Susan B. Sinnott¹, Zugang Mao,², Ki-Ho Lee

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 575-588, 2002, DOI:10.3970/cmes.2002.003.575

Abstract Nanofluidics is an area that has been under study for some time in zeolites and ideal nanoporous systems. Computational studies of the behavior of molecules in nanoporous structures have played an important role in understanding this phenomenon as experimental studies of molecular behavior in nanometer-scale pores are difficult to perform. In this paper computational work to study molecular motion and the separation of molecular mixtures in carbon nanotube systems is reported. The systems examined include organic molecules, such as CH₄, C₂H₆, n-C₄H₁₀, and i-C₄H₁₀, and inorganic molecules, such as CO₂. The interatomic forces in the molecular dynamics simulations are calculated… More >

Zhen Yang¹, Xingsheng Gu², Xiaoyi Liang^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.3&4, pp. 161-182, 2011, DOI:10.3970/cmes.2011.074.161

Abstract Mesoporous carbons are synthesized by organic-organic self-assembly of triblock copolymer F127 and a new type of carbon precursor as resorcinol-furfural oligomers. Some factors will impact the mesoporous carbons pore structure and properties were studied. The main factors, such as the ratio of triblock copolymer F127 and oligomers, degree of polymerizstry of resorcinol-furfural oligomers, the ratio of resorcinol-furfural oligomers - F/R, and their mutual relations were identified. Aimed at balancing the complex characteristic of mesoporous structure and adsorption properties, a classification and optimization model based on support vector machine is developed. The optimal operation conditions of Barret-Joyner-Halenda (BJH) adsorption cumulative volume… More >

G.I. Giannopoulos¹, S.K. Georgantzinos², D.E. Katsareas², N.K. Anifantis²

CMES-Computer Modeling in Engineering & Sciences, Vol.56, No.3, pp. 231-248, 2010, DOI:10.3970/cmes.2010.056.231

Abstract A hybrid finite element formulation, combining nanoscopic and macroscopic considerations is proposed, for the prediction of the elastic mechanical properties of single walled carbon nanotube (SWCNT)-based composites. The nanotubes are modeled according to the molecular mechanics theory via the use of spring elements, while the matrix is modeled as a continuum medium. A new formulation concerning the load transfer between the nanotubes and matrix is proposed. The interactions between the two phases are implemented by utilizing appropriate stiffness variations describing a heterogeneous interfacial region. A periodic distribution and orientation of the SWCNTs is considered. Thereupon, the nanocomposite is modeled using… More >

Eugenio Brusa¹, Matteo Nobile²

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.2, pp. 155-190, 2009, DOI:10.3970/cmes.2009.048.155

Abstract Lightness of high pressure vessels is currently assured by composite materials. Construction of over-wrapped composite pressure vessels with inner metallic liner is for instance compatible with standards requirements of the hydrogen technology of energy storage. Therefore a typical layout manufactured by some industries consists of a cylindrical vessel with covering of carbon-epoxy laminates and metallic impermeable liner. To allow the filament winding of the composite fibres are used hoop and helical layers, respectively. A single nozzle is usually built. It requires that the vessel material is reinforced. This need imposes to have a variable thickness in the composite layer. In… More >

L.Munteanu¹, V.Chiroiu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.1, pp. 27-42, 2009, DOI:10.3970/cmes.2009.048.027

Abstract The long-range nanoindentation response of carbon nanotubes is studied using a new method that combines the features of Nonlocal Theory and Molecular Mechanics. The deformation of compressed multiple walled carbon nanotubes is investigated, with the emphasis on the simulation of the nanoindentation technique in order to compare the present method to available experimental results. More >

M.R. Khoshravan¹, M. Hosseinzadeh¹

CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.2, pp. 179-206, 2009, DOI:10.3970/cmes.2009.045.179

Abstract A sandwich panel's optimum core height and composite face thickness, under defined loading, have been computed in order to reach the structure's lowest weight and highest stiffness. The Tsai-Hill criterion was used in order to control the support of transverse loading by the panel. Regarding the relationships in the sandwich materials, the studied material was modeled with the MATLAB package. The Genetic Algorithm (GA) that is based on statistics was used. Our goal was to obtain the best methods of the GA in order to present an optimization method for the sandwich structure. Hence, a sensibility analysis was performed. In… More >

C. J. Wu¹, C. Y. Chou¹, C. N. Han¹, K. N. Chiang²

CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.1, pp. 49-68, 2009, DOI:10.3970/cmes.2009.041.049

Abstract In this paper, the atomistic-continuum mechanics method (ACM) is applied for carbon nanotube modeling. The atomistic-continuum mechanics is based on the transformation of chemical bonds between atoms in molecular mechanics into appropriate elements in finite element method and continuum mechanics. Spring elements are treated as chemical bonds between carbon atoms in carbon nanotube, whose force-displacement function is determined by the Reactive Empirical Bond Order (REBO) potential model. The advantages and unique feature of ACM method is same analytical model can be used for both tensile and vibration analyses, and most importantly, there are no prior inputs such as Young's Modulus,… More >

H. T. Wang¹, Z. H. Yao²

CMES-Computer Modeling in Engineering & Sciences, Vol.29, No.1, pp. 1-14, 2008, DOI:10.3970/cmes.2008.029.001

Abstract Carbon nanotubes (CNTs) may provide ultimate enhancement in stiffness and strength for composite materials. This paper presents a rigid-fiber-based boundary integral equation formulation for the numerical simulation of debonding process and the corresponding strength of CNT reinforced composites. The CNT/matrix interfaces are assumed to fail when the interfacial shear force reaches a prescribed threshold, and the CNTs and matrix are considered to be detached in the failed areas. The matrix with one or several tens of originally well-bonded CNTs is subjected to an incremental tensile load and the effective stress-strain relations are readily obtained by the introduction of CNT/matrix debonding… More >

Mira Mitra¹, S. Gopalakrishnan²

CMES-Computer Modeling in Engineering & Sciences, Vol.27, No.1&2, pp. 125-136, 2008, DOI:10.3970/cmes.2008.027.125

Abstract In this paper, the wave characteristics, namely, the spectrum and dispersion relations of multi-wall carbon nanotubes (MWNTs) are studied. The MWNTs are modeled as multiple thin shells coupled through van der Waals force. Each wall of the MWNT has three displacements, i.e, axial, circumferential and radial with variation along the axial and circumferential directions. The wave characteristics are obtained by transforming the governing differential wave equations to frequency domain via Fourier transform. This transformation is first done in time using fast Fourier transform (FFT) and then in one spatial dimension using Fourier series. These transformed equations are solved by posing… More >

Wenzhong Tang¹, Suresh G. Advani¹

CMES-Computer Modeling in Engineering & Sciences, Vol.25, No.3, pp. 149-164, 2008, DOI:10.3970/cmes.2008.025.149

Abstract In this paper, a method for studying nanotube dynamics in simple shear flow was developed. A nanotube was described as a flexible fiber with a sphere-chain model. The forces on the nanotube were obtained by molecular dynamics simulations. The motion of the nanotube in simple shear flow was tracked by the flexible fiber dynamics method [Tang and Advani (2005)]. The viscosity of dilute nanotube suspensions was calculated based on the nanotube dynamics, and the effects of the aspect ratio and initial curvature of the nanotube on suspension viscosity are explored and discussed. More >