Sunilkumar N¹, D Roy^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.65, No.2, pp. 107-154, 2010, DOI:10.3970/cmes.2010.065.107

Abstract The element-based piecewise smooth functional approximation in the conventional finite element method (FEM) results in discontinuous first and higher order derivatives across element boundaries. Despite the significant advantages of the FEM in modelling complicated geometries, a motivation in developing mesh-free methods has been the ease with which higher order globally smooth shape functions can be derived via the reproduction of polynomials. There is thus a case for combining these advantages in a so-called hybrid scheme or a 'smooth FEM' that, whilst retaining the popular mesh-based discretization, obtains shape functions with uniform C^p(p ≥ 1) continuity. One… More >

Hsiang-Wen Tang, Cha’o-Kung Chen¹, Chen-Yu Chiang

CMES-Computer Modeling in Engineering & Sciences, Vol.65, No.1, pp. 95-106, 2010, DOI:10.3970/cmes.2010.065.095

Abstract Up to now, solving some nonlinear differential equations is still a challenge to many scholars, by either numerical or theoretical methods. In this paper, the method of the maximum principle applied on differential equations incorporating the Residual Correction Method is brought up and utilized to obtain the upper and lower approximate solutions of nonlinear heat transfer problem of the non-Fourier fin. Under the fundamental of the maximum principle, the monotonic residual relations of the partial differential governing equation are established first. Then, the finite difference method is applied to discretize the equation, converting the differential More >

D. Kakogiannis¹, D. Van Hemelrijck¹, J. Wastiels¹, S. Palanivelu², W. Van Paepegem², J. Vantomme³, A. Kotzakolios⁴, V. Kostopoulos⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.65, No.1, pp. 75-94, 2010, DOI:10.3970/cmes.2010.065.075

Abstract In the present study the estimation of the blast wave by two types of finite element methods is investigated: Eulerian multi-material modeling and pure Lagrangian. The main goal is to compare and study their ability to predict the clearing effect during blast. Element shape and improvements on the codes are also considered. For the Lagrangian finite element models the load is applied by using an empirical method, deriving from databases, for the time-spatial distribution of the pressure profiles. In the ideal case of the above method the blast load is applied as an equivalent triangular… More >

Ahmad Akbari R.¹, Akbar Bagri², Stéphane P. A. Bordas^3,4, Timon Rabczuk⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.65, No.1, pp. 27-74, 2010, DOI:10.3970/cmes.2010.065.027

Abstract This contribution focuses on the simulation of two-dimensional elastic wave propagation in functionally graded solids and structures. Gradient volume fractions of the constituent materials are assumed to obey the power law function of position in only one direction and the effective mechanical properties of the material are determined by the Mori-Tanaka scheme. The investigations are carried out by extending a meshless method known as the Meshless Local Petrov-Galerkin (MLPG) method which is a truly meshless approach to thermo-elastic wave propagation. Simulations are carried out for rectangular domains under transient thermal loading. To investigate the effect More >

Veturia Chiroiu, Ligia Munteanu¹, Adrian Toader²

CMES-Computer Modeling in Engineering & Sciences, Vol.65, No.1, pp. 1-26, 2010, DOI:10.3970/cmes.2010.065.001

Abstract The best methods of the genetic algorithms (GA) are obtained in order to optimize the shape of a thin elastic rod subjected to spatial bending and torsion. The optimal cross-section is determined from the minimum volume condition, against the three modal bucklings. More >

M.K. Kang¹, E.H. Kim¹, M.S. Rim¹, I. Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.64, No.3, pp. 227-250, 2010, DOI:10.3970/cmes.2010.064.227

Abstract An engineering model for predicting the behavior of shape memory alloy (SMA) wire is presented in this study. Piecewise linear relations between stress and strain at a given temperature are assumed and the mixture rule of Reuss bounds is applied to get the elastic modulus of the SMAs in the mixed phase. Critical stresses and strains of the start and finish of the phase transformation are calculated at a given temperature by means of a linear constitutive equation and a stress-temperature diagram. Transformation conditions based on the critical stresses are translated in terms of critical More >

Yang Yang¹, Anil Misra²

CMES-Computer Modeling in Engineering & Sciences, Vol.64, No.1, pp. 1-36, 2010, DOI:10.3970/cmes.2010.064.001

Abstract Gradient theories have found wide applications in modeling of strain softening phenomena. This paper presents a higher order stress-strain theory to describe the damage behavior of strain softening materials. In contrast to most conventional gradient approaches for damage modeling, the present higher order theory considers strain gradients and their conjugate higher-order stress such that stable numerical solutions may be achieved. We have described the derivation of the required constitutive relationships, the governing equations and its weak form for this higher-order theory. The constitutive coefficients were obtained from a granular media approach such that the internal More >

Hideki Fujii¹, Shinobu Yoshimura¹, Kazuya Seki¹

CMES-Computer Modeling in Engineering & Sciences, Vol.63, No.3, pp. 265-282, 2010, DOI:10.3970/cmes.2010.063.265

Abstract Traffic system is a typical complex system emerged through interactions among a large number of traffic actors such as car drivers, pedestrians and others. We model each actor as an intelligent agent that can judge and act by itself autonomously, and develop a traffic simulator named MATES, which is based on an intelligent multi-agent model. In this simulator, microscopic behaviors of the traffic actors cause macroscopic traffic phenomena through their interaction. In this research, we newly develop a coordinative behavior model among multiple cars, and implement it to MATES to enhance the reproducibility of traffic More >

V. Sladek¹, J. Sladek¹, Ch. Zhang²

CMES-Computer Modeling in Engineering & Sciences, Vol.63, No.3, pp. 243-264, 2010, DOI:10.3970/cmes.2010.063.243

Abstract The paper deals with diminishing the prolongation of the computational time due to procedural evaluation of the shape functions and their derivatives in weak formulations implemented with meshless approximations. The proposed numerical techniques are applied to problems of stationary heat conduction in functionally graded media. Besides the investigation of the computational efficiency also the accuracy and convergence study are performed in numerical tests. More >

Kazuhiko Suga^1,2, Takahiko Ito¹

CMES-Computer Modeling in Engineering & Sciences, Vol.63, No.3, pp. 223-242, 2010, DOI:10.3970/cmes.2010.063.223

Abstract Flow passages in micro/nano-electro-mechanical systems (MEMS/ -NEMS) usually have complicated geometries. The present study thus discusses on the latest lattice Boltzmann methods (LBMs) for micro/nano fluidics to evaluate their applicability to micro/nano-flows in complex geometries. Since the flow regime is the continuum to the slip and transitional regime with a moderate Knudsen number (Kn), the LBMs presently focused on feature the wall boundary treatment and the relaxation-time for modeling such flow regimes. The discussed micro flow (µ-flow) LBMs are based on the Bhatnagar-Gross-Krook (BGK) model and the multiple relaxation-time (MRT) model. The presently chosen µ-flow… More >