells is analyzed. The truncated conical shell materials are assumed to be isotropic and inhomogeneous in the longitudinal direction. The two-constituent FG shell consists of ceramic and metal. These constituents are graded through the length, from one end of the shell to the other end. Using Hamilton's principle the derived governing equations are solved using differential quadrature method. Fast rate of convergence of this method is tested and its advantages over other existing solver methods are observed. The primary results of this study were obtained for four...
Development of an accurate finite element model for N-layer MR-laminated beams using a layerwise theory
, Article Mechanics of Advanced Materials and Structures ; 2017 , Pages 1-8 ; 15376494 (ISSN) ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
Taylor and Francis Inc
2017
Abstract
Laminated composite beams incorporated with magneto-rheological fluid are being used in variety of critical applications. An N-layer magneto-rheological-laminated beam based on layerwise theory has been developed to study the dynamic characteristics. For simulation purpose, an MR-laminated beam with five layers is considered in which two layers filled with magneto-rheological and three layers are made of composite materials. The results of simulations are compared with existing layerwise, first-order shear-deformation theory and experimental tests where it shows the accuracy and functionality of the present model. The complex shear modulus of magneto-rheological fluid has been determined...
Buckling and vibration analysis of FG-CNTRC plate subjected to thermo-mechanical load based on higher order shear deformation theory
, Article Mechanics Based Design of Structures and Machines ; 2020 ; Karbon, M ; Eyvazian, A ; Jung, D. W ; Habibi, M ; Safarpour, M ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
In the present study, based on 12-unknown higher order shear deformation theory (HSDT), buckling and vibration analysis of FG-CNTRC rectangular plate are investigated for various types of temperature distribution and boundary conditions. Implementing Hamilton’s principle, the equations of motion are derived and solved by adopting the Navier solution for the simply supported boundary conditions and DQM method for other boundary conditions. Validation is carried out by comparing the numerical results with those obtained in the open literature. Also, a detailed parametric analysis is carried out to illuminate the influence of different system parameters such as CNT distributions, CNT volume...
Free vibration analysis of general stepped circular plates with internal elastic ring support resting on Winkler foundation by green function method
, Article Mechanics Based Design of Structures and Machines ; Volume 44, Issue 3 , 2016 , Pages 212-230 ; 15397734 (ISSN) ; Mofid, M ; Sharif University of Technology
Taylor and Francis Inc
Abstract
Natural frequencies are important dynamic characteristics of a structure. Therefore, the exact solution pertaining to free vibration of stepped circular plate elastically restrained against rotation, translation, and internal elastic ring support resting on an arbitrary variable elastic foundation using Green Function is presented in this paper. Thus, an accurate and direct modeling technique is introduced for modeling stepped circular plate on an arbitrary variable elastic foundation with arbitrary boundary conditions and internal elastic ring support. The effect of the translational along with rotational support flexibilities, as well as, the elastic coefficient of Winkler foundation and...
On an extended Kantorovich method for the mechanical behavior of functionally graded solid/annular sector plates with various boundary conditions
, Article Acta Mechanica ; Volume 228, Issue 7 , 2017 , Pages 2655-2674 ; 00015970 (ISSN) ; Khakbaz, A ; Sharif University of Technology
Springer-Verlag Wien
2017
Abstract
Based on the first-order shear deformation plate theory, two approaches within the extended Kantorovich method (EKM) are presented for a bending analysis of functionally graded annular sector plates with arbitrary boundary conditions subjected to both uniform and non-uniform loadings. In the first approach, EKM is applied to the functional of the problem, while in the second one EKM is applied to the weighted integral form of the governing differential equations of the problem as presented by Kerr. In both approaches, the system of ordinary differential equations with variable coefficients in r direction and the set of ordinary differential equations with constant coefficients in θ direction...
On the nonlinear dynamic responses of FG-CNTRC beams exposed to aerothermal loads using third-order piston theory
, Article Acta Mechanica ; Volume 229, Issue 6 , 2018 , Pages 2413-2430 ; 00015970 (ISSN) ; Rabiei Beheshti, A ; Sharif University of Technology
Springer-Verlag Wien
2018
Abstract
The purpose of this study is to analyze the nonlinear dynamic responses of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) beams exposed to axial supersonic airflow in thermal environments. The dynamic model of the FG-CNTRC beam is developed with regard to the first-order shear deformation theory incorporating the von Kármán geometrical nonlinearity. The thermomechanical properties of the constituents are assumed to be temperature dependent. The third-order piston theory is adopted to estimate the nonlinear aerodynamic pressure induced by the supersonic airflow. Harmonic differential quadrature method is implemented to discretize the equations of motion in the spatial...
Simulation and optimization of pulsating heat pipe flat-plate solar collectors using neural networks and genetic algorithm: a semi-experimental investigation
, Article Clean Technologies and Environmental Policy ; Volume 18, Issue 7 , 2016 , Pages 2251-2264 ; 1618954X (ISSN) ; Kargarsharifabad, H ; Abbasi Godarzi, A ; Ghofrani, A ; Shafii, M. B ; Sharif University of Technology
Springer Verlag
2016
Abstract
This research study presents an investigation on the behavior of a Pulsating Heat Pipe Flat-Plate Solar Collector (PHPFPSC) by artificial neural network method and an optimization of the parameters of the collector by genetic algorithm. In this study, several experiments were performed to study the effects of various evaporator lengths, filling ratios, inclination angles, solar radiation, and input chilled water temperature between 9:00 A.M. to 5:00 P.M., and the output temperature of the water tank, which was the output of the system, was also measured. According to the input and output information, multilayer perceptron neural network was trained and used to predict the behavior of the...
Post-buckling analysis of piezo-magnetic nanobeams with geometrical imperfection and different piezoelectric contents
, Article Microsystem Technologies ; Volume 25, Issue 9 , 2019 , Pages 3477-3488 ; 09467076 (ISSN) ; Forsat, M ; Barati, M. R ; Abdella, G. M ; Hamouda, A. M. S ; Mohasel Afshari, B ; Rabby, S ; Sharif University of Technology
Springer Verlag
2019
Abstract
Thermal post-buckling behavior of a geometrically imperfect/perfect piezo-magnetic nano-scale beams made of two-phase composites is analyzed in the present paper based on nonlocal elasticity theory. For the first time, the material properties of the nanobeam are considered as functions of piezoelectric phase percentage. All previous investigations on piezo-magnetic nanobeams neglect the effect of geometrical imperfection which is very important since the nanobeams are not always ideal or perfect. The post-buckling problem of such nanobeams is solved by introducing an analytical approach to derive buckling temperatures. The present solution is simple and easily understandable. For both...
Nonlinear free and forced vibrations of graphene nanoplatelet reinforced microbeams with geometrical imperfection
, Article Microsystem Technologies ; Volume 25, Issue 8 , 2019 , Pages 3137-3150 ; 09467076 (ISSN) ; Mohasel Afshari, B ; Barati, M. R ; Hamouda, A. M. S ; Sharif University of Technology
Springer Verlag
2019
Abstract
Nonlinear free/forced vibration of a functionally graded graphene nanoplatelet (GNP) reinforced microbeam having geometrical imperfection which is rested on a non-linear elastic substrate have been studied in the present research. Graphene Platelets have been uniformly and non-uniformly scattered in the cross section area of the microbeam. Non-uniform distribution of GNPs is considered to be linear or non-linear type. Geometric imperfection is considered similar to the first vibration mode of microbeam. Size effects due to micro-rotations are captured in this study by means of modified couple stress elasticity. In the case of forced vibration, a uniform harmonic load is exerted to the top...
Application of nonlocal strain–stress gradient theory and GDQEM for thermo-vibration responses of a laminated composite nanoshell
, Article Engineering with Computers ; Volume 37, Issue 4 , 2021 , Pages 3359-3374 ; 01770667 (ISSN) ; Ebrahimi, F ; Habibi, M ; Safarpour, H ; Foong, L. K ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
In this article, thermal buckling and frequency analysis of a size-dependent laminated composite cylindrical nanoshell in thermal environment using nonlocal strain–stress gradient theory are presented. The thermodynamic equations of the laminated cylindrical nanoshell are based on first-order shear deformation theory, and generalized differential quadrature element method is implemented to solve these equations and obtain natural frequency and critical temperature of the presented model. The results show that by considering C–F boundary conditions and every even layers’ number, in lower value of length scale parameter, by increasing the length scale parameter, the frequency of the structure...
On the nonlinear dynamics of a multi-scale hybrid nanocomposite disk
, Article Engineering with Computers ; Volume 37, Issue 3 , 2021 , Pages 2369-2388 ; 01770667 (ISSN) ; Ebrahimi, F ; Habibi, M ; Safarpour, H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
This is the first research on the nonlinear frequency analysis of a multi-scale hybrid nanocomposite (MHC) disk (MHCD) resting on an elastic foundation subjected to nonlinear temperature gradient and mechanical loading is investigated. The matrix material is reinforced with carbon nanotubes (CNTs) or carbon fibers (CF) at the nano- or macroscale, respectively. We present a modified Halpin–Tsai model to predict the effective properties of the MHCD. The displacement–strain of nonlinear vibration of multi-scale laminated disk via third-order shear deformation theory (TSDT) and using Von Karman nonlinear shell theory is obtained. Hamilton’s principle is employed to establish the governing...
Development of a shell superelement for large deformation and free vibration analysis of composite spherical shells
, Article Engineering with Computers ; Volume 37, Issue 4 , 2021 , Pages 3551-3567 ; 01770667 (ISSN) ; Hosseinzadeh, A ; Movahhedy, M. R ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Finite element analysis of huge and/or complicated structures often requires long times and large computational expenses. Superelements are huge elements that exploit the deformation theory of a specific problem to provide the capability of discretizing the problem with minimum number of elements. They are employed to reduce the computational cost while retaining the accuracy of results in FEM analysis of engineering problems. In this research, a new shell superelement is presented to study linear/nonlinear static and free vibration analysis of spherical structures with partial or full spherical geometries that exist in many industrial applications. Furthermore, this study investigates the...
Experimental and numerical simulation of the microcrack coalescence mechanism in rock-like materials
, Article Strength of Materials ; Volume 47, Issue 5 , September , 2015 , Pages 740-754 ; 00392316 (ISSN) ; Khaloo, A ; Marji, M. F ; Sharif University of Technology
Springer New York LLC
2015
Abstract
Rocks and rock-like materials frequently fail under compression due to the initiation, propagation and coalescence of the pre-existing microcracks. The mechanism of microcrack coalescence process in rock-like materials is experimentally and numerically investigated. The experimental study involves some uniaxial compression tests on rock-like specimens specially prepared from portland pozzolana cement, mica sheets and water. The microcrack coalescence is studied by scanning electron microscopy on some of the prepared thin specimens. It is assumed that the mica sheets play the role of microcracks within the specimens. Some analytical and numerical studies are also carried out to simulate the...