Ricardo Perera¹

CMC-Computers, Materials & Continua, Vol.1, No.2, pp. 153-172, 2004, DOI:10.3970/cmc.2004.001.153

Abstract Epoxy-bonding a composite plate to the tension face is an effective technique to repair reinforced concrete beams since it increases their strength and rigidity. In this paper, the structural behavior of reinforced concrete beams with fibre reinforced polymer (FRP) plates is studied numerically. For it, a numerical damage model is used in order to predict their strength, stiffness and failure modes observed in experimental tests taking into account the influence of different variables such as the amount of steel reinforcement, the type and amount of external reinforcement, the plate length, etc. The consideration of concrete More >

Z. D. Han¹, S. N. Atluri²

CMC-Computers, Materials & Continua, Vol.1, No.2, pp. 129-140, 2004, DOI:10.3970/cmc.2004.001.129

Abstract A Meshless Local Petrov-Galerkin (MLPG) method has been developed for solving 3D elasto-dynamic problems. It is derived from the local weak form of the equilibrium equations by using the general MLPG concept. By incorporating the moving least squares (MLS) approximations for trial and test functions, the local weak form is discretized, and is integrated over the local sub-domain for the transient structural analysis. The present numerical technique imposes a correction to the accelerations, to enforce the kinematic boundary conditions in the MLS approximation, while using an explicit time-integration algorithm. Numerical examples for solving the transient More >

gping Shen¹, S. N. Atluri¹

CMC-Computers, Materials & Continua, Vol.1, No.1, pp. 59-90, 2004, DOI:10.3970/cmc.2004.001.059

Abstract This article provides a review of the computational nanomechanics, from the ab initio methods to classical molecular dynamics simulations, and multi- temporal and spatial scale simulations. The recent improvements and developments are briefly discussed. Their applications in nanomechanics and nanotubes are also summarized. More >

X. Han^1,2,3, G. R. Liu^1,2, G. Y. Li ¹

CMC-Computers, Materials & Continua, Vol.1, No.1, pp. 39-50, 2004, DOI:10.3970/cmc.2004.001.039

Abstract An efficient hybrid numerical method is presented for investigating transient response of cross-ply laminated axisymmetric cylinders subjected to an impact load. In this hybrid numerical method, the laminated cylinder is divided into layered cylindrical elements in the thickness direction. The Hamilton principle is used to develop governing equations of the structure. The displacement response is determined by employing the Fourier transformations and the modal analysis. Numerical examples for analyzing transient waves have been provided in axisymmetric laminated cylindrical structures, both for thin cylindrical shells and thick cylinders.
A computational inverse technique is also presented for More >

C. J. Reddy¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.5, pp. 455-462, 2004, DOI:10.3970/cmes.2004.005.455

Abstract This paper presents an efficient algorithm to evaluate multi-spectral and multi-angular monostatic radar cross section (RCS) of large objects with very fine increments. The technique is based on the combination of Model Based Parameter Estimation (MBPE) method with hybrid frequency domain formulations. A general approach to formulation of MBPE is presented along with a similar approach called the Asymptotic Waveform Evaluation (AWE). Various numerical examples are presented for multi-spectral response calculations using method of moments (MoM) and the hybrid Finite Element-MoM technique in conjunction with MBPE. Example application of MBPE for hybrid MoM-Physical Optics approach More >

Raj Mittra¹, V.V.S. Prakash¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.5, pp. 435-442, 2004, DOI:10.3970/cmes.2004.005.435

Abstract In this paper, we introduce a novel approach for the efficient solution of electromagnetic scattering problems from objects that can be represented in terms of facets. The approach is based on the use of the Characteristic Basis Functions (CBFs), which are high-level basis functions of special types, and whose domains are not bound by the conventional Rao, Wilton and Glisson (RWG) discretization using triangular patches that are typically$\lambda$/10 to$\lambda$/20 in size. In contrast, the CBFs are defined over much larger-size domains, even tens of wavelengths in size, with no limit placed on the dimensions of… More >

Jin Fa Lee¹, Robert Lee², Fernando Teixeira³

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.5, pp. 423-434, 2004, DOI:10.3970/cmes.2004.005.423

Abstract This paper presents the application of a p-type Multiplicative Schwarz Method (pMUS) for solving three dimensional waveguide discontinuity with arbitrary shapes. The major ingredients of current approach are: a hierarchical curl-conforming basis functions that incorporates an in-exact Helmholtz decomposition; and, treating each polynomial space (or basis functions group) as an abstract grid/domain in the Schwarz method. Various numerical examples are studied using the proposed approach. The performance has been compared to currently available commercial software and demonstrated superior performance in terms of accuracy as well as efficiency. More >

H. Okada¹, C. T. Liu², T. Ninomiya¹, Y. Fukui¹, N. Kumazawa¹

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.4, pp. 333-348, 2004, DOI:10.3970/cmes.2004.006.333

Abstract Formulations and applications of an element overlay technique for the mesoscopic analyses of composite structures are presented in this paper. As a zooming technique, the element overlay technique has been applied to various engineering problems. A finite element mesh having finer mesh discretization is superposed at the region to zoom the spatial resolution of analysis. Such a numerical technique is known as the s-version FEM (S-FEM). This paper aims at developing an S-FEM technique that is suited for the mesoscopic analysis of particulate composite materials. Local finite element models that contain the second phase material… More >

Qing-Sheng Yang^1,2, Wilfried Becker³

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.4, pp. 319-332, 2004, DOI:10.3970/cmes.2004.006.319

Abstract The present paper focuses on the comparative investigation of different homogenization methods for fiber composites, void solids and rigid inclusion media. The effective properties of multi-phase media are calculated by three methods, i.e. direct average method of stress and strain, direct average method of strain energy and two-scale expansion method. A comprehensive comparison, in principle and numerically, of these methods is emphasized. It is obvious that the two direct average methods are identical in principle and therefore they give the same numerical results. It is shown that the two-scale expansion method is the same as More >

C.-S. Liu^1,2, C.-W. Chang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.3, pp. 277-294, 2004, DOI:10.3970/cmes.2004.006.277

Abstract This paper delivers several new types of representations of the convex plasticity equation and realizes them by numerical discretizations. In terms of the Gaussian unit vector and the Weingarten map techniques in differential geometry, we prove that the plastic equation exhibits a Lie group symmetry. We convert the nonlinear constitutive equations to a quasilinear equations system X = AX, X ∈ Mⁿ⁺¹, A ∈ so(n,1) in local. In this way the inherent symmetry of the constitutive model of convex plasticity is brought out. The underlying structure is found to be a cone in the Minkowski space Mⁿ⁺¹ More >