Hongtao Wang^1,2, Haitao Wang², Lie Jin², Zhenhan Yao³

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.6, pp. 529-552, 2013, DOI:10.3970/cmes.2013.094.529

Abstract Since only the boundary of the analyzed domain needs to be discretized, the boundary element method (BEM) inherently has the advantages of solving crack problems. In this paper, a micromechanics BEM scheme is applied to determine the effective elastic moduli of three-dimensional (3-D) solids containing a large number of parallel or randomly oriented microcracks. The 3-D analyses accelerated by the fast multipole method were carried out to investigate the relations between the effective elastic moduli and the microcrack density parameter. Numerical examples show that the results agree well with the available analytical solution and known More >

Guizhong Xie¹, Jianming Zhang^1,2, Cheng Huang¹, Chenjun Lu¹, Guangyao Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.2, pp. 139-157, 2013, DOI:10.3970/cmes.2013.094.139

Abstract In this work, an improved exponential transformation is presented for nearly singular boundary element integrals in problems of thin structures. Accurate evaluation of nearly singular integrals is an important issue in the implementation of boundary element method (BEM) for thin structures. In this paper, the exponential transformation, which was firstly developed to evaluate nearly singular integrals arising in 2D BEM, is extended into 3D BEM to deal with nearly singular integrals. Firstly, a novel (α,β) coordinate system is introduced. Then, the conventional distance function is modified into a new form in (α,β) coordinate system. Based More >

A. Tadeu¹, P. Stanak², J. Sladek², V. Sladek², J. Prata¹, N. Simões¹

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.6, pp. 489-516, 2013, DOI:10.3970/cmes.2013.093.489

Abstract This paper presents a technique that couples the boundary element method (BEM) with the meshless local Petrov-Galerkin (MLPG) method, formulated in the frequency domain. It is then used to study the transient heat diffusion through a two-dimensional unbounded medium containing confined subdomains where the material properties vary from point to point. To exploit the advantages of each method, the BEM is used for the homogeneous unbounded domain and the MLPG method is used for the non-homogeneous confined subdomains. The nodal points placed at the interface between the confined subdomains and the unbounded homogenous medium are… More >

J.H. Lv¹, Y. Miao^1,2, W.H. Gong¹, H.P. Zhu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.2, pp. 113-131, 2013, DOI:10.3970/cmes.2013.093.113

Abstract Accurate numerical evaluation of the nearly singular boundary integrals is a major concerned issue in the implementation of boundary element method (BEM). In this paper, a general distance function independent on the nearly singular point is proposed. Combined with an iteration process, the position of the nearly singular point can be obtained more easily. Then, an extended form of the sinh transformation using the general distance function, which automatically takes into account the intrinsic coordinate of the nearly singular point and the minimum distance from source point to the element in the intrinsic parameter plane, 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 More >

Harijono Djojodihardjo¹, Irtan Safari²

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.3, pp. 205-234, 2013, DOI:10.3970/cmes.2013.091.205

Abstract A series of work has been carried out to develop the foundation for the computational scheme for the calculation of the influence of the acoustic disturbance to the aeroelastic stability of the structure. The generic approach consists of three parts. The first is the formulation of the acoustic wave propagation governed by the Helmholtz equation by using boundary element approach, which then allows the calculation of the acoustic pressure on the acoustic-structure boundaries. The structural dynamic problem is formulated using finite element approach. The third part involves the calculation of the unsteady aerodynamics loading on More >

J.H. Lv¹, Y. Miao^1,2, H.P. Zhu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.2, pp. 101-117, 2013, DOI:10.3970/cmes.2013.091.101

Abstract The accurate and efficient evaluation of nearly singular integrals is one of the major concerned problems in the implementation of the boundary element method (BEM). Among the various commonly used nonlinear transformation methods, the distance transformation technique seems to be a promising method to deal with various orders of nearly singular integrals both in potential and elasticity problems. In this paper, some drawbacks of the conventional distance transformation, such as the sensitivity to the position of projection point, are investigated by numerical tests. A general distance transformation technique is developed to circumvent these drawbacks, which More >

A. Sellier

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.2, pp. 157-176, 2012, DOI:10.3970/cmes.2012.087.157

Abstract A new approach is proposed to accurately compute at a reasonable cpu time cost the hydrodynamic net force and net torque exerted on a slip and arbitrarily-shaped solid particle experiencing a prescribed slow rigid-body migration in a quiescent Newtonian liquid. The advocated method appeals to a boundary formulation which makes it possible to reduce the task to the treatment of a relevant regularized boundary-integral equation on the particle slipping surface. This integral equation is numerically inverted by implementing a boundary element collocation method. In addition to benchmark tests against analytical and numerical results available in More >

L. Rodríguez-Tembleque¹, R. Abascal¹, M.H. Aliabadi²

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.2, pp. 127-156, 2012, DOI:10.3970/cmes.2012.087.127

Abstract A boundary element based formulation is proposed to simulate 3D fretting wear under gross-sliding and partial slip conditions, assuming anisotropic friction and wear laws. Contact problem is based on an Augmented Lagrangian formulation, and restrictions fulfilment is established by a set of projection functions. The boundary element method reveals to be a very suitable numerical method for this kind of problems, where the degrees of freedom involved are those on the solids surfaces, and a very good approximation on contact tractions is obtained with a low number of elements. The present boundary element anisotropic fretting More >

E.J. Sapountzakis¹, A.E. Kampitsis²

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.2, pp. 97-126, 2012, DOI:10.3970/cmes.2012.087.097

Abstract In this paper a Boundary Element Method (BEM) is developed for the inelastic analysis of beams of arbitrarily shaped constant cross section having at least one axis of symmetry, resting on nonlinear inelastic foundation. The beam is subjected to arbitrarily distributed or concentrated vertical cyclic loading along its length, while its edges are subjected to the most general boundary conditions. A displacement based formulation is developed and inelastic redistribution is modelled through a distributed plasticity model exploiting material constitutive laws and numerical integration over the cross sections. An incremental - iterative solution strategy is adopted More >