Yiming Chen¹, Lu Sun¹, Xuan Li¹, Xiaohong Fu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.5, pp. 359-378, 2013, DOI:10.3970/cmes.2013.090.359

Abstract By using the differential operator matrix and the product operation matrix of the second kind Chebyshev wavelets, a class of nonlinear fractional integral-differential equations is transformed into nonlinear algebraic equations, which makes the solution process and calculation more simple. At the same time, the maximum absolute error is obtained through error analysis. It also can be used under the condition that no exact solution exists. Numerical examples verify the validity of the proposed method. More >

Guanghui Shi¹, Qingsheng Yang^1,2, Xiaoqiao He^3,4, Kim Meow Liew³

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.5, pp. 339-358, 2013, DOI:10.3970/cmes.2013.090.339

Abstract In order to describe the thermomechanical deformation and shape memory effect of shape memory polymers (SMPs), a three-dimensional thermomechanical constitutive model that considers elastic, viscoelastic strain and thermal expansion is proposed for isotropic SMPs. A three-dimensional finite element procedure is developed by implementing the proposed constitutive model into the user material subroutine (UMAT) in ABAQUS program. Numerical examples are used to compare it with existing experimental data in a one dimensional case and to demonstrate the thermomechanical behavior of SMPs with 3D deformation. It is shown that the present constitutive theory and the finite element More >

M. Razzaq¹, C. Tsotskas², S. Turek¹, T. Kipouros², M. Savill², J. Hron³

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.4, pp. 303-337, 2013, DOI:10.3970/cmes.2013.090.303

Abstract The integration and application of a new multi-objective tabu search optimization algorithm for Fluid Structure Interaction (FSI) problems are presented. The aim is to enhance the computational design process for real world applications and to achieve higher performance of the whole system for the four considered objectives. The described system combines the optimizer with a well established FSI solver which is based on the fully implicit, monolithic formuFlation of the problem in the Arbitrary Lagrangian-Eulerian FEM approach. The proposed solver resolves the proposed fluid-structure interaction benchmark which describes the self-induced elastic deformation of a beam More >

H.F. Gao¹, T. Matsumoto¹, T. Takahashi¹ and H. Isakari¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.4, pp. 283-301, 2013, DOI:10.3970/cmes.2013.090.283

Abstract By its very basis, the block Sakurai-Sugiura (SS) method may be applied to solving nonlinear eigenvalue problem formulated by boundary integral equation. In this paper, the methodology of BEM combined with the block SS method is applied to the computation of band structures of phononic structures for acoustic problems. Since the conventional boundary integral equation yields the real fictitious eigenfrequencies when it is applied to an exterior problem of scatters, Burton-Miller’s method is employed to remove the real fictitious eigenfrequencies resulted by the boundary of the scatterers. The application of the method is demonstrated through More >

Weichung Yeih^1,2, Cheng-Yu Ku^1,2,3, Chein-Shan Liu⁴, I-Yao Chan^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.4, pp. 255-282, 2013, DOI:10.3970/cmes.2013.090.255

Abstract In this paper, a scalar homotopy method with optimal hybrid search directions for solving nonlinear algebraic equations is proposed. To conduct the proposed method, we first convert the vector residual function to a scalar function by taking the square norm of the vector function and then, introduce a fictitious time variable to form a scalar homotopy function. To improve the convergence and the accuracy of the proposed method, a vector with multiple search directions and an iterative algorithm are introduced into the evolution dynamics of the solutions. Further, for obtaining the optimal search direction, linear… More >

Christos K. Filelis-Papadopoulos¹, George A. Gravvanis¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.3, pp. 233-253, 2013, DOI:10.3970/cmes.2013.090.232

Abstract During the last decades, multigrid methods have been extensively used in order to solve large scale linear systems derived from the discretization of partial differential equations using the finite difference method. Approximate Inverses in conjunction with Richardon’s iterative method could be used as smoothers in the multigrid method. Thus, a new class of smoothers based on approximate inverses could be derived. Effectiveness of explicit approximate inverses relies in the fact that they are close approximants to the inverse of the coefficient matrix and are fast to compute in parallel. Furthermore, the class of finite difference More >

Jian Hua Rong^1,2,3, Zhi Jun Zhao⁴, Yi Min Xie⁵, Ji Jun Yi^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.3, pp. 211-231, 2013, DOI:10.3970/cmes.2013.090.211

Abstract Similar periodic structures have been widely used in engineering. In order to obtaining the optimal similar periodic structures, a topology optimization method of similar periodic structures with multiple displacement constraints is proposed in this paper. Firstly, in the proposed method, the design domain is divided into sub-domains. Secondly, a penalty term considering discrete conditions of density variables is introduced into the objective function, and the reciprocal density exponents of structural elements are taken as design variables. A topological optimization model of a similar periodic continuum structure with the objective function being the structural mass and More >

Adan Vega, Ernesto Escobar, Amaly Fong, Ninshu Ma, Hidekazu Murakawa

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.3, pp. 197-210, 2013, DOI:10.3970/cmes.2013.090.197

Abstract This paper describes the effect of previous heating on inherent deformation by following heating, more specifically, the case of two heating lines applied parallel to each other. The novelty of the work lies in revealing the parallel effect and how, factors such as, for example, the heating condition and the plate geometry, influence the resulting inherent deformation of parallel heating. In addition, relationships to easily get these influences are provided. The results are suitable for a wide range of heating conditions and plate thickness. More >

Hui Zheng¹, Wen Chen^1,2,3, Chuanzeng Zhang⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.3, pp. 179-195, 2013, DOI:10.3970/cmes.2013.090.179

Abstract This paper develops a multi-domain boundary knot method (BKM) formulation to solve the heat conduction problems of ultra-thin coatings. This approach overcomes the troublesome singular integration difficulty in the boundary element method in the simulation of such ultra-thin coating problems. Our numerical results show that the present BKM is very promising with sufficient accuracy in predicting the temperature distributions and the other physical quantities in thin coated layers even when the thickness ranges from 10-1m to 10-9m. The present method can also easily be extended to the three-dimensional problems. More >

Christian Boe, Jose Rodriguez, Carlos Plazaola, Ilka Banfield A maly Fong, Rony Caballero, Adan Vega

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.2, pp. 165-177, 2013, DOI:10.3970/cmes.2013.090.165

Abstract The authors have developed a remote operate vehicle (ROV) that allow carried out highly risky task, in confined space such as inside of submerged sewers and pipes systems, areas were commercial ROV may not provide good performing. In addition, this ROV is low cost. This paper analyses based on the computational fluid dynamic the hydrodynamic performance of this ROV. The first part of the paper presents the theoretical approach and introduces the finite volume model developed in order to complete the study. Results of the model compare with published research shows good agreement. The second More >