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 >

Adan Vega, Alexandra Camaño, Amaly Fong, Sheriff Rashed, Hidekazu Murakawa

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.2, pp. 147-163, 2013, DOI:10.3970/cmes.2013.090.147

Abstract The inherent deformation produced by two or more overlapped heating lines is not equal to that obtained when individual deformations are simply added. Thus, the effect of overlapping on inherent deformation, need to be clarified in order to achieve full understanding of the phenomenon of plate forming by line heating. In this paper, a 3D thermal-elasto-plastic FEA has been performed to study this problem in details. Using this FEA, the influence of previous heating on the inherent deformation of overlapped heating lines, considering various conditions, is clarified. From the results of this study, a method More >

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

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.2, pp. 91-146, 2013, DOI:10.3970/cmes.2013.090.091

Abstract In this paper, and its companion Part 2 [Dong and Atluri (2013b)], the Symmetric Galerkin Boundary Element Method (SGBEM), and the SGBEM-FEM alternating/coupling methods, are compared with the recently popularized Extended Finite Element Method (XFEM), for analyzing fracture and fatigue crack propagation in complex structural geometries. The historical development, and the theoretical/algorithmic formulations, of each method are succinctly reviewed. The advantages and disadvantages of each method are critically discussed. A comprehensive evaluation of the performances of the SGBEM-based methods, and their comparison with XFEM, in modeling cracked solid structures undergoing fatigue crack-growth is carried out.… More >

Binbin Diao¹, Deli Gao^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 77-90, 2013, DOI:10.3970/cmes.2013.090.077

Abstract The measurement of the relative position of two adjacent wells is one of the key technologies in the directional drilling of twin parallel horizontal wells, and the downhole intersection of two adjacent wells. A new electromagnetic ranging system and a guidance method are introduced for determining the relative position of two adjacent wells. The system mainly consists of two solenoid assemblies, improved surveying instrument for measurement while drilling (MWD), and a computational procedure for guidance. Also, the distribution of the magnetic field of each energized solenoid assembly is discussed, by regarding the solenoid assembly as… More >

Zonglu Guo¹, Deli Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 65-76, 2013, DOI:10.3970/cmes.2013.090.065

Abstract The modeling of the bottomhole assembly (BHA) is an essential problem in directional drilling. Some basic equations for predicting the performance of the BHA are presented in this paper. These equations take into account the effects of the axial displacement. The method of weighted residuals and the Newton-Raphson iterations are used to compute the nonlinear effects of the deformation of the BHA. A computer program is developed for the analysis of the BHA in order to quantitatively predict the performance of the BHA in directional drilling. In addition, a case study is presented to evaluate More >

Hui Zhang¹, Deli Gao^1,2, Xiaopin Xie¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 47-64, 2013, DOI:10.3970/cmes.2013.090.047

Abstract In oil & gas drilling engineering, the rock breaking efficiency as well as the trajectory of the Well should be quantitatively and accurately described by an ideal triaxial Rate of Penetration (ROP) model, taking into account the various objective and subjective factors. However, with the existing triaxial ROP models, it is difficult to achieve these goals. The applications of the existing ROP models are limited, especially in under-balanced drilling (air drilling, foam drilling etc.), because the unloading effect (i.e. the effect of the bottom hole differential pressure on the formation force) has been rarely considered.… More >