Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
7
3
2015
09
30
Axial and Transverse Vibration of SWBNNT System Coupled Pasternak Foundation Under a Moving Nanoparticle Using Timoshenko Beam Theory
239
254
EN
A
Ghorbanpour Arani
Faculty of Mechanical Engineering, University of Kashan---
Institute of Nanoscience & Nanotechnology, University of Kashan
aghorban@kashanu.ac.ir
A
Karamali Ravandi
Faculty of Mechanical Engineering, University of Kashan
M.A
Roudbari
Faculty of Mechanical Engineering, University of Kashan
M.B
Azizkhani
Faculty of Mechanical Engineering, University of Kashan, Kashan
A
Hafizi Bidgoli
Faculty of Mechanical Engineering, University of Kashan, Kashan
In this study, a semi analytical method for transverse and axial vibration of single-walled boron nitride nanotube (SWBNNT) under moving a nanoparticle is presented. The surrounding elastic medium as Pasternak foundation and surface stress effect are included in the formulations of the proposed model. Using Timoshenko beam theory (TBT), Hamilton’s principle and nonlocal piezoelasticity theory, the higher order governing equation is derived. The influences of surface stress effects, spring and shear parameters of Pasternak foundation and aspect ratio are also investigated on the free and forced vibration behavior of SWBNNT under moving a nanoparticle. Through an inclusive parametric study, the importance of using surrounding elastic medium in decrease of normalized dynamic deflection is proposed. It is demonstrated that the values of shear modulus have significant role on the vibration behavior of SWBNNT. The influences of surface stresses on the amplitude of normalized dynamic deflection are also discussed. The output result's of this study has significant influences in design and production of micro electro mechanical system (MEMS) and nano electro mechanical system (NEMS) for advanced applications.
Axial and transverse vibration,SWBNNT,Nanoparticle,Piezoelastic theory,Pasternak foundation,Surface stress effect
http://jsm.iau-arak.ac.ir/article_515346.html
http://jsm.iau-arak.ac.ir/article_515346_7e1fa06790e3ce1d3de705f86177ad92.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
7
3
2015
09
30
Rayleigh Waves in a Homogeneous Magneto-Thermo Voigt-Type Viscoelastic Half-Space under Initial Surface Stresses
255
267
EN
R
Kakar
Faculty of Engineering & Technology, GNA University, Phagwara, India, 163, Chotti Baradari, Phase-1, Garah Road, Jalandhar-144022, India
rajneesh.kakar@gmail.com
This paper deals with the propagation of magneto-thermo Rayleigh waves in a homogeneous viscoelastic half-space under initial stress. It has been observed that velocity of Rayleigh waves depends on viscosity, magnetic field, temperature and initial stress of the half-space. The frequency equation for Rayleigh waves under the effect of magnetic field, stress and temperature for both viscoelastic and elastic medium is first obtained by using classical theory of thermoelasticity and then computed numerically. The variation of phase velocity of Rayleigh waves with respect to initial hydrostatic stress in viscoelastic and elastic half-space is shown graphically. In the absence of various parameters of the medium, the obtained results are in agreement with classical results given by Caloi and Lockett.
Initial stress,temperature,magnetic field,Rayleigh waves,Voigt-type,Viscoelasticity
http://jsm.iau-arak.ac.ir/article_515347.html
http://jsm.iau-arak.ac.ir/article_515347_b42aa22d1e1a1fc8dfd55d60b2dce24e.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
7
3
2015
09
30
Investigation on the Effect of Tigthening Torque on the Stress Distribution in Double Lap Simple Bolted and Hybrid (Bolted -Bonded) Joints
268
280
EN
F
Esmaeili
Department of Mechanical Engineering, Tabriz Branch, Islamic Azad University
f.esmaeili@iaut.ac.ir
T.N
Chakherlou
Faculty of Mechanical Engineering, University of Tabriz
In this research, the effects of torque tightening on the stress distribution in double lap simple bolted and hybrid (bolted-bonded) joints have been investigated numerically. In order to determine the bolt clamping force value due to tightening torque in simple bolted and hybrid joints, which is necessary in numerical simulation, an experimental approach has been proposed. To do so, two kinds of joints, i.e. double lap simple and hybrid joints were prepared. To determine the bolt clamping force or pretension resulting from the torque tightening, at different applied torques, for both kinds of joints a special experimental method was designed using a steel hollow cylinder that was placed between the nut and the plate. In order to obtain the stress distribution in the joint plates for both kinds of the joints, with two different amounts of tightening torque, three-dimensional finite element models were simulated by a general finite element code. The obtained results revealed that the amounts of resultant stresses were reduced by increasing the tightening torque due to compressive stresses. Furthermore, in the hybrid joints, the stress concentration around the hole is reduced significantly. Finally, the comparison of the obtained results, confirms that the hybrid joints have better static strength than simple joints for all levels of the tightening torque.
Clamping force,Bolted joint,Hybrid joint,Tightening torque,Hook's law
http://jsm.iau-arak.ac.ir/article_515348.html
http://jsm.iau-arak.ac.ir/article_515348_5cf56415c79e4563ddc5eeb7f5a43661.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
7
3
2015
09
30
The Effect of Modified Couple Stress Theory on Buckling and Vibration Analysis of Functionally Graded Double-Layer Boron Nitride Piezoelectric Plate Based on CPT
281
298
EN
M
Mohammadimehr
Department of Solid Mechanics ,Faculty of Mechanical Engineering, University of Kashan
mmohammadimehr@kashanu.ac.ir
M
Mohandes
Department of Solid Mechanics ,Faculty of Mechanical Engineering, University of Kashan
In this article, the effect of size-dependent on the buckling and vibration analysis of functionally graded (FG) double-layer boron nitride plate based on classical plate theory (CPT) under electro-thermo-mechanical loadings which is surrounded by elastic foundation is examined. This subject is developed using modified couple stress theory. Using Hamilton's principle, the governing equations of motion are obtained by applying a modified couple stress and von Karman nonlinear strain for piezoelectric material and Kirchhoff plate. These equations are coupled for the FG double-layer plate using Pasternak foundation and solved using Navier’s type solution. Then, the dimensionless natural frequencies and critical buckling load for simply supported boundary condition are obtained. Also, the effects of material length scale parameter, elastic foundation coefficients and power law index on the dimensionless natural frequency and critical buckling load are investigated. The results demonstrate that the dimensionless natural frequency of the piezoelectric plate increases steadily by growing the power law index. Also, the effect of the power law index on the dimensionless critical buckling load of double layer boron nitride piezoelectric for higher dimensionless material length scale parameter is the most.
Buckling and vibration analysis,Modified couple stress theory,Functionally graded double-layer Piezoelectric plate,CPT
http://jsm.iau-arak.ac.ir/article_515350.html
http://jsm.iau-arak.ac.ir/article_515350_4bde3e7858606f8afbd1f062b3a24f91.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
7
3
2015
09
30
Effect of Surface Energy on the Vibration Analysis of Rotating Nanobeam
299
311
EN
M
Safarabadi
School of Mechanical Engineering, College of Engineering, University of Tehran
msafarabadi@ut.ac.ir
M
Mohammadi
Department of Engineering, College of Mechanical Engineering, Ahvaz branch, Islamic Azad University
m.mohamadi@me.iut.ac.ir
A
Farajpour
Young Researches and Elites Club , North Tehran Branch, Islamic Azad University
M
Goodarzi
Department of Engineering, College of Mechanical Engineering, Ahvaz branch, Islamic Azad University
mz.goodarzi.iau@gmail.com
In this study, the free vibration behavior of rotating nanobeam is studied. Surface effects on the vibration frequencies of nanobeam are considered. To incorporate surface effects, Gurtin–Murdoch model is proposed to satisfy the surface balance equations of the continuum surface elasticity. Differential quadrature method is employed and in order to establish the accuracy and applicability of the proposed model, the numerical results are presented to be compared with those available in the literature. The effects of angular velocity, boundary conditions and surface elastic constants on the vibration characteristics are presented. Numerical results show that the softer boundary conditions cause an increase in the influence of the angular velocity on the nanobeam vibration frequencies.
Vibration,Rotating nanobeam,Differential quadrature method,Surface energy
http://jsm.iau-arak.ac.ir/article_515351.html
http://jsm.iau-arak.ac.ir/article_515351_61bc2deb10cd00c4bcc751af86a14844.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
7
3
2015
09
30
Wave Propagation at the Boundary Surface of Inviscid Fluid Half-Space and Thermoelastic Diffusion Solid Half-Space with Dual-Phase-Lag Models
312
326
EN
R
Kumar
Department of Mathematics, Kurukshetra University Kurukshetra-136119, Haryana ,India
rajneesh_kuk@rediffmail.com
V
Gupta
Indira Gandhi National College, Ladwa(Dhanora), Haryana ,India
vandana223394@gmail.com
The present investigation deals with the reflection and transmission phenomenon due to incident plane longitudinal wave at a plane interface between inviscid fluid half-space and a thermoelastic diffusion solid half-space with dual-phase-lag heat transfer (DPLT) and dual-phase-lag diffusion (DPLD) models. The theory of thermoelasticity with dual-phase-lag heat transfer developed by Roychoudhary [10] has been employed to develop the equation for thermoelastic diffusion with dual-phase-lag heat transfer and dual-phase-lag diffusion model. Amplitude ratios and energy ratios of various reflected and transmitted waves are obtained. It is found that these are the functions of angle of incidence, frequency of incident wave and are influenced by thermoelastic diffusion properties of media. The nature of dependence of amplitude ratios and energy ratios with the angle of incidence have been computed numerically for a particular model. The variations of energy ratios with angle of incidence are also shown graphically. The conservation of energy at the interface is verified. Some special cases are also deduced from the present investigation.
Thermoelasticity,Fluid,Elastic,Reflection,Transmission,Amplitude,energy
http://jsm.iau-arak.ac.ir/article_515352.html
http://jsm.iau-arak.ac.ir/article_515352_e05825a161d6b35d46af80a114358a13.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
7
3
2015
09
30
Asymmetric Thermal Stresses of Hollow FGM Cylinders with Piezoelectric Internal and External Layers
327
343
EN
M
Jabbari
Postgraduate School, Islamic Azad University, South Tehran Branch
mohsen.jabbari@gmail.com
M.B
Aghdam
Postgraduate School, Islamic Azad University, South Tehran Branch
In this paper ,the general solution of steady-state one dimensional asymmetric thermal stresses and electrical and mechanical displacements of a hollow cylinder made of functionally graded material and piezoelectric layers is developed .The material properties ,except the Poisson's ration, are assumed to depend on the variable radius and they are expressed as power functions of radius. The temperature distribution is assumed to be a function of radius with general thermal and mechanical boundary conditions on the inside and outside surfaces. By using the separation of variables method and complex Fourier series, the Navier equations in term of displacements are derived and solved.
Hollow cylinder,Asymmetric,FGM,Piezoelectric
http://jsm.iau-arak.ac.ir/article_515355.html
http://jsm.iau-arak.ac.ir/article_515355_44bf509f0bf3e79bb904994f4e168fd7.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
7
3
2015
09
30
On the Magneto-Thermo-Elastic Behavior of a Functionally Graded Cylindrical Shell with Pyroelectric Layers Featuring Interlaminar Bonding Imperfections Rested in an Elastic Foundation
344
363
EN
M
Saadatfar
Faculty of Mechanical Engineering, K.N. Toosi University of Technology
M
Aghaie-Khafri
Faculty of Mechanical Engineering, K.N. Toosi University of Technology
maghaei@kntu.ac.ir
The behavior of an exponentially graded hybrid cylindrical shell subjected to an axisymmetric thermo-electro-mechanical loading placed in a constant magnetic field is investigated. The hybrid shell is consisted of a functionally graded host layer embedded with pyroelectric layers as sensor and/or actuator that can be imperfectly bonded to the inner and the outer surfaces of a shell. The shell is simply supported and could be rested on an elastic foundation. The material properties of the host layer are assumed to be exponentially graded in the radial direction. To solve governing differential equations, the Fourier series expansion method along the longitudinal direction and the differential quadrature method (DQM) across the thickness direction are used. Numerical examples are presented to discuss effective parameters influence on the response of the hybrid shell.
Pyroelectric,magnetic field,Imperfect bonding,Exponentially graded cylindrical shell,Elastic foundation
http://jsm.iau-arak.ac.ir/article_515356.html
http://jsm.iau-arak.ac.ir/article_515356_95271759df91204195846e6a7118cb29.pdf