Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2
1
2016
08
15
Modeling of the intermolecular Force-Induced Adhesion in Freestanding Nanostructures Made of Nano-beams
1
7
EN
Alireza
Yekrangi
Department of Engineering, Ramsar Branch, Islamic Azad University, Ramsar, Iran
yekrangi_ali@yahoo.com
Rahman
Soroush
Department of Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran
eng.soroush322@yahoo.com
10.22055/jacm.2016.12264
Among the intermolecular interactions, the Casimir and van der Waals forces are the most important forces that highly affect the behavior of nanostructures. This paper studies the effect of such forces on the adhesion of cantilever freestanding nanostructures. The nanostructures are made of a freestanding nano-beam which is suspended between two upper and lower conductive surfaces. The linear spring model is applied to derive the elastic force. The Lumped Parameter Model (LPM) is used to obtain constitutive equations of the systems. The maximum length of the nano-beam which prevents the adhesion is computed. Results of this study are useful for design and development of miniature devices.
Adhesion,Casimir force,Van der Waals force,Freestanding nano-beam,Lumped Parameter Model (LPM)
http://jacm.scu.ac.ir/article_12264.html
http://jacm.scu.ac.ir/article_12264_032be72b744fbed8aecf4e6958fd85dd.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2
1
2016
08
07
Investigation of the vdW Force-Induced Instability in Nano-scale Actuators Fabricated form Cylindrical Nanowires
8
20
EN
Rahman
Soroush
Department of Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran
eng.soroush322@yahoo.com
Alireza
Yekrangi
Department of Engineering, Ramsar Branch, Islamic Azad University, Ramsar, Iran
yekrangi_ali@yahoo.com
10.22055/jacm.2016.12265
The presence of van der Waals (vdW) force can lead to mechanical instability in freestanding nano-scale actuators. Most of the previous researches in this area have exclusively focused on modeling the instability in actuators with one actuating components. While, less attention has been paid to actuators consist of two actuating components. Herein, the effect of the vdW force on the instability of freestanding actuators with two parallel actuating components is investigated. Conventional configurations including cantilever and double-clamped geometries are investigated. A continuum mechanics theory in conjunction with Euler-beam model is applied to obtain governing equations of the systems. The nonlinear governing equations of the actuators are solved using two different approaches, i.e. the modified Adomian decomposition and the finite difference method. The maximum length of the nanowire and minimum initial gap which prevents the instability is computed.
Freestanding nanoactuators,van der Waals (vdW) force,instability,modified Adomian decomposition,finite difference method
http://jacm.scu.ac.ir/article_12265.html
http://jacm.scu.ac.ir/article_12265_bc43214d247d95d2a78118aad27820b2.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2
1
2016
08
08
Jeffery Hamel Flow of a non-Newtonian Fluid
21
28
EN
Umar
Khan
Department of Mathematics, Faculty of Sciences, HITEC University, Taxila Cantt, Pakistan
h.msedighi@scu.ac.ir
Naveed
Ahmed
Department of Mathematics, Faculty of Sciences, HITEC University, Taxila Cantt, Pakistan
hmsedighi@yahoo.com
Waseem
Sikandar
Department of Mathematics, Faculty of Sciences, HITEC University, Taxila Cantt, Pakistan
hmsedighi@hotmail.com
Syed Tauseef
Mohyud-Din
HITEC University Taxila Cantt Pakistan
syedtauseefs@hotmail.com
10.22055/jacm.2016.12266
This paper presents the Jeffery Hamel flow of a non-Newtonian fluid namely Casson fluid. Suitable similarity transform is applied to reduce governing nonlinear partial differential equations to a much simpler ordinary differential equation. Variation of Parameters Method (VPM) is then employed to solve resulting equation. Same problem is solved numerical by using Runge-Kutta order 4 method. A comparison between both the solutions is carried out to check the efficiency of VPM. Effects of emerging parameters are demonstrated both for diverging and converging channels using graphical simulation.
Jeffery-Hamel flow,Casson fluid,Variation of Parameters Method (VPM),converging and diverging channels,Runge-Kutta order 4 method
http://jacm.scu.ac.ir/article_12266.html
http://jacm.scu.ac.ir/article_12266_b96694dbc7861d9aa77036add0ac91a5.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2
1
2016
08
01
An Analytical Technique for Solving Nonlinear Oscillators of the Motion of a Rigid Rod Rocking Bock and Tapered Beams
29
34
EN
Gamal
Ismail
Mathematics Department
Faculty of Science
Sohag University
Sohag, Egypt
gamalm2010@yahoo.com
10.22055/jacm.2016.12268
In this paper, a new analytical approach has been presented for solving strongly nonlinear oscillator problems. Iteration perturbation method leads us to high accurate solution. Two different high nonlinear examples are also presented to show the application and accuracy of the presented method. The results are compared with analytical methods and with the numerical solution using Runge-Kutta method in different figures. It has been shown that the iteration perturbation approach doesn't need any small perturbation and is accurate for nonlinear oscillator equations.
Periodic solution,Nonlinear oscillators,Motion of a rigid rod rocking back,Tapered beams
http://jacm.scu.ac.ir/article_12268.html
http://jacm.scu.ac.ir/article_12268_6b4ae7952064eecdfe9ab67bbef9e769.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2
1
2016
08
10
Periodic Solutions of the Duffing Harmonic Oscillator by He's Energy Balance Method
35
41
EN
A. M.
El-Naggar
Department of Mathematics, Faculty of Science, Benha University, Egypt
hmsedighi@yahoo.com
Gamal
Ismail
Mathematics Department
Faculty of Science
Sohag University
Sohag, Egypt
gamalm2010@yahoo.com
10.22055/jacm.2016.12269
Duffing harmonic oscillator is a common model for nonlinear phenomena in science and engineering. This paper presents He´s Energy Balance Method (EBM) for solving nonlinear differential equations. Two strong nonlinear cases have been studied analytically. Analytical results of the EBM are compared with the solutions obtained by using He´s Frequency Amplitude Formulation (FAF) and numerical solutions using Runge-Kutta method. The results show the presented method is potentially to solve high nonlinear oscillator equations.
Energy balance method,Nonlinear oscillator,Duffing-harmonic oscillator,Periodic solutions
http://jacm.scu.ac.ir/article_12269.html
http://jacm.scu.ac.ir/article_12269_93df035a219e7c855ade51e2844c40bc.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2
1
2016
08
20
Saint-Venant torsion of non-homogeneous anisotropic bars
42
53
EN
John
T.
Katsikadelis
School of Civil Engineering
National Technical University of Athens (NTUA)
Zografou Campus
Athens 15773
Greece
jkats@central.ntua.gr
George
C.
Tsiatas
Department of Mathematics, University of Patras, Rio
gtsiatas@gmail.com
10.22055/jacm.2016.12270
The BEM is applied to the solution of the torsion problem of non-homogeneous anisotropic non-circular prismatic bars. The problem is formulated in terms of the warping function. This formulation leads to a second order partial differential equation with variable coefficients, subjected to a generalized Neumann type boundary condition. The problem is solved using the Analog Equation Method (AEM). According to this method, the governing equation is replaced by a Poisson’s equation subjected to a fictitious source under the same boundary condition. The fictitious load is established using the Boundary Element Method (BEM) after expanding it into a finite series of radial basis functions. The method has all the advantages of the pure BEM, since the discretization and integration are limited only on to the boundary. Numerical examples are presented which illustrate the efficiency and accuracy of the method.
Anisotropic materials,Non-homogeneous media,Elasticity,Bars,Torsion
http://jacm.scu.ac.ir/article_12270.html
http://jacm.scu.ac.ir/article_12270_5ba4dad84d8c4e4072ae8097ad43c3dc.pdf