Wen-Hwa Chen^1,2, Chun-Hung Wu¹, Hsien-Chie Cheng^3,4,5

CMC-Computers, Materials & Continua, Vol.25, No.3, pp. 195-214, 2011, DOI:10.3970/cmc.2011.025.195

Abstract The study aims at investigating the linear and volumetric thermal expansion coefficients (CTEs) at temperature below the Debye temperature and phase transformation behaviors at atmospheric pressure of carbon fullerenes, i.e., C₆₀, C₇₀ and C₈₀, through a modified Nosé-Hoover (NH) thermostat method incorporated with molecular dynamics (MD) simulation. The calculated results are compared with those obtained from the standard NH and "massive" NHC (MNHC) thermostats and also with the literature experimental and theoretical data. Results show that at temperature below the Debye temperature, the CTEs of the fullerene molecules would significantly decrease with a decreasing temperature and tend to become negative… More >

Salvatore Brischetto¹

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.4, pp. 305-327, 2015, DOI:10.3970/cmes.2015.104.305

Abstract This paper proposes the free vibration analysis of Double-Walled Carbon NanoTubes (DWCNTs). A continuum elastic three-dimensional shell model is used for natural frequency investigation of simply supported DWCNTs. The 3D shell method is compared with beam analyses to show the applicability limits of 1D beam models. The effect of van der Waals interaction between the two cylinders is shown for different Carbon NanoTube (CNT) lengths and vibration modes. Results give the van der Waals interaction effect in terms of frequency values. In order to apply the 3D shell continuum model, DWCNTs are defined as two concentric isotropic cylinders (with an… More >

Qing Song Tu¹, Michelle Lee², Samuel Zhang², Shaofan Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.3, pp. 247-259, 2014, DOI:10.32604/cmes.2014.098.247

Abstract In this paper, we present molecular dynamics simulations of diffusion of Na⁺, K⁺, and Cl^- ions through the single-walled carbon nanotubes(SWCNTs) that are embedded into the membrane of cells in aqueous solutions. A simplified atomic cell model that considers bilayer membranes is employed to study the transportation of ions inside CNTs. The simulated results indicate that the diffusion properties of ions and selectivity of CNT with respect to ions are affected by biological complexity of the cell membrane. We have found that the ion diffusion only occurs in the CNTs with chirality higher than (8, 8), which is bigger than… More >

Chih-Ping Wu^1,2, Ruei-Yong Jiang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.97, No.3, pp. 239-279, 2014, DOI:10.3970/cmes.2014.097.239

Abstract A state space differential reproducing kernel (DRK) method is developed for the three-dimensional (3D) buckling analysis of simply-supported, carbon nanotube-reinforced composite (CNTRC) circular hollow cylinders and laminated composite ones under axial compression. The single-walled carbon nanotubes (CNTs) and polymer are used as the reinforcements and matrix, respectively, to constitute the CNTRC cylinder. Three different distributions of CNTs varying in the thickness direction are considered (i.e., the uniform distribution and functionally graded rhombus-, and X-type ones), and the through-thickness distributions of effective material properties of the cylinder are determined using the rule of mixtures. The 3D linear buckling theory is used,… More >

B.J. Yang¹, K.J. Cho¹, G.M. Kim¹, H.K. Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.5, pp. 343-365, 2014, DOI:10.3970/cmes.2014.103.343

Abstract The addition of carbon nanotubes (CNTs) to a matrix material is expected to lead to an increase in the effective electrical properties of nanocomposites. However, a CNT entanglement caused by the matrix viscosity and the high aspect ratio of the nanotubes often inhibits the formation of a conductive network. In the present study, the micromechanics-based model is utilized to investigate the effect of CNT agglomeration on the electrical conductivity and percolation threshold of nanocomposites. A series of parametric studies considering various shapes and curviness distributions of CNTs are carried out to examine the effects of entanglement on the electrical performance… More >

Soleiman Ghouhestani¹, Farzad Shahabian¹, Seyed Mahmoud Hosseini^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.100, No.4, pp. 295-321, 2014, DOI:10.3970/cmes.2014.100.295

Abstract In this paper, the meshless local Petrov-Galerkin (MLPG) method is exploited for dynamic analysis of functionally graded nanocomposite cylindrical layered structure reinforced by carbon nanotube subjected to mechanical shock loading. The carbon nanotubes (CNTs) are distributed across radial direction on thickness of cylinder, which can be simulated by linear and nonlinear volume fraction. Free vibration and elastic wave propagation are studied for various value of volume fraction exponent at various time intervals. The layered cylinder is assumed to be under axisymmetric and plane strain conditions. Four types of CNTs distributions including uniform and three kinds of functionally graded distributions along… More >

Seyed Mahmoud Hosseini ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.1, pp. 1-29, 2013, DOI:10.3970/cmes.2013.095.001

Abstract In this article, the effects of carbon nanotubes distributions on natural frequency are studied for a functionally graded nanocomposite thick hollow cylinder reinforced by single-walled carbon nanotubes using a hybrid mesh-free method. The FG nanocomposite cylinder is excited by a shock loading, which is applied on the inner surface of cylinder. The first natural frequency is obtained for various nonlinear grading patterns of distributions of the aligned carbon nanotubes. The effects of various nonlinear grading patterns on natural frequency are obtained and discussed in details. The presented hybrid mesh-free method is based on the generalized finite difference (GFD) method for… More >

A.N. Guz¹, J.J.Rushchitsky¹, I.A.Guz²

CMES-Computer Modeling in Engineering & Sciences, Vol.26, No.3, pp. 139-156, 2008, DOI:10.3970/cmes.2008.026.139

Abstract The basic approach is offered for problems of nanocomposites and their mechanical properties, which includes a short review of modern problems in nanomechanics of materials. The fibrous carbon-polymer composites with carbon or graphite microfibers or carbon nanotubes are especially discussed. The basic model of the linear or nonlinear elastically deforming micro- and nanocomposites is considered. Within the framework of this model, the comparative computer modeling is performed. The modeling permits to observe the features in prediction of values of basic mechanical constants. These results are utilized on next step of modeling -- studying the peculiarities of wave propagation in particular… More >

Xianwu Ling¹, S.N. Atluri

CMES-Computer Modeling in Engineering & Sciences, Vol.14, No.2, pp. 91-100, 2006, DOI:10.3970/cmes.2006.014.091

Abstract In this paper, a lattice-based cell model is proposed for single wall carbon nanotubes (SWNTs). The finite temperature effect is accounted for via the local harmonic approach. The equilibrium SWNT configurations are obtained by minimizing the Helmholtz free energy with respect to seven primary coordinate variables that are subjected to a chirality constraint. The calculated specific heats agree well with the experimental data, and at low temperature depend on the tube radii with small tubes having much lower values. Our calculated coefficients of thermal expansion (CTEs) are universally positive for all the radial, axial and circumferential directions, and increase with… More >

Amitesh Maiti¹

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 589-600, 2002, DOI:10.3970/cmes.2002.003.589

Abstract Atomistic modeling and simulations are becoming increasingly important in the design of new devices at the nanoscale. In particular, theoretical modeling of carbon nanotubes have provided useful insight and guidance to many experimental efforts. To this end, we report simulation results on the electronic, structural and transport properties for two different applications of carbon nanotube-based devices: (1) effect of adsorbates on field emission; and (2) effect of mechanical deformation on the electronic transport. The reported simulations are based on First Principles Density Functional Theory (DFT), classical molecular mechanics, and tight-binding transport based on the recursive Green's function formalism. More >