User talk:Psoltani

A Published Article in Journal of Physics D: Applied Physics

"Vibration and instability of a viscous-fluid-conveying single-walled carbon nanotube embedded in a visco-elastic medium"
By: Payam Soltani, M. M. Taherian and A. Farshidianfar

Abstract: In this study, for the first time, the transverse vibrational model of a viscous-fluid-conveying single-walled carbon nanotube (SWCNT) embedded in biological soft tissue is developed. Nonlocal Euler–Bernoulli beam theory has been used to investigate fluid-induced vibration of the SWCNT while visco-elastic behaviour of the surrounding tissue is simulated by the Kelvin–Voigt model. The results indicate that the resonant frequencies and the critical flow velocity at which structural instability of nanotubes emerges are significantly dependent on the properties of the medium around the nanotube, the boundary conditions, the viscosity of the fluid and the nonlocal parameter. Detailed results are demonstrated for the dependence of damping and elastic properties of the medium on the resonant frequencies and the critical flow velocity. Three standard boundary conditions, namely clamped–clamped, clamped–pinned and pinned–pinned, are applied to study the effect of the supported end conditions. Furthermore, it is found that the visco-elastic foundation causes an obvious reduction in the critical velocity in comparison with the elastic foundation, in particular for a compliant medium, pinned–pinned boundary condition, high viscosity of the fluid and small values of the nonlocal coefficient. http://iopscience.iop.org/0022-3727/43/42/425401

"Studying the Tensile Behaviour of GLARE Laminates: A Finite Element Modelling Approach"
Studying the Tensile Behaviour of GLARE Laminates: A Finite Element Modelling Approach A published research in Journal of Applied Composite Materials"

A published work in "Journal of Applied Composite Materials"

By: Payam Soltani, M. Keikhosravy & R. H. Oskouei & C. Soutis

Abstract:


 * Numerical simulations based on finite element modelling are increasingly being

developed to accurately evaluate the tensile properties of GLARE (GLAss fibre REinforced

aluminium laminates). In this study, nonlinear tensile behaviour of GLARE Fibre Metal

Laminates (FML) under in-plane loading conditions has been investigated. An appropriate

finite element modelling approach has been developed to predict the stress–strain response

and deformation behaviour of GLARE laminates using the ANSYS finite element package.

The finite element model supports orthotropic material properties for glass/epoxy layer(s)

and isotropic properties with the elastic–plastic behaviour for the aluminium layers. The

adhesion between adjacent layers has been also properly simulated using cohesive zone

modelling. An acceptable agreement was observed between the model predictions and

experimental results available in the literature. The proposed model can be used to analyse

GLARE laminates in structural applications such as mechanically fastened joints under

different mechanical loading conditions.

http://www.springerlink.com/content/h831735260162p66/

"An efficient GDQ model for vibration analysis of a multiwall carbon nanotube on Pasternak foundation with general boundary conditions "
An efficient GDQ model for vibration analysis of a multiwall carbon nanotube on Pasternak foundation with general boundary conditions A published work in "Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science"

By: Payam Soltani, P. Bahar and A. Farshidianfar

Abstract:

In this article, the free transverse vibrational behaviour of a multiwall carbon nanotube (MWNT) surrounded by a Pasternak-type elastic medium has been determined using a very generalized model. The model has been made on the basis of Timoshenko elastic beam theory which allows the effects of shear deformation and rotary inertia and supports non-coaxial vibration of the adjacent layers of MWNT using interlayer van der Waals forces. The boundary conditions used in this simulation are such that not only standard and conventional kinds, but also all possible forms, of end conditions are applicable. A generalized differential quadrature method is utilized to solve the governing equations with assorted aspect ratios, various boundary conditions, and different foundation stiffnesses. This study shows that the resonant frequencies of MWNTs are strongly dependent on the stiffness of the elastic medium, aspect ratios, and number of walls in carbon nanotubes and, for short nanotubes, the boundary stiffness plays a significant role on the natural frequencies.

http://www.springerlink.com/content/h831735260162p66/

NONLINEAR VIBRATION AND BENDING INSTABILITY OF A SINGLEWALLED CARBON NANOTUBE USING NONLOCAL ELASTIC BEAM THEORY
A pulished research in "International Journal of Nanoscience"

By: I Mehdipour, Payam Soltani, D. D. Ganji, A. Farshidianfar Abstract:

Due to the nonlocal Euler-Bernoulli elastic beam theory, the e®ects of rippling deformation on the bending modulus and the structural bending instability of a single-walled carbon nanotube (SWCNT) are investigated. The nonlinear vibrational model of a cantilevered SWCNT is solved using the perturbation method of multiscales. The nonlinear resonant frequency and the associated effective bending modulus of the carbon nanotube (CNT) are derived analytically. The effects of the nonlocal parameter, the external harmonic force, and the diameter-to-length ratio on the effective bending modulus are discussed widely. Moreover, the model can predict special kind of structural instability due to the rippling deformation called rippling instability. The results show that the nonlocal theory forecasts larger values for the effective bending modulus compared with the classical beam theory, especially for the stubby CNTs. Meanwhile, the rippling instability threshold will move to the higher values of the diameter-to-length ratio based on the nonlocal beam theory comparing with the local ones.

http://www.worldscinet.com/ijn/10/1003/S0219581X11008216.html