M. Patrício¹, R. Mattheij¹, G. de With²

CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.1, pp. 69-94, 2009, DOI:10.3970/cmes.2009.041.069

Abstract In this paper the effect of the local structure of a highly heterogeneous composite material on the parameters that characterise crack propagation is analysed. The evaluation of stress intensity factors is discussed. A hybrid approach based on domain decomposition and homogenisation methods is employed to obtain accurate solutions with reduced computational complexity. 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 >

V. Minutolo¹, E. Ruocco¹, S. Ciaramella¹

CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.1, pp. 27-48, 2009, DOI:10.3970/cmes.2009.041.027

Abstract A Field Boundary Element Method (FBEM) for Functionally Graded Materials (FGM) is presented and compared with Isoparametric Finite Element Method. The presented formulation, using the Kelvin's fundamental solution, is able to analyse structures although no fundamental solution is actually known. Isoparametric FGM Finite Element Method is a well established tool for FGM structural analysis. The comparison shows that both FBEM and FEM give accurate results. In the paper, the solution of some examples for 2D plates are reported both using FEM and FBEM. Some comparisons with analytical results are discussed and accuracy of the solutions is highlighted. The comparison between… More >

Hung-Chang Lee¹, Chein-Shan Liu²

CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.1, pp. 1-26, 2009, DOI:10.3970/cmes.2009.041.001

Abstract The group-preserving schemes developed by Liu (2001) for integrating ordinary differential equations system were adopted the Cayley transform and Padé approximants to formulate the Lie group from its Lie algebra. However, the accuracy of those schemes is not better than second-order. In order to increase the accuracy by employing the group-preserving schemes on ordinary differential equations, according to an efficient technique developed by Runge and Kutta to raise the order of accuracy from the Euler method, we combine the Runge-Kutta method on the group-preserving schemes to obtain the higher-order numerical methods of group-preserving type. They provide single-step explicit time integrators… More >

S.H. Pyo¹, H.K. Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.3, pp. 271-306, 2009, DOI:10.3970/cmes.2009.040.271

Abstract This paper presents a micromechanical approach for predicting the elastic and multi-level damage response of aligned and randomly oriented whisker-/ short fiber-reinforced composites. Based on a combination of Eshelby's micromechanics and the evolutionary imperfect interface approach, the effective elastic moduli of the composites are derived explicitly. The modified Eshelby's tensor for spheroidal inclusions with slightly weakened interface [Qu (1993b)] is extended in the present study to model whiskers or short fibers having mild or severe imperfect interfaces. Aligned and random orientations of spheroidal reinforcements are considered. A multi-level damage model in accordance with the Weibull's probabilistic function is then incorporated… More >

D. L. Young^1,3, K. H. Chen², T. Y. Liu³, L. H. Shen³, C. S. Wu³

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.3, pp. 225-270, 2009, DOI:10.3970/cmes.2009.040.225

Abstract In this article, a hypersingular meshless method (HMM) is extended to solve 3D potential problems for arbitrary domains after a 2D model was successfully developed (Young et al. 2005a). The solutions are represented by a distribution of the double layer potentials instead of the single layer potentials as generally used in the conventional method of fundamental solutions (MFS). By using the desingularization technique to regularize the singularity and hypersingularity of the double layer potentials, the source points can be located exactly on the real boundary to avoid the sensitivity of locating fictitious boundary for putting the singularity outside the computational… More >

X.G. Yuan^1,2, H.W. Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.3, pp. 201-224, 2009, DOI:10.3970/cmes.2009.040.201

Abstract The radially symmetric motion of the pre-existing micro-void centered at an incompressible hyperelastic sphere under the dynamic surface tensile loads relating to time is investigated in this paper. Some interesting conclusions are obtained by qualitatively analyzing the solutions of the motion equation of micro-void in detail; meanwhile, numerical simulations are used for understanding the obtained conclusions. In particular, it is proved that the motion of the micro-void with time would present a nonlinearly periodic oscillation if the values of the constant tensile load, the material and the structure parameters are given and that the oscillation amplitudes of the micro-void are… More >

Wen-Hwa Chen¹, Cheng-Te Chi, Ming-Hsiao Lee

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.2, pp. 175-200, 2009, DOI:10.3970/cmes.2009.040.175

Abstract Based on an incremental formulation of element-free Galerkin method (EFGM), a highly efficient three-dimensional EFGM analysis procedure is proposed to deal with the structure with extremely large deformation. By this procedure, a fixed and uniform background grid, part of which coincides with the background cells employed in the conventional EFGM for numerical integration, is devised. The background grid is connected by uniformly distributed fictitious nodes which do not move during loading process even if extremely large deformation occurs. A deformable analysis domain, which is discretized by moving boundary nodes and interior nodes, is established for describing the deformation of the… More >

Cha’o-Kuang Chen^1,2, Hsin-Yi Lai¹, Chin-Chia Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.2, pp. 155-174, 2009, DOI:10.3970/cmes.2009.040.155

Abstract Electrostatically-actuated micro circular plates are used in many micro-electro-mechanical systems (MEMS) devices nowadays such as micro pumps and optical switches. However, the dynamic behavior of these circular plates is not easily analyzed using traditional analytic methods due to the complexity of the interactions between the electrostatic coupling effects. Accordingly, this study develops an efficient computational scheme in which the nonlinear governing equation of the coupled electrostatic force acting on the micro circular plate is solved using a hybrid differential transformation / finite difference approximation method. In deriving the dynamic equation of motion of the micro plate, explicit account is taken… More >

Sen Yung Lee¹, Jyh Shyang Wu²

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.2, pp. 133-154, 2009, DOI:10.3970/cmes.2009.040.133

Abstract The three coupled governing differential equations for the in-plane vibrations of curved non-uniform Timoshenko beams are derived via the Hamilton's principle. Three physical parameters are introduced to simplify the analysis. By eliminating all the terms with the axial displacement parameter, then reducing the order of differential operator acting on the flexural displacement parameter, one uncouples the three governing characteristic differential equations with variable coefficients and reduces them into a sixth-order ordinary differential equation with variable coefficients in term of the angle of the rotation due to bending for the first time. The explicit relations between the axial and the flexural… More >