2017-10-24T13:07:18Z
http://jacm.scu.ac.ir/?_action=export&rf=summon&issue=1444
Journal of Applied and Computational Mechanics
JACM
2016
2
1
Modeling of the intermolecular Force-Induced Adhesion in Freestanding Nanostructures Made of Nano-beams
Alireza
Yekrangi
Rahman
Soroush
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)
2016
08
15
1
7
http://jacm.scu.ac.ir/article_12264_032be72b744fbed8aecf4e6958fd85dd.pdf
Journal of Applied and Computational Mechanics
JACM
2016
2
1
Investigation of the vdW Force-Induced Instability in Nano-scale Actuators Fabricated form Cylindrical Nanowires
Rahman
Soroush
Alireza
Yekrangi
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
2016
08
07
8
20
http://jacm.scu.ac.ir/article_12265_bc43214d247d95d2a78118aad27820b2.pdf
Journal of Applied and Computational Mechanics
JACM
2016
2
1
Jeffery Hamel Flow of a non-Newtonian Fluid
Umar
Khan
Naveed
Ahmed
Waseem
Sikandar
Syed Tauseef
Mohyud-Din
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
2016
08
08
21
28
http://jacm.scu.ac.ir/article_12266_b96694dbc7861d9aa77036add0ac91a5.pdf
Journal of Applied and Computational Mechanics
JACM
2016
2
1
An Analytical Technique for Solving Nonlinear Oscillators of the Motion of a Rigid Rod Rocking Bock and Tapered Beams
Gamal
Ismail
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
2016
08
01
29
34
http://jacm.scu.ac.ir/article_12268_6b4ae7952064eecdfe9ab67bbef9e769.pdf
Journal of Applied and Computational Mechanics
JACM
2016
2
1
Periodic Solutions of the Duffing Harmonic Oscillator by He's Energy Balance Method
A. M.
El-Naggar
Gamal
Ismail
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
2016
08
10
35
41
http://jacm.scu.ac.ir/article_12269_93df035a219e7c855ade51e2844c40bc.pdf
Journal of Applied and Computational Mechanics
JACM
2016
2
1
Saint-Venant torsion of non-homogeneous anisotropic bars
John
Katsikadelis
George
Tsiatas
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
2016
08
20
42
53
http://jacm.scu.ac.ir/article_12270_5ba4dad84d8c4e4072ae8097ad43c3dc.pdf