Islamic Azad University Arak BranchJournal of Solid Mechanics2008-35057320150930Axial and Transverse Vibration of SWBNNT System Coupled Pasternak Foundation Under a Moving Nanoparticle Using Timoshenko Beam Theory239254515346ENA Ghorbanpour AraniFaculty of Mechanical Engineering, University of Kashan---
Institute of Nanoscience & Nanotechnology, University of KashanA Karamali RavandiFaculty of Mechanical Engineering, University of KashanM.A RoudbariFaculty of Mechanical Engineering, University of KashanM.B AzizkhaniFaculty of Mechanical Engineering, University of Kashan, KashanA Hafizi BidgoliFaculty of Mechanical Engineering, University of Kashan, KashanJournal Article20150323In 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.http://jsm.iau-arak.ac.ir/article_515346_7e1fa06790e3ce1d3de705f86177ad92.pdfIslamic Azad University Arak BranchJournal of Solid Mechanics2008-35057320150930Rayleigh Waves in a Homogeneous Magneto-Thermo Voigt-Type Viscoelastic Half-Space under Initial Surface Stresses255267515347ENR KakarFaculty of Engineering & Technology, GNA University, Phagwara, India, 163, Chotti Baradari, Phase-1, Garah Road, Jalandhar-144022, IndiaJournal Article20150326This 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. http://jsm.iau-arak.ac.ir/article_515347_b42aa22d1e1a1fc8dfd55d60b2dce24e.pdfIslamic Azad University Arak BranchJournal of Solid Mechanics2008-35057320150930Investigation on the Effect of Tigthening Torque on the Stress Distribution in Double Lap Simple Bolted and Hybrid (Bolted -Bonded) Joints268280515348ENF EsmaeiliDepartment of Mechanical Engineering, Tabriz Branch, Islamic Azad UniversityT.N ChakherlouFaculty of Mechanical Engineering, University of TabrizJournal Article20150529In 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. http://jsm.iau-arak.ac.ir/article_515348_5cf56415c79e4563ddc5eeb7f5a43661.pdfIslamic Azad University Arak BranchJournal of Solid Mechanics2008-35057320150930The Effect of Modified Couple Stress Theory on Buckling and Vibration Analysis of Functionally Graded Double-Layer Boron Nitride Piezoelectric Plate Based on CPT281298515350ENM MohammadimehrDepartment of Solid Mechanics ,Faculty of Mechanical Engineering, University of KashanM MohandesDepartment of Solid Mechanics ,Faculty of Mechanical Engineering, University of KashanJournal Article20150608In 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.http://jsm.iau-arak.ac.ir/article_515350_4bde3e7858606f8afbd1f062b3a24f91.pdfIslamic Azad University Arak BranchJournal of Solid Mechanics2008-35057320150930Effect of Surface Energy on the Vibration Analysis of Rotating Nanobeam299311515351ENM SafarabadiSchool of Mechanical Engineering, College of Engineering, University of TehranM MohammadiDepartment of Engineering, College of Mechanical Engineering, Ahvaz branch, Islamic Azad UniversityA FarajpourYoung Researches and Elites Club , North Tehran Branch, Islamic Azad UniversityM GoodarziDepartment of Engineering, College of Mechanical Engineering, Ahvaz branch, Islamic Azad UniversityJournal Article20150610In 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.http://jsm.iau-arak.ac.ir/article_515351_61bc2deb10cd00c4bcc751af86a14844.pdfIslamic Azad University Arak BranchJournal of Solid Mechanics2008-35057320150930Wave Propagation at the Boundary Surface of Inviscid Fluid Half-Space and Thermoelastic Diffusion Solid Half-Space with Dual-Phase-Lag Models312326515352ENR KumarDepartment of Mathematics, Kurukshetra University Kurukshetra-136119, Haryana ,IndiaV GuptaIndira Gandhi National College, Ladwa(Dhanora), Haryana ,IndiaJournal Article20150620The 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.http://jsm.iau-arak.ac.ir/article_515352_e05825a161d6b35d46af80a114358a13.pdfIslamic Azad University Arak BranchJournal of Solid Mechanics2008-35057320150930Asymmetric Thermal Stresses of Hollow FGM Cylinders with Piezoelectric Internal and External Layers327343515355ENM JabbariPostgraduate School, Islamic Azad University, South Tehran BranchM.B AghdamPostgraduate School, Islamic Azad University, South Tehran BranchJournal Article20150623In 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.http://jsm.iau-arak.ac.ir/article_515355_44bf509f0bf3e79bb904994f4e168fd7.pdfIslamic Azad University Arak BranchJournal of Solid Mechanics2008-35057320150930On the Magneto-Thermo-Elastic Behavior of a Functionally Graded Cylindrical Shell with Pyroelectric Layers Featuring Interlaminar Bonding Imperfections Rested in an Elastic Foundation344363515356ENM SaadatfarFaculty of Mechanical Engineering, K.N. Toosi University of TechnologyM Aghaie-KhafriFaculty of Mechanical Engineering, K.N. Toosi University of TechnologyJournal Article20150629The 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.http://jsm.iau-arak.ac.ir/article_515356_95271759df91204195846e6a7118cb29.pdf