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viscoelasticity
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Forced and free vibrational analysis of viscoelastic nanotubes conveying fluid subjected to moving load in hygro-thermo-magnetic environments with surface effects
, Article Archives of Civil and Mechanical Engineering ; Volume 22, Issue 4 , 2022 ; 16449665 (ISSN) ; Alibeigloo, A ; Borjalilou, V ; Koochakianfard, O ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Forced and free vibrational analyses of viscoelastic nanotubes containing fluid under a moving load in complex environments incorporating surface effects are conducted based on the nonlocal strain gradient theory and the Rayleigh beam model. To model the internal nanoflow, the slip boundary condition is employed. Adopting the Galerkin discretization approach, the reduced-order dynamic model of the system is acquired. Analytical and numerical methods are exploited to determine the dynamic response of the system. The impacts of geometry, scale parameter ratio, Knudsen number, fluid velocity, rotary inertia parameter, viscoelastic parameter, surface residual stress, surface elastic modulus, and...
An intelligent computer method for vibration responses of the spinning multi-layer symmetric nanosystem using multi-physics modeling
, Article Engineering with Computers ; Volume 38 , 2022 , Pages 4217-4238 ; 01770667 (ISSN) ; Baharvand, A ; Tazeddinova, D ; Habibi, M ; Safarpour, H ; Roco-Videla, A ; Selmi, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
This article is the first attempt to employ deep learning to estimate the frequency performance of the rotating multi-layer nanodisks. The optimum values of the parameters involved in the mechanism of the fully connected neural network are determined through the momentum-based optimizer. The strength of the method applied in this survey comes from the high accuracy besides lower epochs needed to train the multi-layered network. It should be mentioned that the current nanostructure is modeled as a nanodisk on the viscoelastic substrate. Due to rotation, the centrifugal and Coriolis effects are considered. Hamilton’s principle and generalized differential quadrature method (GDQM) are presented...
Coupled bending torsional vibrations of viscoelastic rotors with fractional damper
, Article JVC/Journal of Vibration and Control ; 2022 ; 10775463 (ISSN) ; Haddadpour, H ; Zamani, Z ; Sharif University of Technology
SAGE Publications Inc
2022
Abstract
The behavior of a Jeffcott rotor with lateral-torsional coupling is investigated in the presence of internal and external damping and eccentricity. The governing equations are derived based on the Lagrange method. Also, the Laplace method and linearization is used to solve the governing equations for free vibrations analysis. For a rotor with unbalance, the instability occurs when the real part of eigenvalues has positive values, and at the same time, it is the intersection point between the lines of natural frequencies. The instability speed increases with increasing the external damping, yet dependent on the internal damping and unbalance. Also, it is demonstrated that the rotor critical...
Size effects on stability and bifurcation of nonlinear viscoelastic microcantilevers based on strain gradient
, Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 44, Issue 1 , 2022 ; 16785878 (ISSN) ; Ahmadian, M. T ; Monfared, V ; Toghraie, D ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Analytical frequency analysis of a nonlinear viscoelastic microcantilever is performed based on strain gradient theory. The Kelvin–Voigt scheme is utilized to model the viscoelasticity effect. Due to the microcantilever shortening effect via Euler–Bernoulli inextensibility condition, geometric, inertia, stiffness, and inherent damping nonlinearities are considered. The equation of motion is derived from Hamilton’s principle, and discretized using Galerkin method. The multiple timescale perturbation method is performed to solve the time response equation. Implying steady-state condition, the nonlinear relation between detuning parameter and amplitude of the vibration of a nonlinear...
Viscoelastic dynamics and static responses of a graphene nanoplatelets-reinforced composite cylindrical microshell
, Article Mechanics Based Design of Structures and Machines ; Volume 50, Issue 2 , 2022 , Pages 509-536 ; 15397734 (ISSN) ; Ghabussi, A ; Ebrahimi, F ; Habibi, M ; Safarpour, H ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
In this study, a cylindrical microshell stability reinforced by graphene nanoplatelets is investigated while an axial load is applied uniformly. In addition, viscoelastic foundation covers the composite nanostructure. Therefore, the impacts of the small scale parameter are studied while nonlocal strain gradient theory (NSGT) is considered. The present research deals for the first time with the consideration of viscoelastic, strain–stress size-dependent parameters along with taking into account of various boundary conditions (BCs), especially C-F ones put into effect on the proposed theory. The governing equations (G.Eqs) and BCs have been obtained utilizing energy method and solved with...
Characterization of nanoscale structural heterogeneity in metallic glasses: A machine learning study
, Article Journal of Non-Crystalline Solids ; Volume 578 , 2022 ; 00223093 (ISSN) ; Gholamipour, R ; Bokov, D.O ; Suksatan, W ; Samavatian, V ; Mahmoodan, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Atomic force microscopy (AFM) is an efficient tool for studying the structural heterogeneity in metallic glasses (MGs). However, time-consuming analysis and limitations in the scanning process are downsides of this experiment. To tackle these problems, a machine learning (ML) model was developed to predict the distribution of energy dissipation on the MG surface with the increase in number of AFM scanning. The results indicated that it was possible to accurately predict the energy of scanning points, leading to a timesaving and reliable study. Moreover, characterization of structural heterogeneity shows that the viscoelastic response of each nanoscale region under sequences of AFM scans...
A shooting approach to the scaled boundary finite element equations of elastodynamics in the frequency domain
, Article Computer Methods in Applied Mechanics and Engineering ; Volume 387 , 2021 ; 00457825 (ISSN) ; Sotoudeh, P ; Ghaemian, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Dealing with numerical analysis of problems, especially ones with semi-infinite boundaries, scaled boundary finite element method has emerged as one of the efficient tools for the task. Combining the exactness of strong forms with the flexibility of weak formulations makes the method an improvement to its predecessors. Problem with the method arises when the analytical solution of the semi-discretized system is not available, which is the case for numerous problems. In the most recent attempt to solve the issue, a shooting method was proposed for elastostatic problems. Generality of the method removes any concerns regarding the type of governing equations since it no longer needs any...
Frequency characteristics of a viscoelastic graphene nanoplatelet–reinforced composite circular microplate
, Article JVC/Journal of Vibration and Control ; Volume 27, Issue 1-2 , 2021 , Pages 101-118 ; 10775463 (ISSN) ; Habibi, M ; NoormohammadiArani, O ; Shavalipour, A ; Moayedi, H ; Safarpour, H ; Sharif University of Technology
SAGE Publications Inc
2021
Abstract
This is the first research on the frequency analysis of a graphene nanoplatelet composite circular microplate in the framework of a numerical-based generalized differential quadrature method. Stresses and strains are obtained using the higher order shear deformation theory. The microstructure is surrounded by a viscoelastic foundation. Rule of the mixture is used to obtain varying mass density and Poisson’s ratio, whereas the module of elasticity is computed by a modified Halpin–Tsai model. Governing equations and boundary conditions of the graphene nanoplatelet composite circular microplate are obtained by implementing Hamilton’s principle. The results show that outer to inner radius ratio...
Free vibration analysis of an electro-elastic GPLRC cylindrical shell surrounded by viscoelastic foundation using modified length-couple stress parameter
, Article Mechanics Based Design of Structures and Machines ; Volume 49, Issue 5 , 2021 , Pages 738-762 ; 15397734 (ISSN) ; Ashrafi, N ; Shavalipour, A ; Hosseinpour, A ; Habibi, M ; Moayedi, H ; Babaei, B ; Safarpour, H ; Sharif University of Technology
Bellwether Publishing, Ltd
2021
Abstract
Due to the rapid development of process manufacturing, composite materials with graphene-reinforcement have obtained commercially notices in promoted engineering applications. For this regard, vibrational characteristics of a cylindrical nanoshell reinforced by graphene nanoplatelets (GPL) and coupled with piezoelectric actuator (PIAC) is investigated. Also, the nanostructure is embedded in a viscoelastic medium. The material properties of piece-wise graphene-reinforced composite (GPLRC) are assumed to be graded in the thickness direction of a cylindrical nanoshell and estimated through a nanomechanical model. For the first time in the current study is considering the effects of...
Injectable hydrogels based on oxidized alginate-gelatin reinforced by carbon nitride quantum dots for tissue engineering
, Article International Journal of Pharmaceutics ; Volume 602 , 2021 ; 03785173 (ISSN) ; Salavati Niasari, M ; Mohandes, F ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Stem cell treatment is promising in the various disorders treatment, but its effect is confined by the adverse conditions in the damaged tissues. The utilization of hydrogels has been suggested as a procedure to defeat this issue by developing the engraftment and survival of injected stem cells. Specifically, injectable hydrogels have drawn much attention due to their shape adaptability, ease of use, and the capability to reach body parts that are hard to access. In this study, the thermosensitive injectable hydrogels based on oxidized alginate, gelatin, and carbon nitride quantum dots (CNQDs) have been fabricated for tissue engineering. The mechanical characteristics of the nanocomposite...
Implementation of visco-pseudo-elastic dampers for vibration reduction of sandwich shells using a large deformation FE technique
, Article International Journal of Mechanical Sciences ; Volume 207 , 2021 ; 00207403 (ISSN) ; Hosseini Kordkheili, S. A ; Razov, A ; Resnina, N ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study introduces a numerical method for investigating the appropriate arrangement of visco-pseudo-elastic dampers applicable to shell and plate structures under large deformation. These passive dampers are considered as discrete shape memory alloy (SMA) wires and viscoelastic layers. The SMA constitutive model is adopted and developed based on carried out experimental tests (i.e., calorimetry and tensile tests) on Ni-rich Nitinol alloy samples. Pseudoelastic, pseudoplastic, strain recovery and de-twinning phenomena are perceived experimentally. The presented model characterizes pseudoelastic response of shape memory alloys. The current finite element formulation is based on an...
Distribution of seismic damage in steel buildings component equipped by viscoelastic dampers against far-field earthquake
, Article Shock and Vibration ; Volume 2021 , 2021 ; 10709622 (ISSN) ; Hassanpour Yasaghi, A ; Khodaei, B ; Zarei, R ; Sharif University of Technology
Hindawi Limited
2021
Abstract
Damage to structures with the concept of inelastic behavior and consequently hysteresis energy is very close. Therefore, it can be said that hysteresis energy at these levels can be a significant criterion for designing or controlling the structure. In this research, the first three steel frames of 4, 8, and 12 floors with the medium bending frame system have been designed with the statically equivalent method according to valid international regulations; then, all frames have been subjected to nonlinear dynamic analysis by seven accelerometers. The purpose of this study is to investigate the distribution of damage, energy, relative displacement, roof displacement, and base shear in the...
Dynamic analysis of three-layer cylindrical shells with fractional viscoelastic core and functionally graded face layers
, Article JVC/Journal of Vibration and Control ; Volume 27, Issue 23-24 , 2021 , Pages 2738-2753 ; 10775463 (ISSN) ; Permoon, M. R ; Askarian, A ; Haddadpour, H ; Sharif University of Technology
SAGE Publications Inc
2021
Abstract
Natural frequency and damping behavior of three-layer cylindrical shells with a viscoelastic core layer and functionally graded face layers are studied in this article. Using functionally graded face layers can reduce the stress discontinuity in the face–core interface that causes a catastrophic failure in sandwich structures. The viscoelastic layer is expressed using a fractional-order model, and the functionally graded layers are defined by a power law function. Assuming the classical shell theory for functionally graded layers and the first-order shear deformation theory for the viscoelastic core, equations of motion are derived using Lagrange’s equation and then solved via Rayleigh–Ritz...
Energy absorption of the strengthened viscoelastic multi-curved composite panel under friction force
, Article Archives of Civil and Mechanical Engineering ; Volume 21, Issue 4 , 2021 ; 16449665 (ISSN) ; Zhao, Y ; Gao, J ; Habibi, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
This study investigated FG carbon nanotubes filled composites, which are promising metamaterials that can be useful in the energy absorption field. This structure can absorb energy through elastic deformation. For this issue, absorbed energy and dynamic stability analysis of the FG-CNTRC curved panel surrounded by a non-polynomial viscoelastic substrate using three-dimensional poroelasticity theory is investigated. For stability of the structure after vibrating, the viscoelastic substrate as the non-polynomial viscoelastic model is presented. The curved panel comprises multilayer carbon nanotubes (CNT) which are uniformly distributed in all layers of facing sheets; however, the system’s...
Application of exact continuum size-dependent theory for stability and frequency analysis of a curved cantilevered microtubule by considering viscoelastic properties
, Article Engineering with Computers ; Volume 37, Issue 4 , 2021 , Pages 3629-3648 ; 01770667 (ISSN) ; Habibi, M ; Tounsi, A ; Safarpour, H ; Safa, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
The stability analysis of cantilevered curved microtubules in axons regarding various size elements and using the generalized differential quadrature method for solving equations is reported. The impacts of covering MAP Tau proteins along with cytoplasm are taken into account as the elastic medium. Curved cylindrical nanoshell considering thick wall is used to model the microtubules. The factor of length scale (l/R = 0.2) used in modified couple stress theory would result in more accuracy when it comes to comparison with experiments, while alternative theories presented in this paper provide less precise outcomes. Due to the reported precise results, at the lower value of the time-dependent...
Pore scale visualization of fluid-fluid and rock-fluid interactions during low-salinity waterflooding in carbonate and sandstone representing micromodels
, Article Journal of Petroleum Science and Engineering ; Volume 198 , 2021 ; 09204105 (ISSN) ; Fatemi, M ; Masihi, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Low Salinity Waterflooding (LSWF) has become a popular tertiary injection EOR method recently. Both fluid-fluid and fluid-rock interactions are suggested as the contributing mechanisms on the effectiveness of LSWF. Considering the contradictory remarks in the literature, the dominating mechanisms and necessary conditions for Low Salinity Effect (LSE) varies for different crude oil-brine-rock (CBR) systems. The aim of the present study is to investigate LSE for an oil field in the Middle East that is composed of separate sandstone and limestone layers. Contact angles and Interfacial Tension (IFT) are measured to have more insight on the CBR under investigation. Visual experiments were...
Nonlinear oscillations of viscoelastic microcantilever beam based on modified strain gradient theory
, Article Scientia Iranica ; Volume 28, Issue 2 , 2021 , Pages 785-794 ; 10263098 (ISSN) ; Ahmadian, M. T ; Firoozbakhsh, K ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
A viscoelastic microcantilever beam is analytically analyzed based on the modified strain gradient theory. Kelvin-Voigt scheme is used to model beam viscoelasticity. By applying Euler-Bernoulli inextensibility of the centerline condition based on Hamilton's principle, the nonlinear equation of motion and the related boundary conditions are derived from shortening effect theory and discretized by Galerkin method. Inner damping, nonlinear curvature effect, and nonlinear inertia terms are also taken into account. In the present study, the generalized derived formulation allows modeling any nonlinear combination such as nonlinear terms that arise due to inertia, damping, and stiffness, as well...
Synthesis of a custom-made suspension of preformed particle gel with improved strength properties and its application in the enhancement of oil recovery in a micromodel scale
, Article Journal of Petroleum Science and Engineering ; Volume 207 , 2021 ; 09204105 (ISSN) ; Baghban Salehi, M ; Taghikhani, V ; Pahlevani, H ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The objective of this work is to develop a new Preformed Particle Gel (PPG) suspension to enhance oil production and monitor water production in a porous medium on micromodel scale. To achieve the above goal, the following synthetic method was used. At the outset, the PPG samples were synthesized with polyethylene amine (PEI) as a crosslinker, 2,2′-Azobis (2-methylpropionamidine) dihydrochloride (AAPH) as initiator and acrylamide (AM) and 2-Acrylamido-2-methylpropanesulfonic acid (AMPS) monomers to improve the strength properties of PPGs by the radical polymerization method. Also, to characterize the micro and macro structural the samples, the scanning electron microscopy (SEM),...
Crack-based healing master curve derived from linear amplitude sweep tests: a cohesive healing indicator for asphalt binders
, Article Materials and Structures/Materiaux et Constructions ; Volume 54, Issue 4 , 2021 ; 13595997 (ISSN) ; Tabatabaee, N ; Hajj, R ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
This investigation employed an interrupted torsion fatigue test using the linear amplitude sweep procedure to assess the intrinsic self-healing potential of unaged, aged, rejuvenated, and re-aged asphalt binders. Continuous oscillatory shear strain loading at different damage levels were interrupted with a single rest period of different durations. An index based on the decrease in crack length following the rest period (Ha) has been defined to accurately reflect the occurrence of healing. The results indicate that Ha is higher at lower damage levels and for longer rest-period durations. The amount of irreversible crack growth increased with an increase in crack propagation and aging level....
An intelligent computer method for vibration responses of the spinning multi-layer symmetric nanosystem using multi-physics modeling
, Article Engineering with Computers ; 2021 ; 01770667 (ISSN) ; Baharvand, A ; Tazeddinova, D ; Habibi, M ; Safarpour, H ; Roco Videla, A ; Selmi, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
This article is the first attempt to employ deep learning to estimate the frequency performance of the rotating multi-layer nanodisks. The optimum values of the parameters involved in the mechanism of the fully connected neural network are determined through the momentum-based optimizer. The strength of the method applied in this survey comes from the high accuracy besides lower epochs needed to train the multi-layered network. It should be mentioned that the current nanostructure is modeled as a nanodisk on the viscoelastic substrate. Due to rotation, the centrifugal and Coriolis effects are considered. Hamilton’s principle and generalized differential quadrature method (GDQM) are presented...