List of articles (by subject) micro and nano mechanics
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Open Access Article
1 - Effect of Injection Velocity on Heat Transfer of Water/Alumina Nano Fluid in A Rectangular Microchannel
Afshin Ahmadi Nadooshan Afshin Shiriny Morteza BayarehIn this study, forced convection heat transfer of water/alumina Nano fluid in a rectangular microchannel with cross-flow injection is studied. The Nano fluid enters the microchannel with a temperature of 293 K and cools its walls. The upper wall of the microchannel is a MoreIn this study, forced convection heat transfer of water/alumina Nano fluid in a rectangular microchannel with cross-flow injection is studied. The Nano fluid enters the microchannel with a temperature of 293 K and cools its walls. The upper wall of the microchannel is at constant temperature of 303 K. On the lower wall, there are two holes for injection of Nano fluid flow. Other parts of the microchannel wall are insulated. Slip velocity boundary condition is used for the walls of the microchannel. Simulations are performed for different injection velocities and the results are presented as velocity and temperature fields, and variation of the Nusselt number. The results show that the slip velocity on the channel wall and the Nusselt number increase by increasing the injection velocity. It is revealed that the Nusselt number is maximum at the channel entrance and decreases along the channel. After each injection, local Nusselt number increases due to the increase of the temperature gradient in the microchannel. Moreover, an optimal value for the ratio of the injection velocity to the inlet velocity is achieved using performance evaluation criteria (PEC). It is concluded that is an optimal value of the injection velocity, leading to maximum PEC. Manuscript profile -
Open Access Article
2 - Vibration Sensitivity Analysis of Nano-mechanical Piezo-Laminated Beams with Consideration of Size Effects
mostafa nazemizadeh Firooz Bakhtiari-Nejad Behrooz ShahriariThe presented article investigates vibration sensitivity analysis of Nano-mechanical piezo-laminated beams with consideration of size effects. To do this, the vibration governing equation of the stepped Nano-mechanical piezo-laminated beam is firstly derived by implemen MoreThe presented article investigates vibration sensitivity analysis of Nano-mechanical piezo-laminated beams with consideration of size effects. To do this, the vibration governing equation of the stepped Nano-mechanical piezo-laminated beam is firstly derived by implementation of the nonlocal elasticity theory. The nonlocal formulation is considered for both of the beam and the piezoelectric layer and the obtained equation is solved analytically. Moreover, there is a need to recognize the importance and relative effects of the beam parameters on the natural frequencies and resonant amplitudes of the nonlocal beam. Therefore, the Sobol sensitivity analysis is utilized to investigate the relative effects of geometrical and the nonlocal parameters on the natural frequencies and the resonant amplitude of the nanobeam. The obtained results show that the length and the thickness of the piezoelectric layer have prominent effects on the vibration characteristics of the beam. Moreover, it is indicated that nonlocal parameter effect on the resonant amplitudes is more than resonant frequency. Also, the effect of the nonlocal term is more important at higher modes of vibration. Therefore, the nonlocal size effects cannot be ignored in vibration analysis of the nanobeam especially at higher modes. Manuscript profile -
Open Access Article
3 - Buckling Analysis of Orthotropic Annular Graphene Sheet with Various Boundary Conditions in an Elastic Medium
Hamed Vahabi Mohammad Esmaeil Golmakani Ismaeil MobasherIn this study, axisymmetric buckling of annular orthotropic graphene sheet embedded in a Winkler–Pasternak elastic medium is scrutinized for different boundary conditions based on non-local elasticity theory. With the aid of principle of virtual work, the non-loca MoreIn this study, axisymmetric buckling of annular orthotropic graphene sheet embedded in a Winkler–Pasternak elastic medium is scrutinized for different boundary conditions based on non-local elasticity theory. With the aid of principle of virtual work, the non-local governing equations are derived based on First-order Shear Deformation Theory (FSDT). Differential Quadrature Method (DQM) is also used to solve equilibrium equations. Edges of Nano-plate might be restrained by different combinations of free, simply supported or clamped boundary conditions. To confirm results, comparison of studies is made between results obtained and available solutions in the literature. Finally, a detailed parametric study is conducted to investigate the impact of small scale effects, surrounding elastic medium, boundary conditions and geometrical parameters on critical buckling load. The main goal of this work is to study the effect of various non-local parameters on the buckling load of annular Nano-plate for different boundary conditions, Winkler and shear foundation parameters, annularity and thickness-to-radius ratios. It is seen that for Nano-plates without an elastic foundation, the impact of thickness on buckling load does not depend on values of non-local parameter and annularity. Results also show that impact of elastic basis on the buckling load is independent of small scale effects. Manuscript profile -
Open Access Article
4 - Sensitivity Analysis of Piezoelectric Microcantilever Excitability as Resonator
Reza GhaderiPiezoelectric Microcantilevers (MCs) are efficient tools in switches of MEMS, AFMs and nano-resonators. Creating maximum vibrating motion with minimum excitation voltage is important in reducing power consumption and noise in this type of MCs. Therefore, investigating t MorePiezoelectric Microcantilevers (MCs) are efficient tools in switches of MEMS, AFMs and nano-resonators. Creating maximum vibrating motion with minimum excitation voltage is important in reducing power consumption and noise in this type of MCs. Therefore, investigating the factors affecting the excitability of MCs, as well as the degree of the effect of each of these factors, have an important role in the design and optimal selection of this type of resonators. Therefore, the aim of this paper was to investigate the excitability of this type of MCs. Modeling is conducted according to Hamilton principle and Euler-Bernoulli theory. Equation of motion was solved using Galerkin method with respect to geometrical discontinuities. Finally, eFAST sensitivity analysis was performed on excitability of MCs using statistical methods. Sensitivity analysis results show that the length and thickness of the piezoelectric layer are the most influential parameters on the excitability of MCs. At L1/L=0.74, the excitability reaches its maximum value. Manuscript profile -
Open Access Article
5 - Investigation of the AFM Indenter’s Geometry Effect On Micro/Nano Biological Cells’ Indentation
Yousef Habibi Sooha Moharam Habibnejad Zahra RastegarThe elasticity modules of the micro/Nanoparticles, especially biological particles are measured using different tools such as atomic force microscopy. The tip of the atomic force microscopy as an indenter has different shapes such as spherical, conical and pyramidal. In MoreThe elasticity modules of the micro/Nanoparticles, especially biological particles are measured using different tools such as atomic force microscopy. The tip of the atomic force microscopy as an indenter has different shapes such as spherical, conical and pyramidal. In the contact of these tips and biological cells, avoiding the cell damage is a necessity. The goal of this paper is investigation and comparison of different tips’ geometries. Different tip’s geometries and their related theories were collected and proposed. To generalize theories’ application for any kind of particle (even non-biological particles) some of simplifying assumptions used in these theories, such as tip rigidity, were removed. Simulation of the force- indentation depth was done for gold nanoparticle and observed that if simplifying assumptions were not removed there would be big errors in calculating the elasticity module of some particles. Then, simulations were done for two yeast and mouse embryo cells. For both cells, in general, the geometry of the curve group, the geometry of the pyramidal group and finally the geometry of the conical group were positioned from the highest to the lowest places. For hyperbolic, conical and pyramidal tips, the important parameter was semi vertical angel. To observe its effect, different magnitudes of this parameter were simulated. According to observed results in three investigated geometries and for both cells, bigger semi vertical angel created higher curves and this means in bigger angels the possibility of cell damage is higher. Manuscript profile -
Open Access Article
6 - Effect of Deposition Time on the Morphological Features and Structure of DLC Coatings on Aluminuim-T6 by PACVD
seyed mohammad mahdi shafiei Hamed raeiesifard kameleh JafariDiamond like Carbon (DLC) was deposited on aluminum substrate using Plasma Assisted Chemical Vapor Deposition (PACVD) route. Spattering, the surface was activated before deposition for increasing adhesion. Deposition time was varied from 60 minutes to 5 hours. Deposit w MoreDiamond like Carbon (DLC) was deposited on aluminum substrate using Plasma Assisted Chemical Vapor Deposition (PACVD) route. Spattering, the surface was activated before deposition for increasing adhesion. Deposition time was varied from 60 minutes to 5 hours. Deposit was characterized using with grazing incidence X-ray diffraction and atomic force microscope. The mechanical property was measured using microhardness and roughness tester. The analysis showed that the deposit consisted of columnar growth of submicron and micron meter scale. Compared to substrate material, deposit showed higher hardness and roughness. These results show that growth of DLC layer includes three stages. The first stage is primary growth of nuclei, and then these nuclei join together in second stage. In third stage, secondary growth of these nuclei happens. Manuscript profile -
Open Access Article
7 - Mechanical Buckling of Circular Orthotropic Bilayer Nanoplate Embedded in an Elastic Matrix under Radial Compressive Loading
M. Ahmadpour M.E. Golmakani M.N. Sadraee FarThis article investigates the buckling behavior of orthotropic annular/circular bilayer graphene sheet embedded in Winkler–Pasternak elastic medium under mechanical loading. Using the nonlocal elasticity theory, the bilayer graphene sheet is modeled as a nonlocal MoreThis article investigates the buckling behavior of orthotropic annular/circular bilayer graphene sheet embedded in Winkler–Pasternak elastic medium under mechanical loading. Using the nonlocal elasticity theory, the bilayer graphene sheet is modeled as a nonlocal orthotropic plate which contains small scale effect and van der Waals interaction forces. Differential Quadrature Method (DQM) is employed to solve the governing equations for various combinations of simply supported or clamped boundary conditions. The results show that small scale parameter does not have any effect on critical buckling load of cases without elastic medium in simply supported boundary condition. Also, increase of vdW coefficient leads to increase of critical buckling load smoothly then it has no impact on critical buckling load after a certain value. Manuscript profile -
Open Access Article
8 - Vibration Analysis of Rectangular Kirchhoff Nano-Plate using Modified Couple Stress Theory and Navier Solution Method
Behzad Bayati Chaleshtori Ali Hajiahmad Seyed Saeid MohtasebiIn this study, the characteristics of rectangular Kirchhoff nano-plate vibrations are investigated using a modified couple stress theory. To consider the effects of small-scale, the modified couple stress theory proposed by Young (2002) is used as it has only one length MoreIn this study, the characteristics of rectangular Kirchhoff nano-plate vibrations are investigated using a modified couple stress theory. To consider the effects of small-scale, the modified couple stress theory proposed by Young (2002) is used as it has only one length scale parameter. In modified couple stress theory, the strain energy density is a function of the components of the strain tensor, curvature tensor, stress tensor, and symmetric part of the couple stress tensor. After obtaining the strain energy, external work, and kinetic energy equation and inserting them in the Hamilton principle, the main and auxiliary equations of nano-plate are obtained. Then, by applying the boundary and force conditions in the governing equations, the vibrations of the rectangular Kirschhof nano-plate with the thickness are investigated with simple support around. The solution method used in this study is the Navier method and the effects of material length scale, length and thickness of the nanoplate on the vibration are investigated and the results are presented and discussed in details. Manuscript profile -
Open Access Article
9 - Bending and Buckling Analysis of a Nth-Order Shear Deformation Nanoplate using Modified Couple Stress Theory
Majid Eskandari shahraki mahmoud shariati naser asiabanIn this paper a Nth order nanoplate model is developed for the bending and buckling analysis of a graphene nanoplate based on a modified couple stress theory. The strain energy, external work and buckling equations are solved. Also using Hamilton’ principle, main MoreIn this paper a Nth order nanoplate model is developed for the bending and buckling analysis of a graphene nanoplate based on a modified couple stress theory. The strain energy, external work and buckling equations are solved. Also using Hamilton’ principle, main and auxiliary equations of nano plate are obtained. The bending rates and dimensionless bending values under uniform surface traction and sinusoidal load, the dimensionless critical force under a uniaxial surface force in x direction are all obtained for various plate's dimensional ratios and material length scale to thickness ratios. The governing equations are numerically solved. The effect of material length scale, length, width and thickness of the nanoplate on the bending and buckling ratios are investigated and the results are presented and discussed in details. Manuscript profile -
Open Access Article
10 - Bending and Vibration Analysis of a Mindlin Rectangular Nanoplate using Modified Couple Stress Theory and Navier's Solution
Majid Eskandari Shahraki Mahmoud Shariati naser asiabanIn this paper, a Mindlin rectangular nanoplate model is developed for the bending and vibration analysis of a graphene nanoplate based on a modified couple stress theory. In order to consider the small scale effects, the modified couple stress theory, with one length sc MoreIn this paper, a Mindlin rectangular nanoplate model is developed for the bending and vibration analysis of a graphene nanoplate based on a modified couple stress theory. In order to consider the small scale effects, the modified couple stress theory, with one length scale parameter, is used. In modified couple stress theory, strain energy density is a function of strain tensor, curvature tensor, stress tensor and symmetric part of couple stress tensor. After obtaining the strain and kinetic energy, external work and substituting them in the Hamilton’s principle, the main and auxiliary equations of the nanoplate are obtained. Then, by manipulating the boundary conditions the governing equations are solved using Navier approach for bending and vibration of the nanoplate. The bending rates and dimensionless bending values under uniform surface traction and sinusoidal load and different mode frequencies are all obtained for various plate's dimensional ratios and material length scale to thickness ratios. The effect of material length scale, length, width and thickness of the nanoplate on the bending and vibration ratios are investigated and the results are presented and discussed in details. Manuscript profile -
Open Access Article
11 - Leaching of Metals from Dental Silver Alloy Wastes
Razieh Khoshhal Hojjat Mirzaei-Ghasabeh Mohammad Asadrokht Ali HosseinzadehEnvironmental issues of hazardous metal wastes as well as growing demand for metals has increased focus on the forthcoming provision of metals. Therefore, the recovery and recycling processes of precious metals from secondary resources have become more prominent in the MoreEnvironmental issues of hazardous metal wastes as well as growing demand for metals has increased focus on the forthcoming provision of metals. Therefore, the recovery and recycling processes of precious metals from secondary resources have become more prominent in the last years. Silver is one of the precious metals which can be recovered from wastes such as electronic wastes, coin and medal production losses, photographic films, and dental filling materials known as amalgam, which has the highest silver content. The present paper investigates the acid leaching of metals from a waste sample of dental silver alloy generated during the melt spray process. The alloy constitutes of 42.13% Ag, 31.03% Sn, and 26.84 Cu. The phase composition of amalgam generally consists of Ag2Hg3, Ag3Sn, SnxHg, Cu6Sn5, and Cu3Sn. The effects of the system temperature (25-80°C), nitric acid concentration as the leachate (13.75-65%), pulp density (33-200 g/l), and reaction time (0-240 min) on the dissolution recovery of silver, copper, and tin have been investigated. In the best case, we recovered 100% of silver and 98% of copper as soluble nitrates while tin was isolated as solid stannic oxide. Manuscript profile -
Open Access Article
12 - Vibration Analysis and Sensitivity Analysis of Semi-Submerged Multilayer Piezoelectric Microcantilever
Mohamadreza Khosravi Reza GhaderiThe growing development of nanobiotechnology and its applicability resulted in a wider range of use of Microcantilevers (MCs) in liquid. Considering the applications of piezoelectric MCs in the microelectromechanical systems and Atomic Force Microscope (AFM), as well as MoreThe growing development of nanobiotechnology and its applicability resulted in a wider range of use of Microcantilevers (MCs) in liquid. Considering the applications of piezoelectric MCs in the microelectromechanical systems and Atomic Force Microscope (AFM), as well as the high performance of these beams, this article investigates the vibrating behavior of multilayer piezoelectric MCs with geometric discontinuity in liquid environment. Due to the extreme complexity of hydrodynamic forces introduced to MCs, this force may reduce their accuracy. As a result, the MC was considered to be semi-submerged in the liquid medium to reduce the effect of hydrodynamic force. In addition, to reduce the effect of hydrodynamic force on vibrating behavior of the MC, sensitivity analysis was performed on its geometric dimensions to obtain the optimal dimensions, aiming at minimizing the effect of this force. The differential equation of motion was derived using the Euler–Bernoulli theory and the Lagrange method. The hydrodynamic force was exerted on the MC through the sphere string model. The Simulation results indicated that due to reducing resonance frequency variations in the third vibrating mode, the effect of hydrodynamic force on vibrating motion is minimized in this mode and considered as the optimal vibrating mode among the first three modes. The sensitivity analysis results showed that the MC length and piezoelectric layer were geometric parameters with the greatest effect on frequency sensitivity of MC, which should be considered in semi-submerged piezoelectric MC design. Manuscript profile -
Open Access Article
13 - Heat Transfer of Wavy Microchannel Heat Sink with Microtube and Ag/Water-Ethylene Glycol Hybrid Nanofluid
Akram Jahanbakhshi Afshin Ahmadi Nadooshan morteza BayrehIn the present study, novel channel geometries in a wavy channel heat sink (HS) are investigated using ANSYS-FLUENT software. The Ag/water-ethylene glycol (50%) nanofluid is selected for cooling the CPU in this HS. The second-order upwind method is employed to discretiz MoreIn the present study, novel channel geometries in a wavy channel heat sink (HS) are investigated using ANSYS-FLUENT software. The Ag/water-ethylene glycol (50%) nanofluid is selected for cooling the CPU in this HS. The second-order upwind method is employed to discretize the momentum Equation and the SIMPLEC algorithm is employed for coupling velocity and pressure fields. Comparison of the two HSs with and without microtube shows that the presence of the microtube increases the uniformity of the CPU surface temperature distribution and decreases the mean surface temperature of the CPU (TCPU-Mean). However, the pumping power consumption of the system increases about 10 times. The results also demonstrate that the addition of nanoparticles results in intensification in the Performance Evaluation Criterion (PEC) of the system and up to 30%, especially at high Reynolds numbers. Manuscript profile -
Open Access Article
14 - Characterization of DLC Thin Films Deposited by DC-Pulsed PACVD using Methane Precursor
seyed mohammad mahdi shafiei Hamed raeiesifardIn this work, Diamond Like Carbon (DLC) thin films were deposited on aluminum alloy 6061 by Plasma-Assisted Chemical Vapor Deposition (PACVD). Nitiding prior to coated leads to appropriate hardness gradient and it can greatly improve the mechanical properties of the coa MoreIn this work, Diamond Like Carbon (DLC) thin films were deposited on aluminum alloy 6061 by Plasma-Assisted Chemical Vapor Deposition (PACVD). Nitiding prior to coated leads to appropriate hardness gradient and it can greatly improve the mechanical properties of the coatings. The composition, crystalline structure and phase of the films were investigated by Grazing Incidence X-ray Diffraction (GIXRD). Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were employed to observe the morphology and structure of the film. The DLC layer exhibited a columnar structure. The adhesion force between the film and the aluminum alloy 6061 was 30.8 Mpa. The DLC film was determined by the pull of test. The hardness of the DLC film was 12.75 Gpa. The improvement of the adhesion DLC was attributed to a less gradient hardness configuration. In addition, the mean friction coefficient of the films was about 0.2 determined by nanoindentation test. According to the results, the high and unique hardness of this coating leads to increase of the wear resistance and thus the useful life of parts. Manuscript profile -
Open Access Article
15 - Active Control of Sandwich Microbeams Vibration with FGM and Viscoelastic/ER Core
Amir Hossein Yousefi farhad kiani Esmaeil AbediThis study is devoted to analyse of free and forced vibrations and semi-active control vibrations of sandwich microbeam with Functionally Graded Materials (FGM) and viscoelastic/electrorheological (ER) core. The intended model is for top and bottom layers of functionall MoreThis study is devoted to analyse of free and forced vibrations and semi-active control vibrations of sandwich microbeam with Functionally Graded Materials (FGM) and viscoelastic/electrorheological (ER) core. The intended model is for top and bottom layers of functionally graded materials with power law and a core model for Viscoelastic materials with complex shear modulus. Hamilton principle is used to determine the governing Equations of motion on the sandwich microbeam based on the modified couple stress theory. Mesh less method of Radial Basis Functions (RBF) is used to calculate natural frequency and the loss factor. All the effects of length scale parameter, shear modulus and changes due to variation of the electric field on the natural frequency and loss factor have been drawn. Combination of RBF method and forward difference led to evaluation of forced vibration and deflection of microbeam for length scale parameters and different electric fields under the dynamic load have been calculated and drawn. The feedback effects are analyzed for vibration amplitudes of sandwich microbeam by using Linear Quadratic Gaussian (LQG) and optimal control method. At the end, the results are compared with papers for different viscoelastic models such as Kelvin model, Bingham plastic model and complex modulus. Manuscript profile