Z. Y. Yan^1,2, J. Zhang¹, W. Ye¹, T.X. Yu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.55, No.1, pp. 33-60, 2010, DOI:10.3970/cmes.2010.055.033

Abstract An 3-D precorrected-FFT accelerated BEM approach for the linear elastic analysis of porous solids with randomly distributed pores of arbitrary shape and size is described in this paper. Both the upper bound and the lower bound of elastic properties of solids with spherical pores are obtained using the developed fast BEM code. Effects of porosity and pore shape on the elastic properties are investigated. The performance of several theoretical models is evaluated by comparing the theoretical predictions with the numerical results. It is found that for porous solids with spherical pores, the performances of the generalized self-consistent method and Mori-Tanaka… More >

Luca Bergamaschi^1,2, ,Ángeles Martínez², Giorgio Pini²

CMES-Computer Modeling in Engineering & Sciences, Vol.49, No.3, pp. 191-216, 2009, DOI:10.3970/cmes.2009.049.191

Abstract A meshless model, based on the Meshless Local Petrov-Galerkin (MLPG) approach, is developed and implemented in parallel for the solution of axi-symmetric poroelastic problems. The parallel code is based on a concurrent construction of the stiffness matrix by the processors and on a parallel preconditioned iterative method of Krylov type for the solution of the resulting linear system. The performance of the code is investigated on a realistic application concerning the prediction of land subsidence above a deep compacting reservoir. The overall code is shown to obtain a very high parallel efficiency (larger than 78% for the solution phase) and… More >

I. Karagoz, F.Kaya

CMES-Computer Modeling in Engineering & Sciences, Vol.43, No.2, pp. 111-130, 2009, DOI:10.3970/cmes.2009.043.111

Abstract The aim of this work is to investigate the suitability of various turbulence models and their options for highly complex swirling flows in tangential inlet cyclones. Three-dimensional, steady governing equations for the incompressible, turbulent flow inside the cyclone are solved numerically. The prediction performance of three popular turbulence models and various options available for these models was evaluated by comparing the computed velocity profiles and pressure drop with the experimental data given in the literature. Results obtained from the numerical tests have demonstrated that the swirl factor for the RNG k-emodel has considerably influence on the prediction performance of the… More >

G. Narbona-Reina¹, J.D.D. Zabsonré², E.D. Fernández-Nieto¹, D. Bresch³

CMES-Computer Modeling in Engineering & Sciences, Vol.43, No.1, pp. 27-72, 2009, DOI:10.3970/cmes.2009.043.027

Abstract In this work we present a new two-dimensional bilayer Shallow-Water model including viscosity and friction effects on the bottom and interface level. It is obtained following [Gerbeau and Perthame (2001)] from an asymptotic analysis of non-dimensional and incompressible Navier-Stokes equations with hydrostatic approximation. In order to obtain the viscosity effects into the model we must have into account a second order approximation. To evaluate this model we perform two numerical tests consisting of an internal dam-break problem for both, one and two dimensional cases. In the first one we make a comparison between the model obtained and the Navier-Stokes simulation. More >

Chunhai Kou¹, Ye Yan², Jian Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.3, pp. 301-318, 2009, DOI:10.3970/cmes.2009.039.301

Abstract In the paper, stability for fractional order differential equations is studied. Then the result obtained is applied to analyse the stability of equilibrium for the model of HIV. More >

Patrícia C.T. Gonçalves^1,2, João Manuel R.S. Tavares^1,2, R.M. Natal Jorge^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.32, No.1, pp. 45-56, 2008, DOI:10.3970/cmes.2008.032.045

Abstract The main goals of the present work are to automatically extract the contour of an object and to simulate its deformation using a physical approach. In this work, to segment an object represented in an image, an initial contour is manually defined for it that will then automatically evolve until it reaches the border of the desired object. In this approach, the contour is modelled by a physical formulation using the finite element method, and its temporal evolution to the desired final contour is driven by internal and external forces. The internal forces are defined by the intrinsic characteristics of… More >

S S Panda¹, C S Manohar^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.3, pp. 161-184, 2008, DOI:10.3970/cmes.2008.028.161

Abstract The problem of reliability analysis of randomly parametered, linear (or) nonlinear, structures subjected to static and (or) dynamic loads is considered. A deterministic finite element model for the structure to analyze sample realization of the structure is assumed to be available. The reliability analysis is carried out within the framework of response surface methods which involves the construction of surrogate models for performance functions to be employed in reliability calculations. This construction, in the present study, has involved combining space filling optimal Latin hypercube sampling, kriging models and methods from data-based asymptotic extreme value modeling of sequence of random variables.… More >

Chun Yang¹, Dalin Tang², Chun Yuan³, Thomas S. Hatsukami⁴, Jie Zheng⁵, Pamela K. Woodard⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.19, No.3, pp. 233-246, 2007, DOI:10.3970/cmes.2007.019.233

Abstract It has been recognized that fluid-structure interactions (FSI) play an important role in cardiovascular disease initiation and development. However, in vivo MRI multi-component FSI models for human carotid atherosclerotic plaques with bifurcation and quantitative comparisons of FSI models with fluid-only or structure-only models are currently lacking in the literature. A 3D non-Newtonian multi-component FSI model based on in vivo/ex vivo MRI images for human atherosclerotic plaques was introduced to investigate flow and plaque stress/strain behaviors which may be related to plaque progression and rupture. Both artery wall and plaque components were assumed to be hyperelastic, isotropic, incompressible and homogeneous. Blood… More >

Chun-Ying. Wu¹, R. Al-Khoury², C. Kasbergen², Xue-Yan. Liu², A. Scarpas²

CMES-Computer Modeling in Engineering & Sciences, Vol.17, No.3, pp. 163-172, 2007, DOI:10.3970/cmes.2007.017.163

Abstract 3D spectral element method in the article is presented to predict the pavement layer modules using field measurement of Falling Weight Deflectometer (FWD). To improve the computational efficiency of the layer-condition assessment, one type of spectral element is proposed to develop the dynamic analysis of 3D multi-layered system subjected to an impulsive load. Each layer in structure is simulated as two-noded layer spectral element or one-noded spectral element in frequency domain. In order to identify the parameters of layered structures, a nonlinear optimization method called Powell hybrid algorithm is employed. The optimization procedure is performed in frequency domain and aims… More >

M. Kailasam¹, N. Aravas², P. Ponte Castañeda³

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.2, pp. 105-118, 2000, DOI:10.3970/cmes.2000.001.265

Abstract A constitutive model for a porous metal subjected to general three-dimensional finite deformations is presented. The model takes into account the evolution of porosity and the development of anisotropy due to changes in the shape and the orientation of the voids during deformation. A methodology for the numerical integration of the elastoplastic constitutive model is developed. Finally, some sample applications to plane strain extrusion and compaction of a porous disk are considered using the finite element method. More >