Le-Le Zhang¹, Xue-Qian Fang¹, Jin-Xi Liu¹, Ji-Hong Ma¹

CMC-Computers, Materials & Continua, Vol.21, No.3, pp. 171-186, 2011, DOI:10.3970/cmc.2011.021.171

Abstract On the basis of continuum surface elasticity, two interacting cylindrical nano-inhomogeneities with surface/interface effect in a small-sized solid under anti-plane shear waves are investigated, and the dynamic stress around the nano-inhomogeneities is analyzed. The wave function expansion method is used to expressed the wave field around the two nano-inhomogeneities. The total wave field is obtained by the addition theorem for cylindrical wave function. Through analysis, it is found that the distance between the two nano-inhomogeneities shows great effect on the dynamic stress in nano composites. The effect of the distance is also related to the properties of the nano-inhomogeneities and… 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 >

Adel A. Abdel-Wahab¹, Angelo Maligno¹, Vadim V. Silberschmidt¹

CMC-Computers, Materials & Continua, Vol.19, No.3, pp. 217-238, 2010, DOI:10.3970/cmc.2010.019.217

Abstract Bone is the principal structural component of a skeleton: it assists the load-bearing framework of a living body. Structural integrity of this component is important; understanding of its mechanical behaviour up to failure is necessary for prevention and diagnostic of trauma. In dynamic events such as traumatic falls, involvement in car crash and sports injuries, bone can be exposed to loads exceeding its structural strength and/or fracture toughness. By developing adequate numerical models to predict and describe its deformation and fracture behaviour up to fracture, a detailed study of reasons for, and ways to prevent or treatment methods of, bone… More >

M. Demiral, A. Roy, V. V. Silberschmidt¹

CMC-Computers, Materials & Continua, Vol.19, No.2, pp. 199-216, 2010, DOI:10.3970/cmc.2010.019.199

Abstract Static indentation experiments are typically performed to characterize the mechanical properties of a material of interest by a rigid indenter of known geometry to various depths. In contrast, dynamic indentation of materials has not been fully studied. Evaluating material performance under dynamic loading conditions is a challenge and we demonstrate that various modelling schemes may be appropriate for different flavours of dynamic indentation. In order to compare underlying thermo-mechanics and deformation processes in a static and dynamic indentation process, indentation of a rigid indenter into a workpiece to a fixed chosen penetration is extensively studied. A nonlinear strain rate and… 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 >

Lutz Nasdala¹ , Andreas Kempe¹ and Raimund Rolfes¹

CMC-Computers, Materials & Continua, Vol.19, No.1, pp. 57-104, 2010, DOI:10.3970/cmc.2010.019.057

Abstract In order to understand the underlying mechanisms of inelastic material behavior and nonlinear surface interactions, which can be observed on macroscale as damping, softening, fracture, delamination, frictional contact etc., it is necessary to examine the molecular scale. Force fields can be applied to simulate the rearrangement of chemical and physical bonds. However, a simulation of the atomic interactions is very costly so that classical molecular dynamics (MD) is restricted to structures containing a low number of atoms such as carbon nanotubes. The objective of this paper is to show how MD simulations can be integrated into the finite element method… More >

Xue-Qian Fang^1,2, Xiao-Hua Wang¹, Le-Le Zhang³

CMC-Computers, Materials & Continua, Vol.16, No.3, pp. 229-246, 2010, DOI:10.3970/cmc.2010.016.229

Abstract In the design of advanced micro- and nanosized materials and devices containing inclusions, the effects of surfaces/interfaces on the stress concentration become prominent. In this paper, based on the surface/interface elasticity theory, a two-dimensional problem of an elliptical nano-inhomogeneity under anti-plane shear waves is considered. The conformal mapping method is then applied to solve the formulated boundary value problem. The analytical solutions of displacement fields are expressed by employing wave function expansion method, the expanded mode coefficients are determined by satisfying the boundary conditions at the interfaces of the nano-inhomogeneity. Analyses show that the effect of the interfacial properties on… More >

Hieu H. Pham¹, Tahir Ça ˇgın¹

CMC-Computers, Materials & Continua, Vol.16, No.2, pp. 175-194, 2010, DOI:10.3970/cmc.2010.016.175

Abstract We analyze the lattice dynamics of Fe in different crystal phases (bcc, fcc and hcp) by using density-functional theory. The study on equations of states indicates that bcc Fe is more stable than fcc and hcp Fe at low pressures. However, dynamical instabilities in lattice vibrations of bcc Fe predict a phase transformation from bcc to hcp at higher pressures. We reported a complete set of second-order and third-order elastic constants of Fe in these three phases. We observed a linear variation in the values of second order elastic constant as a function of increased pressures. The phonon spectra were… More >