eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2016-08-15
2
1
1
7
10.22055/jacm.2016.12264
12264
مقاله پژوهشی
Modeling of the intermolecular Force-Induced Adhesion in Freestanding Nanostructures Made of Nano-beams
Alireza Yekrangi
yekrangi_ali@yahoo.com
1
Rahman Soroush
eng.soroush322@yahoo.com
2
Department of Engineering, Ramsar Branch, Islamic Azad University, Ramsar, Iran
Department of Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran
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.
http://jacm.scu.ac.ir/article_12264_032be72b744fbed8aecf4e6958fd85dd.pdf
Adhesion
Casimir force
Van der Waals force
Freestanding nano-beam
Lumped Parameter Model (LPM)
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2016-08-07
2
1
8
20
10.22055/jacm.2016.12265
12265
مقاله پژوهشی
Investigation of the vdW Force-Induced Instability in Nano-scale Actuators Fabricated form Cylindrical Nanowires
Rahman Soroush
eng.soroush322@yahoo.com
1
Alireza Yekrangi
yekrangi_ali@yahoo.com
2
Department of Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran
Department of Engineering, Ramsar Branch, Islamic Azad University, Ramsar, Iran
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.
http://jacm.scu.ac.ir/article_12265_bc43214d247d95d2a78118aad27820b2.pdf
Freestanding nanoactuators
van der Waals (vdW) force
instability
modified Adomian decomposition
finite difference method
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2016-08-08
2
1
21
28
10.22055/jacm.2016.12266
12266
مقاله پژوهشی
Jeffery Hamel Flow of a non-Newtonian Fluid
Umar Khan
h.msedighi@scu.ac.ir
1
Naveed Ahmed
hmsedighi@yahoo.com
2
Waseem Sikandar
hmsedighi@hotmail.com
3
Syed Tauseef Mohyud-Din
syedtauseefs@hotmail.com
4
Department of Mathematics, Faculty of Sciences, HITEC University, Taxila Cantt, Pakistan
Department of Mathematics, Faculty of Sciences, HITEC University, Taxila Cantt, Pakistan
Department of Mathematics, Faculty of Sciences, HITEC University, Taxila Cantt, Pakistan
HITEC University Taxila Cantt Pakistan
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.
http://jacm.scu.ac.ir/article_12266_b96694dbc7861d9aa77036add0ac91a5.pdf
Jeffery-Hamel flow
Casson fluid
Variation of Parameters Method (VPM)
converging and diverging channels
Runge-Kutta order 4 method
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2016-08-01
2
1
29
34
10.22055/jacm.2016.12268
12268
مقاله پژوهشی
An Analytical Technique for Solving Nonlinear Oscillators of the Motion of a Rigid Rod Rocking Bock and Tapered Beams
Gamal Ismail
gamalm2010@yahoo.com
1
Mathematics Department
Faculty of Science
Sohag University
Sohag, Egypt
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.
http://jacm.scu.ac.ir/article_12268_6b4ae7952064eecdfe9ab67bbef9e769.pdf
Periodic solution
Nonlinear oscillators
Motion of a rigid rod rocking back
Tapered beams
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2016-08-10
2
1
35
41
10.22055/jacm.2016.12269
12269
مقاله پژوهشی
Periodic Solutions of the Duffing Harmonic Oscillator by He's Energy Balance Method
A. M. El-Naggar
hmsedighi@yahoo.com
1
Gamal Ismail
gamalm2010@yahoo.com
2
Department of Mathematics, Faculty of Science, Benha University, Egypt
Mathematics Department
Faculty of Science
Sohag University
Sohag, Egypt
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.
http://jacm.scu.ac.ir/article_12269_93df035a219e7c855ade51e2844c40bc.pdf
Energy balance method
Nonlinear oscillator
Duffing-harmonic oscillator
Periodic solutions
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2016-08-20
2
1
42
53
10.22055/jacm.2016.12270
12270
مقاله پژوهشی
Saint-Venant torsion of non-homogeneous anisotropic bars
John Katsikadelis
jkats@central.ntua.gr
1
George Tsiatas
gtsiatas@gmail.com
2
School of Civil Engineering National Technical University of Athens (NTUA) Zografou Campus Athens 15773 Greece
Department of Mathematics, University of Patras, Rio
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.
http://jacm.scu.ac.ir/article_12270_5ba4dad84d8c4e4072ae8097ad43c3dc.pdf
Anisotropic materials
Non-homogeneous media
Elasticity
Bars
Torsion