Lifeng Wang¹, Zhijun Meng¹, Yunpeng Ma¹, Zeyan Wu²

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.4, pp. 269-287, 2013, DOI:10.3970/cmes.2013.091.269

Abstract In this paper, we present a computational method for solving a class of fractional partial differential equations which is based on Haar wavelets operational matrix of fractional order integration. We derive the Haar wavelets operational matrix of fractional order integration. Haar wavelets method is used because its computation is sample as it converts the original problem into Sylvester equation. Finally, some examples are included to show the implementation and accuracy of the approach. More >

Q. G. Liu¹, B. Šarler^1,2,3,4

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.4, pp. 235-266, 2013, DOI:10.3970/cmes.2013.091.235

Abstract The purpose of the present paper is development of a Non-singular Method of Fundamental Solutions (NMFS) for two-dimensional isotropic linear elasticity problems. The NMFS is based on the classical Method of Fundamental Solutions (MFS) with regularization of the singularities. This is achieved by replacement of the concentrated point sources by distributed sources over circular discs around the singularity, as originally suggested by [Liu (2010)] for potential problems. The Kelvin’s fundamental solution is employed in collocation of the governing plane strain force balance equations. In case of the displacement boundary conditions, the values of distributed sources are calculated directly and analytically.… More >

Xiaoxia Yang¹, Shili Chen¹, Fang Sun¹, Shijiu Jin¹, Wenshuang Chang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.6, pp. 487-500, 2013, DOI:10.3970/cmes.2013.090.487

Abstract Ultrasonic phased array inspection technology is widely used in nondestructive evaluation (NDE) applications and it has been proved to be an effective method for flaw detections in industry. In our study, this nondestructive evaluation method is proposed to detect the corrosion defects on engine cylinders. In order to demonstrate its feasibility, it is necessary to study the characteristics of the acoustic field produced by a linear phased array ultrasonic transducer in the engine cylinders. In this paper, according to multi-Gaussian beam model and ray acoustics theory, we derive the expression of the acoustic field from a linear phased array ultrasonic… More >

Pratibhamoy Das¹, Srinivasan Natesan²

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.6, pp. 463-485, 2013, DOI:10.3970/cmes.2013.090.463

Abstract Adaptive mesh generation has become a valuable tool for the improvements of accuracy and efficiency of numerical solutions over fixed number of meshes. This paper gives an interpretation of the concept of equidistribution for singularly perturbed problems to obtain higher-order accuracy. We have used the post-processing Richardson extrapolation technique to improve the accuracy of the parameter uniform computed solution, obtained on a mesh which is adaptively generated by equidistributing a monitor function. Numerical examples demonstrate the high quality behavior of the computed solution. More >

L.Q. Liu¹, H.T. Wang^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.6, pp. 439-462, 2013, DOI:10.3970/cmes.2013.090.439

Abstract A line model-based fast boundary element method (BEM) is presented for the large-scale cathodic protection (CP) analysis of three-dimensional pipelines in layered soils. In this approach, pipelines are treated as lines with potentials assumed constant over the cross-section and the boundary integrals happen on the associated cylindrical surfaces. The advantage of this model is that pipelines can be meshed with line elements while the boundary integrals are based on the original shapes. Therefore, the number of unknowns is significantly reduced with accuracy effectively retained. A unified formulation of the multipole moments is developed for the mixed boundary element types in… More >

Yonghua Zhou¹ , Xun Yang¹ , Chao Mi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.6, pp. 415-437, 2013, DOI:10.3970/cmes.2013.090.415

Abstract High-speed train transportation is organized in a way of globally centralized planning and locally autonomous adjustment with the real-time known positions, speeds and other state information of trains. The hierarchical integration architecture composed of top, middle and bottom levels is proposed based on model predictive control (MPC) for the real-time scheduling and control. The middle-level trajectory configuration and tractive force setpoints play a critical role in fulfilling the top-level scheduling commands and guaranteeing the controllability of bottomlevel train operations. In the middle-level MPC-based train operation planning, the continuous cellular automaton model of train movements is proposed to dynamically configure the… More >

Leiting Dong^1,2, Satya N. Atluri^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.5, pp. 379-413, 2013, DOI:10.3970/cmes.2013.090.379

Abstract The SGBEM-FEM alternating method is compared with the recently popularized XFEM, for analyzing mixed-mode fracture and fatigue growth of 3D nonplanar cracks in complex solid and structural geometries. A large set of 3D examples with different degrees of complexity is analyzed by the SGBEM-FEM alternating method, and the numerical results are compared with those obtained by XFEM available in the open literature. It is clearly shown that: (a) SGBEM-FEM alternating method gives extremely high accuracy for the stress intensity factors; but the XFEM gives rather poor computational results, even for the most simple 3D cracks; (b) while SGBEM-FEM alternating method… More >

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 method can effectively simulate the… 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 attached to a cylinder in… More >