K. Kakuda¹, A. Seki¹, Y. Yamauchi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.3, pp. 281-306, 2010, DOI:10.3970/cmes.2010.069.281

Abstract A finite element scheme based on the concept of TVD (total variation diminishing) with a flux-limiter for the hyperbolic systems of conservation laws is presented. The numerical flux is formulated effectively by the weighted integral form using exponential weighting functions. The TVD finite element scheme is applied to a Riemann problem, namely the shock-tube problem, for the Euler system of equations. Numerical results demonstrate the workability and the validity of the present approach through comparison with the exact solutions. More >

Adan Vega, Naoki Osawa, Sherif Rashed, Hidekazu Murakawa

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.3, pp. 261-280, 2010, DOI:10.3970/cmes.2010.069.261

Abstract A three dimensional thermal-elasto-plastic FEA has been performed to predict the heat induced (inherent) deformation produced in thick steel plates formed by line heating. Using this FEA, the edge effect on inherent deformation is clarified. From the results of this study, a method to predict the edge effect is developed. Using this method, the edge effect on inherent deformation, for a wide range of plate thickness and heating condition, can be easily predicted, been this, an important step toward the automation of the process. More >

J. Dujc^1,3, B. Brank^1,2, A. Ibrahimbegovic³

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.3, pp. 223-260, 2010, DOI:10.3970/cmes.2010.069.223

Abstract We present a quadrilateral finite element with discontinuous displacement fields that can be used to model material failure in 2d brittle and ductile solids. The element provides mesh-objective results. The element's kinematics can represent linear displacement jumps along the discontinuity line in both normal and tangential directions to the line. The cohesive law in the discontinuity line is based on rigid-plasticity model with softening. The material of the bulk of the element is described by hardening plasticity model. Static condensation of the jump-in-displacements kinematic parameters is made, which provides standard form of the element stiffness matrix. However, in order to… More >

Xianqiao Wang¹, James D. Lee²

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.3, pp. 199-222, 2010, DOI:10.3970/cmes.2010.069.199

Abstract This paper presents an atom-based continuum (ABC) method aiming at a seamless transition from the atomistic to the continuum description of multi-element crystalline solids (which has more than one kind of atom in the unit cell). Contrary to many concurrent multiscale approaches, ABC method is naturally suitable for the analysis of multi-element crystals within a finite element (FE) framework. Taking both efficiency and accuracy into account, we adopt a cluster-based summation rule for atomic force calculations in the FE formulations. Single-crystals MgO, BaTiO₃ and Cu under mechanical loading are modeled and simulated. With a coarse-grained mesh, ABC method is shown… More >

Y.C. Shiah¹, C. L. Tan², R.F. Lee¹

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.2, pp. 167-198, 2010, DOI:10.3970/cmes.2010.069.167

Abstract In this paper, fully explicit, algebraic expressions are derived for the first and second derivatives of the Green's function for the displacements in a three dimensional anisotropic, linear elastic body. These quantities are required in the direct formulation of the boundary element method (BEM) for determining the stresses at internal points in the body. To the authors' knowledge, similar quantities have never previously been presented in the literature because of their mathematical complexity. Although the BEM is a boundary solution numerical technique, solutions for the displacements and stresses at internal points are sometimes required for some engineering applications. To this… More >

Yantao Zhang¹, Xiong Zhang^1,2, Yan Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.2, pp. 143-166, 2010, DOI:10.3970/cmes.2010.069.143

Abstract Material point method(MPM) is a promising method in solving problems involving large deformations, especially explosion and penetration. In MPM, particles can move around the computing domain dynamically, which can result in load imbalance easily. In parallelizing MPM using OpenMP, data races will occur in the stage of grid node updating if we use loop-level parallelism for these loops. Huang et al. proposed a domain decomposition method to overcome data races [Huang, Zhang, Ma and Wang (2008)]. However, significant modifications of the original serial code are required. In this paper, we proposed a new alternated grid updating method to avoid data… More >

Ching Kong Chao^1,2, Chin Kun Chen³, Fu Mo Chen⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.2, pp. 119-142, 2010, DOI:10.3970/cmes.2010.069.119

Abstract A general solution to a three-phase elliptic inclusion problem subjected to a remote uniform load is provided in this paper. Analysis of the present elasticity problem is rather tedious due to the presence of material inhomogeneities and complex geometric configurations. Based on the technique of conformal mapping and the method of analytical continuation in conjunction with the alternating technique, the general expressions of the displacement and stresses in each layer medium are derived explicitly in a series form. The effects of the material combinations and geometric configurations on the interfacial stresses are discussed in detail and shown in graphic form. More >

A. Arefmanesh¹, M. Najafi², M. Nikfar³

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.2, pp. 91-118, 2010, DOI:10.3970/cmes.2010.069.091

Abstract Procuring a numerical solution through an application of the meshless local Petrov-Galerkin method (MLPG) on the fluid flow and mixed convection in a complex geometry cavity filled with a nanofluid is the scope of the present study. The cavity considered is a square enclosure having a lower temperature sliding lid at the top, a differentially higher temperature wavy wall at the bottom, and two thermally insulated walls on the sides. The nanofluid medium used is a water-based nanofluid, Al₂O₃-water with various volume fractions of its solid. To carry out the numerical simulations, the developed governing equations are determined in terms… More >

Anant Diwakar¹, D. N.Srinath¹, Sanjay Mittal¹

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 61-90, 2010, DOI:10.3970/cmes.2010.069.061

Abstract Aerodynamic shape optimization of airfoils is carried out for two values of Reynolds numbers: 10³ and 10⁴, for an angle of attack of 5^o. The objective functions used are (a) maximization of lift (b) minimization of drag and (c) minimization of drag to lift ratio. The surface of the airfoil is parametrized by a 4^th order non-uniform rational B-Spline (NURBS) curve with 61 control points. Unlike the efforts in the past, the relatively large number of control points used in this study offer a rich design shape with the possibility of local bumps and valleys on the airfoil surface. The… More >

Ewa Majchrzak¹

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 43-60, 2010, DOI:10.3970/cmes.2010.069.043

Abstract Heat transfer processes proceeding in domain of heating tissue are discussed. The typical model of bioheat transfer bases, as a rule, on the well known Pennes equation, this means the heat diffusion equation with additional terms corresponding to the perfusion and metabolic heat sources. Here, the other approach basing on the dual-phase-lag equation (DPLE) is considered in which two time delays τ_q, τ_T (phase lags) appear. The DPL equation contains a second order time derivative and higher order mixed derivative in both time and space. This equation is supplemented by the adequate boundary and initial conditions. To solve the problem… More >