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 >

H. T. Chen¹,K. H. Hsu¹, S. K. Lee¹, L. Y. Haung¹

CMC-Computers, Materials & Continua, Vol.22, No.3, pp. 239-260, 2011, DOI:10.3970/cmc.2011.022.239

Abstract The inverse scheme of the finite difference method in conjunction with the least-squares scheme and experimental measured temperatures is proposed to solve a two-dimensional steady-state inverse heat conduction problem in order to estimate the natural-convection heat transfer coefficient under the isothermal situation [`h] iso from three vertical fins mounted on a vertical plate and fin efficiency hf for various values of the fin spacing and fin height. The measured fin temperatures and ambient air temperature are measured from the present experimental apparatus conducted in a small wind tunnel. The heat transfer coefficient on the middle fin of three vertical fins… More >

Chia-Cheng Tsai ¹

CMC-Computers, Materials & Continua, Vol.22, No.3, pp. 197-218, 2011, DOI:10.3970/cmc.2011.022.197

Abstract This paper describes the combination of the method of fundamental solutions (MFS) and the dual reciprocity method (DRM) as a meshless numerical method to solve problems of Kirchhoff plates under arbitrary loadings. In the solution procedure, a arbitrary distributed loading is first approximated by either the multiquadrics (MQ) or the augmented polyharmonic splines (APS), which are constructed by splines and monomials. The particular solutions of multiquadrics, splines and monomials are all derived analytically and explicitly. Then, the complementary solutions are solved formally by the MFS. Furthermore, the boundary conditions of lateral displacement, slope, normal moment, and effective shear force are… More >

P. Zhao¹, G. Shi^1,2

CMC-Computers, Materials & Continua, Vol.22, No.2, pp. 147-168, 2011, DOI:10.3970/cmc.2011.022.147

Abstract The Poisson ratio is a very important mechanical parameter for both single-walled carbon nanotubes (SWCNTs) and graphene. But, the Poisson ratios of SWCNTs and graphene can not be determined by the direct measurement on the nanoscale specimen, and Poisson ratios of SWCNTs and graphene predicted by different models vary in a huge range. An improved molecular structural mechanics model, where the bond angle variations are modeled by the flexible connections of framed structures, is employed in this paper to predict the Poisson ratios of SWCNTs and monolayer graphene sheets. The present results indicate that the Poisson ratios of both SWCNTs… 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 >

Wen-Hwa Chen^1,2, Tsung-Yu Huang¹

CMC-Computers, Materials & Continua, Vol.20, No.1, pp. 63-84, 2010, DOI:10.3970/cmc.2010.020.063

Abstract The contact characteristics between a droplet and a microchip/binding site strongly affect the accuracy of self-alignment in the self-assembly of micro-electronic-mechanical systems. This study is mainly to implement the Surface Evolver Program, which is commonly adopted for studying surface shaped by surface tension and other energies, to investigate comprehensively the contact characteristics between the small droplet and the microchip/binding site. The details of changes in the contact line and the contact area when the microchip is subjected to translation, compression, yawing and rolling are drawn. The three-dimensional deformation of the droplet between the microchip and the binding site is also… 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 >

Sujoy Mukherjee¹, Ranjan Ganguli^1,2

CMC-Computers, Materials & Continua, Vol.19, No.2, pp. 105-134, 2010, DOI:10.3970/cmc.2010.019.105

Abstract In this study, variational principle is used for dynamic modeling of an Ionic Polymer Metal Composite (IPMC) flapping wing. The IPMC is an Electro-active Polymer (EAP) which is emerging as a useful smart material for `artificial muscle' applications. Dynamic characteristics of IPMC flapping wings having the same size as the actual wings of three different dragonfly species Aeshna Multicolor, Anax Parthenope Julius and Sympetrum Frequens are analyzed using numerical simulations. An unsteady aerodynamic model is used to obtain the aerodynamic forces. A comparative study of the performances of three IPMC flapping wings is conducted. Among the three species, it is… More >