N.Kringos¹, A.Scarpas¹, A.P.S. Selvadurai²

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.3, pp. 147-160, 2008, DOI:10.3970/cmes.2008.028.147

Abstract This paper presents a numerical approach for the modeling of water flow induced mastic erosion from a permeable asphalt mix and is part of an ongoing effort to model moisture-induced damage in asphalt mixes. Due to the complex composite structure of asphalt mixtures, moisture can infiltrate in various ways into the components and have an adverse effect on its mechanical performance. Depending on the gradation of the asphalt aggregates and the mixing procedure, asphalt structures with a variable permeability may result. Open-graded asphalt mixes are designed with a high interconnected air void content to serve More >

Atsuya Oishi¹, Shinobu Yoshimura²

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.2, pp. 127-146, 2008, DOI:10.3970/cmes.2008.028.127

Abstract This paper describes new methods based on genetic approaches for finding approximating expressions of local coordinates of a contact point in a local contact search process. A contact search process generally consists of the following two phases: a global search phase for finding the nearest node-segment pair and a local search phase for finding an exact local coordinate of the contact point within the segment. The local contact search can be regarded as the mapping from the coordinates of nodes to the local coordinates of contact points. In this paper, two methods are proposed to… More >

X.Y. Cui^1,2, G. R. Liu^2,3, G. Y. Li¹, X. Zhao², T.T. Nguyen², G.Y. Sun¹

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.2, pp. 109-126, 2008, DOI:10.3970/cmes.2008.028.109

Abstract A smoothed finite element method (SFEM) is presented to analyze linear and geometrically nonlinear problems of plates and shells using bilinear quadrilateral elements. The formulation is based on the first order shear deformation theory. In the present SFEM, the elements are further divided into smoothing cells to perform strain smoothing operation, and the strain energy in each smoothing cell is expressed as an explicit form of the smoothed strain. The effect of the number of divisions of smoothing cells in elements is investigated in detail. It is found that using three smoothing cells for bending More >

Chun Yang¹, Dalin Tang², Chun Yuan³, William Kerwin², Fei Liu³, Gador Canton³, Thomas S. Hatsukami^3,4, Satya Atluri⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.2, pp. 95-108, 2008, DOI:10.3970/cmes.2008.028.095

Abstract Atherosclerotic plaque rupture and progression have been the focus of intensive investigations in recent years. Plaque rupture is closely related to most severe cardiovascular syndromes such as heart attack and stroke. A computational procedure based on meshless generalized finite difference (MGFD) method and serial magnetic resonance imaging (MRI) data was introduced to quantify patient-specific carotid atherosclerotic plaque growth functions and simulate plaque progression. Participating patients were scanned three times (T₁,T₂, and T₃, at intervals of about 18 months) to obtain plaque progression data. Vessel wall thickness (WT) changes were used as the measure for plaque progression.… More >

Chein-Shan Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.2, pp. 77-94, 2008, DOI:10.3970/cmes.2008.028.077

Abstract The method of fundamental solutions (MFS) is a truly meshless numerical method widely used in the elliptic type boundary value problems, of which the approximate solution is expressed as a linear combination of fundamental solutions and the unknown coefficients are determined from the boundary conditions by solving a linear equations system. However, the accuracy of MFS is severely limited by its ill-conditioning of the resulting linear equations system. This paper is motivated by the works of Chen, Wu, Lee and Chen (2007) and Liu (2007a). The first paper proved an equivalent relation of the Trefftz… More >

J. Sladek¹, V. Sladek¹, P. Solek², P.H. Wen³

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.1, pp. 57-76, 2008, DOI:10.3970/cmes.2008.028.057

Abstract A meshless local Petrov-Galerkin (MLPG) method is applied to solve thermal bending problems described by the Reissner-Mindlin theory. Both stationary and thermal shock loads are analyzed here. Functionally graded material properties with continuous variation in the plate thickness direction are considered here. The Laplace-transformation is used to treat the time dependence of the variables for transient problems. A weak formulation for the set of governing equations in the Reissner-Mindlin theory is transformed into local integral equations on local subdomains in the mean surface of the plate by using a unit test function. Nodal points are More >

S. S. Chen¹, Y. H. Liu^1,2, Z. Z. Cen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.1, pp. 39-56, 2008, DOI:10.3970/cmes.2008.028.039

Abstract In most engineering applications, solutions derived from the lower-bound theorem of plastic limit analysis are particularly valuable because they provide a safe estimate of the load that will cause plastic collapse. A solution procedure based on the meshless local Petrov-Galerkin (MLPG) method is proposed for lower-bound limit analysis. This is the first work for lower-bound limit analysis by this meshless local weak form method. In the construction of trial functions, the natural neighbour interpolation (NNI) is employed to simplify the treatment of the essential boundary conditions. The discretized limit analysis problem is solved numerically with More >

G. M. Kulikov¹, S. V. Plotnikova¹

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.1, pp. 15-38, 2008, DOI:10.3970/cmes.2008.028.015

Abstract This paper presents a robust non-linear geometrically exact four-node solid-shell element based on the first-order seven-parameter equivalent single-layer theory, which permits us to utilize the 3D constitutive equations. The term "geometrically exact" reflects the fact that geometry of the reference surface is described by analytically given functions and displacement vectors are resolved in the reference surface frame. As fundamental shell unknowns six displacements of the outer surfaces and a transverse displacement of the midsurface are chosen. Such choice of displacements gives the possibility to derive strain-displacement relationships, which are invariant under arbitrarily large rigid-body shell More >

Adan Vega¹, Sherif Rashed², Yoshihiko Tango³, Morinobu Ishiyama³, Hidekazu Murakawa²

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.1, pp. 1-14, 2008, DOI:10.3970/cmes.2008.028.001

Abstract Experimental observations have shown that the inherent deformation produced by multi-heating lines is not a simple addition of the inherent deformation produced by single heating lines. Therefore, to accurately predict inherent deformation, the method of superposing inherent deformation of single heating lines is not appropriate. To overcome this difficulty, the authors investigate the influence of multi-heating lines on line heating inherent deformation. First, the influence of previous heating lines on inherent deformation of overlapping, parallel and crossing heating lines is clarified. The influence of the proximity to plate side edge on inherent deformation is also More >

F. Cosmi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.27, No.3, pp. 187-196, 2008, DOI:10.3970/cmes.2008.027.187

Abstract The Cell Method is a recent numerical method that can be applied in several fields of physics and engineering. In this paper, the elastodynamics formulation is extended to include system internal damping, highlighting some interesting characteristics of the method. The developed formulation leads to an explicit solving system. The mass matrix is diagonal (without lumping) and in the most general case a time-dependent damping coefficient can be defined for each node. \newline Accuracy and convergence rate have been tested with reference to the classical problem of a particle free vibration with viscous damping.
An application More >