Open Access
EDITORIAL
S. Ghosh 1
CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 1-4, 2004, DOI:10.3970/cmes.2004.005.001
Abstract This article has no abstract. More >
Open Access
ARTICLE
H.J. Bohm¨ 1, W. Han1,2, A. Eckschlager1,3
CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 5-20, 2004, DOI:10.3970/cmes.2004.005.005
Abstract Three-dimensional periodic micromechanical models are used for studying the mechanical behavior of discontinuously reinforced ductile matrix composites. The models are based on unit cells that contain a number of randomly positioned and, where applicable, randomly oriented spherical, spheroidal or cylindrical reinforcements. The Finite Element method is used to resolve the microscale stress and strain fields and to predict the homogenized responses under overall uniaxial tensile loading in the elastic and elastoplastic regimes. Periodicity boundary conditions are employed in the analyses.\\ The main emphasis of the contribution is put on studying the microscale stresses in the reinforcements, which are evaluated in… More >
Open Access
ARTICLE
N. Chandra1 and C. Shet
CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 21-34, 2004, DOI:10.3970/cmes.2004.005.021
Abstract Cohesive Zone Models (CZMs)\ are increasingly being used to simulate fracture and fragmentation processes in metallic, polymeric, ceramic materials and composites thereof. Instead of an infinitely sharp crack envisaged in linear elastic fracture mechanics, CZM assumes the presence of a fracture process zone where the energy is transferred from external work both in the forward and the wake regions of the propagating crack. In this paper, some of the mechanistic and computational issues in the application of CZM \ to model failure and fracture in real materials are discussed. In specific we address the issue of CZM in relation to… More >
Open Access
ARTICLE
Youping Chen1, James D Lee2, Azim Esk,arian1
CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 35-44, 2004, DOI:10.3970/cmes.2004.005.035
Abstract This paper addresses the need of theories and simulations for material body of mesoscopic and microscopic sizes. An overview of polar theories is presented. The micropolar theory proposed by Eringen is introduced and compared with other polar theories. Constitutive equations of micropolar thermo-visco-elastic solid are derived. Finite element analyses have been performed for a few sample problems with wide range of length scales. Based on the discussion, comparison and computer simulations, the unique feature and applicability of micropolar theory are demonstrated. More >
Open Access
ARTICLE
Peter W. Chung1, Raju R. Namburu2, Brian J. Henz3
CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 45-62, 2004, DOI:10.3970/cmes.2004.005.045
Abstract A method is developed based on an additive modification to the first Lagrangian elasticity tensor to make the finite element method for hyperelasticity viable at the atomic length scale in the context of lattice statics. Through the definition of an overlap region, the close-ranged atomic interaction energies are consistently summed over the boundary of each finite element. These energies are subsequently used to additively modify the conventional material property tensor that comes from the second derivative of the stored energy function. The summation over element boundaries, as opposed to atom clusters, allows the mesh and nodes to be defined independently… More >
Open Access
ARTICLE
Y. W. Kwon1, K. Roach1
CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 63-72, 2004, DOI:10.3970/cmes.2004.005.063
Abstract A micromechanical unit-cell model was developed for 2/2-twill woven fabric composites so that the model could be implemented for the multi-scale micro/macro-mechanical analysis of 2/2-twill composite structures. The unit-cell model can compute effective material properties of a 2/2-twill composite and decompose the effective stresses (strains) of the woven fabric composite into the stresses (strains) of the tows. When this unit-cell module is incorporated into the multi-scale analysis by combining with other modules developed previously, the residual strength and stiffness of a laminated structure made of 2/2-twill woven fabric composites can be predicted along with damage progression in the structure. Damage… More >
Open Access
ARTICLE
J. Larsson1, J. Faleskog1, A.R. Massih2,3
CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 73-80, 2004, DOI:10.3970/cmes.2004.005.073
Abstract We consider certain constitutive laws for analyzing the elastic-plastic behavior of granular material, which is subjected to compressive hydrostatic stresses and concomitantly undergoing swelling. The plastic yield functions for this kind of materials are pressure and porosity dependent. The constitutive laws are formulated in a finite element (FE) framework for applications to structures involving granular/porous materials. We have employed an implicit and unconditionally stable algorithm for numerical integration of the constitutive relations. The numerical method has been programmed in a FE computer code. The code is then used to study a plane strain problem for a range of model parameters… More >
Open Access
ARTICLE
W. Li1 and T. Siegmund1
CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 81-90, 2004, DOI:10.3970/cmes.2004.005.081
Abstract Results of a computational study of the mechanics of indentation induced interface delamination are described for a system consisting of a ductile film on an elastic substrate. Special attention is paid to the properties of the interface between film and substrate, and the influence of the interface properties on the indentation response. Specifically, strong interfaces are considered. The interface is characterized by the use of a cohesive zone model. The finite element method is used to solve the boundary value problem, with the interface behavior incorporated via a cohesive model in a traction-separation formulation. The model does not include any… More >
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