K.B. Mustapha ^1,2

CMC-Computers, Materials & Continua, Vol.42, No.2, pp. 141-174, 2014, DOI:10.3970/cmc.2014.042.141

Abstract This study investigates the sensitivity of the flexural response of a ribconnected system of coupled micro-panels with traction-free surfaces. Idealized as a two-dimensional elastic continuum with a finite transverse stiffness, each micropanels’ behavior is examined within the framework of the biharmonic mathematical model derived from the higher-order, size-dependent strain energy formulation. The model incorporates the material length scale, which bears an associative relationship with the underlying polymer’s averaged Frank elastic constant. Upper estimates of the eigenvalue of the system, under fully clamped edges and simplysupported edges, are determined by the Rayleigh method. The adopted theory for the micro-panel’s behavior takes… More >

R. R. Valisetty¹, A.M. Dongare², A.M. Rajendran³, R. R. Namburu¹

CMC-Computers, Materials & Continua, Vol.36, No.3, pp. 231-255, 2013, DOI:10.3970/cmc.2013.036.231

Abstract Materials used in soldier protective structures, such as armor, vehicles and civil infrastructures, are being improved for performance in extreme dynamic environments. Nanocrystalline metals show significant promise in the design of these structures with superior strengths attributed to the dislocation-based and grain-boundary-based processes as compared to their polycrystalline counterparts. An optimization of these materials, however, requires a fundamental understanding of damage evolution at the atomic level. Accordingly, atomistic molecular dynamics simulations are performed using an embedded-atom method (EAM) potential on three nano-crystalline aluminum atom systems, one a Voronoi-based nano-crystalline system with an average grain size of 10 nm, and the… More >

Ching-Feng Yu¹, Wen-Hwa Chen^1,2, Kun-Ling Chen¹, Hsien-Chie Cheng^2,3

CMC-Computers, Materials & Continua, Vol.36, No.2, pp. 203-229, 2013, DOI:10.3970/cmc.2013.036.203

Abstract The investigation assesses the thermal-mechanical and thermodynamic properties of various graphene sheets using a modified Nosé-Hoover (NH) thermostat method incorporated with molecular dynamics (MD) simulation. The investigation begins with an exploration of their thermal-mechanical properties at atmospheric pressure, including Young’s modulus, shear modulus, Poisson’s ratio, specific heats and linear and volumetric coefficients of thermal expansion (CTE). Two definitions of the line change ratio (ΔL/L) are utilized to determine the linear CTE of graphene sheets, and the calculations are compared with each other and data in the literature. To estimate the volumetric CTE values, the Connolly surface method is applied to… More >

A. M. Dongare^1,2, A. M. Rajendran³, B. LaMattina⁴, M. A. Zikry¹, D. W. Brenner¹

CMC-Computers, Materials & Continua, Vol.24, No.1, pp. 43-60, 2011, DOI:10.3970/cmc.2011.024.043

Abstract Large-scale molecular dynamics (MD) simulations are used to investigate the effects of microstructure and loading conditions on the dynamic failure behavior of nanocrystalline Cu. The nucleation, growth, and coalescence of voids is investigated for the nanocrystalline metal with average grain sizes ranging from 6 nm to 12 nm (inverse Hall-Petch regime) for conditions of uniaxial expansion at constant strain rates ranging from 4x107 s - 1 to 1010 s - 1. MD simulations suggest that the evolution of voids can be described in two stages: The first stage corresponds to the nucleation of voids and the fast linear initial growth… More >

Cheng-Hung San¹, Che-Wun Hong^1,2

CMC-Computers, Materials & Continua, Vol.23, No.2, pp. 101-118, 2011, DOI:10.3970/cmc.2011.023.101

Abstract Poly(ethylene oxide) (PEO) is a commonly used electrolytic polymer in lithium ion batteries because of its high viscosity which allows fabricating thin layers. However, its inherent low ionic conductivity must be enhanced by the addition of highly conductive salt additives. Also its weak mechanical strength needs a complementary block, such as poly(styrene) (PS), to strengthen the electrolytic membrane during charging/discharging processes. PS is a strong material to complement the PEO and to create a reinforced copolymer electrolyte termed as the poly(styrene-b-ethylene oxide) (PS-PEO). In this work, molecular dynamics simulations are employed to study the effects of doping the PS constituents… More >

Yihua Xiao¹, Xu Han^1,2, Dean Hu¹

CMC-Computers, Materials & Continua, Vol.23, No.1, pp. 9-34, 2011, DOI:10.3970/cmc.2011.023.009

Abstract For impact computations, it is efficient to model small and large deformation regions by Finite Element Method (FEM) and Smoothed Particle Hydrodynamics (SPH), respectively. However, it requires an effective algorithm to couple FEM and SPH calculations. To fulfill this requirement, an alternative coupling algorithm is presented in this paper. In the algorithm, the coupling between element and particle regions are achieved by treating elements as imaginary particles and applying equivalent tractions to element sides on coupling interfaces. In addition, an adaptive coupling technique is proposed based on the algorithm to improve the computational efficiency of FEM-SPH coupling further. For this… More >

Xiaozhi Tang¹, Yafang Guo¹, Yu Gao¹

CMC-Computers, Materials & Continua, Vol.23, No.1, pp. 1-8, 2011, DOI:10.3970/cmc.2011.023.001

Abstract Atomistic simulations were performed to study the nanoindentation for two kinds of FCC metals, aluminum and copper. Due to the higher stacking faults in aluminum than in copper, two different deformation mechanisms were observed in our simulation under exactly the same simulation condition. Aluminum and copper also showed different mechanical properties in the unloading stage. The influence of stacking sequence along the loading direction on deformation mechanism was also investigated in this paper. More >

W.H. Chen¹, C.W. Hong^1,2

CMC-Computers, Materials & Continua, Vol.21, No.2, pp. 147-170, 2011, DOI:10.3970/cmc.2011.021.147

Abstract Nanorod/nanowell/nanotube arrays are effective nanotechnologies that can increase the performance of a photo-electrochemical solar cell by increasing the reaction area of the working electrode. However, the confined space due to the nano-arrays also tends to decrease the redox ion diffusivity. This paper describes computer modeling on the ionic diffusion of the active species (I-/I3-) among the nano-arrays of the working electrode material (TiO2). A three dimensional periodic boundary molecular dynamics simulation technique is employed to simulate the nano-scale transport phenomenon. Performance improvement tendency can be evaluated from the Butler-Volmer equation. Simulation results reveal that the increasing reaction area times the… More >

V.G.Yakhno¹

CMC-Computers, Materials & Continua, Vol.21, No.1, pp. 1-16, 2011, DOI:10.3970/cmc.2011.021.001

Abstract Homogeneous non-dispersive anisotropic materials, characterized by a positive constant permeability and a symmetric positive definite conductivity tensor, are considered in the paper. In these anisotropic materials, the electric and magnetic dyadic Green's functions are defined as electric and magnetic fields arising from impulsive current dipoles and satisfying the time-dependent Maxwell's equations in quasi-static approximation. A new method of deriving these dyadic Green's functions is suggested in the paper. This method consists of several steps: equations for electric and magnetic dyadic Green's functions are written in terms of the Fourier modes; explicit formulae for the Fourier modes of dyadic Green's functions… More >

Pavel Grinfeld¹

CMC-Computers, Materials & Continua, Vol.19, No.3, pp. 239-254, 2010, DOI:10.3970/cmc.2010.019.239

Abstract We model viscosity in the framework of the exact nonlinear equations of fluid film dynamics. The proposed approach yields monotonic dissipation of energy and guarantees that viscous forces are not engaged when the film undergoes rigid motion. With the addition of viscosity, the governing system has all the essential elements - inertia, surface tension, interaction with the ambient medium, influence of external fields and, now, viscosity - for accurate prediction and interpretation of experimental observations. The fluid film is modelled as a two-dimensional manifold. The film's thickness is represented by a surface density function. The resulting system is the fluid… More >