Tai-Ming Chang¹, Chien-Chou Weng¹, Mei-Jiau Huang^1,2, Chun-KaiLiu², Chih-Kuang Yu²

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.1, pp. 47-66, 2009, DOI:10.3970/cmes.2009.050.047

Abstract We employ the non-equilibrium molecular dynamics (NEMD) simulation to calculate the in-plane thermal conductivity of silicon thin films of thickness 2.2nm and 11nm. To eliminate the finite-size effect, samples of various lengths are simulated and an extrapolation technique is applied. To perform the quantum correction which is necessary as the MD simulation temperature is lower than Debye temperature, the confined phonon spectra are obtained in advance via the EMD simulations. The investigation shows the thermal conductivities corrected based on the bulk and thin-film phonon densities of states are very close and they agree excellently with More >

Z.H.Yao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.1, pp. 21-46, 2009, DOI:10.3970/cmes.2009.050.021

Abstract The traditional time domain boundary integral equation (TDBIE) of elastodynamics is formulated based on the time dependent fundamental solution and the reciprocal theorem of elastodynamics. The time dependent fundamental solution of the elastodynamics is the response of the infinite elastic medium under a unit concentrate impulsive force subjected at a point and at an instant, including not only the pressure wave and shear wave, but also the Laplace wave with speed between that of P and S waves. In this paper, a new TDBIE is derived directly from the initial boundary value problem of the… More >

Haiping Ye¹, Yongsheng Ding²

CMES-Computer Modeling in Engineering & Sciences, Vol.49, No.3, pp. 255-268, 2009, DOI:10.3970/cmes.2009.049.255

Abstract A fractional-order model for the immunological and therapeutic control of HIV is studied qualitatively. The equilibria are found and their local stability are investigated. Also the global stability of the infection-free equilibrium is established. The optimal efficacy level of anti-retroviral therapy needed to eradicate HIV from the body of an HIV-infected individual is obtained. More >

J.M.C.Pereira¹, N.A.R.Maia¹, J.C.F.Pereira¹

CMES-Computer Modeling in Engineering & Sciences, Vol.49, No.2, pp. 113-142, 2009, DOI:10.3970/cmes.2009.049.113

Abstract We present a 2D incompressible Navier-Stokes numerical simulation of a virtual model of an elliptic, or flat plate, foil in hovering flight configuration. Computations obtained with a general purpose solver were validated against reference data on forward flapping flight, normal or dragonfly hovering. The moving mesh technique allows airfoil translation and angular mesh movement accompaining the airfoil stroke motion. Close to the ground the mesh deforms to occupy the narrow computational domain formed between the airfoil and the ground. Computations have been carried out for some parameters, including the distances h between the foil center and… More >

I. Emiroglu¹, F. Tasci¹, S. D. Akbarov²

CMES-Computer Modeling in Engineering & Sciences, Vol.49, No.1, pp. 47-68, 2009, DOI:10.3970/cmes.2009.049.047

Abstract The time-harmonic dynamical stress field in the system comprising two axially pre-stressed covering layer and two axially pre-stressed half space was studied under the action of uniformly distributed forces on free face plane of the covering layer. It is assumed that the forces are distributed within the rectangular area. The study was conducted within the scope of the piecewise homogeneous body model with the use of three-dimensional theory of elastic waves in an initially stressed bodies. The materials of the layer and half-space were assumed to be isotropic and homogeneous. The corresponding three-dimensional boundary-value-contact problem… More >

K.Willner ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.3, pp. 303-336, 2009, DOI:10.3970/cmes.2009.048.303

Abstract The dynamic behavior of structures with joints is strongly influenced by the constitutive behavior within the contact areas. In this paper the influence of an elaborate constitutive contact model based on a rough surface model is investigated. The contact model is able to describe several effects like pressure dependent contact stiffness in normal and tangential direction as well as microslip effects. The corresponding constitutive contact laws are implemented in a finite element code. Numerical simulations are compared to experimental results of a clamped double-beam experiment. More >

M. De Munck¹, D. Moens², W. Desmet³, D.Vandepitte³

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.2, pp. 119-166, 2009, DOI:10.3970/cmes.2009.047.119

Abstract Deterministic simulation tools enable a very precise simulation of physical phenomena using numerical models. In many real life situations however, a deterministic analysis is not sufficient to assess the quality of a design. In a design stage, some physical properties of the model may not be determined yet. But even in a design ready for production, design tolerances and production inaccuracies introduce variability and uncertainty. In these cases, a non-deterministic analysis procedure is required, either using a probabilistic or a non-probabilistic approach. The authors developed an intelligent Kriging response surface based optimisation procedure that can More >

Xie Ming-Liang^1,2, Zhou Huai-Chun¹, Chan Tat-Leung³

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 271-290, 2009, DOI:10.3970/cmes.2009.046.271

Abstract A Fourier-Chebyshev Petrov-Galerkin spectral method is described for computation of temporal linear stability in a circular jet. Basis functions presented here are exponentially mapped Chebyshev functions. They satisfy the pole condition exactly at the origin, and can be used to expand vector functions efficiently by using the solenoidal condition. The mathematical formulation is presented in detail focusing on the analyticity of solenoidal vector field used for the approximation of the flow. The scheme provides spectral accuracy in the present cases studied and the numerical results are in agreement with former works. More >

Itsuo Hanasaki, Hirofumi Shintaku, Satoshi Matsunami, Satoyuki Kawano¹

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.2, pp. 191-208, 2009, DOI:10.3970/cmes.2009.046.191

Abstract Self-assembly is one of the physical phenomena that are promising for the manufacturing process of the devices on which DNA molecules are mounted as the components. We have conducted a structural study of self-assembled poly(dA)\discretionary poly(dT) DNA networks on mica surface to discuss the design requirements. The results indicate that the network formation process consists of the adsorption and the subsequent coarsening. The final form of the component filaments are roughly straight. These characteristics imply the possible tensile loads during the network formation. Therefore, we have conducted molecular dynamics simulations of tensile tests of a More >

Tao Cui¹, Wenhao Liao¹ and Daren Yu ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.3, pp. 273-294, 2009, DOI:10.3970/cmes.2009.045.273

Abstract Aerodynamic hysteresis is of practical importance for the flying airfoils. Motivated by the problem of global description on the hysteresis behaviors, this paper proposes a topological approach to analyze and model the hysteresis behaviors exhibited in the airfoil flow from a viewpoint of dynamic system theory. The approach is based on the topological invariant rules of singular points under topological mapping. It is able to theoretically explain such discontinuous hysteresis phenomena, and make consistent and accurate predictions of the hysteresis behaviors in the airfoil flow. The model results have shown that the present model is More >