M.R. Hematiyan^1,2, A. Khosravifard¹, Y.C. Shiah³, C.L. Tan⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.1, pp. 55-76, 2012, DOI:10.3970/cmes.2012.087.055

Abstract An inverse technique, based on the boundary element method (BEM) and elastostatic experiments for identification of elastic constants of orthotropic and general anisotropic 2D bodies is presented. Displacement measurements at several points on the boundary of the body, obtained by a few known load cases are used in the inverse analysis to find the unknown elastic constants of the body. Using data from more than one elastostatic experiment results in a more accurate and stable solution for the identification problem. In the inverse analysis, sensitivities of displacements of only boundary points with respect to the elastic constants are needed. Therefore,… More >

Yoshihiro Ochiai¹, Vladimir Sladek², Jan Sladek²

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.1, pp. 41-54, 2012, DOI:10.3970/cmes.2012.087.041

Abstract The conventional boundary element method (BEM) requires a domain integral in unsteady thermal stress analysis with heat generation or an initial temperature distribution. In this paper it is shown that the three-dimensional unsteady thermal stress problem can be solved effectively using the triple-reciprocity boundary element method without internal cells. In this method, the distributions of heat generation and initial temperature are interpolated using integral equations and time-dependent fundamental solutions are used. A new computer program was developed and applied to solving several problems. More >

W.J. Santos¹ , J.A.F. Santiago¹, J.C.F Telles¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.1, pp. 23-40, 2012, DOI:10.3970/cmes.2012.087.023

Abstract The aim of this paper is to present numerical simulations of Cathodic Protection (CP) Systems using a Genetic Algorithm (GA) and the Method of Fundamental Solutions (MFS). MFS is used to obtain the solution of the associated homogeneous equation with the non-homogeneous equation subject to nonlinear boundary conditions defined as polarization curves. The adopted GA minimizes a nonlinear error function, whose design variables are the coefficients of the linear superposition of fundamental solutions and the positions of the source points, located outside the problem domain. In this work, the anodes added to the CP system are considered as point sources… More >

Y.C. Shiah¹, C. L. Tan², C.Y. Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.1, pp. 1-22, 2012, DOI:10.3970/cmes.2012.087.001

Abstract The fundamental solution, or Green's function, for 3D anisotropic elastostatics as derived by Ting and Lee (1997) [Q.J. Mech. Appl. Math.; 50: 407-426] is one that is fully explicit and algebraic in form. It has, however, only been utilized in boundary element method (BEM) formulations quite recently even though it is relatively straightforward and direct to implement. This Green's function and its derivatives are necessary items in this numerical analysis technique. By virtue of the periodic nature of the angles when it is expressed in the spherical coordinate system, the present authors have very recently represented the Green's function as… More >

Wanil Byun¹, Seung Jo Kim²

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.6, pp. 551-576, 2012, DOI:10.3970/cmes.2012.086.551

Abstract A structural eigensolver for large-scale finite element analysis is developed. The algorithms and data structures implemented in this paper are well suited for a distributed memory environment. As an eigenvalue extracting algorithm, the well-known M orthogonal block Lanczos iteration incorporated with a parallel multifrontal solver (PMFS) was chosen. Basically, for the better performance of this algorithm in parallel computation, Lanczos vector allocation, mass matrix multiplication, and M inner product procedures were efficiently implemented. And the PMFS for a linear equation which is the most time-consuming part during Lanczos iterations was improved. The idea was to optimize network topologies of parallel… More >

Yonghua Zhou¹, Chao Mi¹, Xun Yang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.6, pp. 533-550, 2012, DOI:10.3970/cmes.2012.086.533

Abstract The cellular automaton (CA) model for traffic flow describes the restrictive vehicle movements using the distance headway (gap) between two adjacent vehicles. However, the autonomous and synergistic behaviors also exist in the vehicle movements. This paper makes an attempt to propose a microscopic traffic simulation model such that the feedback control behavior during the driving process is incorporated into the CA model. The acceleration, speed holding and deceleration are manipulated by the difference between the gap and the braking reference distance the driver perceives, which is generally observed in the realistic traffic. The braking reference distance is related to the… More >

H. Zheng¹, X. Peng^1,2,3, N. Hu^1,4

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.6, pp. 505-532, 2012, DOI:10.3970/cmes.2012.086.505

Abstract The static and kinematic shakedown of a functionally graded plate (FGP) is analyzed. The FGP is subjected coupled constant mechanical load and cyclically varying temperature. The FGP is composed of elastoplastic matrix and elastic particles, with the particle volume fraction varying along its thickness. The thermal and mechanical properties and their distributions are evaluated with a mean filed approach, which is based on the Eshelby's inclusion theory and takes into account directly the interaction between particles. The FGP is assumed to be separated into a number of thin layers, the thermal and mechanical properties in the thickness direction of each… More >

J. Herrmann¹, M. Junge¹, L. Gaul¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.6, pp. 487-504, 2012, DOI:10.3970/cmes.2012.086.487

Abstract The influence of an acoustic field on the dynamic behavior of a flexible structure is a common issue in automotive applications. An example is the pressure-induced structure-borne sound of piping and exhaust systems. Efficient model order reduction and substructuring techniques accelerate the finite element analysis and enable the vibroacoustic optimization of such complex systems with acoustic fluid-structure interaction. This research reviews the application of the Craig-Bampton and the Rubin method to fluid-structure coupled systems and presents two automotive applications. First, a fluid-filled piping system is assembled by substructures or superelements according to the Craig-Bampton method. Fluid and structural partitions are… More >

Souli M.¹, Bouamoul A.², Nguyen-Dang T.V.³

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.5, pp. 469-486, 2012, DOI:10.3970/cmes.2012.086.469

Abstract Protection of military vehicles against blast mine and high explosive in air is of a great concern in defence industry. Anti-Vehicle (AV) mines and Improvised Explosive Devices (IED's) are capable of inflecting damage to heavy vehicles. For the last decades, numerical simulation of blast wave propagation and its interaction with surrounding structures becomes more and more the focus of computational engineering, since experimental tests are very expensive and time consuming. This paper presents an experimental and numerical investigation of blast wave propagation in air, using an Arbitrary Lagrangian Eulerian (ALE) multi-material formulation developed in LS-DYNA with the contribution of the… More >

E. Ferretti¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.5, pp. 435-468, 2012, DOI:10.3970/cmes.2012.086.435

Abstract A recent experimental programme with the aim of acquiring the strains induced by aircraft traffic in concrete pavements [Ferretti and Bignozzi (2012); Ferretti (2012a)] has provided the opportunity of reviewing the classical solution of Boussinesq's problem for a homogeneous linear-elastic and isotropic half-space subjected to a point-load. In this document, we have proposed a second order solution to Boussinesq's problem, which allows us to account for the new experimental evidence. More >