Hui-Fen Guo^1,2, Bin-Gang Xu^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.61, No.3, pp. 201-222, 2010, DOI:10.3970/cmes.2010.061.201

Abstract A numerical method is developed for modeling the dynamics of a flexible fiber immersed in a compressible swirling flow. The modeling approach is based on combining an Eulerian finite volume formulation for the fluid flow and a Lagrangian small-deformation formulation for the dynamics of the fiber. The fiber is modeled as a chain of beads connected through mass-less rods. The bending and twisting deformation of the fiber are represented by the displacements of the successive beads. A computational strategy is proposed for the computation of the fluid parameters at the center of discrete fiber sections. To deal with the fiber-wall… More >

R. Valisetty^1,2, A. Rajendran^1,3, D. Grove²

CMES-Computer Modeling in Engineering & Sciences, Vol.60, No.1, pp. 41-72, 2010, DOI:10.3970/cmes.2010.060.041

Abstract A multi-scale model exhibiting progressive damage is considered for a 3D-woven composite. It is based on the evolution of some fundamental damage modes in a representative volume element (RVE) of a composite's woven architecture. The overall response of a woven composite due to a variety of damage modes is computationally obtained through a transformation field analysis (TFA) that is capable of quantifying the effects of spatial distribution of micro stresses and strains on strength. Since the model is computationally intensive, its numerical requirements are to be understood before it can successfully be used in design studies or in conjunction with… More >

M. R. Swager¹, L. J. Gray², S. Nintcheu Fata²

CMES-Computer Modeling in Engineering & Sciences, Vol.58, No.3, pp. 297-312, 2010, DOI:10.3970/cmes.2010.058.297

Abstract A linear element Galerkin boundary integral analysis for the three-dimensional Helmholtz equation is presented. The emphasis is on solving acoustic scattering by an open (crack) surface, and to this end both a dual equation formulation and a symmetric hypersingular formulation have been developed. All singular integrals are defined and evaluated via a boundary limit process, facilitating the evaluation of the (finite) hypersingular Galerkin integral. This limit process is also the basis for the algorithm for post-processing of the surface gradient. The analytic integrations required by the limit process are carried out by employing a Taylor series expansion for the exponential… More >

A. Papacharalampopoulos², G. F. Karlis², A. Charalambopoulos³, D. Polyzos⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.58, No.1, pp. 45-74, 2010, DOI:10.3970/cmes.2010.058.045

Abstract A Boundary Element Method (BEM) for solving two (2D) and three dimensional (3D) dynamic problems in materials with microstructural effects is presented. The analysis is performed in the frequency domain and in the context of Mindlin's Form II gradient elastic theory. The fundamental solution of the differential equation of motion is explicitly derived for both 2D and 3D problems. The integral representation of the problem, consisting of two boundary integral equations, one for displacements and the other for its normal derivative is exploited for the proposed BEM formulation. The global boundary of the analyzed domain is discretized into quadratic line… More >

S. Ullah¹, B. Pichler¹, S. Scheiner^1,2, C. Hellmich^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.57, No.3, pp. 279-316, 2010, DOI:10.3970/cmes.2010.057.279

Abstract Point-wise optical measurements of 3D displacement vectors over time are a key input for monitoring shotcrete tunnel shells during construction according to the New Austrian Tunnelling Method (NATM). Aiming at estimation of the stresses prevailing in the highly loaded, hydrating material, we here deal with two different interpolation strategies for reconstructing, from measured displacement vectors, the 3D displacement field histories of the inner surface of the tunnel shell. The first approach considers spatial interpolation of displacement components in a fixed Cartesian base frame, while the second (new) approach refers to displacement components in a moving base frame consisting of vectors… More >

C. Becker¹, S. Jox², G. Meschke³

CMES-Computer Modeling in Engineering & Sciences, Vol.57, No.3, pp. 245-278, 2010, DOI:10.3970/cmes.2010.057.245

Abstract A three-dimensional numerical model based on the Extended Finite Element Method (X-FEM) is presented for the simulation of cohesive cracks in cementitious materials, such as concrete, in a hygro-mechanical framework. Enhancement functions for the small scale resolution of the displacement jump across cracks in the context of the X-FEM is used in conjunction with a higher order family of hierarchical shape functions for the representation of the large scale displacement field of the investigated structure. Besides the theoretical and computational formulation in a multiphase context, aspects of the implementation, such as integration and crack tracking algorithms, are discussed. Representative numerical… More >

J.T. Zhou¹, Q.W. Ma^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.56, No.2, pp. 179-210, 2010, DOI:10.3970/cmes.2010.056.179

Abstract In this paper, the Meshless Local Petrov-Galerkin method based on Rankine source solution (MLPG_R) is further developed to model 3D breaking waves. For this purpose, the technique for identifying free surface particles called Mixed Particle Number Density and Auxiliary Function Method (MPAM) and the semi-analytical technique for estimating the domain integrals for 2D cases are extended to 3D cases. In addition, a new semi-analytical technique is developed to deal with the local spherical surface integrals. The numerical results obtained by the newly developed method will be compared with experimental data available in literature and satisfactory agreement will be shown. More >

S. Hartmann¹, R. Weyler², J. Oliver¹, J.C. Cante², J.A. Hernández¹

CMES-Computer Modeling in Engineering & Sciences, Vol.55, No.3, pp. 211-270, 2010, DOI:10.3970/cmes.2010.055.211

Abstract This work describes a three-dimensional contact domain method for large deformation frictionless contact problems. Theoretical basis and numerical aspects of this specific contact method are given in [Oliver, Hartmann, Cante, Weyler and Hernández (2009)] and [Hartmann, Oliver, Weyler, Cante and Hernández (2009)] for two-dimensional, large deformation frictional contact problems. In this method, in contrast to many other contact formulations, the necessary contact constraints are formulated on a so-called contact domain, which can be interpreted as a fictive intermediate region connecting the potential contact surfaces of the deformable bodies. This contact domain has the same dimension as the contacting bodies. It… More >

A. Vukovic¹, P. Sewell¹, T. M. Benson¹

CMES-Computer Modeling in Engineering & Sciences, Vol.55, No.2, pp. 171-190, 2010, DOI:10.3970/cmes.2010.055.171

Abstract A fast and accurate method is developed for the analysis of a class of metal three-dimensional resonators with rotational symmetry. The analysis is formulated using the Body of Revolution approach and the Method of Analytical Regularization. This development is motivated by the need for three-dimensional analytical solvers that could enable fast and accurate analysis of photonic resonant structures which support very high Q whispering gallery modes and which are computationally challenging for numerical simulations. The paper outlines the formulation of the method and demonstrates the stability and the source of computation errors of the method. As a practical illustration, the… More >

David Stevens¹, Henry Power^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.55, No.2, pp. 111-146, 2010, DOI:10.3970/cmes.2010.055.111

Abstract Problems involving nonlinear time-dependent heat conduction in materials which have temperature-dependent thermal properties are solved with a novel meshless numerical solution technique using multiquadric radial basis functions (RBFs). Unlike traditional RBF collocation methods, the local Hermitian interpolation (LHI) method examined here can be scaled to arbitrarily large problems without numerical ill-conditioning or computational cost issues, due to the presence of small overlapping interpolation systems which grow in number but not in size as the global dataset grows. The flexibility of the full-domain multiquadric collocation method to directly interpolate arbitrary boundary conditions is maintained, via the local interpolations. The Kirchhoff transformation… More >