Linjun Wang¹, Xu Han², Youxiang Xie³

CMES-Computer Modeling in Engineering & Sciences, Vol.82, No.3&4, pp. 179-194, 2011, DOI:10.32604/cmes.2011.082.179

Abstract In this paper, a new homotopy perturbation method (IHPM) is presented and suggested to solve an ill-posed problem of multi-source dynamic loads reconstruction. We propose a stable and reliable modification, and obtain a new regularization method, then employ it to find the exact solution for the multi-source dynamic load identification problem. Also, this present method only needs easy computations rather than successive integrations. Finally, the performances of two numerical examples are given. Comparisons are performed between the original homotopy perturbation method (HPM) and IHPM. The results verify that the present method is very simple and More >

Mehdi Tatari¹, Maryam Kamranian², Mehdi Dehghan²

CMES-Computer Modeling in Engineering & Sciences, Vol.82, No.1, pp. 1-28, 2011, DOI:10.32604/cmes.2011.082.001

Abstract In this paper, the finite point method (FPM) is presented for solving nonlinear reaction-diffusion systems which are often employed in mathematical modeling in developmental biology. In order to avoid directly solving a coupled nonlinear system, a predicator-corrector scheme is applied. The finite point method is a truly meshfree technique based on the combination of the moving least squares approximation on a cloud of points with the point collocation method to discretize the governing equations. The lack of dependence on a mesh or integration procedure is an important feature, which makes the FPM simple, efficient and More >

Marcin Kamiński¹, Rafał Leszek Ossowski¹

CMES-Computer Modeling in Engineering & Sciences, Vol.81, No.3&4, pp. 311-334, 2011, DOI:10.3970/cmes.2011.081.311

Abstract The main aim of this article is numerical solution of the fully coupled Navier-Stokes equations with Gaussian random parameters. It is provided thanks to the specially adopted Finite Volume Method, modified using the generalized stochastic perturbation technique. This Stochastic Finite Volume Method is applied to model 3D problem with uncertainty in liquid viscosity and a coefficient of the heat conduction, separately. Probabilistic moments and characteristics of up to the fourth order are determined with the use of the Response Function Method realized numerically via the polynomial inpterpolation. Although mathematical formulation of the SFVM has been More >

V. Kozulić¹, B. Gotovac¹

CMES-Computer Modeling in Engineering & Sciences, Vol.80, No.3&4, pp. 251-274, 2011, DOI:10.3970/cmes.2011.080.251

Abstract The numerical model for the elasto-plastic analysis of prismatic bars subjected to torsion is developed. The functions implemented in this model are Fup basis functions which belong to the class of atomic functions. The collocation method is used to form a system of equations in which the differential equation of the problem is satisfied in collocation points of closed domain, while boundary conditions are satisfied exactly at the domain boundary. The propagation of plastic zones in the cross-section is monitored by applying the incremental-iterative procedure until failure. An approximate solution of arbitrary accuracy is attained More >

V.G.Yakhno¹, T.M. Yakhno²

CMES-Computer Modeling in Engineering & Sciences, Vol.80, No.3&4, pp. 233-250, 2011, DOI:10.3970/cmes.2011.080.233

Abstract The time-dependent Maxwell's equations in non-dispersive homogeneous bi-anisotropic materials are considered in the paper. These equations are written as a symmetric hyperbolic system. A new method of the computation of the electric and magnetic fields arising from electric current is suggested in the paper. This method consists of the following. The Maxwell's equations are written in terms of the Fourier transform with respect to the space variables. The Fourier image of the obtained system is a system of ordinary differential equations whose coefficients depend on the 3D Fourier parameter. The formula for the solution of More >

M.M. Kaminski

CMES-Computer Modeling in Engineering & Sciences, Vol.80, No.2, pp. 113-140, 2011, DOI:10.3970/cmes.2011.080.113

Abstract The main aim of this work is to demonstrate a solution to the transient problems for the statistically homogeneous media with random physical parameters. This is done with the use of the stochastic perturbation technique based on the general order Taylor series expansions and the additionally modified implementation of the Finite Element Method. Now, both the Direct Differentiation Method as well as the Response Function Method are employed to form and solve up to the nth order state equations. Computational implementation of both approaches is illustrated using two examples - by determination of the probabilistic More >

A. Khosravifard¹, M.R. Hematiyan^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.78, No.3&4, pp. 185-208, 2011, DOI:10.3970/cmes.2011.078.185

Abstract An inverse method for optimal control of the freezing front motion in the solidification of pure materials is presented. The inverse technique utilizes the idea of a pseudo heat source to account for the latent heat effects. The numerical formulation of this inverse method is based on a formerly introduced meshless technique. In this method, the flux and the velocity of the liquid-solid interface are treated as secondary variables and the liquid and solid domains are modeled simultaneously. Some numerical examples are provided to demonstrate the efficiency of the presented method. The effects of regularization More >

Chein-Shan Liu¹, Chung-Lun Kuo²

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.1, pp. 57-80, 2011, DOI:10.3970/cmes.2011.077.057

Abstract In this paper, the solutions of inverse Cauchy problems for quasi-linear elliptic equations are resorted to an unusual mixed group-preserving scheme (MGPS). The bottom of a finite rectangle is imposed by overspecified boundary data, and we seek unknown data on the top side. The spring-damping regularization method (SDRM) is introduced by converting the governing equation into a new one, which includes a spring term and a damping term. The SDRM can further stabilize the inverse Cauchy problems, such that we can apply a direct numerical integration method to solve them by using the MGPS. Several More >

A. Rezaei Mojdehi^1,2, A. Darvizeh³, A. Basti²

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.1, pp. 1-32, 2011, DOI:10.3970/cmes.2011.077.001

Abstract In this paper, a meshless method based on the local petrov-galerkin approach is proposed for the three dimensional (3D) elasto-plastic problems. Galerkin weak-form formulation is applied to derive the discrete governing equations. A weak formulation for the set of governing equations is transformed into local integral equations on local sub-domains by using a unit test function. Nodal points are distributed in the 3D analyzed domain and each node is surrounded by a cubic sub-domain to which a local integral equation is applied. Three dimensional Moving Least-Square (MLS) approximation is used as shape function to approximate More >

Xiao Zhao¹, Haitian Yang^1,2, Qiang Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.2, pp. 139-160, 2011, DOI:10.3970/cmes.2011.074.139

Abstract A piecewised adaptive algorithm in the time domain is presented to solve the transient convection-diffusion heat transfer problem. By expanding all variables at a time interval, an initial and boundary value problem is decoupled into a series of recursive boundary value problems which can be solved by FEM or other well developed numerical schemes to deal with boundary value problems. A steady computing accuracy can be adaptively maintained via the power increase of the expansion, particularly when the step size varies in the whole computing process. Additionally for the nonlinear cases, there is no requirement More >