D. Ngo-Cong^1,2, N. Mai-Duy¹, W. Karunasena², T. Tran-Cong^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.3, pp. 275-310, 2012, DOI:10.3970/cmes.2012.083.275

Abstract In this paper, natural convection flows in concentric and eccentric annuli are studied using a new numerical method, namely local moving least square - one dimensional integrated radial basis function networks (LMLS-1D-IRBFN). The partition of unity method is used to incorporate the moving least square (MLS) and one dimensional-integrated radial basis function (1D-IRBFN) techniques in an approach that leads to sparse system matrices and offers a high level of accuracy as in the case of 1D-IRBFN method. The present method possesses a Kronecker-Delta function property which helps impose the essential boundary condition in an exact More >

Y.C. Cai¹, S.N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.3, pp. 249-274, 2012, DOI:10.3970/cmes.2012.083.249

Abstract This paper presents a very simple finite element method for geometrically nonlinear large rotation analyses of plate/shell structures comprising of thin members. A fully nonlinear theory of deformation is employed in the updated Lagrangian reference frame of each plate element, to account for bending, stretching and torsion of each element. An assumed displacement approach, based on the Discrete Kirchhoff Theory (DKT) over each element, is employed to derive an explicit expression for the (18x18) symmetric tangent stiffness matrix of the plate element in the co-rotational reference frame. The finite rotation of the updated Lagrangian reference… More >

M.R. Myers¹, A.B. Jorge², D.E. Yuhas³, D.G. Walker¹

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.3, pp. 221-248, 2012, DOI:10.3970/cmes.2012.083.221

Abstract An adaptive extended Kalman filter is developed and investigated for a transient heat transfer problem in which a high heat flux spot source is applied on one side of a thin plate and ultrasonic pulse time of flight is measured between spatially separated transducers on the opposite side of the plate. The novel approach is based on the uncertainty in the state model covariance and leverages trends in the extended Kalman filter covariance to drive changes to the state model covariance during convergence. This work is an integral part of an effort to develop a… More >

L. Dong¹, S. N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.2, pp. 183-220, 2012, DOI:10.32604/cmes.2012.083.183

Abstract In this paper, we develop T-Trefftz Voronoi Cell Finite Elements (VCF -EM-TTs) for micromechanical modeling of composite and porous materials. In addition to a homogenous matrix in each polygon-shaped element, three types of arbitrarily-shaped heterogeneities are considered in each element: an elastic inclusion, a rigid inclusion, or a void. In all of these three cases, an inter-element compatible displacement field is assumed along the element outer-boundary, and interior displacement fields in the matrix as well as in the inclusion are independently assumed as T-Trefftz trial functions. Characteristic lengths are used for each element to scale… More >

K.I. Tserpes¹, A.S. Koumpias¹

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.2, pp. 169-182, 2012, DOI:10.32604/cmes.2012.083.169

Abstract In this work, a comparison between a cohesive zone model and a continuum damage model in predicting the mode-I fracture behavior of adhesively bonded joints is performed on the basis of reliability and applicability. The cohesive zone model (CZM) is based on an exponential traction law characterizing the behavior of the interface elements. The continuum damage model (CDM) is based on the stiffness degradation of adhesive elements imposed by a damage parameter. Both models have been implemented by means of a 3D finite element model. Mode-I fracture behavior of the bonded joints was characterized using… More >

M.M. Kamiński¹, J. Szafran¹

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.2, pp. 143-168, 2012, DOI:10.32604/cmes.2012.083.143

Abstract The main issue in this article is computational probabilistic analysis and reliability assessment of the steel telecommunication towers subjected to material and environmental uncertainty. Such a discussion is important since very wide, frequent and relatively modern application of these structures, which are subjected to various sources of uncertainty and having at this moment no rich and time-dependent failure evidence. Numerical analysis is based on the generalized stochastic perturbation technique implemented as the Stochastic Finite Elements using the Response Function Method applied with the use of computer algebra system. A simultaneous usage of the engineering FEM… More >

P.D.Gosling¹, L. Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.2, pp. 97-142, 2012, DOI:10.32604/cmes.2012.083.097

Abstract The analysis of membrane structures is made complex by the essentially anti-clastic geometry and flexibility introducing significant geometric non-linearities. With the increasing application of these structures in high-profile projects, the introduction of new materials in the form of ETFE foil, for example, and the impending requirements of a membrane structures-specific Eurocode, the need for high quality analysis capabilities is paramount. Existing formulations lag behind shell element counterparts and are based on a range of principles, from discrete to continua, and uniaxial to plane stress constitutive laws. In this paper, we present a linear strain triangular More >

Zhen Luo^1,2, Nong Zhang^1,3, Yu Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.1, pp. 73-96, 2012, DOI:10.3970/cmes.2012.083.073

Abstract This paper aims to present a physically meaningful level set method for shape and topology optimization of structures. Compared to the conventional level set method which represents the design boundary as the zero level set, in this study the boundary is embedded into non-zero constant level sets of the level set function, to implicitly implement shape fidelity and topology changes in time via the propagation of the discrete level set function. A point-wise nodal density field, non-negative and value-bounded, is used to parameterize the level set function via the compactly supported radial basis functions (CSRBFs)… More >

Kazuhiko Kakuda¹, Shunsuke Obara¹, Jun Toyotani¹, Mitsuhiko Meguro¹, Masakazu Furuichi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.1, pp. 57-72, 2012, DOI:10.3970/cmes.2012.083.057

Abstract The application of a particle method to incompressible viscous fluid flow problem and its physics-based computer graphics are presented. The method is based on the MPS (Moving Particle Semi-implicit) scheme using logarithmic weighting function to stabilize the spurious oscillatory solutions for the pressure fields which are governed by Poisson equation. The physics-based computer graphics consist of the POV-Ray (Persistence of Vision Raytracer) rendering using marching cubes algorithm as polygonization. The standard MPS scheme is widely utilized as a particle strategy for the free surface flow, the problem of moving boundary, multi-physics/multi-scale ones, and so forth. More >

S.R. Santos¹, L.C. Matioli², A.T. Beck³

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.1, pp. 23-56, 2012, DOI:10.3970/cmes.2012.083.023

Abstract Solution of structural reliability problems by the First Order method require optimization algorithms to find the smallest distance between a limit state function and the origin of standard Gaussian space. The Hassofer-Lind-Rackwitz-Fiessler (HLRF) algorithm, developed specifically for this purpose, has been shown to be efficient but not robust, as it fails to converge for a significant number of problems. On the other hand, recent developments in general (augmented Lagrangian) optimization techniques have not been tested in aplication to structural reliability problems. In the present article, three new optimization algorithms for structural reliability analysis are presented.… More >