J.L. Morales¹, I. Alhama¹, M. Alcaraz¹, F. Alhama

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.3, pp. 261-277, 2013, DOI:10.32604/cmes.2013.094.261

Abstract In this paper, the propagation of 2-D, transversal elastic waves is simulated by using the network method. The spatially discretized wave equation is the basis for designing the model of the volume element which contains as many components as addends in the governing equation. The whole network model, including the boundary conditions, is run in a suitable circuit simulation code such as PSpice with a relatively small computational time. The rules for the design are very few since there is a special component in the libraries of such codes, named controlled source, that is capable More >

Cao Guohua¹, Zhu Zhencai¹, Peng Weihong², Wang Jinjie¹, Liu Zhi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.2, pp. 119-138, 2013, DOI:10.3970/cmes.2013.094.119

Abstract The single helical structure is twisted by surrounding helical units with clearance or not between two layers. In order to master the thermal expansion behavior, the theory has been developed for the analysis of these helical structures. The previously deduced linear expressions of thermal expansion coefficients for the gapless structure model (GM) is used and the analytical method is applied to the clearance structure model (CM) and clearance-gapless structure model(CGM) under two boundary conditions. For further evaluating the analytical expressions of two models, the finite element models of the single helical structure surrounding by helical… More >

Jun-Sheng Duan^1,2, Randolph Rach³, Abdul-Majid Wazwaz⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.1, pp. 77-118, 2013, DOI:10.3970/cmes.2013.094.077

Abstract In this paper, we propose a new modification of the Adomian decomposition method for solution of higher-order nonlinear initial value problems with variable system coefficients and solutions of systems of coupled nonlinear initial value problems. We consider various algorithms for the Adomian decomposition series and the series of Adomian polynomials to calculate the solutions of canonical first- and second-order nonlinear initial value problems in order to derive a systematic algorithm for the general case of higher-order nonlinear initial value problems and systems of coupled higher-order nonlinear initial value problems. Our new modified recursion scheme is More >

Yixian Du^1,2,3,4, De Chen¹, Xiaobo Xiang¹, Qihua Tian¹, Yi Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.1, pp. 53-75, 2013, DOI:10.3970/cmes.2013.094.053

Abstract Topological design of continuum structures usually involves numerical instabilities, such as checkerboards and mesh-dependency, which degenerate the manufacturability, the efficiency and the robustness of the optimal design. This paper will propose a new topology optimization method to suppress numerical instabilities occurred in the topology optimization of continua, according to the principle of error amplifier and feedback control in the control system. The design variables associated with topological design are updated based on the Cellular Automata (CA) theory. A couple of typical numerical examples are used to demonstrate the effectiveness of the proposed method in effectively More >

Tao Zhang^1,2, Leiting Dong^2,3, Abdullah Alotaibi⁴, Satya N. Atluri^2,5

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.1, pp. 1-28, 2013, DOI:10.3970/cmes.2013.094.001

Abstract In this paper, a novel Meshless Local Petrov-Galerkin (MLPG) Mixed Collocation Method is developed for solving the inverse Cauchy problem of linear elasticity, wherein both the tractions as well as displacements are prescribed/measured at a small portion of the boundary of an elastic body. The elastic body may be isotropic/anisotropic and simply connected or multiply-connected. In the MLPG mixed collocation method, the same meshless basis function is used to interpolate both the displacement as well as the stress fields. The nodal stresses are expressed in terms of nodal displacements by enforcing the constitutive relation between… More >

Dan Xie¹, Min Xu²

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.5, pp. 377-409, 2013, DOI:10.3970/cmes.2013.093.377

Abstract We apply a simple proper orthogonal decomposition (POD) method to compute the nonlinear oscillations of a degenerate two-dimensional fluttering plate undergoing supersonic flow. First, the von Karman’s large deflection theory and quasi-steady aerodynamic theory are employed in constructing the governing equations of the simply supported plate. Then, the governing equations are solved by both the Galerkin method and the POD method. The Galerkin method is accurate but sometimes computationally expensive, since the number of degrees of freedom (dofs) required is relatively large provided that nonlinearity is strong. The POD method can be used to capture… More >

Tai C. Lee¹, Huan J. Keh²

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.5, pp. 317-333, 2013, DOI:10.3970/cmes.2013.093.317

Abstract A theoretical study of the thermocapillary migration of a fluid sphere located at an arbitrary position inside a spherical cavity is presented in the quasisteady limit of small Reynolds and Marangoni numbers. The applied temperature gradient is perpendicular to the line through the drop and cavity centers. The general solutions to the energy and momentum equations governing the system are constructed from the superposition of their fundamental solutions in the spherical coordinates originating from the two centers, and the boundary conditions are satisfied by a multipole collocation method. Results for the thermocapillary migration velocity of… More >

Bing Li^1,2, Zhengjia He¹

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.4, pp. 293-316, 2013, DOI:10.3970/cmes.2013.093.293

Abstract The vibration-based crack identification problem insists of finding a measured vibration parameter from a complete crack-detection-database constructed by numerical simulation. It is one of the classical optimization problems. Many intelligence methods, such as neural network (NN), genetic algorithm (GA), determinant transformation (DT), and frequency contour (FC) etc., have been extensively employed as optimization tools to achieve this task. The aim of this paper is to propose a benchmark problem to compare these extensive-used optimization methods in terms of crack identification precision and computational time. The merit and demerits for each method are discussed. The results More >

C. K. Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.3, pp. 221-234, 2013, DOI:10.3970/cmes.2013.093.221

Abstract By extending Bückner’s superposition principle and alternating iteration method, this presentation studies the dual holes interactions. A newly developed numerical scheme is embedded in the conventional Gauss-Legendre quadrature routine for evaluating the boundary integral holding stress singularities. This developed scheme can avoid numerical singularity and facilitate the achieved stress field to be exact as that of analytical solution; however the chosen Gaussian integration points must enter a large quantity. This presentation uses an infinite plate with a centered hole strained by remote axial loading as a testing example, and the numerical results are capable of More >

Wen-Hwa Chen^2,3, Ming-Hsiao Lee⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.2, pp. 149-166, 2013, DOI:10.3970/cmes.2013.093.149

Abstract A novel meshless analysis procedure is established for practical implementation in dealing with three-dimensional structures with complicated geometry. By this procedure, to describe the surface of structure, the Stereo-lithography (STL) geometry technique is first adopted. Nodes are then generated and paved uniformly in the space over the entire structure analyzed. To decide the node distribution inside the structure, a geometry-related treatment scheme with relevant checking mechanisms is developed. Besides, a simple and direct spatial integration scheme is also proposed. By this integration scheme, integration points are evenly distributed in the structure and can be adjusted More >