Y.C. Shiah¹, Y.M. Lee², T.C. Huang²

CMC-Computers, Materials & Continua, Vol.39, No.1, pp. 49-71, 2014, DOI:10.3970/cmc.2014.039.049

Abstract A common difficulty arises in characterizing the anisotropic properties of a thin sheet of anisotropic material, especially in the transverse direction. This difficulty is even more phenomenal for measuring its mechanical properties on account of its thickness. As the prelude of such investigation, this paper proposes a novel approach to identify the thermal conductivities of an unknown thin layer of anisotropic material. For this purpose, the unknown layer is sandwiched in isotropic materials with known conductivities. Prescribing proper boundary conditions, one may easily measure temperature data on a few sample boundary points. Therefore, the anisotropic More >

Y.C. Shiah¹, Y.M. Lee², Chi-Chang Wang²

CMC-Computers, Materials & Continua, Vol.33, No.3, pp. 229-255, 2013, DOI:10.3970/cmc.2013.033.229

Abstract In this paper, the boundary integrals for treating 3D field problems are fully regularized for planar elements by the technique of integration by parts (IBP). As has been well documented in open literatures, these integrals appear to be strongly singular and hyper-singular for the associated fundamental solutions. In the past, the IBP approach has only been applied to regularize the integrals for 2D problems. The present work shows that the IBP can also be further extended to treat 3D problems, where two variables of the local coordinates are involved. The presented formulations are fully explicit More >

Ewa Majchrzak^*

Molecular & Cellular Biomechanics, Vol.10, No.3, pp. 201-232, 2013, DOI:10.3970/mcb.2013.010.201

Abstract Heat transfer processes proceeding in the living organisms are described by the different mathematical models. In particular, the typical continuous model of bioheat transfer bases on the most popular Pennes equation, but the Cattaneo-Vernotte equation and the dual phase lag equation are also used. It should be pointed out that in parallel are also examined the vascular models, and then for the large blood vessels and tissue domain the energy equations are formulated separately. In the paper the different variants of the boundary element method as a tool of numerical solution of bioheat transfer problems More >

Marek Jasiński^*

Molecular & Cellular Biomechanics, Vol.10, No.3, pp. 183-199, 2013, DOI:10.3970/mcb.2013.010.183

Abstract In the paper the numerical analysis of thermal processes proceeding in the biological tissue is presented. The tissue is subjected to the external heat flux and 2D problem is taken into account. In order to determine the influence of variations of thermophysical parameters of tissue on the value of Arrhenius injury integral the direct approach of sensitivity analysis is applied. On the basis of tissue damage fraction the thermal injury formation process is analysed. At the stage of numerical realization the boundary element method is used. In the final part of the paper the example More >

R. Q. Rodríguez¹, A.F. Galvis¹, P. Sollero¹, E. L. Albuquerque²

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.4, pp. 259-274, 2013, DOI:10.3970/cmes.2013.096.259

Abstract Over recent years the rapid evolution of the computational power has motivated the development of new numerical techniques to account for engineering solutions. The Boundary Element Method (BEM) has shown to be a powerful numeric tool for the analysis and solution of many physical and engineering problems. However, BEM fully populated and non-symmetric system matrices implies in higher memory requirements and solution times. This work analyze the application of hierarchical matrices and low rank approximations, applying the Adaptive Cross Approximation - ACA, to multiple inclusion potential problems. The use of hierarchical format is aimed at More >

Mikael A. Langthjem¹, Masami Nakano²

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.4, pp. 227-241, 2013, DOI:10.3970/cmes.2013.096.227

Abstract This paper is concerned with a mathematical model of a simple axisymmetric silencer-like model, consisting of a hole-tone feedback system equipped with a tailpipe. The unstable shear layer is modeled via a discrete vortex method, based on axisymmetric vortex rings. The aeroacoustic model is based on the Powell- Howe theory of vortex sound. Boundary integrals are discretized via the boundary element method; but the tailpipe is represented by the exact (one-dimensional) solution. It is demonstrated though numerical examples that this numerical model can display lock-in of the self-sustained flow oscillations to the resonant acoustic oscillations. More >

A. Sellier

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.3, pp. 159-176, 2013, DOI:10.3970/cmes.2013.096.159

Abstract The rigid-body migration of a slip and arbitrary-shaped solid particle freely suspended in a prescribed and arbitrary ambient Stokes flow is determined after calculating the hydrodynamic force and torque exerted on the particle when it either experiences a given rigid-body in a quiescent liquid or is held fixed in the ambient Stokes flow. It is also shown how one can subsequently obtain the velocity and surface traction on the particle boundary and thereafter, if necessary, the flow about the particle in the entire liquid domain. The advocated procedure extends a recent work (see Sellier (2012)) More >

L. Rodríguez-Tembleque¹, A. Sáez¹, F.C. Buroni¹

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.2, pp. 131-158, 2013, DOI:10.3970/cmes.2013.096.131

Abstract A boundary element based formulation is applied to study numerically the tribological behavior of fiber-reinforced plastics (FRP) under different frictional contact conditions, taking into account the micromechanics of FRP. Micromechanical models presented consider continuous and short fiber reinforced plastics configurations. The Boundary Element Method (BEM) with an explicit approach for fundamental solutions evaluation is considered for computing the elastic influence coefficients. Signorini’s contact conditions and an orthotropic law of friction on the potential contact zone are enforced by contact operators over the augmented Lagrangian. The proposed methodology is applied to study carbon FRP under frictional More >

A. F. Galvis¹, R. Q. Rodriguez¹, P. Sollero¹, E. L. Alburquerque²

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.2, pp. 103-115, 2013, DOI:10.3970/cmes.2013.096.103

Abstract Polycrystalline structures are present on metal alloys. Therefore, it is necessary to understand and model the mechanical behavior of this media. Usually, this is accomplished by the use of different numerical methods. However, the analysis of polycrystalline materials leads to other type of problems, such as high computational requirements generated in order to get an efficient solution. In this work, the 2D polycrystalline structure is generated using an average grain size through the Voronoi tessellation method and discretized through simulations with random material, crystalline orientation and orthotropic behavior [Sfantos and Aliabadi (2007a)]. BEM discretization requires More >

M. G. He¹, C.L. Tan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.4, pp. 317-349, 2013, DOI:10.3970/cmes.2013.095.315

Abstract The self-regularization technique in the Boundary Element Method (BEM) originally proposed by Cruse and Richardson (1996, 1999) in their work for two-dimensional (2-D) stress analysis is extended to three-dimensional (3-D) elastostatics in this paper. The regularization scheme addresses the issue of accurate numerical evaluation of the integrals due to the singularity of the kernel functions of the integral equations. It is first implemented for the determination of displacements and stresses at interior points of the solution domain, and very accurate results are obtained even when these points are very close to the surface of the More >