Thermal, electrical and mechanical buckling loads of sandwich nano-beams made of FG-CNTRC resting on Pasternak’s foundation based on higher order shear deformation theory

Ali Ghorbanpour Arani,Mahmoud Pourjamshidian,Mohammad Arefi,M.R. Ghorbanpour Arani 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.4

This research deals with thermo-electro-mechanical buckling analysis of the sandwich nano-beams with face-sheets made of functionally graded carbon nano-tubes reinforcement composite (FG-CNTRC) based on the nonlocal strain gradient elasticity theory (NSGET) considering various higher-order shear deformation beam theories (HSDBT). The sandwich nano-beam with FG-CNTRC face-sheets is subjected to thermal and electrical loads while is resting on Pasternak's foundation. It is assumed that the material properties of the face-sheets change continuously along the thickness direction according to different patterns for CNTs distribution. In order to include coupling of strain and electrical field in equation of motion, the nonlocal non-classical nano-beam model contains piezoelectric effect. The governing equations of motion are derived using Hamilton principle based on HSDBTs and NSGET. The differential quadrature method (DQM) is used to calculate the mechanical buckling loads of sandwich nano-beam as well as critical voltage and temperature rising. After verification with validated reference, comprehensive numerical results are presented to investigate the influence of important parameters such as various HSDBTs, length scale parameter (strain gradient parameter), the nonlocal parameter, the CNTs volume fraction, Pasternak's foundation coefficients, various boundary conditions, the CNTs efficiency parameter and geometric dimensions on the buckling behaviors of FG sandwich nano-beam. The numerical results indicate that, the amounts of the mechanical critical load calculated by PSDBT and TSDBT approximately have same values as well as ESDBT and ASDBT. Also, it is worthy noted that buckling load calculated by aforementioned theories is nearly smaller than buckling load estimated by FSDBT. Also, similar aforementioned structure is used to building the nano/micro oscillators.

Application of nonlocal elasticity theory on the wave propagation of flexoelectric functionally graded (FG) timoshenko nano-beams considering surface effects and residual surface stress

Ali Ghorbanpour Arani,Mahmoud Pourjamshidian,Mohammad Arefi,M.R. Ghorbanpour Arani 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.2

This research deals with wave propagation of the functionally graded (FG) nano-beams based on the nonlocal elasticity theory considering surface and flexoelectric effects. The FG nano-beam is resting in Winkler-Pasternak foundation. It is assumed that the material properties of the nano-beam changes continuously along the thickness direction according to simple power-law form. In order to include coupling of strain gradients and electrical polarizations in governing equations of motion, the nonlocal non-classical nano-beam model containg flexoelectric effect is used. Also, the effects of surface elasticity, di-electricity and piezoelectricity as well as bulk flexoelectricity are all taken into consideration. The governing equations of motion are derived using Hamilton principle based on first shear deformation beam theory (FSDBT) and also considering residual surface stresses. The analytical method is used to calculate phase velocity of wave propagation in FG nano-beam as well as cut-off frequency. After verification with validated reference, comprehensive numerical results are presented to investigate the influence of important parameters such as flexoelectric coefficients of the surface, bulk and residual surface stresses, Winkler and shear coefficients of foundation, power gradient index of FG material, and geometric dimensions on the wave propagation characteristics of FG nano-beam. The numerical results indicate that considering surface effects/flexoelectric property caused phase velocity increases/decreases in low wave number range, respectively. The influences of aforementioned parameters on the occurrence cut-off frequency point are very small.

Non-linear free and forced vibration analysis of sandwich nano-beam with FG-CNTRC face-sheets based on nonlocal strain gradient theory

Arani, Ali Ghorbanpour,Pourjamshidian, Mahmoud,Arefi, Mohammad Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.22 No.1

In this paper, the nonlinear free and forced vibration responses of sandwich nano-beams with three various functionally graded (FG) patterns of reinforced carbon nanotubes (CNTs) face-sheets are investigated. The sandwich nano-beam is resting on nonlinear Visco-elastic foundation and is subjected to thermal and electrical loads. The nonlinear governing equations of motion are derived for an Euler-Bernoulli beam based on Hamilton principle and von Karman nonlinear relation. To analyze nonlinear vibration, Galerkin's decomposition technique is employed to convert the governing partial differential equation (PDE) to a nonlinear ordinary differential equation (ODE). Furthermore, the Multiple Times Scale (MTS) method is employed to find approximate solution for the nonlinear time, frequency and forced responses of the sandwich nano-beam. Comparison between results of this paper and previous published paper shows that our numerical results are in good agreement with literature. In addition, the nonlinear frequency, force response and nonlinear damping time response is carefully studied. The influences of important parameters such as nonlocal parameter, volume fraction of the CNTs, different patterns of CNTs, length scale parameter, Visco-Pasternak foundation parameter, applied voltage, longitudinal magnetic field and temperature change are investigated on the various responses. One can conclude that frequency of FG-AV pattern is greater than other used patterns.

The effect of nanoparticles on enhancement of the specific mechanical properties of the composite structures: A review research

Arani, Ali Ghorbanpour,Farazin, Ashkan,Mohammadimehr, Mehdi Techno-Press 2021 Advances in nano research Vol.10 No.4

In this review, composite structures are used for many industries for at least four decades. Polymeric composites are one of the important structures in the aerospace and aviation industry because of their high strength and low weight. In this comprehensive review, mechanical behaviors, physical and mechanical properties of polymeric composites, different types of reinforcements, different methods to fabricate polymeric composites, historical structural composite materials for aviation and aerospace industries, and also different methods for the characterization are reported. How to use various methods of composite preparation using different nanofillers as reinforcements and its effect on the physical properties and mechanical behavior of composites are discussed as well.

The effect of CNT volume fraction on the magneto-thermo-electro-mechanical behavior of smart nanocomposite cylinder

Arani A. Ghorbanpour 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.8

In this article, using analytical approach, the stress analysis of a long piezoelectric polymeric hollow cylinder reinforced with carbon nanotube (CNT) under combined magneto-thermo-electro-mechanical loading is investigated. Considering three combined loading conditions such as pressure-electric, pressure-electric magnetic and pressure-electric thermal, the governing equation of the problem is obtained. The rule of mixture and modified multiscale bridging model are used to predict effective properties of nanocomposite. The magneto-thermo-electro-mechanical stresses in hollow cylinder are discussed in detail. It can be concluded that increasing CNT volume fraction enhances strength of the nanocomposite cylinder. The results of this work could be useful in view of optimum design of the smart nanocomposite cylinder under magneto-thermo-electro-mechanical loadings and could also be as a reference for future related works.

Characterisation of forests with trivial game domination numbers

Nadjafi-Arani, M. J.,Siggers, M.,Soltani, H. Springer Science + Business Media 2016 Journal of combinatorial optimization Vol.32 No.3

<P>In the domination game, two players, the Dominator and Staller, take turns adding vertices of a fixed graph to a set, at each turn increasing the number of vertices dominated by the set, until the final set dominates the whole graph. The Dominator plays to minimise the size of the set while the Staller plays to maximise it. A graph is -trivial if when the Dominator plays first and both players play optimally, the set is a minimum dominating set of the graph. A graph is -trivial if the same is true when the Staller plays first. We consider the problem of characterising -trivial and -trivial graphs. We give complete characterisations of -trivial forests and of -trivial forests. We also show that -connected -trivial graphs cannot have large girth, and conjecture that the same holds without the connectivity condition.</P>

Induced nonlocal electric wave propagation of boron nitride nanotubes

A. Ghorbanpour Arani,A. Hafizi Bidgoli,A. Karamali Ravandi,M. A. Roudbari,S. Amir,M. B. Azizkhani 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.10

Axial displacement and electric wave propagation of single-walled Boron-Nitride nanotubes (SWBNNTs) induced by alternating current (AC) are investigated in this study. A single- walled zigzag structure BNNT is modeled based on nonlocal piezoelasticity theory and Euler-Bernoulli beam (EBB). Equations correspond to lateral displacement have been obtained. Using Hamilton’s principle and considering charge equation for coupling of electrical and mechanical fields, the higher order of governing equations are derived. Analytical solution is applied to solve governing equations. Also the axial and lateral displacement of a SWBNNT and electric potential induced by AC through it are presented. The detailed parametric study is conducted, focusing on the remarkable effects of the half wave number on the behavior of the SWBNNT. The results indicate applying alternating field, leads to propagation of axial displacement along the SWBNNT. Also the result of this study can be useful to design and manufacture of smart micro/nano-electro-mechanical systems in advanced biomechanics applications by controlling axial and lateral displacements.

Electro-thermo nonlocal nonlinear vibration in an embedded polymeric piezoelectric micro plate reinforced by DWBNNTs using DQM

A. Ghorbanpour Arani,H. Vossough,R. Kolahchi,A. A. Mosallaie Barzoki 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.10

In the present paper, electro-thermo nonlinear vibration of a piezo-polymeric rectangular micro plate made from polyvinylidene fluoride (PVDF) reinforced by zigzag double walled boron nitride nanotubes (DWBNNTs) is studied. This plate is embedded in an elastic medium which is simulated by Winkler and Pasternak foundation models. Using nonlinear strain-displacement relations and nonlocal elasticity plate theory as well as considering charge equation for coupling between electrical and mechanical fields, the motion equations are derived based on energy method and Hamilton's principle. The differential quadrature method (DQM) is employed to computation of nonlinear frequency for different mechanical and free-free electrical boundary conditions. The results indicate that smart composite and consequently the generated Φ improved sensor and actuator applications in several process industries, because it increases the nonlinear vibration frequency. Furthermore, it can be also found that the nonlinear frequency increases as the values of the elastic medium constants,the geometrical aspect ratios and DWBNNTs volume fraction increase but it decreases as nonlocal parameter increases.

IR-initiated preparation method of high performance nanofiltration membranes using graft polymerization of acrylic acid onto polyacrylonitrile surface

Zeinab Khani-Arani,Ahmad Akbari 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10

A new facile, cost-effective and safe approach is introduced for the modification of polyacrylonitrile (PAN) membrane surface by a polymerization process in order to improve hydrophilicity and antifouling. For this purpose, membrane activated by IR-initiated, and acrylic acid (AA) as a monomer was successfully grafted on the membrane surface. The surface properties of membranes were characterized by means of various techniques: infrared spectroscopy, zeta potential, water contact angle, atomic force microscopy (AFM), and scanning electron microscopy (SEM). The experimental results indicate that the membrane surface becomes more hydrophilic by reducing the contact angle from 67.1o to 52.5o. The existence of hydrophilic chains on the membrane surface facilitates the creation of a negative charge on the membrane surface unto 2.99 mV (from 3.51 mV in based-membrane). The separation performance of the modified membrane showed a desirable yield. For a membrane photografted for 25 min with acrylic acid solution (2 wt%), the retention of Na2SO4, MgSO4, NaCl, and CaCl2 was in the order of 81%, 67%, 34%, and 28%, respectively. The membrane retention is expressed the values of 90.37%, 87.17%, and 79.5% for Acid Blue 92, Acid Red 114, and Ibuprofen. The optimized NF membrane showed a permeability factor (Lp) of 6.48 L·m2·h1·bar1. Furthermore, the surface modification of the PAN membrane via the IR-induced graft polymerization exhibits an enhancement of the membrane antifouling property.

Buckling analysis of multi-walled carbon nanotubes under combinedloading considering the effect of small length scale

A. Ghorbanpour Arani,R. Rahmani,A. Arefmanesh,S. Golabi 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.3

The torsional and axially compressed buckling of an individual embedded multi-walled carbon nanotube (MWNTs) subjected to an internal and/or external radial pressure was investigated in this study. The emphasis is placed on new physical phenomena which are due to both the small length scale and the surrounding elastic medium. Multiwall carbon nanotubes which are considered in this study are classified into three categories based on the radius to thickness ratio, namely, thin, thick, and almost solid. Explicit formulas are derived for the van der Waals (vdW) interaction between any two layers of an MWNT based on the continuum cylindrical shell model. In most of the previous studies, the vdW interaction between two adjacent layers was considered only and the vdW interaction among other layers was neglected. Moreover, in these works, the vdW interaction coefficient was treated as a constant that was independent of the radii of the tubes. However, in the present model the vdW interaction coefficients are considered to be dependent on the change of interlayer spacing and the radii of the tubes. The effect of the small length scale is also considered in the present formulation. The results show that there is a unique buckling mode (m,n) corresponding to the critical shear stress. This result is obviously different from what is expected for the pure axially compressed buckling of an individual multi-walled carbon nanotube.